today on the show we're taking a look at funeral for a friend part six super girl in action comics number 686 so stay tuned all right guys as i said today we're taking a look at funeral for a friend part six super girl in action comics number 686 who's buried in superman's tomb by stern guys and rodier and why is lux luther so as you can see there's a nice shot of the matrix super girl on the front cover we open with a shot of guardian chasing after a van of criminals he starts attacking them and they pretty much say that you know they're going to sue him and all this other crap they're going to get him arrested because they're innocent but he's got cameras on his motorcycle and everything to prove otherwise so more guardian action uh for those of you don't know guardian i believe is a jack Kirby creation modeled after captain america uh there was a hero back during world war two called guardian but he he was killed and cadmus cloned him uh they continued to clone him every time he died uh so this is not the original guardian this is a clone of a clone of a clone you know so on and so forth um you get some lex luther here uh showing how his he had his body cloned uh to be younger so that he could pull off the lex luther junior thing and because of his cancer and everything he had his um brain removed from his old body and transplanted into the clone body guardian coming up to one of his uh bases uh lex luther junior uh showing up pretty much where the last issue left off at superman's tomb uh super girl explaining what happened uh guardian realizing that cadmus had stolen superman's body um and then he realizes you know maybe this could do some good he doesn't agree with how they would about it uh but he's gonna go along and he's gonna oversee the cloning of superman because the world needs superman uh once again super girl back at the tomb uh they're trying to get in find out what's going on uh lois lane uh lona lang mon paul kent uh mon paul kent are getting ready to leave for the uh airports um some more of super girl in underworld uh the superman worshippers lona lang and lois having a good cry together pretty much uh essentially finally becoming sisters um not not in the literal sense but more um spiritual sisters they both loved clark um they were both in love with clark and they're both going to miss them while he's gone um but there you guys go this was another issue that didn't really push the narrative forward as much part five was didn't push it forward at all uh part six pushed it forward a little bit with the guardian uh but that's about it again not much happened um this was more or less a guardian issue they should have pretty much made it guardian in action comics rather than super girl in action comics but since action comics is a super family title they had to do super girl in action comics but anyway if you like this video make sure you hit the subscribe button so you don't miss out on future videos i'm shannon for come again tv the only place on youtube where all geek culture collides take care my friends


As of December 26, 2021, St. Nushahar's diagnosed a total of 13,319 cases in country, with 204 active cases presently. The daily infection rate for the past seven days is 11.6 per 100,000 population per day with a 7% testing positivity rate and a transmission rate of 1.9. We have noted a total of 292 COVID-19 deaths. We have 18 positive cases admitted at the respiratory hospital. Two cases are critically ill and two are severely ill. We note increases in most of our public health indicators over the last seven days. The transmission rate, the test positivity rate, increased active cases and the epidemiological wave depicts the upward trajectory of the start of the fifth wave. We are at high risk of introduction of the American variant which is characterized with a high level of transmission and we still have the Delta variant in circulation locally. December is our highest risk month for COVID-19 transmission. We understand the COVID-19 fatigue experienced by the population at this time and the nature of the festive season. However, it is imperative at this point that we reduce the level of social activities and ensure compliance to all of the public health measures. Health and safety must be our priority. The Ministry of Health, Wellness and Early Affairs also received a notification from the Caribbean Public Health Agency of 20 new cases of the Delta variant. 14 of the cases are nationals and six are visitors. The majority of the local cases are from Ancillary and Dennery. 13 of them are female, seven are male and the age ranges from three months to 77 years. A total of 54 cases of the Alpha variant and 71 cases of the Delta variant have been diagnosed in country thus far. We remind you of the following important measures. Avoid large crowds and crowded areas. Ensure the protocols are maintained at workplaces, on minibuses and commercial and tourism sector. Use face masks when in public places. Ensure you remain in quarantine or isolation if you are direct contact of a case. If you develop respiratory symptoms, seek medical care and avoid contact with others. The Pfizer AstraZeneca and Johnson & Johnson vaccines are available at the various wellness centers and advertised sites. These vaccines have been proven to be safe and effective in protecting persons from developing COVID-19. It's severe forms, complications, hospitalizations and death. The booster Pfizer vaccine is also available for persons who have had both doses of the AstraZeneca for over six months. Everyone who has not been vaccinated is urged to get vaccinated urgently. The Ministry of Health Wellness will continue providing updates to the public as new information becomes available.


