We've spent some time talking about general networking concepts. We first went through switching to deliver data across a network. We saw that there's circuit and packet switching and in packet switching, datagram and virtual circuit packet switching ways to deliver data via intermediate nodes, intermediate switches. And we'll come back to that today. We saw routing. To do switching, we need to know which switches to send via, which paths to take, and routing involves usually discovering information about the network, the link cost, the topology, calculating least cost routes, and then creating routing tables, which are stored at the switching nodes to say where to send to next. And the previous topics were about LANs and WANs, local area and wide area networks and other classifications of networks. But a very broad classification of the many types of networks, we can say some are local area, some are wide area networks. Now that's very broad because local area may cover centimetres, it may cover a whole campus and there may be many different technologies. What we want to do now is assuming that across the world, there are many different network technologies in use. Inside SIT, we have both wired LAN ethernet and Wi-Fi wireless LAN. Inside the factory next to us, maybe they're using an old LAN technology. They used it in the factory and there's no need to upgrade, a different technology. And in other locations, they have different technologies to suit their requirements. And again, for wide area networks, some wide area networks may be using satellite, optical fiber, an entire network across the country. There are different technologies available for both LANs and WANs. What we want to do is to be able to allow anyone on any network to communicate with anyone else and we'll see that's what the internet allows us to do. So today we'll introduce this concept of how do we join networks together and maybe finish with one or two examples. So we just said that different types of LAN technologies available. The one that an organization will choose will depend upon what their requirements are for cost, performance, reliability, ease of access. We know of ethernet and Wi-Fi, two very common ones, but there are many others. We can connect LANs with different technologies together and we do that with an access point. The access point on the wall back there, it connects the wireless LAN. When my laptop talks to the access point, it's using Wi-Fi, but the access point also has a LAN cable plugged into it, so it's using wired LAN on the other side. So that access point is sometimes what we call a bridge. It bridges two different LAN technologies together, so we can do that. But bridges usually need to be specific to the technologies and only work for some technologies, so we often would like a more generic approach to allow people using different LAN technologies to communicate with each other. I'm using Bluetooth to talk to some device. You're using an old token ring LAN technology. I want to be able to send to you, even though we're using different technologies. We know wide area networks connect across a large distance. Usually they're used inside the core or backbone networks. The access networks, the local area networks where the end user accesses the network, then the wide area networks connect those access networks together. The end user doesn't necessarily directly connect to a wide area network. And again, different technologies available, wide and wireless for wide area network. It may be a single link or it may be an entire network itself. We haven't discussed too many of the technologies, but some of the names are listed here and we mentioned a few in the previous topic. What we would like is to be able to connect a device from any LAN technology and allow it to communicate with a device on any other network. That's our aim. We want to be able to connect multiple LANs and wide area networks together, allow any computer to communicate with any other computer, independent of what technology they use. And that's important. And we'll say that the process for doing this, we'll call internet working. So we'll spend some time through an example showing that. Let's consider a small example where we have maybe two LANs. Maybe one LAN could represent here at our bunk at eCampus and another one at Runxit. And we want to connect them together via a single wide area network. Let me draw that and we'll look at the issues involved with communicating across those two LANs. So we'll start with a LAN, our first LAN with a few computers attached. There will be five computers in this LAN. So we're going to have a LAN, we have five computers, I'll call them, so we can refer to them, one, two, three, four, five. And we want to use, let's say that's four in one location. And we want to use wired LAN technology, Ethernet. Everyone studied Ethernet in the previous topic. How am I going to communicate between these five computers using Ethernet? How is computer one going to talk to computer five, for example? You should have studied Ethernet in the previous topic. What did you learn? If you can't remember, look at your slides now. How do computers communicate using Ethernet, typically? What topology do they use? A star topology? And a star topology involves us having some new central device that they all connect to. And Ethernet called a switch, an Ethernet switch. So we want to use a star topology or sometimes simply called a switch topology where we introduce another device, our switch, and each computer has a point-to-point link, a dedicated link, into the switch. So this is the typical use of Ethernet today. This computer one, if it wants to send to computer five, actually sends to the switch, and the switch must have some way to know to send that on to five. So we'll create an Ethernet frame. Computer one will create an Ethernet frame, send it to the switch. The switch will look at that frame and realize it needs to send that frame on to five. This is the typical way we use Ethernet. How does the switch know when it receives a frame from one to send it on to five? One wants to send data to computer five using Ethernet. One sends an Ethernet frame to the switch. There's no one else. One can send the frame to it. It only has a link to the switch. It sends the frame to the switch. The switch gets the frame and it has four really destinations, two, three, four, or five. It's not going to send back to one. How does the switch know that this frame needs to go to computer five, not two, three, or four? What do we use to tell the switch who to send it to? Look at the destination, I gave the answer. Look at the frame and the slides again. Destination address. Inside the frame we have a header, a field inside the frame that says who is the destination of this frame. So when computer one creates the frame, it puts in some data, it attaches a header. One of the things inside the header is the destination address which will be the address of computer five. So when we send to the switch, the switch should be configured to know, it looks at the frame, destination five, I know that computer five is attached by this port in the switch. The switch has ports where the cables plug into it. So it simply sends the frame out on this link to five. So we need some addresses. Because to indicate who to send to, we need to attach or include the destination address inside the frame header. And when five sends back a response, because usually we communicate in both directions, where does five send to? If five wants to reply, it should send back to computer one. So how does it know this message came from computer one? We'll also include the source address. So computer one creates a frame with a source address to be itself and the destination address to be computer five. Actually while we're here to remind you, this is from the Ethernet lecture slides. So the Ethernet frame, the structure is that the header contains a six byte destination address who we're sending to, who sent it, the source. It contains two bytes saying what type of data is included. Then it includes the data and then an error detecting code to check if there are any errors in the data at the receiver. Of importance, the destination and source address are included in the header. How long is an Ethernet address? Again, you studied Ethernet in the previous topic. How long is an address? How many bits or how many bytes? Again? 48. The source address is on the screen, six bytes. If we include the address in the header, how big is that field? All the picture shows us that the destination address is six bytes or 48 bits. The source address is the same. So Ethernet uses a 48-bit address. So each computer is assigned a 48-bit address. It turns out Wi-Fi uses the same address format. They both use this 48-bit address format. So let's assume that computers 1, 2, 3, 4 and 5 all have 48-bit addresses. The normal assumption with addresses is that they should be unique amongst a set of computers. We can't have two computers with the same address because then we can't identify who's the destination. Let's write down a 48-bit address. Well, that's going to be too hard to write down. Then rather than representing addresses in binary, for humans we convert it into a little bit simpler form. 48 bits is hard to write down, hard to read. It's easy for a computer to deal with, but with addresses we convert them into different easier forms. So as an example, let's look at the address of my laptop. How many network interfaces does my laptop have? How many network interfaces do you think my laptop has? What are the network interfaces of my laptop? First one, how does my laptop connect to networks? What technologies does it use? Wired LAN, Wi-Fi, any others you think? Bluetooth. It does have Bluetooth. So Bluetooth is another way to connect to a network. Even if the network is quite simple of containing just one other device, it's still a network. So I can think that the interfaces to networks that my laptop has are Ethernet or Wired LAN, Wi-Fi or wireless LAN, Bluetooth, which is sometimes a wireless personal area network technology, and that's all my laptop has. I can see the network interfaces and the configuration of those interfaces running IF config. I'll do it on my Ethernet wired interface and I'll also do it for the wireless LAN interface. If we zoom in, my wired Ethernet interface has a hardware address. This is the address used by or given to my computer when I communicate inside a wired LAN. If I plug the LAN cable in and it's connected to a switch and some other computers, when those other computers want to send something to mine, they would set the destination to this hardware address. This is a 48-bit address, but it's shown in a human-friendly form of hexadecimal values. Instead of 48 bits, which would take up a lot of space, the computer converts it into 12 hexadecimal digits. Hex goes from 0 to 15, we need 4 bits per 1 hex digit, so 12 hex digits is 48 bits. Both wired LAN and wireless LAN use the same address format, so if I look at my wireless LAN interface, it also has a hardware address, 12 hex digits, 48 bits, it's a different value. Our devices should have different addresses. You can convert that to binary if you want, just convert 8 into a 4-bit value, C into a 4-bit value and so on, you'll get 48 bits. What's the structure of these, let's think of it in hexadecimal now, what's the structure of these 12 hex values? Where do they come from? Why does my computer have this address? That's the hardware address, where did it get this value? Who gave it to it? The brand or the company that manufactured the network device assigned the address. So when some company manufactured my LAN card or the chip inside my computer, when they created it, they assigned this 48-bit address. In fact, the structure is that the first six hex digits are assigned to the company, the manufacturer, so every device created by that same company will have the first same six hex digits and then the company assigns the last six hex digits to be unique. So the company makes a million devices, the first six hex digits will be the same, the last will be