Seeing the presence of the forum, I would like to call to order the special meeting of the Amherst Regional School Committee on Thursday, January 21st, 2021. When I call your name, would you please indicate your presence? Mr. Damling. Damling President. Mr. Harrington. Harrington President. Ms. Spitzer. Spitzer President. Ms. Lord. Lord President. Ms. McDonald. McDonald President. Ms. Seager. Seager President. Mr. Sullivan. Sullivan President. And I think that's everybody and stance are present. Ms. McDonald, are you, do you want me to turn the meeting over to Ms. Cunningham or to Dr. Morris or are you ready to take over? I think at this point we will turn it over to our, to Ms. Cunningham, assuming he's here. He is here. This meeting was great. Tiffany, did you have your hand up? I'm sorry, but Ms. Cunningham could call on you. I just want to make sure Ms. Cunningham was able to see that. Thank you. Hi Ms. Tiberdell. Is there something you'd like to state? You might already be ready to talk about it, but I know there was the clarification about the agenda and I wasn't sure that was part of the school committee's road for roll. Yes, sorry. Sorry, thank you for reminding us. Yes, there is a site, the published agenda. If the rest of the regional school committee is okay with this change, we'd like to change it so that instead of having, that we would like to have the bulk of the meeting for the discussion as opposed to the welcome and conversation. Are folks amenable to that? Seeing some tiny nodding heads. Okay, so we will make that change. Thank you, Tiffany. Thank you all for that. So welcome everyone to the third meeting of the school committee and the APEA executive board. Many have expressed their appreciation for the steps that we have taken so far and for the continued commitment to be transparent and collaborative. So once again, before we start, there are norms that we have all abided by in the past two meetings and just going to state them again for this meeting. First norm is that we will assume positive intentions. One person will speak at a time. We will focus on solutions. We will listen in order to understand. And finally, we will accept and expect non closure. So once again, staying on this call shows that you are willing to abide by those norms. Okay, I see everyone has stayed. So with that being said, the district and the APEA has had two discussions so far about the directives that were issued by the school committee to the superintendent. And we have potential dates next week where we will continue to collaborate. And the reason I state that is because the prompt that we ended with last week talked about the things or let me read it directly. Knowing that there are educators, families and various members of the community who are interested in a safe return of staff and students to the APEA. What protections are you asking the district to ensure is in place. And to the school committee, what protections can you currently ensure will be in place. So me stating that the district and the APEA have already started communication is just so that the community understands the transparency that we have started the communication. And that here we're going to talk about the protections that both of you would like to see in place on behalf of our staff and our students. So with that being said, I know that we had ended very quickly once that question was posed. And so I'm going to ask Mcdonald if she can repeat what she had said. If she can remember if she can repeat at least the premise of what the protections are that the school committee is ready to provide. And I'll ask for the APEA to let me know who will be able to respond as Miss McGee is not here today. Thanks for the refresher. I believe that what we what I had started with was in terms of protections. That we as a school committee are committed to all of the protections that we outlined and have settled and agreed to in in our current memorandum of understanding. And our two groups are representatives are bargaining representatives worked really hard over the summer to come to those agreements and we stand by those and fully expect that the district will continue to to uphold those those protections that we've we've described. Thank you. And I'd like someone on behalf of the APEA except for it. Okay, Miss. Thank you. And we were also reassured as the APEA Executive Board, when Ms. McDonald shared last week that the safety protocols currently stated in our memorandum agreement with continue to be followed, even with this possible proposal of voluntary return to in person. And so in those are the protections that we are looking to or feeling our members are saying that they would like to have in place in order to feel like they can have a safe return. Along with that, we, we see the side letters as a way of having them documented in writing to support our members and being protected. In addition, we also know that the staff members that previously the Federal Family Coronavirus Act the FF CRA was extended to March 31, but not sure whether that falls in line with our district. I know you have to opt into it. So any details that you can give us about our district committing to offering that to staff members who may be returning to in person. And then one other question we had was relating to the pool testing and knowing that I think there are like over 300 schools who are hoping to be a part of this program and wondering where the camera stands in terms of whether we had any notification about acceptance or when we should expect to know that. I think I believe that I sort of highlighted the main things that were coming from our members and from our board. With that being said, I would like to still open the floor to any board member from the APA who would like to comment. Ms. Jagadish. You are muted, please unmute unbelievable. So backing up just a little bit in terms of communication. We'd like to have a shared understanding of how communication will happen between school committee and APA and what and how things will be communicated to families in the community. So there's already been. When our staff members heard about the school committee's directive to Dr. Morris. There was a lot of misunderstandings and there continue to be misunderstandings about when and how. So really having a plan of how school committee APA and the district is going to communicate would really be helpful in moving this process forward. And in that collaborative spirit, we really like to issue joint statements with the school committee in the district, but understand that that's not always possible. And if that's not possible to extend the courtesy of sharing with each other before the same time that we share things with the press. And then another really important question we had was, has school committee authorized Dr. Morris can negotiate directly with APA. So there was a directive that was given to Dr. Morris that he should collaborate with us, but it would be helpful to have that clarified whether that is indeed the school committee authorizing Dr. Morris to negotiate with APA. The executive board as Ms. Cunningham stated has already had some positive conversations with the district about how to move forward and we're feeling really good about that. We would really need to know the parameters of that collaboration. And if Dr. Morris can make decisions with us and can move forward without further authorization from the school committee, that would really enable things to move more smoothly and expedite the process. So we would need to know if Dr. Morris is authorized to negotiate in order to be able to collaborate with the superintendent, as was the school committee's charge in their directive. Thank you. Ms. Rhodes. Thank you. I just want to add a little bit to what month one just shared and I think that first of all, we received the nexus reports this week so thank you we really appreciate having those reports and some of our APA members are looking over those now. And I think that, you know, continuing to share any of that information as soon as we have it is really important. I know there's ongoing work being done all the time and any reports that we get are updated reports it would be really beneficial for us to have those as soon as possible, if we can get into the habit of that. In addition, I think that it would be really important for our members to understand what isn't isn't in place right now, as far as safety parameters go. So if things are ongoing or work is being done being really having a really clear system set up so that our members know what rooms are open what rooms are not open. So they know what the contact tracing protocol is if those have changed or any other safety protocols have changed I know that there's a lot of work being done on these things behind the scenes. But just a way for that to be really clearly communicated with all staff through all buildings so everyone's hearing the same messages, I think is really important to our members. And finally we'd love to know what the family responsibilities are going to be under this new program and maybe that's something we're going to work on developing together. It's really important for our members to know what's expected of families who are sending their students in in this first wave of of having students in person over the next month or so. So those are things that I would add that