So, we were actually looking at the SIP reply actually last time and we have looked at that. So, request and response these two things actually technically was actually was covered. But when you actually the abstraction the way it is being defined defined in the SIP RFC, we do not define everything in one single go we define it in form of layers. So, the lowest layer which is being specified is how basically the syntax and encoding of all the request and responses that is the first and foremost thing. So, this is nothing but syntax and encoding of all kind of possible request and all kind of possible responses. So, there is a generic definition and this is can be done through a grammar and this grammar is known as BNF is something very similar to ASN, abstract syntax notation. This is a thing let me write down the proper spelling. So, this is a formal way of a specifying the syntax I will give an example of this we will specify in our own way and most likely that is BNF and once you have this specification at least you know how to form a request and how to form a response for every request. There can be multiple requests there can be multiple responses which are permitted. So, once this abstraction is clear so, at least you know how the message will be from this like how to write a letter there will be DRSR there will be address there will be date then you will write how are you whatever it is then you will write whatever you want to say after all preamble then you will say thank you goodbye your name it is a format it is a syntax you will be using English language or you will be using Urdu or Hindi that is kind of encoding how it will be depicted in text. You might write in Roman for example, to write in actually Roman script, but you are writing Hindi language that is possible ok. So, we do that actually once in a while so, all that is specification is given by this. So, once the letter is being written closed sealed what has to be done with that ok. So, next layer is talks about how it will be transported. So, next layer will be transport so, this is the lowest one so, next on top of it so, layers are like this. So, whatever functionality abstraction or whatever it is provided by it is need not be known by this guy. This guy just passes on the information and this takes care of it ok. Basically this is the way it is going to happen is whatever you are going to generate with this BNF grammar specification the message this will be passed using a transport ok. So, transport layer can be UDP can be TCP can be STTP or can be anything is a basically message being encapsulated and then being transported over to the other person. So, it defines that particular transport and similarly how the responses will be sent back. So, this can be any one of those that this is basically mechanism how the message will be transported. So, this how the message is formed and this is how the message is transferred from one entity to another entity that is a transport layer ok. So, I think I should not call it a lower layer because it is not running on top of it actually because whatever you create that is being transported. So, that becomes an entity for this these two are separate, but that is the way it has been written lowest in transport layer in RFC. Then there is a third layer they do not write bottom most upper layer kind of thing the structure is not used the way it is using a networking. Third is what is known as transaction layer what does it mean? For any kind of signalling I will any signalling will consist of multiple transactions ok maybe I will send you an invite the response will come for the first transaction over based on that I will decide on some some other transaction which need to be done. So, there is time every time there is one transaction which will happen fully and it is possible I do a transaction with you and you give responses that is a transaction running he is now on my behalf is transacting with somebody else ok. So, a client will be transacting with CIP proxy, CIP proxy will be transacting with another CIP proxy ok and each transaction is separate each transaction is independent, but they are initiated by earlier transaction. What is the difference between transaction and message? Transaction there is a finite state machine the message once you transfer see for example how you will ensure reliability I am transporting over UDP UDP has no reliability you send a message you create the lowest layer thing the message through encoding and whatever it is message format you transcend the message over UDP using that transport you have done the transaction now you are waiting for the response message lost what you should do. So there has to be at some transaction machine a finite state machine which has to be implemented which will keep track of the transaction till the transaction is complete or abundant. Stateful proxies if they are implemented between client I can have a transaction with this it is not transparently moved out ok this transaction is only between these this will result in a separate transaction with another proxy. The transaction is point to point messaging is end to end. Not necessary not necessary transaction is point to point transaction is point to point yes it is point to point unless you have a state less proxy in between because any request which you will send through the transport will be transparently transmitted to the next guy it does not maintain any states if it is a transaction then this will maintain the state of that within transaction whenever you are sending messages you are changing your state when you are getting back the message your responses for the transaction you are changing the state. In the stateful proxies there are two transactions server transaction client transaction for one side. For a stateful there is no client and server whatever comes it is simply just transports whatever is coming back simply transferring here is a state less it cannot maintain a state. Stateful there is only one transaction it can result into another transaction which is coming here. There is a server here and there is a client here there is a client here there is a server here. There is one client transaction other one is server transaction client transaction server transaction are actually finite state machines it is not one transaction they with this actually the term which is used here. So transaction layer is what is the third layer and formally transaction is defined as a request which is sent by client transaction transaction is a instance which gets created in the client. It is not a transaction client transaction is an entity running in the client. Similarly there is a server transaction so request is going from client transaction which will cause a state to be changed. So if loss happens it has to be retransmitted after certain time out for example this is going to be taken so reliability is the responsibility of this irrespective of what kind of transport is used. Transport can be anything remember if it is TCP most likely it is reliable UDP it is not reliable remember when I took the Bob and that Alice example it was UDP based transaction which was there in that request response message could have been lost in UDP what we will do in that case. So client transaction will remember that the something was the response has not come within certain time I have to again retransmit the transaction request. So it is a request sent by the client transaction along with all the responses which you receive not one response. You send a client transaction sends a request then the all responses which comes will be included and this whole thing together will form a transaction actually and this is sent using transport layer is a different kind of instructions not exactly the same way. So it takes your reliability but when you implement a client transaction there is a finite state machine which is going to be maintained for that. So the remember if for data link layer we had a finite state machine on two sides which can take care of the reliability of the message transfer.  