different, maybe they'll just increment for each device they manufacture. So that's the way that the addresses are managed and are assigned by the manufacturer. We can think that it's fixed for your device. There are ways to change it but we'll assume that once you buy your device it's fixed and we'll assume it's unique, no one else has this address. It's not necessarily true. So where are we? Each of these five computers have such a hardware address and I'll not write them down because it's hard to write down even 12 hex digits. Instead of writing down, I'll just label them as a hardware address. That is computer one has hardware address one, computer two has a 48-bit hardware address. Instead of writing the actual address I'll just label it as HW2 and so on for the others. We refer to it as a hardware address because it's assigned to that specific hardware or sometimes a MAC address or an Ethernet address. That's a four. So each have a 48-bit address. When one wants to send to five, one creates a frame. It sets the destination address field to be the hardware address of computer five and sets the source address field to be the hardware address of computer one. The frame is sent to the switch and the switch is pre-configured to know that the computer plugged into this port has hardware address five. So when it receives a frame with destination hardware address five it simply sends that frame to computer five. You know all this because this was the topic about Ethernet. What we want to know is let's add in another LAN and how can we communicate between these other LANs. So we'll draw another LAN in this case. Maybe we have a different LAN with four computers and maybe it uses an older bus topology. It's not a switched Ethernet, it's a wired network using a bus topology. Let's give them numbers and let's say that they also have hardware addresses. So we have two LANs now. Importantly, two different LANs may use a different protocol to communicate and may have different types of addresses. So my first LAN, maybe that has the 48 bit Ethernet addresses, maybe this older network uses a different type of address, 16 bit addresses, I don't know. But they can be different because they may use a different technology inside here. This is in one organization, this is in another organization. We assume the devices can talk to each other inside the LAN. What we want to allow them to do is to talk to people in the other LAN, even though they use different technologies. I want to allow a computer one to send to computer eight. Well, we need another link, currently we have no link. So let's introduce another few devices, which will play a special role in this. Let's add a third network, in this case assume it's a wide area network that connects, we're going to connect two devices, let's say by a single link and this will be a wide area network and be across a large distance and let's call them AMB. And these devices are going to have the role of a switch in switching. Remember in switching, we send to an intermediate device, which then sends on to another intermediate device and then to the destination, AMB are going to be these types of switches. And in the internet, they are datagram packet switches. So these devices are actually connected to two networks at the same time, A is connected to the first LAN via the switch and B is connected to the second LAN via the bus. So really what we have in this case is three different networks and let's label them before we give the hardware addresses. We think we have a LAN here, let's draw it and let's group them together and common way we group them together is some form of cloud. And similar we have a second LAN here, this cloud and let's label this one as LAN1 and this is LAN2 and we have a third network, which is our wide area network connecting them. It's a very simple network with just two devices attached but still we can call it a network. So now we have three smaller networks connected together and our aim is to allow anyone to communicate with anyone else. For example, one should be able to send to eight. Let's complete the addressing. Note that computer A is attached to LAN1, so it also needs a hardware address. It's another computer on that first LAN. So let's denote the hardware address of A, A1 and B has a hardware address. I'll call it A1 and B1 because we'll see that computer A is connected to two networks. It has two interfaces in use at the same time. It has a hardware address on this LAN and another hardware address for the connection to the wide area network. So we'll label them as well. So here we have hardware address A2 and hardware address B2. There are different values, maybe even different formats. In each of the component networks, LAN1, LAN2, the wide area network, we use some technology to communicate inside that network and that may specify the type of addresses, maybe a 48-bit address in LAN1. Maybe in the wide area network, the addresses are just zero and one. There's just two devices. Just a one-bit address to identify, even they may not have an address if it's a point-to-point link. And in the LAN2, maybe different types of addresses. If B wants to send to A, B needs to know the destination is HWA. If 5 wants to send to A, it needs to know the destination is HWA1, the address of computer A on that LAN. We want to allow, for example, Computer 1 to communicate with Computer 8. With Ethernet, when we create an Ethernet frame, where would Computer 1 send to to get to Computer 8? One wants to send to 8. It's going to use Ethernet to send the data. What's the source address of that Ethernet frame? The source address first. Who's sending it? The address of one is HW1. We can refer to Computer 1, but the address, let's say, is the value HW1. We want to create an Ethernet frame from 1. We want to get the data to 8. To get the data to 8, who should we send to? What path are we going to take to get to 8? There's only one possible path, isn't there? We're going to send via the switch to A, and then A should send to B, and then B should send to 8. That's the path we're going to take. Let's look at the addressing. When A, Computer 1, the source creates an Ethernet frame, Ethernet is only used internally on this LAN. The source address is HW1. The destination address is not that of Computer 8, because Computer 1 may not know what technology 8 is using. It knows nothing about HW8. It knows it wants to send to Computer 8, but the type of address that Computer 8 is using, it doesn't know. They're on separate networks, different locations. So we'll actually send to Computer A. That is, the destination will be HWA1. And then Computer A will act as a packet switch, a datagram packet switch. It'll take that, send it on to B, HWB2, and when B gets it, it'll take it and send it on to HW8, to Computer 8. On the individual networks, Computer 1 knows the address, needs to know the address of A, HWA1. When A gets the data, it needs to know the address of B, HWB2. And when B gets the data, it needs to know the address of 8, HW8. The source doesn't need to know the LAN address of 8. We can't assume it will, because it's maybe on the other side of the world. We know nothing about that computer, other than we want to get data to it. So even though we can connect the networks together physically, to get data from Computer 1 to Computer 8, we need some other form of address, and some other way to deliver the data, rather than just Ethernet and the LAN and WAN technologies. We need some way to specify a Computer 1, the destination is Computer 8, and 1 will send it to A, A will see the destination is 8, send it to B, and then B will send it to 8. But we cannot use the LAN and WAN address formats, because they are different across different technologies. So what we do is we introduce a second address for the devices. We'll assume every device has two addresses. The second one is sometimes called a network or a logical address. We will simply refer to it by the common technology used, an IP address. So every device will give it not just a hardware address for communicating locally inside its network, but an IP address for communicating globally across multiple networks. Think of hardware addresses of internal communications, IP addresses are for across networks, across an Internet. So before we see how that's used, let's write down some IP addresses. Maybe not all of them, but we'll get some in. All of our devices will give an IP address. IP. Instead of, I won't necessarily start at 1, we'll start at some other number, just to be different, 20, for example, meaning that's not the actual value, but just a variable we indicate this is an IP address, and this one may be an IP address 21, and these may be other IP addresses, I will not write them down. This one down here may have IP address 57, just making up some random numbers. There will be some structure we'll see later, but let's think every device has an IP address. Even these devices connected to both sides, on both interfaces, that's a three. Don't worry about the values, just be aware that each network interface has an address of the same format. Here we're calling an IP address. For example, computer nine may be IP 56, and six and seven, three, four, and five would also have IP addresses, all of the computers. What we do to allow communications across multiple networks ensure that every device has an address of the same format, irrespective of the technology used in the LAN or wide area network, they all have in this case an IP address, and then we use another protocol to communicate across the set of networks. We use what we call an internet working protocol to create a packet at the source, specify the source and destination, and send that via our path to the destination. Let's try and draw that. The packet created by computer one has some data and a header. Inside the header will at least include a source address and a destination address, where the source address will be the source IP address, IP 20, and the destination address will be the destination IP address, the final destination, IP 57, that's 57 down there. Everyone can read the picture, maybe the next two quizzes should be in class, so make sure you can read and draw these pictures, because it's very important of how IP works. The bottom, the destination IP address is IP 57, that is the IP address given to computer eight. This is the packet created by computer one, it's not the ethernet frame, it is the packet created by what we call a new protocol, an internet working protocol, a new protocol to get data across multiple networks, and the protocol we use in the internet for internet working is the internet protocol, IP, so an IP address, IP stands for the internet protocol. So we create an IP packet, also called an IP datagram. The source will be that of computer one, IP 20, the destination will be that of computer eight, IP 57, and then where do we send this datagram? Where should computer one send this datagram? Who's going to get it next? Computer one creates this datagram and sends it to A, well via the switch sends to A. How does it know to send to A? How do we know to take this path? What's the process for finding the path? Routing, remember back to routing, we create some routing table that says if the destination is IP 57, the next node is IP 25 or computer A. A routing table would be used by computer A to know, sorry, by computer one to know, to reach eight, send to A. We will send to A and A will look at the destination, destination is 57 and A will have a routing table that says to reach 57, IP address 57, which is computer eight, send to B. It will send this datagram on to B. B will have a routing table that says, all right, computer eight is on this LAN, so send it direct and we'll send it to computer eight and that will receive the data. And the way that computer one sends this datagram to A is using the LAN technology, it creates an ethernet frame. I will not draw it, but there will be an ethernet frame, the source will be HW1, the destination will be HWA1. Sends it to A, A sends a frame to B, B finally sends a frame to eight. This is a, maybe we've gone into too much detail before we look