we're looking for. Anyone else from the APA executive board. Okay, seeing as no one has raised their hand, I will turn back to the school committee. There were questions I don't know Allison if you had an opportunity to write down some of the things that were stated but I can just repeat them one by one so that you or Dr Morris may have an opportunity or any school. Hold on one second please. Miss McDonald let me pause just to go back to the APA for a moment. Okay miss Todd. Hi, good evening everybody. So there has been some discussion to on clarification on what's being communicated to the to the community and to families and we want to have a shared understanding of what it's like when we discuss the metrics, what are like what are we actually discussing because metrics are so much broader than just like case numbers. And it's important that you know the community is aware of that and that our, you know, staff members are aware of that and things like that. So, thank you. Did you just want me to know them as Todd's hands were up. Okay, thanks. Okay, so miss McDonald going back to you. I probably will need your help because I was switching devices and so my note taking is not not quite up to par. But I do I did. The first question was about, or at least the first question they noted about what and how will communication happen between the APA, the school committee and the district. And I frankly would love to hear ideas from this assembled group to hear sort of what what you all are thinking would be helpful. I personally find these meetings to be helpful. I don't know if we need to do them on a weekly basis throughout the year. Maybe sort of at certain points in time but I do find these convert open conversations and sharing of ideas and concerns to be really helpful. There could be one one way for communication to go. I also personally have found our emails that you're, you have an email distribution group. And I've, I've found that that our responsiveness and sort of openness within that email has been which has been helpful and supportive and moving this conversation forward so those are just my two ideas but I think that's something that this group is really ideally suited to sort of sharing ideas and sort of coming up with an action plan there. And I don't remember what the other questions were. I'm not going to say that I have 100% of what was said but I will try my best. The FFC RA was extended until March 31. And there was a question as to whether the district will be willing to extend it to the staff. I think that in a couple of the other questions are probably questions that are best dealt with in within the confines of the collaboration with the district. And that's to one of the other questions that I did write down which was because I don't just to say that I'm not trying to defer or deflect I don't know the answer to that. So I would have to ask that question myself of Ms. Conningham and Dr. Morris and maybe they can speak to that but my thought is, in terms of authorizing the district to negotiate. You mentioned that that would help move things along more quickly. That's something that the regional school committee would need to sort of discuss separately. Probably in executive session I'm sort of looking at my expert on this that to make that decision and then officially appoint and agree to authorizing the district to do so on our behalf. We would need an extra meeting to do that and I think several of these items would fall under under that conversation sort of once you know assuming we do empower them to represent and negotiate on our behalf. I feel like a bunch of those would probably fall under that. I don't know Dr. Morris or Ms. Conningham if you have other thoughts on that. Since I'm me doing the facilitating I am going to take off the hat of HR director slash assistant superintendent and just focus on the hat of being the facilitator. So I will leave it to Dr. Morris if he'd like to answer that. Yeah, so I mean obviously I can't speak for the committee. But I think in terms of FFC RA I'd be curious what causes of FFC RA relate to this voluntary approach. And I don't expect you all to have that map that maybe do but I don't expect you to have it on the spot. FFC RA was a wide sweeping piece of legislation so I guess I'd be curious about what aspects of that what provisions of that relate to voluntary return to work that you're looking to be asking for it to be extended. That's it's not it's it's not about school committee and me and who has the authority I think it's just as we get down to it there's plenty of parts of FFC RA that actually, in my opinion, aren't related to a volunteer return to work and, and some perhaps are I think digging in on what aspects of it that the APA is looking for to be extended and how it relates to the current school committee vote. I guess that that would be the kind of data, you know, I would need to then engage in the conversation further. Sorry, long winded. I could have said that quicker. Ms. McDonald, there was also a question about pool testing. I want to know if you or Dr. Morris have an answer to that. I can definitely speak to that one. So we were one of the districts that did apply. As I think it's been shared before we have our by next system up and running. We applied for pool testing I think the thing to note is all of those same with by next their site specifics so I think if we do move forward, it's not like we get in and all the sites are then good. We do expand to multiple sites. We need different people to go undergo training and to get licensed to be able to administer those tests. So there is a bit of a time lag. So right now we're we for by next, for instance, we are cleared for student, you know, a nurse at the high school. The high school is a site that has been approved for by next testing and it's the same kind of process for pool testing. I think as we develop our system and our approach, given the kind of the vote in this collaboration, there's going to be some further applications to state for the not just the test but actually to be licensed to offer those. It's my understanding from our nurse leader is there's that they are site specific and you can only apply for schools that are open. So it would involve some re applications as we go down, but you know the district, you know, did put in its application which gets it in the queue which makes my understanding is makes further applications a little bit easier. The sort of once you're in expanding it is a little easier than being out of it, not hitting a deadline and then asking to get back in. But that application did go in before the deadline if you look at like, I saw a couple articles that listed all the districts that opted to opted to apply we're in that we haven't received any confirmation or more information. It does a conference call tomorrow but I don't think it'll be it's a general one it's not like a specific one for our district so as we get more information we're happy to share it, but I did want to just mention that it is our understanding at the current time and by next time it's like that you get an official certificate from the Department of Health of the state that listed as a site where those those kind of testing to those tests can happen. But applications and we'll see what happens. Thank you. Ms. McDonald it seems like the rest of the questions or thoughts that I have listed basically falls under communication, basically clarifying what's being committed communicated family responsibilities. Having joint statements if possible, if not preview having a preview of what's going to be communicated. And what is in place, as far as safety parameters and how they will be clearly communicated with staff. Also the Nexus and other updated reports that's also under communication. They want the updated reports do you have anything to state or share with that. Yeah, I'm the question about joint statements or sharing sharing comments, or statements, communication that might be going public beforehand. I'm definitely open to that and I do think that there's a there's a valuable role that our two organizations issuing joint statements can really have for the community and for for our schools and families to show that we are coming together on and sharing these statements so you know as as any two groups we will probably disagree on some things and so we can't sort of say that we'll always have joint statements together but I think I can definitely commit to sharing any letters any public statements or public letters that we might be issuing prior to making them public just as as you did over the weekend frankly was sharing the statement I think was over the last weekend it all blurs together. But recently when you shared your statement to the press with with us on the same day so you know at a minimum we can definitely commit to that and I my hope would be that we could come up with a joint statement particularly around the collaboration that is starting for this voluntary return I think that would be a really helpful one for us to sort of aim for. And the other ones I think have more to do with the implementation of that family of the of the in person voluntary return. And I know that we commit to open communication but I think some of those have more to do with the actual implementation of what the plan is so I don't know if I'm in a position to be able to answer