When it sends any server suppose if the schedule process is there it is acting whether the client server is sending the request can make the request or send to other. It will it will it is going to have a transaction user setting inside. So when it is a returning the response you will receive the response how it might be it is a same response of this particular transaction you are saying this in sense when I send a request forwarded process forwarded request and we will receive the response. There is a dialogue and there is a corresponding a remember sequence number for the command. So dialogue will give the basically complete dialogue which is happening for that corresponding that call setup and then command sequence tell this transaction corresponds to which command. For each command there will be one transaction which will be created. Transaction user can issue multiple commands. So the layer on top of it is transaction user. So this will handle all application retransmissions matching of responses to request and application layer timeouts that is what I was telling this will take care of I think this is important thing because otherwise there is no reliability built in because application can actually use UDP. Re-transmission responsibility. Is by this transaction layer. Transaction layer is proxy everywhere. Transaction is between two end points. See it is not between Alice and Bob is between Alice and proxy whatever was that at Atlanta proxy there is a transaction which is going to run between them similarly between this proxy and another proxy there is another transaction between this and Bob there is another transaction which is running. Who will realize they will have to re-transmit Alice will realize for retransmission here this will realize for retransmission of message here this will realize for this section. What is happening is in between this there is something called transaction user TU. So when this guy actually sends a message this will create a transaction before corresponding to. So these are transaction user is a layer which is on top of transaction layer except state full proxy state less proxy all other entities will have a transaction user. So this transaction user has to talk to this transaction user. So for that it will create a transaction layer a transaction will be created. So transaction instance will get created for invite and this will go here and there is going to be what we got this is a client transaction a server transaction will get created which will then send a for example I am still trying 100 and then this will be giving a message to transaction user. Now this server transaction will remain as it is this will not still be dead its transaction is not over transaction user will now know that I am a proxy I have to now forward it to appropriately. So transaction user now will try to find out which is other proxy to whom I need to send the message further. My question is it when the proxy there retransmission is message of done by Alice whether this retransmission message will be further polluted by proxy. No retransmission is only for the reliability between these points see message can be lost here UDP is lost for example this guy never received anything what you will do this will still keep on waiting I have send an invite I will get a response that can happen it is a UDP transmission. See if I do a very simple thing I want UDP I am transmitting transaction user got created you want to make a call it creates a client transaction it sends a invite and there is no client transaction technically you are saying I am directly going to use transport this layer is not there. You form an invite you send it it went through UDP it was lost this guy even is not aware that there was an invite being sent to me then what you will do UDP packets are encrypted on IP packets IP packets can be lost because of congestion then she will keep on waiting for all the time for getting even 100 ok kind of response so there has to be time out you have to again try it but should it be done by transaction user is intention is I want to make a call that is it invite is sent so let this be responsibility of the client transaction for retransmission why proxy will maintain this will maintain a timer now client transaction will maintain a timer there is a time I said there is a finite state machine with each client transaction and each server transaction so when this guy want to send invite it will create a client transaction which will have a finite state machine along with all timers and everything which in turn will send invite request through a transport mechanism encoded as per this Lewis layer and it will maintain a state now it will wait for some time when timer expires it will assume it has not been done it will again send the thing remember command sequence will tell if this has been received correctly here time out has happened even if a duplicate goes it knows that it is a duplicate I have already received this command sequence there is a serial number being assigned and the reasons why serial number has been assigned and this is a traditional number it keeps on incrementing every time you put next command for every command you are going to create a separate client transaction it is possible that you can do even a cancel for example cancel is a special command when you give a cancel it will create another client transaction not the same client transaction which is supposed to be cancelled and this new client transaction will send the cancel command and it will refer to the earlier transaction earlier command which in turn will go here and then this there will be a server transaction which will now clear all the state for corresponding to this will send the appropriate response if it requires or the cancel will send a response back in turn it will tell the transaction user which in turn will clear up the client transaction so cancel is also tricky in this case it is not a state forward it is not control all del in fact no where it is control all del control all del itself is a complicated process if you put it in the shell or a control see if you do in a telnet transaction a very similar things actually almost will happen everywhere sometimes you can abort tcp connections server side time out if you do not get a packet with or a message within certain time see most of the protocols by design use something called soft state they do not have hard state so they remain alive they are active if they keep on getting something what do you call heartbeat messages from the other end the moment that heartbeat pass message does not come for certain time it will assume the other guy is dead or he has forgotten or something has happened you simply reset everything all data structure on the server side client side usually will keep on will time out if the response does not come again try it will do it multiple time it does not happen server must have been dead it aborts and tell the higher layer something has happened same procedure will be followed here but it is done in a different way the naming is different that is the only thing and it is on an application layer because your transport is directly UDP this is only the encoding of the message in the application so this message is technically being routed over this transport but this message is generated by transactions and client transactions and server transactions are created by transaction users only in a state less proxies this is not the transaction user is not there so correspondingly there is no server transaction and there is no correspondingly client transaction so whatever comes you simply change the header what as per the policy and transfer it you do not even worry about it what has happened what has not happened it is the end points which will worry if it is lost or if I have done a wrong translation reverse whatever come you again do the translation pass it back so they actually take handle what we call application take care of application layer retransmission I think I will write it then matching of responses each request will have a separate client transaction being created so when the responses come back they are transferred to appropriate client responses and of course what we call application layer timeouts so any what we call u s e u s e was user agent client and whatever it will do it will be through a series of transactions so u s e is as well as so this is always will be working through series