at the formats of addresses, but it's trying to illustrate the concept to connect multiple different networks together. We need one common protocol that they all support. In the internet, that one common protocol is called the internet protocol. And with that common protocol, we also need a common address that each device understands and that is called an IP address. So even though internally we may use different techniques to communicate, we still have a common thing amongst all the computers in this network IP address and they all support the internet protocol. This concept of connecting LANs and WANs together is called internet working. We connect networks together, internet working and when we connect them together, we create an internet work and what's short for an internet work? What is short for an internet work? Internet work, what is a short word for that? Internet. Okay? So the internet is short for an internet work. So we've connected three networks together in this case to create one internet work or one internet. We'll see that terminology is on some later slides. While we're on terminology, computers A and B play a special role. They play a role of forwarding the data between different LANs and WANs. So computer A and B, these two, they actually in the internet use datagram packet switching so they are packet switches but we call them routers. A and B are what we call routers so that's some new terminology. But from our old topic on switching, they are essentially datagram packet switches. They receive a packet, look at it, using the routing table determine who to send it to next. We refer to them as routers. So this is the concept which is the internet is built upon. We have many different LANs and WANs across the globe and they are all connected together via routers and both the routers and the end-users devices support a common protocol called the internet protocol allowing anyone to communicate with anyone else. The last form of terminology, if we call these two routers, what do we call the end-user devices? Hosts. The computers which are not routers are hosts in this case. For example, one, two, three, four, five, six, seven, eight, nine are hosts. So our internet is made up of hosts and routers. In this case, nine hosts, two routers, how many networks? Nine hosts, two routers, how many networks in this picture? Nine hosts, two routers, how many networks? Not one, not three, combine them, not two, how many networks here? Not eleven, not nine. How many networks? How many can you see? How many green clouds? How many networks? Well, yes, there are three of the smaller networks. When we combine them together, we make one big network. So we can say there are the three component networks or sub-networks. When we join them together, we get one large network and internet work or an internet. So we think maybe there are four networks here, the three sub-networks and the one internet work, or we refer to as three sub-nets in this internet. This internet contains three sub-nets. So be careful now when we have networks, there may be a hierarchy. Here we have one network, inside that there are three networks. One internet, three sub-nets. When we study internet working, rather than drawing the details of the links between the computers, inside each sub-net, sometimes we simply draw a cloud, meaning there may be multiple computers in there. We don't care whether it's a switched network or a bus topology or a point-to-point link, there are some devices in there. So let's summarize what we've learned so far. Internet working involves connecting many lands and lands together, with the aim of allowing any computer on any network using any technology to communicate with any other. And the way they do that, they use an internet working protocol. One part of that protocol is to define the address format. There are different internet working protocols, but there's one very popular one, very widely used, the internet protocol, IP. And that's all we're going to study in this course, not any of the others. The others are maybe very old or used in very special cases. We'll see there are actually two versions of the internet protocol available, IP version four and version six. Here's another example where we have how many networks, how many networks in this example, count them, how many hit there on the screen and their slides, how many networks, don't say nine, ten. We have nine subnets, one internet, by joining those subnets together. And those nine subnets are joined together via routers. So in this picture, the routers are these shape devices, these cylinders. So in general, we're not showing the hosts. Land three may have a hundred hosts, I don't know. We're just drawing it as an abstract, saying there's a land here with multiple hosts, and those hosts would send via this router to reach other destinations. So that's the general structure of an internet. We connect different subnets together via routers. The routers in the internet are datagram packet switches. So we know about datagram packet switching. And in terms of a protocol architecture or a layered stack, we think they operate at the third layer, the middle layer called the network layer. What we're going to do, and we'll maybe do it in the next lecture, is talk about how IP works, the internet protocol. But you know the basics already. This is how IP works. Everyone has IP addresses. When we want to create or send someone data, we create a datagram. Inside that datagram, it has an IP header. Two fields inside are the source address and destination address. We send the datagram to routers. Which router will use routing tables to tell us to reach destination IP 57? The next node is A, send it to A. A will get the datagram. To reach 57, the next node is B. B will get the datagram. B will use its routing table to send it to computer 8. And that's how IP works. There are no retransmissions. If something goes wrong and A sends to B, but B has an error and loses the data, there's no retransmissions by computer 1. It's very simple. There's no flow control. There's no concept of window sizes. So you just send. If it gets there, good luck. If it doesn't, then something else will need to deal with that. And one of the reasons why the internet protocol is widely used, and it's been very successful, is because of its simplicity, it means it can be used in many different devices and for many different purposes. So the internet protocol is an internet working protocol used in the internet. We use it every day. And it's implemented in both hosts and routers. Both of them need to use IP. If you look in the source code of my operating system, you'll see the source code for IP in there. Every computer will implement IP. It uses datagram packet switching at the network layer. We'll give an example and we'll spend some time about the addresses. In the example before I said IP57, well, it actually has some structure that we'll look at. And a few other features like it can split data into smaller fragments and reassemble it. Some of these other features we'll talk about, not today, we'll talk about later after we go through IP addresses. In this course, we're going to focus on just one of the two versions, IP version four. IP version four is the most widely used version today. When we use it, the internet, we're most likely using IPv4. There's another version, IPv5 was essentially skipped. It was assigned for some other obscure purpose. There's IP version six. Even though most of our computers support IPv6, our network operators, our internet service providers don't really enable it so that we can use it. So it's not widely used yet, but it's planned to be used in the future. In this topic, we're just going to talk about IP version four. Coming back to my laptop interfaces, my wireless LAN interface. We said it had a hardware address, this 48-bit address. But we said in the concept, in the internet working, our devices need not only a hardware address, but also an IP address. And this shows me my IP address, my internet address, is this value. <IP_ADDRESS>, that's my laptop's IP address for the wireless LAN interface. My laptop also has an IPv6 address, that's the IP version six address. They use different formats of addresses between the two versions. And one of the main enhancements of version six was allowed for more addresses, a larger address space. So we'll see that when we look at the IPv4 address space. But my computer inside the SIT network does not use that IPv6 address. It's not supported inside this LAN. My wired interface has a hardware address, but no IP address. We only, in many practical cases, we only have an IP address when we're actually using that interface. If I plug in a LAN cable, I may get an IP address. But currently, I'm not using that interface, and I have no IP address. So what we'll do to finish today is briefly look at the structure of the IP datagram. That is, this datagram or packet created by one, what does it look like? And then finish with an example of an IP address. So we'll skip some terminology, which we've mainly covered. And we'll go direct to the IP datagram structure. We'll return to those slides I skipped over next week and explain more about the IP datagram next week as well. But let's quickly introduce it. The IP datagram contains a header plus data. By default, the header contains 20 bytes of information. 20 bytes and then a variable length of data. There's an upper limit. The total size is limited to about 65,000 bytes. Usually that's not applied. Usually it's much smaller than that. The header of 20 bytes, this picture shows a common way to draw a packet structure, a packet header. And it shows that we draw the fields in the packet row by row. That is, the header is just a sequence of bits. But rather than drawing 160 bits in a row, we split it across multiple lines. So the way to read this, the first bit, bit 0, bit 1, bit 2, bit 3, bit 4, bit 8, bit 31, bit 32, we wrap around, if we want to visualize, bit 32 would be here. And we go through. So this is just a way to draw the header. When the header is long, we can't draw on one row. We wrap it across multiple rows. That's all. In this picture, each row is 32 bits or four bytes. And there are five rows making 20 bytes. And the names in here give the purpose of the fields. We'll not go through all of them at the moment. A couple we can recognize from the name. The first four bits in the header indicate the version of IP we're using. If we're using IP version 4, it's set to 4. If we're using IP version 6, it's set to 6. Very simple. Move on. The total length field, which is 16 bits long, indicates the total length of this datagram, header plus data. So because we can have a variable amount of data, we need to tell the receiver where does the data end. If we know the header length, which is actually included in an earlier field, and the total length, we know how much data is included. Then the two important ones just for today. The last two fields inside the mandatory header are the source address and the destination IP address. The original source computer and the final destination. How many possible IP addresses are there in theory? Get your calculator out. If you're looking at your phone now, here's a chance to get your calculator open. How many possible IP addresses are there? About. To know that, you need to know how long is an IP address. Look at the picture. It shows you how long an IP address is. The field of the source IP address is how long? 32 bits. So this picture is showing 32 bits per row, or four bytes. First four bytes, 8, 12, 16, 20 bytes of header. It's just a way to show that. So every IP address is 32 bits long. How many possible IP addresses in the world? About. Use your calculator. If there are 32 bits, how many possible values? Has anyone got a phone? And has that phone got a calculator? Yes? How are you going to calculate it? Not 10 to the power of 32. Binary, not decimal. 