those right now. Thank you. The floor is open to anyone who'd like to add something up on either side whether it's the APA Executive Board or the school committee who would like to add to the prompt or just state something that they wanted to share. This is before I move to the next prompt. I think Mr. Sullivan has his hand up. Mr. Sullivan go ahead. Yeah, I'm kind of super confused by the mention of negotiating with the superintendent. I don't understand where that's coming from and it sounds to me almost like it's circumventing the school committee. Are they talking about the actual MOA or are they talking about separate things and the other like the safety protocols. From my understanding this, the district was ready to roll with phase one and phase two by September 29 and if anything by now that we're into January that even be better protocols in place so I'm not quite sure what that was about either. So if I'm hearing you correctly. Ms. McDonald go ahead. Sorry. And my understanding and maybe I misunderstood was that when we were talking about sort of authorizing a superintendent and the district to to sort of work on our behalf it was not related to the MOA but to the side letters for the voluntary return. So, is that did I misunderstand note that's correct. Okay. So, does that answer your question Mr. Sullivan. Okay. Thank you Ms. McDonald. And with her answering I don't have to. All right, so the question that I have or the prompt. I want both sides to just let teachers know those who would like to voluntarily return. What, what do you want them to know from each of each of you. So from the AP a what do you want teachers who are going to volunteer to know that you are doing on their behalf. What would you like teachers to know or anyone who's volunteering to return to know what you are going to do on their behalf. We have teachers who are coming back. Ms. Jagadish. So I think if I'm under, I mean, this might not exactly be an answer to your prompt, but I think what teachers really need to know and what teachers I think need the community to know is. So especially for primary school teachers, we take parents are sending their children to us and expecting us to keep their children safe. And that's something that is true, you know, outside of the pandemic that we're in right now. Primary school teachers make sure that when we're on the playground, the games that are being played the interactions that are happening between students, we take that responsibility very seriously of keeping children safe and parents trust us with that safety. So teachers really need to know and feel that they can do that. And a lot is involved in being able to do that. So, Mr. Sullivan asked that question about the safety protocols being in place that so from our point of view and we've been working with the district on this and JLMC SC is working on this. There are still a lot of safety protocols that are not sufficiently in place for many teachers to feel that they can take on this charge of keeping the children safe. So it isn't just about the level of risk that that an individual teacher may be able to accept in in order to be able to come in person under the, you know, with the case numbers that the way that they are, but it's also teachers being able to feel like they can keep the children safe. Thank you. Ms. Rhodes. I just want to take on a slightly different angle than Mongolia's I really appreciate your response Mongolia. But I want to speak to how, especially the APA exact board can support teachers who are thinking about going in voluntarily to the school. And I think that we are here to do what is asked of us by our members so our members tell us what they would like and that's what we work towards. So we're here to support teachers who are feeling comfortable going in voluntarily and helping them ensure that they have everything they need to feel safe and supported while being in person. We're here to support our teachers who need to stay remote and we're here to provide everything they need and are asking us to do to help them feel safe and supported while working remotely, whether that's job security or whether that is the impact of making that really hard decision to stay remote when there's a choice to go in voluntarily and what that does emotionally for teachers who are making that choice. So really that is our role as the is the exact word to get all the information we can from our members and then work with the district to help our teachers teach the best they can by providing them with those safeties and securities. Thank you. Mr. Demling. Yeah, I'd say so two things from the prompt of what what I want teachers who are considering volunteering to know. One is that. And the school committee discussed this a lot when we made the motion, but there's total respect for teacher autonomy when it comes to the, the, the, this is a, this is a choice. It's an opportunity with and that we should not be pressuring. You know, the, there should be no school committee member or district member or public or teacher anybody who is pressuring one way or the other and that, you know, you know, we're committed as public figures to, to modeling that. You know, as, yes, it's obviously true that the school committee has been asking to change the MOA for a while but the legal reality is that we have an MOA in place and that has metrics and it does not require staff to be back right now. And so that's a complete legal right that I completely respect and that the school committee completely honors and respects and that this when we say volunteer, we mean, you know, voluntary, you know, and I think that's a big. That that's a really important point that I don't think we can make enough because I've lived in communities where it's gotten pretty nasty between, you know, unions and management before and it doesn't have a great lasting effect on the community. You know, so I think I think that's, that's important. The other thing is, you know, I heard someone mentioned before about the safety protocols and wanted to make, you know, what what what a what are they and then be are they sufficiently in place I think a commitment. Certainly I have on school committee is that if we've committed to safety protocols that are there in the MOA that are not changed. If they're not sufficiently in place, you know, the school committee wants to know about it. It's like, we, we expect the, the superintendent and the district to be implementing what we've agreed to. And so if, if, as, and, you know, school committee obviously isn't on the ground, right, we're not in the buildings to be able to say exactly how these things are, are, are not being met. And so, you know, part of that the JLMC is part is part of that but I think also, you know, part of that maybe more open communication is, is letting the school committee know, hey, you know, if, if you're particularly concerned about some aspects that we've already agreed to right that we are obligated to implement that's not being met then we want to know about that so we can bring it up superintendent and he can get on it. So I think I think that's, it's, it gets really about assuring staff that we're committed to what we've already committed to, right, which is the MOA that does not require you to go in right now. And, and it includes a number of safety protocols and, and whatnot that that we expect to be fully and completely implemented. Thank you. The floor remains open for anyone who would like to speak. Yeah, I think I'd like to sort of restate what I'm hearing several folks say is, is this sense of you, you asked the question about teachers who are volunteering and I, and I think in terms, I think it's also who are not volunteering and as you know, we're choosing, as Ms. Rhodes said, making the really hard decision in some cases emotional decision to, to remain remote and to know that whatever the decision is of any individual teacher or educator that that we support that. And, and that that was the point of asking for a voluntary return was that it's really, it's, it really should be voluntary instructional situation, because it's, you know, we're, we're opening up another opportunity but the choice is in front of the individual to make to choose either remote or in person. And I think, so I just really want that was came up in our committee conversations that I absolutely believe that myself and know that the others my colleagues do too that we respect all decisions. And, and that for those who do opt to be in the building with students that a we want to make sure that the protections that we've documented and settled in our in our MOA are being implemented and are working. And, you know, to help everybody feel safe. And if they're not then use our avenues of communication whether it's the JLMSC or other avenues to to reflect that so that it's the communication is continuing. And if something isn't happening, you know, sort of like the norms that we have here don't, you know, assume best intent. Because we've never been in a pandemic before. And so I think, you know, it's, it's, there's a little bit of ingenuity and innovation that will need to happen, even once, even once where they are and sort of keeping that this communication going I think is super helpful. Thank you. This question is going to be posed to only the APA exec board. And I know it may be tough to respond to, but the question