of transactions so now it is important that u s e and state full proxies have transaction layer in fact I should write transaction because TLV use for transport layer most state less proxy no transaction layer and of course all the time this client transaction and server transaction they are always represented by finite state machine finite state machine is where finite states are there and depending on whatever is the input the state will change and there will be corresponding output which will be coming out FSM is that FSM stands for finite state machine and of course the fourth layer as I mentioned is always going to be transaction user is known as T u transaction user is a user which is technically a software running there which creates transaction machines client transactions and server transactions and except all except the state less proxy all SIP entities are transaction users there is no separate all entities itself are transaction users so proxy is a transaction user it is not nothing inside the proxy proxy itself is transaction user user agent client is itself is a transaction user because it creates transactions proxy also does the same thing register also does the same thing so except state less proxies everything else is every other entity is a transaction user so the way it is going to be done is what you will do is it will create a client transaction and for this it will create client transaction instance actually there can be multiple client transaction instance as he has mentioned as a case you want to make multiple calls or multiple invites to be sent you will create for every kind of thing a separate instance I already gave an example you create an invite you create a client transaction instance you want to cancel it you will create another client transaction instance in that case which will then be referring back to this because is a cancel it is a separate transaction but it is going to refer to an earlier transaction so there will be a server transaction correspondingly which will go and do all cancellation thing on the server side and once the confirmation come from that side it will do the cancellation on the client side. So here cancellation is slightly different so you create a transaction which is a invite for example on the server side suddenly you want to cancel it you will do not cancel it directly you will start a separate transaction which goes creates a cancel server transaction it will refer reference will be given to this this goes from that reference this has to be cancelled this will be cleared off the response will come back once the response comes back you will clear this thing you will tell to you and this will clear off this one whether two separate transaction instances which gets created and for creating a transaction instance you require a request you require a destination IP you require a port you require a transport UDP TCP or HTTP whatever it is and once you give this thing based on this is where the request has to be sent this will always lead to creation of client instance client transaction instance and transaction instance will be of the type request and the message will be transported to an entity on this side where server will keep on waiting the moment a request come it will check it will find out there is no server instance for this it will create a server instance it is like forking for example whenever you are doing telnet to a server or SSH to a server there is only one server running there first time the request goes it will figure out there is no instance running so it will actually do a fork fork is creating a copy of yourself and then it that will be made responsible to response to this. So, you will create in client server transaction instance this will be done exactly same way the way it is done in network you will create an instance on the server side also. Cancel thing I have already told and of course this is basically what are the layers which will be used for communication purpose. Now most of this elements we define something called core core is the functionality of course this is only an abstraction this does not tell that software has to be designed only in this way it depends whatever fail you way you feel comfortable you can design your software, but this is an abstraction given in RFC. So, you assume that if somebody else design software in whatever way, but he is following this abstraction you should be able to communicate with him only that thing has to be ensured by you you do not know how the other person other server or other SIP entity have been implemented. So, it you should have to ensure if you are making a client it should be able to work with anybody is proxy which is SIP compliant. If you are designing proxy it should be able to talk with any other proxy built by anybody else or any client register it should be able to talk with any kind of proxy, but internally how you implement it is your it is I think implement this issue. So, that IETF should not govern because that innovation we I think we should live it to the invent I leave it to the inventors you can do lot of innovation by implementing the software itself. So, in fact every entity every SIP element we defined course actually in this case core is the implementation core is technically the implementation and they are they technically represents T U client transaction instance creation mechanism client transaction instance everything put together in software that is core and this will be existing for every entity except the state less proxy. So, that is core and core will depend on whether it is a proxy core or whether it is a user client core or whether it is a user server user US user agent server actually core or it can be register core. So, you can define or you can redirecting server redirection server which is there it can be core for that and remember for every transaction transaction will get completed when you will get a final response it cannot be completed before you get a final response. So, transaction client transaction and server transaction this transaction will get completed then this entity server entity can go away if it requires and this will happen only when the final transaction has happened a final response has been received for a request. So, now if you carefully note when the LIS actually has sent a request there was a invite which was sent final transaction happens final response comes only when the final response is from all others have reached here then only you get an ok an ok is kind of a final response. So, in fact, all response codes which starts with 2 x x 3 x x 4 x x 5 x x 6 x x they are all final responses 1 x x is not a final response it is a kind of a temporary response you call it provisional and it will not terminate that transaction. So, your client transaction have to be maintained if you are getting these provisional responses you cannot terminate that you cannot closer 1 x x series will not close the client transaction only anything related to this will close. Now, these request and responses now can actually can keep on moving from one person to another person and so on. So, there are terms which actually things which can happen which we define. So, one thing which can happen is known as loop. So, this is a shift phone talk to a proxy figures out still transaction is not over this request is sent to another proxy this proxy analyze the invite or whatever request which was sent and this request comes back to this guy and this request again goes back in this direction that is very important then it is known as a loop which is going to happen. So, this is loop something also another interesting thing which can happen is you send a request to a proxy this can send to another proxy this in turn sends it back, but this new request which has come back through some whatever way there can be other proxies also is not going to go in the same way it goes to somebody else. So, this is different than loop actually this can happen because of redirection this can happen because of redirection because you are probably registered with this domain, but then you have moved to some other place. So, you told this guy you tell this person where I am. So, it tells this person that I am here. So, it actually passes all