2 to the power of 32. Plug it into your calculator and see what it tells you. Again, four. Four by 10 to the power of nine. Four billion. Four thousand million. About four billion possible addresses. Now, if every device needs a unique IP address, that means we can have about four billion computers attached to the internet. Now, how many computers do you think attach to the internet every day or every year? More than four billion or less? Right, I'm hard to tell, but getting close to four billion, we have seven billion people in the world. Not everyone has internet access, but many people have multiple devices. And there are many devices that humans don't use, but just also have an IP address, like sensors, servers, routers, and so on. So there are some issues that address space of four billion possible values is not enough for everyone to use. There are some ways around that, but the long-term solution is to move to IP version six. IP version six has addresses of 128 bits. Calculate two to the power of 128. Your calculator may not do it on your phone, but something like billions and billions of addresses per person to the power of 128, so that should be enough. But we're not touching IPv6 in this course, but one reason for it is it gives more possible addresses. So let's look at an IP address. Remember, an IP address is 32 bits long. The IP address given to my laptop for the wireless LAN interface is <IP_ADDRESS>. We don't see 32 bits here. We actually see some decimal numbers. Again, to make it easier for humans, the commuter doesn't normally present to us 32 bits in a row. It presents us in some easier to read form, easier to write form. So same as a hardware address, it's 48 bits, but shown in hexadecimal. An IP address is 32 bits, but shown in what we call dotted decimal notation. Let's do the conversion. From <IP_ADDRESS> into a 32-bit value. So let's start with our IP address for my laptop, and I'll just spread it out. That's the IP address presented to me, the human-friendly form. Let's convert it to binary, the actual value the computer uses. And it's very simple. We have four decimal numbers separated by dots, and we want to convert to a 32-bit value. Each decimal number is converted to an 8-bit value. So we convert each decimal to an 8-bit value, and we get four by eight or 32 bits. And that's our IP address. So let's just convert 10 in decimal to binary, and an 8-bit binary value. What is 10 in binary? Write it down. 10 in binary. 101.0, that's 10. But we need an 8-bit value, so we'll put four zeros out the front. Didn't line up very well. So that's 10 as an 8-bit value. And the next one's easy. 8-bit value, what's the same? 10 again. 101, try. You'll remember your conversions to binary, 101. And seven, that's an easy one. We now have the actual computer form of this IP address, the actual value that's included in the header, and sent across the network. So the computer always deals in the binary value. It's just that when it presents that value to humans, it converts to the dotted decimal notation, just to make it easier. Easier to write down, easier to tell someone else, easier to type in. And you can convert back, of course, given the 32-bit value, break it into four by eight bits, convert each 8-bit value into a decimal number, separate by dots. Any IP address, any IP version four 32-bit address, can be converted into its dotted decimal notation. So as homework, you'll go home today and record your laptop or even your phone, find their hardware address, find their IP address, and convert your IP address into binary. And if you are really excited, convert your hardware address into binary. So just be aware, especially with the IP address, is how to convert from dotted decimal notation into binary notation. And it's important to know on your phone or on your computer where to find those addresses. Different operating system will present them in different ways. There's some structure in these addresses. That is, your computer doesn't have just a random 32-bit value. There's some structure that the values in this address are related to what subnet I'm in, in the internet. And we'll see in the next topic or in the next lecture, we'll look at what is the structure of the IP address. But it's not simply 32-bits for every computer. There's some split between the subnet and the device in that. That'll be the next lecture. Let's stop there and we'll continue next lecture and go back to IP, go through IP addresses and see some more examples.


the best e-commerce platform in 2020. Have you been trying to figure out, I mean, there's so many different platforms out there to sell goods on. Where do you go to? What's the best ones? Well, you've come to the right place. In this video, I'm gonna cover the top 12 platforms to sell online, and I'm gonna show you the pros and cons of each one, and we're starting right now. Hey, I'm JR Fisher. If you're new to my channel, welcome. And don't forget to subscribe. There's a big subscribe button down there. Make sure you hit that subscribe button. And don't forget, turn on notifications. There's a bell right next to it. You've gotta click that, and then turn on all notifications so that you don't miss a single video. You become part of the Fisher family, and I can let you know every time I do a new video. Now, on this channel, I teach you how to start, run, and grow online businesses. I've been selling online since 2009. I have my branded products on thousands of websites, including Walmart. And on this channel, I share with you the things you need to do to grow your business. So let's go ahead and get started. I wanna go through the top 12 e-commerce platforms that you can use to sell your products. Also, before I forget, I'm giving away a $97 e-commerce course. You can get the link to it down in the description there. Click that link and learn absolutely free. No credit card needed. Now, the first one I'm gonna go over is probably the most popular one Number one is Shopify. Shopify is a pretty amazing platform. Let's go through some of the pros. Number one, most people use it. Most people use Shopify because of its ease of use. And number two, it was built for e-commerce. When you get a platform that was really designed to do exactly what you wanna do, it's gonna be easier and it's gonna work better for you. So a lot of people have picked it for that reason. Also, down in the description, I'll put a link down there where you can actually get a free trial of Shopify. And then if you wanna go ahead and move forward, you can use that link to get a big discount on it. The next thing that's a big advantage about Shopify is that it has a lot of useful applications and integrations that you can use on Shopify. Since it's been around for a while, there's literally thousands and thousands of them that you can pick from. I guess we gotta go over some of the cons. Really, it's a great platform. I have nothing bad to say about it. If anything, I would say it's a little expensive depending on what your finances are. It's $29 a month. So if you don't wanna spend any money at all, then it wouldn't be the best platform for you. But if you can afford it, I would definitely suggest you starting off with Shopify. Now, the next thing I wanna talk about is big commerce. Big commerce is another online platform that you can use for e-commerce. And it's a good platform. There's nothing really wrong with it. It has some built-in features. It's not quite as good as Shopify, but it's under the same type of design and idea. It also has a 14-day free trial.  The next thing I would tell you as far as the cons go is it's expensive. It's gonna cost you a little bit more to use it. It also doesn't have as many features as Shopify has. So you're paying the same kind of money, but you're getting less features. And additionally, it has selling limits. So you're gonna be limited on that. The next one I wanna tell you about is big cartel. Now, big cartel is really more designed for artists, people who are creating things like that. And if you're selling less than five products, it's absolutely free. So it would be good for you if you only have a few products to start with when you plan on building. It is fairly simple to use and design a small store. Now, the cons would be, it doesn't really have that many features and it doesn't have that many integrations. So there's not a lot you can actually do with it to customize it. Now, this site is not really built for e-commerce. So since it's not built for e-commerce, it doesn't have the design that's gonna allow you to scale if your business really grows, you're gonna end up having to move to another platform. Now, the next one we wanna look at is Volusion. Volusion is one of the platforms I actually started with. I actually started on eBay and then had an eBay store and then I moved over to Volusion. And it's a pretty good platform, it too has its pros and cons. Now I would say the good thing is on Volusion, it's got some built in features that on Shopify, you actually have to pay a little extra for. It also allows for different skews and colors. So if you have a lot of variations in your product, Volusion's a good choice for that. Some of the cons I don't personally like are bad business practices. They started upping people's rates without notifying them in advance, which I don't think is a good thing to do. Some people were having issues also with the add to cart button. And if that's not working, that's how you make money. So that's pretty big issue. Now the next thing I'll tell you is the customer support was not good. When I used it, I don't think it's that good today. It's not one of the platforms I'm gonna recommend. I will tell you, I won't even put a link down there to it. If you wanna look it up, you can look it up. It's just not something I would recommend. The pricing is similar to Shopify, but it's not near as good as Shopify. Next one I wanna talk about is WooCommerce. Now WooCommerce is essentially free. You don't have to pay for it. It integrates with a WordPress website. Now it's probably one of the most popular platforms because it's free, because it works with WordPress and you can integrate it. And that's pretty simple. So a lot of people use it for that reason. I don't see a lot of really serious e-commerce people using WooCommerce. They generally will move over to Shopify. But if you wanna get started and you don't wanna pay for a platform, it's an alternative for you. It does offer a lot of plug-ins and add-ons. So you can customize it more so than a lot of the other ones. Now as far as the cons go, it is technically free. But if you have it integrated with your WordPress website, obviously you gotta pay for a hosting. And that's gonna be maybe three or $4 a month, something along those lines, depending on who your hosting company is. I'll also tell you, the next thing is it's not that easy to do. You're gonna need a little bit of tech skills to work in there. It's not as simple as some of these other platforms. Now since it is a, I guess, a free item that hooks into WordPress, it can be easily hacked. And since it can be easily hacked, it could cost you a lot of money to have some tech person go in there and fix things and make things work properly. So that is a warning I wanna give you. Now you'll also find that it has a lot of add-ons, but you gotta pay for the add-ons. And since you gotta pay for the add-ons, it kinda wipes out the fact that it's free to start with. So if you think you're gonna grow your business a little bit, it may not be the best way to start. Now the next one I wanna talk about is Squarespace. Squarespace is a good product and you can make some really cool-looking websites with Squarespace. Now it is fairly easy to use. It's great for a podcast or if you wanna just do a website for a restaurant or nail salon or hair salon, something along those lines. I will warn you though, the cons are it's not made for e-commerce. So if you plan on selling a lot of products online, it would not be your best pick. If you just have a business and you wanna have a website presence, then it would work for you. And the downside also is that it costs about what Shopify costs and it doesn't have the e-commerce capabilities of Shopify, but you're having to pay the same price.  