is, why go the route of side letters instead of reopening the MOA. Like what. Why would we do side letters instead of reopening MOAs. Sure. So, you know, we've had this conversation a lot with our membership. When we are surveying or speaking to our membership, we have, like we said, we've yet to get a mandate to reopen the MOA. And we dig deeper into the feelings around what people are willing or thinking about is important to have changed. We do get a lot more consensus. So that's where our side letters of intensive needs and preschool came from, because the consensus was there that these students need in person learning now and how can we get that for them now. When our membership in our membership, we've shared is split on this. There's, there's a lot of feelings about this. Most of the talk of reopening the MOA goes back to the metrics conversation. And I think that that's what we've been hearing and we might not be hearing fully. So we are really open to the school committee telling us that there are other areas of the MOA that they're looking to be talking about and renegotiating. And what we've been hearing is it's really around that number around that metric and at this time our membership has not told us that that's something there that we're willing to reopen the MOA around. We continue to want to move forward. And I think the membership is an agreement on that. The areas that we want to move forward is really addressing the needs of our students for not accessing remote learning in a way that is working for them or their families. And that's really what we're hearing from our members. And that isn't something that was written into the MOA because we weren't really anticipating that as we were writing the MOA. So the areas where we're looking to move forward and change and really help our students and their families are things that are outside of the MOA. And we're continuing when we ask our membership around renegotiating the MOA to hear that they're not ready to do that. Thank you Ms. Rose for responding to that. I know that was a very difficult question. I know that your response will help many in the community to understand the difference between the MOA and the side letter. So thank you again for responding. Yeah, I know in conversation yesterday there were some things that was brought up to say that there were some miscommunication and that there were some who thought that the superintendent was directed to start and possibly open schools beginning February 1st. I know the APEA wanted an opportunity to say something regarding that and possibly Dr. Morris if I'm correct. So we will turn the floor over to anyone who is willing to respond and raise their hand. I think I can try and Tiffany anyone who because we talked about this yesterday. If I'm getting something wrong just let me know. But I think what I heard yesterday was that there were a lot of rumors out there for some reason February 8 was a date that people believed that this option you know the voluntary program would start. I want to be really clear that I've never said that date my administrative team have never said that date it came as a huge surprise to me. I think the school committee. I'm pretty confident intentionally left that as the month of February because they understood that there was going to be a tremendous amount of logistics. And they would be entailed in voluntary program or voluntary in person program both in terms of staff who want to return but also students. Right. So there's a lot of people we have to get lots of opinions about and then match our capacity to have seats with people who want them in the school. There's not been a date established and I think one of the other parts of that vote was that a directive to collaborate with a PA and as was mentioned earlier we've had two meetings and I think we're making substantial progress. Appreciate the collaboration with the executive board. But just to be really clear February 8 is not a date that I uttered until tonight because I heard it yesterday. And I think when we are able to establish specific dates will certainly communicate them out. There was conversation before about joint statement I think that's a really good one to have that if we can kind of understand best how to survey family survey staff survey families and do the matching you know if you hear a date before you hear it from me or from us. Please know that it's not a real date and then when we have that date established will be communicating that out all together and not piecemeal so I think you know I appreciate that. Sometimes rumors get to me sometimes they don't this one had not so I appreciate it being shared with me and just the opportunity to clarify that for anyone who's watching. And if I missed the detail you know anyone please jump in. And for the exact board is there anything else that you want to clarify it on this call. Miss dancer. Um, so we had this this is the third meeting with screwed together. Am I hearing that. Other meetings are going on to talk about the side letters. Um, somebody said something about progress being made with the superintendent so I'm just a little vague on. Details you know we're not talking about any details in this like you know what are the specific things that maybe aren't being met safety wise and you can't fix them if you don't know what they are so. What what's happening besides just these meetings if anything. Dr Morris. Yeah, so a lot of those go through as per the MOA go to the JLMC. So, as I think has been talked about before there's a JLMC that is a small group meeting. And because some issues come up that are confidential. And then there's a larger group meeting and like last week I understand Mr Harrington that that couple protocol issues came up that will be talked about in their next meeting. So that'd be the place I think in terms of meetings that Miss Cunningham or sorties myself have had with the executive board. A lot of them are, and this is pretty typical or just routine meetings that we try to have because issues accumulate, you know, and they're not necessarily just issues about an MOA or issues about COVID related challenges just, you know that we're trying to reestablish strong issues. Now, truth be told, we're in a context where a lot of the issues do relate to those but typical, you know, and Miss Cunningham leads, you know routinely over the years that I've worked with her joint labor management meetings. So, you know, at no point was we're talking about the MOA or anything that would be school committee specific information but it is an opportunity to share and work on any protocols that come up or any feedback but JLMC is the primary issue for discussions about protocols and the way that was described before. Does that help Miss Dancer. It does on this. I'm sorry, Miss Cunningham should I wait. Okay, go ahead Miss Dancer. Thank you. Sure. I understand about the JLS MC, but how, how is the actual, how are things actually going to move forward. You know, I don't, that's what I'm wondering about. I'm just going to talk how, how are things going to start to happen. Are they going to be in these meetings are they going to be in other meetings, because I feel like we're spending a lot of time talking about important things but we're not talking about happening. Dr. Morris. Oh, I saw actually. Yeah, her hand was up before mine so. Well, I'm probably going to say the same thing that you were going to say. So, when I mean school committee is going to meet to, to talk about whether they can authorize Dr. Morris to negotiate directly with a PA. So that would be a first step. Dr. Morris and the executive board have already spoken about what first steps would be in order to move forward with a voluntary program so first step would be surveying staff and we were going to work together to do a survey for staff to see what kind of students we would have to work with in terms of building a bond building a program and what students we would be able to offer something to and then we would need to reach out to families and work on how we could match up the staff who we have with the students with the students who we could learning to. So those are the first two steps that we would be taking together and through that process if we get authorization from school committee, we would be able to write side letters to kind of put all of this in writing of, of what would be expected of staff members who were who were able to assume the risk of in person instruction and maybe Dr. Morris can go from there. I guess that's as far as we've gotten in terms of thinking how this would move forward. Okay. Thank you. Dr. Morris, I'm going to have Mr. Demling go before you. Go ahead, Mr. Demling. Yeah, I mean, I just want to say briefly, I mean, go back to the language of the motion. The school committee directs the superintendent to develop and implement a plan and then describes what the plan is and then to work closely in collaboration with APA leadership. So this is, this is a, so we mentioned this at the committee being as well. This is a huge ask of the superintendent, right? We didn't, this wasn't the school committee saying here's how it's going to go and then just, you know, fill in the details. It's, it's not just implementing the plan, it's developing the plan as well. And so Dr. Morris has a tremendous amount of work to do to lead this effort. And