the request to this guy this guy then looks because now that remember that when I do redirection. So, redirection means the source the original destination is moved to converted map to another new destination. So, Bob was at block c dot com and then he has moved to say some x y z at Atlanta dot com. So, that is a redirection. So, Atlanta dot com is back here. So, request comes here for x y z or may be some other guy whom this guy cannot go directly it comes back here which in turn sends a response request here. This kind of thing is known as spiral in this case. This is a legitimate. This is a legitimate is a legitimate loop will be endless or I mean it will come out. It depends loop usually is not desirable, but yes it is possible. Loop is there and loop is estimate yes it is possible, but loops need to be resolved in that case. The probably one example is Bob at block c dot com. His job actually got moved. So, still retained that account he did a redirection. He joined somewhere as say Johnny at Atlanta dot com. So, the call was deducted here and then by the time he also actually has moved this entry is still retained and now is some. So, loop is still valid thing, but this signaling is happening in the loop. So, ideally speaking he should have actually the error here is that he should have now told this guy that whatever is Bob at the block c dot com is same as jojo at block c dot com. So, redirection can happen here itself directly. So, earlier this loop is nothing, but what we call a data which is not required, a configuration which is bad actually. Of course, it is not going to impact the call can still be rooted, but it is not desirable. Mostly it will happen because of redirection because for whatever reasons. This redirection is probably you are moving and then you are even returning your earlier account and redirecting to somebody else like dot forward in email. But dot forward in email for example, from IITK you say it goes to whatever is x y z at gmail.com. There you do a dot forward to go to somebody else here. It come to IITK dot ac dot roman, but different name, but server is still the same, but name is already changed and that dot forward again send it to gmail.com with a different name ID, different mail ID and of course, if you create a loop same mail error it will keep on looping indefinitely. Now, that is invalid thing it will not terminate. Invalid loops are not allowed and how that valid loops will be terminated? Yes, there is a maximum forward limit and that will be terminated it should not happen keep on happening indefinitely. So, loops usually which are invalid loops are taken care of by maximum forward house which are there. And then of course, this is You do not handle it simple. So, if you see see I am telling here it is a loop only way this can be said is if as of now because there is nothing has been received from the end point. The call ID and that the tag of the sender these two pairs actually if you combine and those are registered here you just keep check if there is any other request which is coming a while it is this particular transaction is pending which corresponds to the same particular call ID and same particular this thing and same particular what we call sequence command sequence if that thing comes yet probably is a loop that time you have to decide what has happened then you check this this this then you actually can do that these two can do the pairs can do the check and then user need not even offer you can directly say bob.blogsy.com should be now directly forward to this loop is removed that intelligence can be built in this system. Now, that is left to the programmer RFC does not talk about it. So, if you are smart enough actually you can implement this and then make your proxy better or you can at least inform the user we found a loop for you would you like to correct it and this is a way to correct it at least. Spirals also can exist, but I think spirals are also not desirable if this could have been directly from here it would have been better. Now, this guy can do this job and short circuit directly from here. So, you will actually reduce a lot of load on these machines final loops and spirals. They have to do it, but if these machines are entity they can figure out a call lag what not call lag that is dialogue, but dialogue is not there unless you get the response back. So, only the invite will go in this way, but the response will come pretty fast basically they will always say they will not put what we call that thing via field. So, whenever you are doing redirection do not put a via add entry into that, but the problem is if this is going to send to another proxy then this will not know it is going to go back to this guy and it puts a via add or then it becomes a problem. Now, those complications are there and we have to live with those and these kind of things I think has to be identified by processing see because this will not be cleared remember. So, whenever a new call new invite comes whatever is the current transactions which are pending which are not clear compare with all of them compare with all of them and based on that you decide if something is being duplicated you identify loops or something and then at least talk with those proxy servers directly and resolve the met. So, that intelligence has to be part of the proxy design. So, it is not a trivial thing. So, this is also not an obvious stuff. Now, I talked about that back to back user agent I talked about a state less proxy state full proxy I can now diagramtically actually represent them once I have come with this transaction stuff. So, I talked about this thing B2B user agent. So, this is a special kind of proxying thing, but actually it is not a proxy. Proxy is only for signaling back to back user agent also takes care of media. So, there is a proxy there is a proxy this is a B2B user agent. So, media is going to be transacted on this signaling through this particular path. So, there is one user agent there is another user agent client user agent server media and signaling both will be in transacted here and this can make and the ship trapezoid that is a back to back user agent. If it would have been the proxy the media is always transacted directly between these certain media gateways this can be built it can be of this kind signaling in data signaling in data both or media you call it this will not be called a proxy this is not a proxy this is a back to back user agent. How can you differentiate? Proxy is only for signaling part there is no role for media media is transacted directly between peers, but this is like another peer. So, this guy cannot see this and this guy cannot see this they both have to go through this. So, signaling as well as media this kind of a media gateway if you want to tap the call along with all signaling information here this is the best approach back to back user client is the best approach in that case. So, do not allow the call to be set up between these two entities use between. So, tapping usually will require this because I am now not using mega co here for controlling this particular entity media gateway I am using ship only. So, it is you will actually see your user like is this, but actually it is not this. So, similarly this guy will feel as if this guy is here, but actually he is not and they just back to back connected it splice together in software. But whenever he is given as a address of an IP as a back response we do not know. No, this guy will do the signaling here this will still keep in pending. This B2B user agent will ask this client to actually not talk to this guy with all the information given by him and it will behave as if he is this guy. He is approaching the request to go through this part, but it is not a normal feature. It is not normally it will not be done normally it will not be done, but this kind of specialized entities will also exist. So, I think call a stateful proxies and transaction a stateful proxies also need to be explained. Sir, how is the difference between poking? Poking will also be normal response though. Can we get the best response? We can use the poking also you know poking in this part. Poking is when the proxy on the receiver side gets a message it now signals to many entities