Now the next one I wanna tell you about is Magento. Magento is a really cool platform. We actually use Magento for a survival food company. It's really for big commerce. Now the reason we use it is because we have different type of login capabilities. So we have people who sell our products to the general public and we also have the general public coming to our website. So when a regular customer comes to the website, they log in, they see a certain set of pricing. I can set it up for all my vendors out there depending on what their pricing levels are so that when they log in, they're gonna see their wholesale pricing. They can put in their orders and then we can ship it out for them. So that's why we use Magento. Now there's a lot of big companies like Nike and Ford and Coca-Cola that use Magento. But it's a really high level type website. I don't know if I would suggest somebody using it right from the get go if you're just starting a business. Now it is an open source coding website. So you can hire developers and you can highly customize this site. You can do a lot of things with it. You can also handle high volumes of orders.  That's one of my companies. And sometimes we'll get 100 or 1,000 orders at a time and that would crash any other cycle with Magento. We can handle it without any problems. Yeah, it also integrates really well with any other high level platforms. And technically the open source one that we use is free. But if you wanna get support and all that kind of stuff it can get really expensive. It can be $10,000, $20,000 a year to use this platform if you're gonna need assistance. Now we have people who work on Magento and I can work on it, my wife can work on it. So we don't have a problem there. We use the free version. However, if you don't have those capabilities, if you don't have those skills you're gonna find yourself spending probably in the thousands of dollars for help. So I guess the cons would be you're gonna need some technical expertise yourself or you're gonna have to hire somebody and the paid version is like really expensive. So unless you have deep pockets in the beginning I would not suggest that. However, for our use, there's no other platform that would do what we need that website to do. So it works great for us. Just to give you an idea I will put some of the costs associated with Magento on the screen. Website development by an agency, you get 25 bucks an hour and then you've got a freelance or maybe 10 bucks an hour. If you've got Magento development by an in-house team it can cost you about 60 grand a year.  The extensions can be anywhere from 50 to 500. Graphics and brand collateral can be $10,000 to $18,000.  Hosting's gonna be roughly $10 a month. If you need SEO help that's can cost you another 60 to 80 grand a year. Maintenance can be 80 to 125 an hour. Not to mention if you buy the support package I'm showing 30 to 40 grand a year here. You can go 10, 20 grand, but it's a lot of money. The next one I wanna talk about is GoDaddy. Now GoDaddy is really simple and easy to set up and it's cheap. But the problem is it's not designed for e-commerce. So if you're gonna be doing any type of e-commerce that you think you're gonna scale on down the road GoDaddy's just not the way to go. Now GoDaddy's fine if you just wanna buy a domain and there's nothing wrong with buying your domain there. You can buy it in any number of places. They're good for that, they have good support but it's just not a place you wanna build your e-commerce store. Next one up is Wix, W-I-X, and you do see Wix advertised a whole lot and it's a great place to really just build a website.  Now there's other alternatives to doing this too. In the next three I'm gonna kinda lump together but those are Amazon, eBay and Etsy. Now you can sell on any of those platforms and they only have their pros and cons.  They already have people coming to the site so you don't have to drive any traffic whatsoever. All you have to do is put your products there. It's also super easy to get started. I mean you're not building a website, the site is already there. All you're doing is listing your products on their website. So if you wanna get started you could literally in 10 minutes start putting your products on one of these sites and start getting traffic and start selling. Now the cons, the biggest con I think is that they own the customer. You don't actually own this customer.  And the next thing I wanna tell you is that they have super high fees. So you're gonna pay fees on these sites, pretty high fees. So if you've got a small profit margin it's just not gonna work out for you.   And the last thing I would tell you is that they don't allow you to contact customers. They don't want you to contact customers. If you try to contact customers outside of their platform, that is a violation in itself and they can actually kick you off the platform. So bottom line is you can get set up on one of those platforms, Amazon, eBay, Etsy and you can start selling the problem is they're gonna give you all this traffic but they can also take all that traffic away immediately too. So you don't really have control of your business. I wouldn't suggest that being your only way to do stuff. You could still have another website. You could still build your website someplace else and list your products on Amazon, eBay and Etsy. That's not a problem. Now the last one I wanna add is Cartra. I freaking love Cartra. Cartra is really not an e-commerce site. It's a whole bunch of things rolled into one but it's a great place to make your sales pages, your sales funnels, membership sites, all those good things. And you can have that along with a website someplace else like a WordPress website or a Shopify store. But I highly recommend Cartra because it does so much for you. It's inexpensive. I'll also put a link in the description below so you can go ahead and click on that. There's a video you can go watch absolutely free and if you decide to get Cartra, my link will provide you with a $1 trial on Cartra. Now I gotta tell you, a lot of these sites were not even available when I got started in 2009. Cartra wasn't around. I don't think Shopify was around. So what I would have used then and what I use now are two different, entirely different things. So there you have it. I guess my top picks are gonna be Shopify which I talked about in the beginning. I'll put a link down there to Shopify so you can get your free trial on that. I also recommend Cartra. I think that's really good. If you've got a huge e-commerce business already and you need some really high level stuff, Magento is great. And I will tell you all of these things I use personally so I can recommend them in some of the other ones I have used in the past. So that's my recommendation on this video. What have you tried?  I want you to put your comments down there. Let me know what you've tried, what platforms you know, you've tried to sell on. If you have questions about any of this, feel free to put those questions down there too. I'll be happy to answer them. Don't forget, I have a $97 e-commerce course. You can get absolutely free. I'll put a link in the description down there. Don't forget, if you haven't done so, to subscribe. Become part of the Fisher family by what? Bringing the bell, turn in on your bell notifications. If you do that, I can notify you every single time I do a video.  Thank you so much for watching this video and I'll see you in the next one. Hey, thanks for watching my video. Don't forget to subscribe to my channel and click that little bell right there so you can be notified every time I do a new video. Also, click on one of those videos there. Keep watching on my channel.


Kurt Russell, Simon Jackson, thanks for speaking to the conversation. I got a chance to see The Hateful Eight last week. What's most striking about it, I suppose initially, is this huge canvas you've got to work on, this panavision, the 17mm. As actors, how does that shape your performance? I'm thinking of earlier Westerns, I'm thinking of Magnificent Seven famously, Yule Brenner was the lead, but Steve McQueen was an up-and-comer at the time, and he would often steal focus. There were bits of business in the corner, and those huge vista vision would allow him to do that because, of course, it was a wider aspect. No, the director allowed him to do that. No, it's not that. Because we all had lives outside of the main focus of what was going on. Like Kurt says, if you watch the movie a second or a third time and follow somebody other than the person that's the major focus of the shot, you'll see all kinds of stuff happening. So it certainly changes the experience watching the film. What about actually on set? Is it more collaborative? Does it become ever competitive? Or is it more conducive to just interacting with your fellow cast? Everything we did always felt we did to enhance what was going on in the room, to create the reality that Quentin wanted to transpire in that space. Nobody was trying to act bigger or act smaller or steal a scene. You just did what came naturally. You were going to get your opportunity to be a part of this. So there was no worry about that. Is there a sense of don't want to drop the ball? I said that's fair. And is there a sense of helping in any way you could somebody carry the ball? There's a big sense of that. Because when you're a character, he leaves the film slightly early than some of the others, you stay on set. There were two reasons for that. One was I thought there was every possibility that John Ruth dead was a bigger problem than John Ruth alive. And I didn't know if Quentin would do something with that. Because this was the type of film where, and Quentin's the type of director where he may just come up with an idea and he wants to shoot something. Well, that idea involves something. I didn't want to be, you know, oh gee, Kurtz in Tijuana, we don't know where he is. No, that was the number. But number one was I spent so much time working with Jennifer that when it came to that part of the movie, it was obvious that she should have John Ruth, John Ruth's body there for her to be referring to or not referring to and then dealing with. And I think that it would have, if I would have been her, if it had been reversed and she would have taken off and said, well I'm dead now, so there's a dummy that looks a lot like me. We had a good one, too. That looks a lot like me. And I would have just, I just would have hurt, I just would have said, oh, okay, well, I guess that's, I guess I read that one wrong. I thought we were a little more invested, but anyway, you know, so you know. And is that always the case? I mean, you do countless films, the collegiality, that friendliness, that sort of sense of kind of cooperation or is that unique to the type of film as well as the type of story, the type of cast? I think it's unique to this particular film, mainly because we rehearsed it so long and we spent so much time together before we got to that particular place. And once we got to tell you right, Quentin still finds unique ways of bringing us all together, cast and crew, in terms of, you know, even if it's just Quentin Tarantino Theatre on the weekend, or we go to dailies and watch dailies and laugh together or the fact that there are no cell phones or iPads or anything else on set. So when he says, cut, people talk to each other or laugh together and you form a bond that's very unique and different on his set than you don't any other set. And between you, you've starred in pretty much every Quentin Tarantino film, or he's contributed to every Quentin Tarantino film, except Rise for our Dogs. How have you seen his style change over time? And where do you think The Hateful Eight fits in that sort of larger filmography? He was in his prime here. I think that was one of the things that I take away from this experience that I feel very fortunate about. Sometimes you get to work with great directors, but unfortunately they weren't in their prime. We can honestly say, yeah, it was one thing to work with them perhaps before or after, but when you get to work with Orson Welles, absolutely in his prime. You get to work with Quentin Tarantino, absolutely in his prime. That's one to hold on to.