so, you know, if like in terms of like negotiation negotiating, you know, I'm not, I can't say like how that affects contracts and whatnot, but I would, my expectation would be that working closely in collaboration with APA means don't waste any time now. And I imagine Dr. Morris feel the same way, but, you know, you have a lot to do and the example that was brought up just brought up about surveys that's that's perfect example there's a detail, one of many details right that's going to have to get settled. And so, you know, but that, at least in my sense of the motion, it's, you know, sort of has given the superintendent sort of broad direction to go forth and implement and, and don't waste time in developing the plan. I don't know if you've received it in the same sense, Dr. Morris. Yeah, we have six minutes, and we, we have many people who may want to respond. Go ahead, Dr. Morris. Yeah, and we do need actually Amherst media is letting me know that you need a minute or two gap between this meeting and then the joint meeting that happened that follows it so I can try to get that one set up. But it, I think we probably ending it at the latest 630, if not a minute or two earlier would help Amherst media. I have nothing more to add on this part other than I agree with what Ms. Jack said, that's exactly what it would have said she was she was right at the beginning of her statement. Mr. Goodies, excuse me, and then I agree with what Mr. Deming said as well. That I think if we're going to, if we're going to do this, we have to do it, you know, relatively aggressively in terms of a timeline I mean aggressively in terms of the approach, terms of safety but aggressively, in terms of the timeline to meet the school committee expectations and I'll be giving an update at the school committee meeting in a couple minutes during superintendent update about. I'll be basically restating probably less well what Ms. Jagadish shared here, just about our meeting and, and the collaboration and some of the next steps we're taking we're planning on taking. Thank you, Ms. Rhodes. I just want to ask the clarifying point Mr. Deming around what you just said. So I think that, you know, we have the same expectation as, you know, moving quickly and and really trying to get into this work because we do know it's a lot of work ahead and talking to Dr. Morris about the collaborative process we know it's going to take a lot of time and effort to do that and we want to do this for our members who are looking to go back voluntarily I think the piece that we were trying to state with the negotiations and the side letters is that we also want to ensure just as we did with the preschool and the intensive needs that it's written in a side letter what you're stating you're willing to do which is keep the protections of the MOA while we're implementing that and I think that's all we're looking for just to clarify in on that point. Thank you. And just through this meeting, many of these intentions have been stated to the commit community. And so, you know, putting them in writing is going to just solidify that these are what we have committed to, and plan to do for the rest of the 2021 school year. So, with four minutes remaining, I know that there's a lot of questions still like what would you like the community to know, you know, things like that, moving forward, what our timelines may be, how soon will we have a timeline how soon will we have something to share with the community, you know, things like that are questions that are going through the heads of many out there many teachers many staff many family members. I don't have the time today to do this, or talk about it but I do know that Miss McDonald had talked about one of her thoughts that she put out there was to have a way that we can communicate. You mentioned possibly weekly transparency meetings, and I'm not saying that that's what we're going to do I'm just saying it was something that you had, you know, touched on. And so, Miss McDonald is there something that you can share with the community because I'm sure they'd like to know today was the third meeting what should they expect next. And if you can share that I'm going to turn the meeting back over to you with three minutes remaining so that you can respond to that and possibly close out the meeting. Thank you, Miss Cunningham and thank you for your expert facilitation yet again, really, really deeply appreciative of your, your willingness to do that and help us out through this. This is, it's been great. You know, in the interest of time, I might suggest and the regional school committee can sort of address this in our, in our next regular meeting when we talk about future agenda planning but I might suggest that I coordinate with, with the APA executive board to sort of plan two things. A communication plan sort of a joint communication I think I'm sensing just from the, from the head nods going around that there's an interest in, in planning a joint statement and communication to the community about the work that the collaborative work that's that's beginning on this voluntary return. And then maybe get some ideas from, from the executive board APA group on sort of future meetings like this or similar to this frequency and sort of what our desire is there that then we can sort of take that back with the with the regional school committee just instead of talking about it right now our folks okay with that. Great. So, I will move to adjourn the regional school committee. Second. Move by McDonald and second by stancer and it's a roll call vote Mr. Demlin. I miss stancer. Stancer I miss Spitzer. Spitzer I. Mr. Sullivan. Miss Lord. Lord I. Mr. Harrington. Harrington I. Ms. Seeger. Seeger I. Mr. Sullivan. I'm McDonald I did I did I get your vote, Mr. Demlin? The region is adjourned.


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So where We introduce communication systems very simple concepts in the first lecture. What is a communication system what? That we want to get information from one point to another that's communication and now we're trying to characterize How could we measure how good a communication system works? So our aim is to get information from one Location to another data communications what we looked at towards the end of the previous lecture was different types of information quite simply we looked at some examples of Okay, how big is a web page? How big is a song or a movie and we did a few calculations to finish to to give an idea of Typical sizes of information we want to transfer Towards the end of this topic. We'll try and say well If we want to transfer a movie Photo a web page from one entity one entity to another What does the user require in terms of performance? That's what we'll get to at the end of this topic Which one was biggest those that were here last lecture of those examples, which one was the biggest and remember The movie we did some calculations of an example movie and it turned out that the movie a two-hour movie was about 10 gigabytes nine gigabytes of actually video one and a half gigabytes of audio Let's keep going Sometimes the types of information we we group together sometimes we talk about audio voice calls Radio streaming as example other times video Which usually includes audio someone talks about a video application? It usually means that the the picture and as well as the audio so video conferencing video streams and Other applications or other information types Sometimes just referred to as data Data is a bit confusing sometimes data the word refers to all or any type of information Other times it refers to specific non audio non video types. We'll try and avoid that confusion But there are many applications In the data classification What we want to get to we'll start with today is How do how do we know if a communication system is good or effective? and the three basic measures delivery accuracy and timeliness Okay, a good or an effective communication system will have all three of these as We go through the topic today. We'll see some more details of each of them, especially the last two They're quite simple Delivery means that the data that we send from one point to another should get to the correct destination Remember we want to get information from a to be a sends the data our communication system Whether it's a single link or or the entire internet should get that data To the correct destination be in this case. That's almost obvious that case Accuracy is to say that if a sends data to be Assuming it's delivered to be that the data that is received by be is an accurate representation of what a sent a has some data to send to be they send it what be received should be the same or More generally an accurate representation will look look in some cases. It doesn't have to be identical Okay, so some measure of accuracy Timeliness is that a sends data to be a sends the data now Be should receive that within some reasonable time You shouldn't be delayed too much and we'll talk about how much is too much as we go through these slides an example You need to submit an assignment tomorrow For this course deadline is 5 p.m. Tomorrow, and you need to email it to me. Okay, I'm Getting old and I mainly use email for communications. So you need to email me the assignment By 5 p.m. Tomorrow if you don't email by the deadline then you get zero for the assignment so tomorrow you