not one entity which are registered for the same user. Is a parallel thing and the responses will come all of from all of them and it will intelligently will figure out as per the policy that only one of the message have to be passed back. So, when we do the parallel poking and when we use a sequential poking? Parallel poking for example, if you have set up as a feature with your registrar you want that all three of my phone should ring when a call should come and I can pick up from any one of those. You can say first of all try at my home phone give four rings if I do not pick up then my office phone should ring four rings should be there if again it is not picked up then my mobile should ring that is a serial. Yes you can that is your thing you have to do the everything has to be with registered with the registrar and this will inform get everything from registrar and do as per that. So, policy of polling is again left to the implementer and users RFC does not define that. In fact, there are many set of RFCs other RFCs talk about this thing. So, next is the message format. This I have already mentioned, but I am just formally writing that they should not take much time. So, genetic message will be always look like this I am now writing the grammar of that actually it will always consist of start line, optional headers which will be there CRLF carriage return line feed a gap and then you will have the message body which is optional. I think optional is with this and this is a compulsory thing flexible and start line can be either request line or a status line and even when message body is not there this is an optional thing, but CRLF is compulsory start line is compulsory. This is a variable field actually message header they have to be there message body is optional. So, because I know there will be one line this is a variable number of lines the end of the header will be identified by CRLF which is again compulsory thing you cannot identify the end of this number of header fields unless this is there. So, that is why this always has to be present this is an optional thing that is the BNF grammar actually which I am writing now and request line will look now these are two options request line or response line. So, request line will be a method that is a space I have already mentioned this thing earlier, but I am now writing formally then there will be request URI there will be a space single space character and then of course, sieve version line feed sieve version and sorry CRLF you call it carriage return and line feed you will come back to the first thing. So, that is the request line which will be there then this length of the message and all that will not be there after message body the length of the message. Length of the message will be part of the message header it is part of the message header content length that will define how many bytes will be there in the message body. So, if it is 0 there is no message body. So, the methods which are permitted so far I have not talked about all methods. So, all the methods which are there are these which can go in any SIP request. So, one is a register invite we all know what is invite you also know what is act it is not a response remember it is a method in the request in the request line status line is where the ok will come. So, act is not an response act is a request then there is a cancel by options this is for registering the contact information this is used for setting up of your sessions this is for terminating the sessions this is for querying the servers for their capabilities. So, this is S by RFC 3261 for other RFCs also actually specify other methods, but these are the ones which are required by every implementation other things are nothing, but SIP extensions actually the other methods also very variable length variable number of headers it is not one line there can be multiple lines see that is why CRLF is there. So, you identify you know first line is this line you know the CRLF all lines in between them is message header. So, it can be one line it can be 2 it can be 10 it can be 20 nobody stops one of the field always will be content length which will define what is the message body size ok. There is no CRC in this case. There is no CRC that is taken care of by UDP or IP packet or data link control. So, usually if there is going to be noise DLC will take care of that and will do the retransmission. And this is for setting of sessions. Session management if you do reinvite that is also again invite command only, but you with a different parameters. Modification of parameters also and termination everything here this by is for management or you change the parameters of the media ok. So, I close here and then most more of it actually will discuss tomorrow morning.


Hello friends, myself, Professor S.P. Mankani, Assistant Professor, Department of Mechanical Engineering, Walchand Institute of Technology, Solapur. Today we are going to study the reciprocating pump. At the end of this lecture, students will be able to understand the working principle of reciprocating pump and also understand the different types of heads are concerned. If the mechanical energy is converted into a stored mechanical energy or pressure energy by sucking the liquid into a cylinder in which a piston is reciprocating backward and forward which exerts the thrust on the liquid and increases its hydraulic energy or pressure energy in the hydraulic machine will be termed as reciprocating pump. So here the different parts we are going to be studying before going actually the working is concerned. So this is the water level from where we are going to be sucking the water is concerned and this we are going to be calling it as a sump level and this one is a suction pipe and this is the suction wall is concerned. So here this is the piston and cylinder arrangement. This is piston and this is the piston rod and here is the cylinder and this is the connecting rod and this one the crank we are going to be considering this as a crank and this is going to be a rotation is going to be taken place through this one. It is initially as shown here as a theta degree and next further calculation of this total stroke length and other things are concerned not required at this stage is concerned when only we are going to be expected to understand the working principle of this particular reciprocating pump is concerned and this is the delivery pipe and where this is the delivery wall is there.  So means suction head is from this particularly sump level up to the center of this particular piston is concerned we are going to be calling this as a suction head means water is available to pump from a level as this suction head and water is expected to delivery the level at a height of this particularly the over a tank is concerned this is we are going to be taken this as a delivery head. So this particularly we are going to be using in most of the application related as in the water this particularly vehicle servicing centers are concerned where the discharge is required as a less with a higher pressure is concerned. So here in this particularly initially supposed to be the piston and cylinder position is here consider this is a position of the piston at the top dead center and this there is a gap is there this much. So here there is already the space available with this particular as a water is already there just you consider this water is there already here which is at a pressure and now so this side also there is a water is there here this side also there is a water is because it is a they are going to be providing here as a outlet is going to be closed at this particular stage and here this wall is closed. So at this stage whenever this piston is going to start moving in the backward direction means this particularly is going to be rotated in this way is concerned here this particular shaft this is connected with the motor electric motor is connected here and whenever it starts rotation this is going to be coming in this direction when it is coming in this direction means the theta angle is going to be increased when it moving in this direction this is a linkage is going to be pulling this particular connecting rod in this backward direction when it pulling this one and