Hi, good evening everyone. Thanks for coming. We're going to give a few mixed presentations about the infrastructure here at EMF camp. My name's Will Hargrave and I've been kind of looking after some of the teams all together who are delivering this stuff. I'll just introduce my... I'm going to say colleagues but it doesn't seem like the right word. This is Ayan who's been mostly dealing with Wi-Fi. I have David C who's been heading up the nog team. Equi has been working on a lot of the core network and other interesting things. And Peter who has come from Germany to do the VOC video casting. So thanks very much. So I'm just going to talk briefly about the power situation myself.  Of course you can't see any of this stuff but can you see it perfectly? I put it up here earlier when we were building it. It's pretty nice to see. We actually have a bunch of Python scripts that I smashed together in 2014 because I got really frustrated with Excel spreadsheets for planning power and using NetworkX and some cool stuff like that and spitting out a diagram to make sure that we don't order the wrong connectors. They're all in GitHub by the way. You can have a look and look at my terrible coding. So this time we have two power grids actually for the critical stuff. BS7909, code of practice for temporary electrical installations requires us to have two sources of input for site lighting. So we actually have a mains failure panel somewhere out here. So if one grid goes down the essential services are protected. Which we didn't do before. So we have two 200 KVA generators, one droning away down there and the droning way up there. I'm sure you've heard them. Otherwise it's actually remarkably similar to 2014, those of you that are there. We have a lot of distros out around the field. We've got 30 nm sockets in done and closed. We've got 16 nm on the field for you to plug into. We didn't really have enough stuff this time. Our rental company were, yeah, a load of stuff didn't come back from hire. So we've had some challenges there and I know a few of you had to wait a little while to get connected and we're pretty sorry about that. But yeah, we just need more next time. More and more stuff. So basically on this diagram everything that's in red is a three phase connection. So we've basically got a tree spanning out from the generator down. It's one, two, five and sixty-three. I'm three phase cables that you've probably tripped over. They're the big rubber ones. And then down and down to the edge. Here's the second diagram. This is the north grid. Yeah, so that's the one to north. This is all the way, by the way, on GitHub. You can have a look should you desire. We did some awesome graphing this time. Rust has made some generator monitoring tools which plug into generators RS4 at five ports and the power from the generators DC bus.  You know, some of this is actually useful and I don't really care that much how warm or cool it is as long as it's not boiling. It's about 82 degrees C, by the way, mostly. Anyway, here's a total power. One is the north one and two is the south. We just... Yeah. Anyway, quickly, this is a stack graph, basically, so you can see the total usage, which kind of peaks around 100 kilowatts, which is roughly about right for a couple of 200 kV generators. I mean, I wouldn't want to run out... I wouldn't want to run out of power. Sorry. Heaven forbid we should run out of power. We'd have had a few power arches. The catering always uses a lot and because we've actually managed to get a lot more food vendors and stuff like that this time, they've been using a lot more electricity, so we'll have to beef that area up a little bit in future because 163.3 phase is not really enough. Yeah, all of this stuff, a lot of the generator starts and stuff are available on dashboard.emf.camp. You can click around it now and look at the generators and see what we're up to. Other than that, that's about it from the PowerPoint view. We're in kind of practical stuff. We are going around and trying to unplug cables when you need them. We are planning to power off the north side of the site tomorrow morning or earlier if we run out of fuel. But yeah, so most people need to be offsite by midday, so if you're not helping, so yeah, we'll be saying goodbye to the power up there and rolling all that out tomorrow morning when we're running around as quickly as we can to unplug your cables and et cetera, et cetera, when you need it. So thanks for that. I'll pass over to, who wants to talk about the uplink? David? So I'm going to talk a little bit about how we get the internet to the field and then I'll pass on to Equi to talk about how it comes around the field and to AgA about the wireless. One of the first questions we get is how do you actually get a really fast internet connection to a field potentially in the middle of the nowhere and certainly not near any useful internet points of presence? Well, in 2012, this is what we did. We did a microwave point-to-point link to a local data center. It wasn't fun. Even if you pay someone else to do it for you, there's an awful lot of faff to get it set up and get it aligned and get it working and getting the speed that you want. So we said, in 2012, we're never doing microwave again. And then in 2013, we did this. 13. Oh, yeah. Electromagnetic. And then in 2014, we did this. And then in 2016, well, mission accomplished. We finally have a fiber connection all the way down to the site from a provider. So as you are probably aware, Loasley House is just up a few hundred meters up from our field. And they renovated their business park a few years ago, and they had the immense foresight to not only dig a very large trench all the way towards Guilford, several miles across their land so they could have better access to fiber, but they also have a fiber network running around the business park as well. And that network is managed by a company called Fiber Options, who've been incredibly helpful to us. And we simply had to run a fiber of our own up to their nearest outside splice point and plug into their network, mostly along hedges and fences at one point, along some steel wire up at a couple of trees just to allow vehicular access if needed. And terminating Tuesday evening, I believe this was late in some late night splicing in the dark just to test everything was working. So a passive optical network, as many of you will know, is generally designed to get a lot of fiber to a lot of places, whether that's along a large area or to a lot of businesses. And it does that by having passive optical splitters along the network that are relatively cheap and it just basically forks the signal off and then recombines it on the way back up. And that's the technology they use up on the business park. But fortunately, I'll get to that in a moment. So this is what we were given as the ONT, the Optical Network Termination Device. It weighs a few grams. It contains a router, a four-port switch, a couple of Vipe ports, and a Wi-Fi access point. Made of plastic. It is made of plastic. The only difference from your typical Soho router is that it's got a fiber input there. And I'm sure it's fine for most of their customers, a small business or a home user who only needs to do a small amount of traffic. And I'm sure it's fine when it works in rooted mode where it can use hardware acceleration to actually shuffle packets around. Unfortunately, what we wanted is a bridge connection and what we wanted was a VLAN that is presented here to us and presented to our router up in London, Docklands, and has nothing on a logical level, has nothing else in the way. So this device was put into bridge mode, and it turns out that it does bridging in software on a 600 MHz CPU. So before we even send any traffic down it, simply announcing our roots, which is the best part of a slash 16, so 40,000-50,000 IP addresses, simply the background noise of the internet, the port scams and things like that was enough to completely lock this device out. I don't think they're used to dealing with such large address space going through these devices. But we talked to FiberOptions, who, as I say, have been incredibly helpful. We proposed a solution because it turns out that, although they use Pop Passive Optical Network and technology on the business park, there's not actually any splitters in the ground. The only splitter is the lower rack unit you see there. It's simply a way to get many ports into a single interface on their optical head end, which we noticed also had some SFP ports. And given that this is the only splitter, there was a clear fiber path, a single mode core, going all the way from this site, all the way up to their comms room up on the estate. And they very kindly allowed us to plug one of our SFPs into their unit there, running Gigabit Ethernet again on a single core because it's bidirectional optics so it transmits and receives in different frequencies in different directions. And yes, unfortunately, we also had Flex Optics, another one of our amazing sponsors that sent us a large number of optics and we were simply able to recode them to work in this device. So at which point, a Gigabit down to the field? So how did you use this Gigabit? Well, disappointingly. I think we averaged over the weekend probably about 100 megabits in, not so much up. We have this dashboard, which you should feel free to look at, ideally before you leave camp because I don't know how long we can keep it running after camp, but do have a look at that. It's got more stuff underneath, all the useful stuff that we use to monitor the network and that is interesting. So the total amount of traffic, our peak was 505 megabits, so we used at our peak, we used about half of our capability. And the total amount of traffic, I'm afraid to say, is... I have hard disks bigger than that. Come on, guys. So I'll pass over to Equinox to talk about how we get the network around the field from our data center here. So I'm Equinox.  