Do the assignment? Don't worry. This is just an example. There's no assignment Tomorrow you do the assignment and you Finished you've got the answer and you're typing up the email and send me the email Okay, so in there when you compose the email you say to address to Steve at SIT dot tu ac dot th. That's my email address And you type in the message and the answer and you press send now delivery is saying well What happens if when you press send For some reason that email message goes to dr. Tanarak It goes to his email box, but not mine What's your problem? You get zero for your assignment your problem is because I don't receive the assignment by the deadline therefore This has been ineffective communications the communications is sending me an email But if for some reason the system delivers the email to someone else That's ineffective communications. That's all why would it deliver to someone else? Maybe there's an error in the setup of One part of the communication system So that's delivery if we send to some destination it must be delivered to that destination Otherwise, it's ineffective accuracy You compose the email and in the email you must include the answer for the assignment and You type in the nice email. Here's my answer to the assignment. The answer is 42 that's the answer and you press send and you send the email and It's delivered across the internet arrives at my email inbox and the text says here's the answer the answer is 43 The received message is different from the sent message again. You fail because you gave me the wrong answer So if for some reason the data received is different from what was sent Because of usually a failure in the communication system then it's ineffective communications So accuracy is making sure that what's received is Accurate from the receivers perspective Sometimes it needs to be identical in the case of the email. It should be identical if you compose an email and press send The email I receive should be identical to what you typed in If not, it's not a very good email delivery system But in some cases we'll see it doesn't have to be 100% Timeliness you send the email tomorrow at 4 p.m. The deadlines 5 p.m The internet delays this email and it arrives in my email inbox at 6 p.m. You get zero again. Okay, so The communication system must deliver the data in a timely manner in within reasonable time What's reasonable for an email anyone From when you press send and to when someone receives the email, what do you think is a reasonable time? How long should they wait? Yeah, it depends on size, but how long would you wait? Yeah Two seconds a few seconds maybe Okay Maybe an easier one Let's say you're using Some instant messaging application old days MSN line or similar where you type a message Press enter the other person sees it and they immediately respond or immediately What's the time? What's reasonable time from when you press enter until when the other person receives the message? At most ten seconds, okay, what if it was one hour? You're using line you press enter and they receive it one hour later in effective communications one second, okay Milliseconds, okay, so Different applications will have different requirements of what timeliness is good Similar what accuracy is good towards the end of these slides will give some more examples of them So that general measures of what is effective data communications We're going to have some more specific measures in a moment, but before that what of what is this? again, sometimes applications that transfer information are classified by different names or different groups in In terms of the internet applications we use in the internet Sometimes we refer to traditional or normal internet-based applications and And other types being multimedia or real-time applications some examples Internet-based file downloads email web browsing instant messaging Sometimes remote logging connect to another computer databases In these types of applications accuracy is usually most important again Yes, you type in an email you press send The data received should be identical to what was sent accuracy should be 100% you Visit a website, which is really downloading a web page from a server to your browser The web page that your browser gets should be the same as what was on the server The accuracy should be 100% with multi-media or real-time applications like audio or video streaming watching YouTube Maybe more so Interactive applications like voice or video calls Skype or similar gaming Collaborative desktop sharing applications in those applications Timeliness isn't usually more important You are talking using Skype or similar using your computer or phone From when you say something on your device Until when the other person receives the audio representing what you said the delay should be quite small Otherwise if the delay is in the order of a few seconds you speak and Then there's a delay before they receive it and while they're waiting for to receive and hear you speak they start speaking and you start to overlap in your talking and Most studies show that delays in the order of several hundred milliseconds is usually desired gaming if you play online games you Multiplayer games for example you see the screen where you see other players which are nearby And you press the button to shoot someone else Then from their perspective the other player they should get feedback of what happened almost immediately If there's a large delay from when you do something until when they see something the game will not work very well People talk about a lag in the game That's too much delay or not timeless timeless delivery Email web browsing can usually tolerate more Delay or less timeliness delivery than these applications Whereas these applications and we'll get to it later can tolerate some less or lower accuracy when you're Streaming a video you're watching a video on YouTube There's a video on the YouTube web server and They send it to you to your browser and the browser displays the video If you don't receive 100% of the video you can still play it back and watch the video What may happen is that you start to see some small artifacts in that in the video on your screen that is You're watching the video. It's high resolution high quality But some of the data doesn't get received by a browser most video Formats and players are smart enough to handle less than 100% accuracy of the data delivery that is Imagine you send in the server sending the video some of the data sent doesn't get to your browser in That case what happens? Well, maybe some of the pixels in the video are not displayed correctly on your browser but if a few pixels out of Five million pixels are not displayed correctly for a fraction of a second then you usually don't notice that So and we'll see some more examples of this as we go through through this lecture and even the course With multi-media applications accuracy Doesn't have to be 100% sometimes the data received doesn't have to be the same as what we send What about delivery? Three measures delivery accuracy time limit us delivery in both cases needs to be correct Delivery is usually you have it or don't We both both cases need correct delivery Let's move forward so we can get some examples so our Three effective measures of communication are quite general delivery. Yes, or no, we have it But accuracy what how do we measure accuracy? How do we measure timeliness and how do we measure other aspects of communication systems? We'll talk about performance metrics Ways to measure the performance of a communication system So a metric and we'll go through some example metrics some common ones that you probably already know about There are others, but we'll go through ones which I think most of you will know or have seen in some examples We use metrics So a metric is a way to measure the performance of a communication system We'll look at different metrics Why do we use them? How do we use them? Sometimes we want to measure the performance of real systems. We build a communication system. How does it perform? So we use metrics to compare to see how it performs Well, sometimes I want to predict or estimate what the performance will be of a new system So we use metric metrics to do that so you get a job and your job is to Choose the communication system for your company For a particular purpose. You need to choose a technology and one way you do it is compare based upon some of these metrics Other things will be cost and other factors. We represent the different metrics usually using different statistics But let's come back to them as we after we go through a few of the metrics themselves I'm about to show you on the following slide some example metrics, but there are others Some of the others will see during the later lectures Let's go direct into the simpler ones Data rate is a common thing that we will refer to and we'll see When you need to select a particular communication technology. I'll try and give a simple definition of these metrics Maybe some other names which you may have heard of which mean the same thing or a similar thing and some examples By data rate, I mean the rate at which the data the information is delivered from one point to another So it's a rate think of a speed Data we will normally measure in bits bits or bytes If I use bits you can easily convert the bytes vice versa So the data rate will use as a base