automatically this piston rod is going to be coming in the outside the piston sorry outside the cylinder. So when it is moving in this way is concerned this is a backward direction and this is a forward direction when it is moving in the backward direction so that time whatever the available this water is going to be coming in the backside. So that time this particularly the volume is going to be increased here and because of that it is going to be suction is going to be taken place here because of that one this wall is going to be closed and the same time this wall is going to be opened because the space is available here that time it is going to be opening this way when it is a vacuum is going to be created here because of the suction and that time this water is going to be sucked in the upward direction means whenever this piston is coming up to this particular that is a this particular position this is a when it comes in this particular as a backward direction this is top-date center and this is bottom-date center if it is coming at the bottom-date center so that time this completely cylinder is going to be filled up with the water this completely cylinder is going to be filled up with the water. At the same time this wall is also closed and this wall is also called because it does not move further it does not move further so that time is closed particularly it is coming to be this particular position is closed and this is closed means this having a moment from this particular position up to this particular position. When it reaches this particular position, so that time it is there as a bottom dead center. Now it is so now when it is there at this particular position, so that time here it is this position when it starts moving in this direction means this is going to be rotating further in this direction. So that time this particularly piston is going to be pushed in the inward direction, in the forward direction it is going to be pushing it. When it is pushing it that time this door is this particularly suction wall is going to be automatically closed because the pressure is going to be increased here and this wall is going to be closed. When it pressure is going to be increased that time this wall is going to be opened because whatever available pressure at this particular position in the delivery pipe this is lesser pressure than this particularly whatever pressure is here. And because of that when it pushes that time this particular wall is going to be opened and the water does not have space other than moving in this direction means water is going to be moving in the particular delivery pipe is concerned water is going to move in the delivery pipe. So that delivery pipe through this when it is connected as a outside then the water is going to be at a higher pressure it come out here. So means so whenever this is coming from this particularly bottom dead center up to the top dead center it is nothing but a from this particularly end right side end to this particular as a left side end. So when it comes to this particular position that time almost the water whatever it is there at the higher pressure it is going to be delivered through this particular delivery pipe. So then the pressure inside this pipe is going to be increased then this particular pressure is concerned this wall is going to be closed. This wall that is a delivery wall is going to be closed because pressure is this side is more compared with inside this wall is going to be closed. When it closed so that time it is there as a position of this particular point at that time. This is rotated and it is coming to this particular position. Once again this cycle is going to be repeated by moving this one in this direction means once again the suction is going to be taken place in this way. When suction is going to be taking place in this way once again this wall is going to be opened and this wall opened once again there is a entry of water is going to be taken place through this suction pipe inside the cylinder means this cycle is going to be continued in this way. So like this the reciprocating pump is going to be working. So depending upon the requirement they are going to be using the different types of the pumps are considered. In the previous case we have studied as a centrifugal pump and this is particularly studied in this one as the case of reciprocating pump. So now let me tell me that is the major application of reciprocating pumps are considered. Major application of reciprocating pumps are considered. In general practically where exactly you have seen this particular type of pumps are considered. So this particularly pump you have seen in almost all the service centers where you are going to wash your vehicles are considered either two wheeler or four wheeler where you are going to wash the vehicles. There you are going to be observing this type of the pumps are considered that is a reciprocating pump.  It is the vertical height from the center of the piston of reciprocating pump above the water surface in the tank or the pump from which the water is to be lifted as shown in this particularly figure is considered.  This is from this particularly center of the piston up to this particular delivery. It is a vertical distance from the center of the piston of the reciprocating pump to the delivery wall up to this particular delivery wall. We are going to be calling this as a delivery head and represented as HD. So just you can see the animation of this particularly working principle. Now here the end now suction is going to be started and because of this wall is opened and this is the bluish color I have shown it here it will reach up to this particularly end. So then it comes in this particular last in this direction. So that time this is a higher pressure this wall is going to be outlet wall. This is a delivery pipe and this is a suction pipe. So now once again you can see that is a suction is going to be taken place and reaching at the end side then it is coming in the forward direction. So that time higher pressure and this water is going to be flowing through this outlet suction completely filled up with the water the cylinder is going to be filled up with the water at the end once again it is coming back the forward stroke the water is going to be flowing through the outlet. This is just concept of how the piston and cylinder is going to be working and this is connecting rod and once again there is a crankshaft and all the that is connected to the motor this side.


Hi friends, welcome back to my channel and welcome if you're new here. My name is Jen. I'm a certified weight loss and nutrition coach and I'm on the WW or the Weight Watchers Blue Plan. Happy Friday. It's Friday, so it's weigh-in day. I'm here to share with you my weigh-in results for the week, kind of how my week went. We'll set some goals for next week and of course we'll go over the WW workshop topic. It's actually a pretty darn good one all about tracking. So if you're excited for today's weigh-in video, please give it a big huge thumbs up. It lets me know that you enjoy these weigh-in videos and to keep putting them out every single week and if you're new or you're not yet subscribed to my channel, what are you waiting for? I'd love to have you. Hit the little subscribe button and of course the bell next to it so you're notified whenever new videos are uploaded. Make sure you're checking out the description box down below for my brand new meal planner that was just released a few weeks ago. You guys are absolutely loving it. I'm loving it and we are down to less than 10 on hand. So make sure that you order those before they're gone. Also you'll find my nutrition coaching where I offer personalized macro and calorie calculation. Absolutely essential to losing weight.  