So what you can see here is the physical overview of the data loose which you've seen around. So the core network is built on fiber, which is patched to maybe half of the data loose. What we do here is we just go into the data loop and patch the fibers through to the next data loop so we don't lose them when they are behind something that goes down. And then the stuff that is further around is connected by copper. You can see those on the black lines under diagram. So we try to minimize the stuff that we do with copper, but it's not really viable to do everything with fiber. But, yeah. So the good thing about patching stuff through the data loose without going into the device is that the actual logical diagram becomes very simple because most of the switches that are in fiber, connect directly to our core switch so there's no instance of something on fiber that is behind something else on fiber and that makes the network relatively easy to manage. Obviously the copper connected switches are behind a fiber switch but that we can deal with. Most of the hardware you see here is what we usually work with on other events as well. We had some new hardware from Arista this time around so we got to find out how that behaves in the field. I think it turned out pretty well, but yeah, it's okay. So this is what the head of the logical diagram looks when you have it in the data center. The actual network part is on top of the table which you can see there's the wireless controller and the core switch. And by the way, the core switch is 10G and the uplink on the fibers is mostly 10G so the data loose have 10 gigabit Ethernet which I don't think were needed anywhere, but in theory you could have filled that. Yeah, also the middle of that core switch is 6x 100 gigabit Ethernet which if anyone brings a device I guess we can find some way to plug that in but we didn't need that. So below the table is the service to the left is actually the walk encoding streaming stuff. On the right side is our own servers DHCP, wireless management stuff things like that. And I think this is actually the first outdoor event that we had UPSs in the data center which we didn't end up needing. However, that was pretty nice to have anyway since the UPSs gave us a power reading. So this is 2kW of power in total which you have to move out of the container somehow because it all ends up in thermal energy. So you can already see there's two air conditioning units in this picture. There's actually a third one behind the camera so you can't see that. And there's the fourth one at the bottom which was in the infotainment as well called bike up I guess. And I need to point out here that we started with only one of them and it built up a lot of ice on its back and then it went to the defrosting mode and then it suddenly turned up the heat to 35 degrees celsius which 44 I'm told. So the servers didn't quite like that so at some point we went like hey why is the server off? So luckily we noticed that pretty early so we ordered the additional air conditioning units and that turned out to work pretty well. So this is down from 20 degrees celsius so the unit is wrong, 22 to 15 at which point it's actually pretty annoying to work in the data center. But it works out. Obviously that doesn't help you to get any internet because you're not next to the data center so we have the data loose around and first of all I would like to thank to all of the volunteers who went around with the key and plugged in people and plugged in power and are hopefully going to unplug people as well. So you can see inside of the data loose there is one of the Rista switches some power supply for the access point that is actually mounted outside on the pole. You can also see there is this let's call it interesting light which fulfills the purpose which is to monitor that the data loose actually working since if it stops working the light will either freeze or turn off so if the light is working then you know well the problem might not be the network I should better check my laptop. You can also see the fibers pulled on the bottom of the picture we try to only have one of them in each data loop that works out usually because we just put them away from the core and yeah we use by the optics by the way so it's only one fiber used in both directions that makes things just easier to manage and patch so yeah it's a total of 3.3 kilometers this is only the fiber so this was shipped in it's the inventory that we have and there's two kilometers of copper and I should point out this is only between the fiber data loose and the copper data loose basically and for some tense so this doesn't include anything that people bring themselves or people patch themselves or stuff like that so we come up to just above 5 kilometers of patching and that's quite a bit of work to do in the heat something new that we did this time around was to run a VoIP network which mostly we did because it doesn't work which usually does this isn't here and we needed a little bit more communication we didn't have enough radios and this is actually Arian's setup who also ran the Wi-Fi so I'm going to patch over to Arian at this point I guess so Wi-Fi on EMF 2016 some statistics we had 66 access points deployed this time it's a whole mixture of Aruba access points there are either dual radio 8211N or 8211AC most of them are indoor and some of them are outdoor rated so the AP247 277 and we had a lot of the AP135 in the plastic boxes on top of the data close we had a peak of 2084 clients 50% of those were on 5 GHz and that's including the badges which were 2.4 only 350 megabits of traffic we've seen at a peak and a total of 4200 unique devices we've seen on the Wi-Fi network and it's actually only 300 unique devices we've seen on the wired network so almost everybody was on Wi-Fi and I think it's quite a bit lower wired uses compared to the CC camp and the Dutch hacker camp so 1400 badges we've seen on the Wi-Fi network and that total up to 65% of the clients were using 821X so they were using WPA2 Enterprise properly encrypted Wi-Fi network and that's without the badges because they were on the Wi-Fi network so 65% 821X includes the EMF camp or EMF camp legacy network which was 821X we ran with our radio server and then we also had Spacenet which is a federated authentication platform for hacker spaces and we had EdoRome which is also a federated authentication platform but for educational institutions so in total we saw about 300 clients 300 unique devices on EdoRome and most of the people were actually on the EMF camp network which is 821X and 5GHz only this whole internet of things of stuff yeah so the badge was 2.4GHz only unfortunately we've also noticed that the badge wasn't doing any channel 13 so we're actually running a 4 channel setup on 2.4GHz on the Wi-Fi network so we're using channel 15 and 9 and 13 but the badges were running on a I think a US fixed country code when they were handed out so they couldn't see channel 13 so they had 25% less coverage around the field so Acronux actually wrote a patch for that and I think it's upstream on GitHub or something I don't know and at first 821X was also not working for the badges and we were running out of time to get that fixed and we also we fixed it afterwards so they are also able to do 821X so they can actually get off the insecure network so some obligatory device and username, statistics as we do in other presentations as well so mostly smart devices on the Wi-Fi network so your smartphones and your tablets and that kind of stuff and a lot of embedded devices so that includes all of the badges so that's and if we were looking at the operating system families that is on number one of course the badge with 1400 devices or at least the Texas Instruments as we classified that with dgp fingerprinting then we have androids a lot of Apple devices and apparently more Windows than Linux which is sad by one, yeah well it's sad and actually for the 821X network you could choose your own username password almost nobody did that because I think everybody read the booklet and it said EMF, EMF so that's on number one and there's also some realms on the right table for mostly Ethereum users so a lot of yeah nothing hack is actually from SpaceNet and the rest of the realms is from from Ethereum so we like to collect a lot of statistics so we also are collecting statistics about where in which rooms or which areas are a lot of people so we also look at how many people are in which states and we can correlate that data with which kind of talks there are so this is on above you see all of the interesting talks we had a lot of visitors so we had the opening talk and then on the first day and then sex robots and after that people were going to sleep and apparently a lot of people are sleeping in field G so we can see that at night and then the next day we're seeing the talks of the Simpsons and how I used to rob banks that were extremely popular and today we've seen a very popular talk in stage B on hobby electronics like a pro we've also been fiddling around with a project of ours which is a Wi-Fi project where we have an open DRT device which will look for nearby access points and try to associate with the access point try to get an IP address send some traffic that kind of stuff and it will report back to our graphite server about what kind of results it got while doing those kind of tests so we can try and monitor the network from a different perspective so this is also on GitHub and if you feeling like helping out with this project then be very welcome lastly some pictures of our Wi-Fi deployment so on the left we have I think Leon and I were a bit bored yesterday so we saw a lot of people sitting around the big tree near the bar slash knock so we thought we had to put up an access point in the tree and at the back of the field there were almost no diving clothes anymore but there were still people camping there so we had to do something to get a little bit of coverage there so we mounted an access point to the fence which is actually has a directional antenna so should be able to get pretty far on the right you will see the whole pool with the plastic boxes with the Aruba 1 AP-135 ready to be deployed to the Dutton Close anyway that's it for Wi-Fi, I'll go hand it over to Aquinox again I guess or David or yeah okay we didn't start the timer so I don't know how much time we have so well I'll be very quick on this part for the first time ever first day evening the network was set up we were scratching our heads thinking what have we forgotten usually we're running around still during the opening ceremony putting switches out but this time as soon as all the power was completed Friday morning the network looked like this and it stayed pretty much like that the whole weekend so some knock members took on additional projects like monitoring the background radiation in the data center to be able to use more bandwidth or monitoring the stock of Marta in the bar we've had three copyright complaints so far although we're not convinced that it's not just an elaborate troll because they're for some quite bad movies there was another one recently actually we have one for so time to do some quick thanks so many thanks so I'm building a network the size of a medium-sized ISP for the course of three days and then tearing it down again it's not a cheap thing to do and less than well around 1% of your ticket price actually goes to the knock and most of that is for sundries like cables and tools and cable ties that we are always running out of so building this network at all is only possible thanks to our amazingly generous and helpful sponsors and I'd like to thank all of them in no particular order but I will go alphabetically so many thanks to aruba booking.com the Chaos Computer Club Comtech Enterprises EventInfo.org FiberOptions FlexOptics LONAP and Sargasso Networks so many thanks can have a round of applause for the sponsors so as I'm sure you all know people volunteer their time and for those who have we thank you very much some of us have been here for a week now we've got another three or four days here on site if you have time to stick around for the teardown it would be very much appreciated if you don't want to work on the network stuff I know all the other teams need help as well if you do want to work on tearing down the network it's not quite as simple as just unplugging all the things so please come along tomorrow morning at 9.30 outside the knock for a quick meeting and that's 09.30 hours tomorrow morning 09.30 and hand over to Peter yeah hello so we are a team from the German Chaos Computer Club who tries to cover events with video recording and streaming so as but not much people watch streams here so we don't have fancy graphs to show so I'll show you a little bit what we did instead so this is the signal path how the video comes from the cameras to the CDN and to the recording so we many of you have volunteered here and have seen the video mixer and the operated the cameras so the cameras of course are the source of the picture and also we have a frame grabber that gets the slides so you will see in the recording that sadly if the video is played from the notebook