unit as bits per second How many bits per second can we get from one point to another? I didn't bring my land cards today, but those that were here in the last lecture. Remember the old land cards My land card in my old computer at least and the ones that I had last week could send the technology Built into those land cards could send 100 million bits every second So when you buy the land card, that's a characteristic of that hardware That it transmits at a maximum speed of 100 million bits every second quite simply The data rate would say is 100 megabits per second So it's a measure of how fast our device can send our data our bits Can anyone remember or know the data rate if I send wirelessly from my laptop to the access point on the wall? No, I want to have a guess Maybe check on your phone It may even tell you the data rate when you connect to a Wi-Fi access point. You want to know the typical values How fast can I send that access point on the wall? What's the data rate? It's an old one if you can't see it. Is that the answer? Okay, anyone want to make a guess 100 100 watt megabytes per second All right my The typical speed that you get when you plug the LAN cable into your computer is either 100 megabits per second Or if you're lucky 1,000 megabits per second Typical depending on where you are and how old your device is Do you think Wi-Fi is slower or faster than wired LAN? Hands up for faster Good good hands up for slower Wi-Fi is slower than wired generally Okay, that's not always true, but generally this the similar Type or cost of technology wireless is slower than wired This old ish access point supports a data rate of a maximum 54 million bits per second 54 megabits per second my old wired LAN 100 megabits per second wireless 54 about half But newer ones can support faster Up to several hundred megabits per second Similar that newer LAN cards can support one gigabit per second 1,000 megabits per second They are the What we call the data rate the rate which we can send bits across a link normally Anyone know of some other examples who has home Internet in their dorm not wireless, but ADSL or cable anyone Anyone who's used it before Has anyone used the internet before just just check if people have pans they can put up Sure, you've not used the internet Okay, it'll be hard subject Okay, if maybe if you've used home ADSL Okay, or your parents or your friends have ADSL ADSL is a technology for Commonly used for internet access inside homes Where you use the telephone line? The data rates which the modem supports usually in the order of several megabits per second The maximum around here is around 24 megabits per second For example at home I have a plan that I pay I don't know 600 baht per month and The data rate at which I can download is a maximum of 10 megabits per second Upload may be different anyone have cable cable internet and how fast 10 Usually you you pay for faster as as normal you but generally cable can go faster But you need to pay more Any people from outside of Thailand here and he maybe have different technologies or different speeds How fast is home or internet in the dorm or in an apartment? examples Ten around ten megabits per second Yeah, okay, so in the order that's around the tens of or few to tens of megabits per second, okay let's look at Some other examples of technologies that you may have come across and I'll use Where I just grabbed some or go to Wikipedia and I'll just grab a few examples of different technologies This is the list of device bit rates Another name. I will call it a data rate, but sometimes called a bit rate Some of them you'll know of Before we go to it who uses internet on their phone Okay Not Wi-Fi, but what 3g how fast 3g 42 what Mega bits usually not always the case, but usually data rates are measured in bits per second not bytes the B means bits You buy a hard drive and it's usually measured in bytes you buy an internet connection or you pay for it It's usually the B means bits per second. Okay, not always but common. So some 3g or three and a half g why wireless mobile phone data rates are in the order of 42 megabits per second 14 megabits per second was an older one, but again you may pay The faster the speed the more you pay Let's find a few this is a quite a large web page with many different examples. I'll just go to If you can't see it You can have a look in your own time. Just Who did their homework? You still got some time to do the homework the homework is simple from last week visit the website log in and Make sure you're aware of how to use the website and even try one of the practice lessons there The first practice lesson talks about bits bytes megabits megabytes giga and so on the different prefixes and different units that we come and commonly come across and These numbers are an example and Just quickly see the the lesson to get further explanation, but when I say mega I mean 1 million as here One followed by six zeros mega one million in some forms of computing We use binary prefixes For example kilobyte is not one thousand, but one thousand and twenty four When you talk about hard disks and file sizes often One thousand and twenty four is meant by kilo, but I will not use that in this course It's much easier for me to calculate in terms of thousands millions and billions To see that explained see that try the lesson Let's go through These are old ones remember old-style modem how fast Dial-up modem the strange noise modem Sorry, there's a lot of information here. I'll just select a few of them the typical speeds the normal speeds For the dial-up modem Around 56 kilobits per second If you had that dial-up internet access 56 kilobits per second 56,000 bits per second some other ADSL to There are different variations of ADSL for home internet access ADSL Maximum speed because it can be lower than this 24,000 kilobits per second or 24 megabits per second That's download when you download from say the internet to your home Upload is limited to about three and a half megabits per second. So there's different speeds up and down Cable modem if you have cable internet access a common one around here is What's called doxis version 2? 38 megabits per second down 27 megabits per second up There's in fact a doxis version 3 which goes up to 160 megabits per second down So doxis or cable modem and ADSL are commonly used for home internet access or business internet access Many other technologies there. Let's just skip through to a few that we may You may know mobile phones many different ones here Edge maybe before 3g you may have been using edge which Was the order of hundreds of kilobits per second internet access to your mobile phone? 3g There are different technologies here's one HSPA Three and a half g listed here 14 megabits per second So just some examples of data rates of different technologies And there are extensions up to 42 megabits per second for for 3g sorry control and Some of the later Mobile phone internet technologies go up to 300 megabits per second 4g or LTE is sometimes the name What about for example, so that are the things that we may use mobile phones home internet Wi-Fi is listed here. We'll see it later, but we'll see some different ones What about that companies may use to connect between officers between cities? What about when we connect say from Bangkok to Singapore for the international internet access? How fast do you think? Let's see some examples. These are connecting between cities or between countries sometimes we refer to as wide area networks a Network across a wide area The older technologies with the order of one two megabits per second still around some of them We go down OC means optical carrier which is referring to optical fiber and the different Standards of optical fiber common ones OC 192 10 gigabits per second. Okay, so International links commonly using optical fiber in the order of tens of giga 10 gigabits per second and Up to maybe 160 gigabits per second for latest technologies. That's enough for them Lands inside an office or a home Where do we get to and down the bottom? I hope wireless lands this Wireless access point is 802.11 g 54 megabits per second But newer ones go up to 11 n 600 megabits per second and the latest Technology released is AC up to seven gigabits per second under under very special conditions Have a look through there just to get some examples of different data rates sometimes called Bit rate the rate at which bits are sent across a link Capacity that is how much what's the maximum we can send across a link What's the capacity of the link and we'll see a few others that may come up in the later lectures? similar names for data rate delay another metric this comes back to our timeliness measure The time it takes to get data from one point to another Also called latency The latency is equivalent to delay Delay we usually mean to get from one point to another but sometimes we're interested in to get from one point to another and then back Okay, to get there and back to get there and back is called the response time or sometimes the round-trip time Response time send a request get a response. What's the total delay round-trip time time to get there and Back make a trip all the way around measured in seconds Two quick examples I send an email at 10 a.m Press send it arrives at the destination at 10.03 the delay is three minutes The email delay is three minutes I'm web browsing. I