It's really important to know where you should fall every single day. If you're looking for a little bit more one-on-one help, I can offer that to you as well in both 30 and 60 minute one-on-one sessions. Just you and I talking about anything that you need help with, we'll set some goals and get you off on the right foot. So definitely check out my nutrition coaching website down in the description box. You'll also find links, discount codes to all of my very favorite things and my Facebook group, another community that would love to have you. So head on over and join us. So let's jump into this week's weigh-in workshop topic and kind of letting you guys know how my last week went and what my goals are moving into the next week. I shared with you in last week's weigh-in. It was my least favorite time of the month. It actually started last Thursday. So I'm just now about a week in. I'm coming to an end of my cycle, which is always, always such a huge blessing. And if you also didn't remember from last week, I shared that I am weighing in every day in the month of February. And let me just tell you how interesting the week of my cycle was. I literally every day was up, up, up, up, maintain, up a little, down a little. It was just a crazy roller coaster ride during the week of my cycle, which is to be expected. I know that I'm going to gain weight like I did last week, the 1.2 pounds. I know that that's coming and I can expect that. But it was interesting to actually see what happens on a daily basis during my cycle. So like I said, I'm doing that the month of February and I'm not sure whether I will continue in the month of March. But I'll definitely let you know next week because that's the last weigh-in of February. I seriously can't believe February is almost over. Who's with me on that? It went super, super fast. So being on my cycle all week was a bit of a challenge. I would say that overall I made good food choices. There was two days during the week that I was above my calories and way over my smart points, which I'm okay with because I use my weeklies every single week. And I generally like to have a high calorie day, as you guys know, once a week as well. Now twice a week, no, but once a week, yes. So I did over-indulge a little bit last week. And I did, though, get in my workout. And my workouts have been excellent. I have been nailing my workouts, feeling so, so good. I'm going three times a week. But my goal in the month of March is to actually go four times a week. So now that I've gotten back in the groove of things, my schedule's gotten a little less crazy.  So I'm excited for that and I'll definitely let you guys know kind of as we get closer to the month of March. So overall, I feel like my week was good. I definitely had 80, 20, 80% good eating, 20%, maybe not the best eating, got in my exercise. So I'm pretty thankful for how last week went. So let's jump into this week's workshop topic, which is how to make tracking work for you. We all know that it's really hard and almost impossible to lose weight without tracking your food. Tracking and weighing and measuring your food are the two things that you have to do to see success on the scale. But there's a lot of people out there, myself included, that tracking gets really boring. And a little bit frustrating and mundane. So we need to talk about how to make tracking work for us when we're struggling to track our food or not tracking our food at all, or even worse yet, not tracking honestly. So WW shared five questions with us that we need to ask ourselves to figure out what our tracking strategy should be. Give it a try for a week once we've answered the questions and see if we get a little bit better or more consistent with our tracking. So question number one, is it easier for you to track your food on the go or to track your food all at once, whether that's at the beginning or the end of the day? Question number two, do you prefer to track before, during or after you've eaten? Question number three, how do you handle smart point values when you don't know the exact value? Question number four, do you save your most used WW meals or foods in the tracker so that you can simply click on them and add them at a glance? Or do you tend to start from scratch each time by searching for the food or creating the recipe? And question number five is what strategies do you lean on? Are you someone that takes pictures of your meals so that you can track them later or do you rely heavily on the barcode scanner? So once you've answered those five questions, let's dive a little bit deeper. We know that studies show that tracking and consistently tracking is the easiest way to see success on the scale.  That's why figuring out what type of tracking works best for you is absolutely essential. If you're someone who prefers to track every little thing, your best plan would most likely be the green plan. If you're someone that wants to track the majority of your food, then you would be great on the blue plan. And if you're someone that has a hard time consistently tracking and you just kind of want to eat the foods that you know are good for you, then the purple plan would probably be your best option. We need to think about what WW plan fits into our life better. Which plan is more on point for us to consistently track? Consistency is way more important than perfection. Based on your answers to those questions, there's two things that we need to figure out. Number one is figure out how you can track. That means snapping photos of your food and then tracking them later.  And then number two, you need to figure out when you're planning on tracking. When in your day works best for you to track your food. That may mean setting aside five to 10 minutes after dinner or first thing in the morning or allowing yourself a couple minutes after every snack or meal to track your food. Now that you've figured out what type of tracking works best for you and maybe what WW plan works best for you, now it's time to set your environment up for success. Have the app on your phone. If you're someone that tracks on paper, have your tools available for you when works best for you to track. Whether that's in the morning, at night, after you snap photos or with every single meal. Just make sure you're setting yourself up for consistency in tracking. And a fun fact for you, did you know that 74% of WW members reported tracking most of the time or always. So they're consistent in their tracking and those are the members that are seeing success. So I think this is a great topic because tracking isn't for everyone. The WW plan isn't for everyone. You have to find the plan that works for you and you have to find the way that you will track consistently. So I think this topic is great because we all know again that tracking is how you lose weight. So now let's talk about this week's weigh-in. If you remember last week, I actually gained 1.2 pounds but again, I was just starting out my cycle which is to be expected. So when I stepped on the scale this morning I'm down 0.8 of that. So I've lost most of the weight that I gained and I'm just rounding out my cycle. So I anticipate that the rest of that will come off in the next couple of days. But fun fact, number two for you in this video is the fact that when I weighed in that last week I saw that like upward movement. When I weighed in Thursday I was down over a pound and when I weighed in today I was also down a little bit. So as my cycle is finishing I'm seeing my weight go down which is something that's important to take note of and that's partially why I chose to track the entire month of February. So if you are someone that's tracking every day right along with me definitely let me know down in the comments. So now I wanna hear from you guys how your week went. What do you think of this WW topic and do you think that you are a consistent tracker?  That's really the key to success. So definitely let me know down in the comments. And if you enjoyed today's video please don't forget to give it a big huge thumbs up and of course if you are new or you're not yet subscribed make sure that you hit the subscribe button and the bell next to it so that you don't miss a single video. I do these weigh-ins every Friday so you definitely don't wanna miss out. Check out the description box for the meal planner, nutrition coaching, links and discount codes to my favorite things and my Facebook group. We definitely love to have you be part of that community. It's a pretty fun Facebook group to be in. Thank you guys so much for spending a little bit of your Friday with me. I hope you have a fan-tastic weekend and I have a really fun grocery haul coming your way tomorrow so I'll see you then. Bye.