there will be some delay we will see it in the recording but it doesn't matter so and everything below the top row is done with open source software and most of some of them also written by us so you're all welcome to copy that basically it's a bunch of ffmpeg scripts and a video mixer that's called VoktoMix and on the CDN side we are running nginx service with rtmp that provide hls streams for the apple users and the rest of the planet gets webm via an icecast server and also besides that there is opos and mp3 audio streams after you record a talk or you record many talks like here you have the problem that you have many hard disks full of talks and that's usually not really nice to handle so we have a post processing system for that that keeps track of all the talks and also handles the recording encoding afterwards this is also soon to be open source so if you're running a conference or a hacker space which does regularly events please get in contact we love that people play around with it so at the end everything ends up on media.ccte which is our own video platform and also in the YouTube channel of the EMF camp so whatever you prefer you can see it there I think there is only one talk whose explicitly opted out from YouTube but it's not from our platform so you may be better there and there is also a treat but you can follow that has now treated I think 500 times this event about to know your recording so yeah it was about 52 hours of talks that end up in 2.5 terabytes of data which are encoded to about 40 gigabytes of releases so each release is available at H.264 and WebM in SD and Full HD and also in audio releases in mp3 and opus as I said you can and watch them on our video platform and the EMF YouTube channel and if you're a user of the Kodi media center you can also just call the cc plugin and then have it on your nice tv screen the both machines you see on the slides the one on top are the machines that are in the tents that getting the feeds from the cameras and do the stream encoding and record to the hardest an MPEC TS stream and the smaller ones below are the ones that are also shown in the picture from the stock from the data center these are really tiny boxes where a strange company fits in desktop i7 CPUs with 4 cores which makes them basically a plasma cutter on the output but if you put them in the data center it's okay and these two boxes are handled nearly all of the encodings you will see so they did really much work because we couldn't travel with our big server case here we are now nearly done with I think 4 talks everything else is cut and all recordings will be online tomorrow morning when the encodings are done here is a screenshot of media cccd which is already filled with many talks so if you want to download something for the way home do it as long as the camp is still online and maybe we get another peek in the banter's graph yeah thanks for all of you who have volunteered to do video shifts because we couldn't do it without you also big thanks to the emf crew that made this event possible and if you want to do something with video streaming or recording you can find us at erc at irc.huggin.eu in walk launch or follow us on twitter or look at cdrive.de or everything we do is documented in our wikis so if you are interested more in details look at the wiki and yeah thanks for being part of emf I think we've got a small amount of time for some questions as usually some people who want to ask something so feel free to do so I wonder if it's possible to download a raw data that mends all the graphs we need to make sure we sanitize anything that's sensitive data I haven't really thought about that actually there's obviously that you can look at the dashboard in the day trial of that yeah for example for the power stuff to get what is the peak power to be honest the most useful stuff about the power is actually the design and the experience from doing it yeah we get the figures and stuff like that and we can really it's really nice to verify that we've approximately done it right but yeah a lot of this is kind of experience like oh my god the food vendors use a lot of power that kind of experience or unfortunately for instance with the power we were really lucky that it didn't rain because as soon as it rains all the really nasty extension leads everyone's left in a puddle outside the tent and we have the RCDs tripping everywhere which is actually what we had a lot of in 2014 and we've been pretty lucky here I think we've seen on the main sub mains like maximum 18 mA of Earth leakage which is perfectly fine no one's dying now so yeah yeah what are your main learnings for next time from the camp here it's all gone very smoothly but what would you make better? thanks for saying it's gone really smoothly there's been a certain amount of running around a couple of hours fly we we need we actually use a lot of 13 amp sockets and actually getting that number is actually hard because there's not many events like us that provide powers of so many people so getting all of these from one supplier is a little bit tricky from the network point of view Fibre is great Fibre is good yeah I mean really 2014 we spent really a lot of time on complicated solutions and stuff with micro if you're sure it works and it is a way to do it but it's really nice to have Fibre anything interesting from the VOC? no so just have a question firstly how long will we videos be available for on CCC I'm just wondering forever the rest of eternity fantastic and second I was wondering something I can't remember so yeah good was there a question at the front? I can't see anything from up here something's there hi you've got a lot of different kinds of network devices in your network how are you managing them are you just going in on the console or if you've got some kind of tools for automating it to some extent HP open view not so we started building scripts in 2012 and have been improving them year on year to automate all the things we have a google doc spreadsheet is our ultimate source of truth and everything is built from that you may have a different preference we find it convenient to be able to collaboratively edit it at the same time it has everything from our switches, their locations, our access points our addressing scheme, our VLANs so all the data is consistent and then we have a bunch of Python scripts which you'll find in that github account that just generate everything sorry how much did the network influence the choice of location or were you given the location then told what are you going to do here there is a bit of influence on that obviously being in the home counties we have a lot more options we have looked at some fabulous sites in really nice areas of the UK where you look at it and you say well my options for internet here are so limited sure you can throw money at the problem but we don't actually like to throw money at the problem we like to have a friendly supplier that's local and you know every EMF until now and also the other similar camps have relied on the generosity of supporters sure I mean I can go and spend serious amounts of cash on an expensive circuit here but it doesn't actually it's not actually appropriate for this sort of event so yeah there is some influence there and there's a lot of it is one of the factors as well as alongside all the more complicated things like you know what's the road layout like all of these sort of physical layout issues that are quite complicated it is a factor but not a huge one question for the VOC guys those i7 plasma cutters what were they are they it's a gigabyte bricks and they sell it as a gaming PC which I don't know who will game on it but thank you hey so what happens to the fiber and the copper left after the event do you intend to repurpose it and how much do you think you will be able to repurpose so actually the fiber is some of this is kind of been going around multiple events we realized with I think CCC camp and ohm and so on that we actually can pre-terminate all this stuff in advance and have the ends of the fiber in boxes and on nice drums and document it all so actually what we did was like select a series of fibers from the CCC storage where they live a lot of the time and it's actually happened before 2014 EMF and it was like oh we need one of these one of these one of these and then put them on a pallet ship them in this case from Berlin to here and roll them out onto the field so actually we roll this back up and we use it for the next event wherever that may be or whatever it may be is kind of a variety of events so it means that that effort is not wasted you know actual field deployable fibers kind of expensive so that works pretty well the copper yeah Dave is a copper expert if you would like some copper if you see a copper cable that has boots on it don't take it because it's one of Arians that he's brought to power the access points but if you see anything that we've strung between a dart and clay that's just been crimped for the event feel free to have it otherwise it just ends once it has already been removed from the dart and clay otherwise we have a local scrap merchant picking it up on Wednesday I'm told we're out of time because the next talk wants to start okay are you able to take questions afterwards if anyone's got any more grab us just out the back so thank you very much and a lot team


Well, staying on the ice, but Midgey Boy's looking for their fifth straight, hosting Alexandria Brock, Waldhausen getting the start for Matt Fitzgerald. No score, second period, but Cardinals get on the board. Jacob Stenner from a tough angle and in on nothing visitors. But Lumberjack's answer later, pressure in the zone. Joel Leitner then with the puck, turn around and fires it in the back of the net. Game tied at one, but Midgey then on a power play. Puck finds Casey McNamara at the point. He fires the rister in for a goal. Lumberjack take the lead, then just moments later Hunter Olsen shot just off. Brian Pogetz the rebound and scores, but Midgey goes up by two. But Alexandria would answer with two goals themselves, it goes to overtime. And Alexandria scores, they win four, three in that overtime. If you enjoyed this segment of Lakeland News, please consider making a tax deductible contribution to Lakeland PBS.


Yeah, as far as the turn-ups, I'm definitely better than that. That just mishaps on our part. I'm going to work this next bi-week to focus on honing in on those details, as we said. Feels good, just kind of disappointed about the loss. I feel like we could have left a lot on the field, could have did more about it. I'm never surprised. Every time I touch, I want to score. O-line did a wonderful job moving guys around, creating those lanes for me to get through. I commend them for that for sure. On my scene there, I just hit it. Definitely had a winning game plan. I commend the coaches for that, putting together a great package this week. We just went out there, kind of did ourselves a bad favor with a lot of the things that were going on. We just got to come back next time to touch the field and put it all together. It's motivation is how we're going to look at it from this point. Just focusing on the things that we've done wrong. We look at those. AL has a lesson, so we're just going to focus on the things that we didn't get right and try to focus on those things and get better at it. Very confident, even though the opponents that we play are good opponents, but a lot of the damage we've done ourselves. So very confident. We just got to put it out, go out and put it all together.