click on a link at Time 1.4 seconds. Okay, if I start the clock then and And at time 2.6 seconds so 1.2 seconds later I receive the web page displayed on my web on my browser Then we'd say the response time is 1.2 seconds Because we covered in the first lecture web browsing is you send a request to a server for a web page The server sends back a reply a response So how long does it take from when you send the request? Until you get the response That's the response time in this case. I send the request at time 1.4 I get the response at time 2.6. So the response time is 1.2 seconds the difference between as anyone Come across delay latency a response time or round-trip time in any other applications Does anyone ever played an online game? Maybe a multiplayer game you may have heard of ping time The time it's some measure used to to measure how good the network is to play that game because again You want a quick response time the ping time is really a measure of round-trip time Time to get to some destination and back maybe to a server and back We will look at some more detail of how how do you calculate delay or what contributes to delay? There's a few slides later for that one. What else? Error rate Something you may not have seen so much but now a measure of accuracy our two general measures of Timeliness and accuracy timeliness we can measure by delay accuracy by error rate sometimes I Send data from A to B B doesn't receive all of the data How much didn't it receive? Well, we can talk about well the data not received That means it's an error. It wasn't delivered What rate of errors do we have out of the total being sent? So error rate I'll define as the fraction of data sent That doesn't get delivered to the destination We want it to be low Sometimes it's the bit error rate. I send a Thousand bits across a link on average 23 bits arrive, but they don't they're in error What does it mean if a bit is in error? I transmit a bit one I Transmit a bit one it arrives at the destination as a bit zero That's a bit error When I transmit a bit one when it arrives at the destination the destination should interpret it as a one That's successful delivery if it arrives is the opposite bit and it's an error So if for example, I have a link where I send a thousand bits and on average 23 of those bits arrive in error They arrive But they are wrong and we could say the bit error rate is 23 divided by 1000 23 out of a thousand or 2.3 percent or as a fraction zero point or a decimal 0.023 There are no units here. It's a ratio or More generally I send an email to all 100 students in a group Something goes wrong. Five students don't receive the email. I can say there's an error rate of 0.05 five out of 100 Or five percent We'd like the error rate generally to be low Okay, we're getting into some newer ones here that you may not have come across But I think not too hard to understand Actually before we go let's go back a step and look at some examples of delay How do we measure delay in a computer network does anyone measure the delay before now Play a game and then Specifically in that game. What's the term on or what's the thing that measures the delay? lag is sometimes used another name you may see is Ping okay ping refers to actually an application the concept of peeing something is at least in computer networking is send a message to see if it's there and That entity will tell you It's there by saying a response if you get a response, you know that you can communicate with that entity But in terms of delay ping is we send a message to some destination The destination when it gets that message sends back a response The time from when you send the message until you get the response is called the ping time or the response time or round-trip time I have a Program called ping on my computer. We can test the round-trip time for different locations. Let me get this correct Let me just set up and make sure we have our network working. It's slow Okay, be patient I have my computer and I'm going to use the ping application just to test the delay or the response time from one location to another To do this demo I'm going to use my computer in Japan. Okay It doesn't work inside SIT okay the SIT network does not do not does not allow us to do the things that I'm about to do So I'm actually Remotely connected to my computer in Japan and we'll do it from there. So everything I do imagine we're sitting in Japan at the moment We'll use ping to test the delay between my computer in Japan to other computers in the world Don't worry about the commands. I'm typing. It's not so important, but I'm going to ping the Google web page in Japan a lot of information shown I'll just highlight what we care about What happened? I? pinged from my computer in Japan to the Google website in Japan the idea was to send a message to the Google web server and That would send back a response and I did it five times a count of five send first message Get a response and the first response Focus ignore that most of this focus on time the time from when I sent the request and Till I received the response was 2.13 milliseconds That's called a ping time the round-trip time or the response time It's time to get there and back and then My application sent a second request and got a second response the time was 1.8 milliseconds and then the other three requests and responses Because I specified to do just five the count of five and It gives us some summary statistics the round-trip time RTT Minimum average maximum and the mean deviation the average 1.865 milliseconds roughly it's about Close to two milliseconds from my computer in Japan to the Google web server in Japan It doesn't matter about the command or all these details just take note of the time Let's try a different one a different destination from Japan to the SIT web server Anyone want to estimate what the time will be? seven hours Seven seconds seven milliseconds Let's find out about a hundred and fifteen hundred and twenty milliseconds okay, so My computer's in Tokyo SIT web servers in Bangkok So what's happening? My computer sends a message Tokyo to Bangkok Takes about 60 milliseconds 60 milliseconds to get there and Then the server responds about another 60 milliseconds to get back I estimate meaning a total of about 120 milliseconds. Remember. This is the round-trip time The one-way delay Would probably about half of that Okay About 120 milliseconds. Why is it much much larger? Japan to Google Japan two milliseconds Japan to Bangkok 120 milliseconds. Why? It's further away so We will do calculations later and see how we could calculate delay in ideal conditions and People are right and it's further away One aspect of that is the signal That represents the information must travel a larger distance Remember how fast a signal travels a signal like light Travels at the speed of light the further it needs to travel The longer the time it will take so one aspect of the delay is how far physically it must travel In the physical distance, but there are many other aspects as well Like the speeds of the links like the speeds of the computers one or two more Japan to The UK okay, so here from Japan to the UK I Don't know which direction it takes across the world Does it go across the Pacific across the US or does it go? West across Asia, I don't know but it takes about 240 milliseconds in that case much larger distance But there may be other factors in play You can test this maybe from a computer at home using ping it works in Windows it works on a Mac It doesn't work so well inside SIT, but at home it will any questions Questions so far. How's time going 30 minutes? Everything okay first lecture Okay, good Do I have an example of error rate? No not yet overhead in many cases We introduced in the first lecture. We use protocols to communicate protocols to find how we send our messages In many cases to work correctly We can't just send the original data as is We need to send some extra information to make it work correctly That's that's hopefully he's successful here Good everyone's comfortable for the last 30 minutes We survive anyway Overhead The amount of additional data Needed in order to deliver useful data Now we're going to distinguish between two types of data. I want to get I Want to get a What's an example? I want to get an I want to download a file. Okay, the file is one megabyte So the file is on some server And I want to get that one megabyte to my computer We mentioned in the last lecture. We don't just send the file as one large piece of data one large Megabyte we may break it into smaller chunks into packets and send them one at a time and The protocols involved in doing that every time they send part of that one megabyte They may add some add some extra information to keep track of those chunks Let's say I split those one thousand one million bytes into one thousand packets one thousand chunks Then when I send a chunk or the server sends a chunk it would include extra information identifying This is chunk one This is chunk two chunk three and so on it may include a sequence number in there What else may be included Every time we send a message the message may include the address of the destination Last lecture we mentioned addresses like URLs IP addresses To make sure we get effective delivery to the correct destination when we send our data The message may contain the destination address So it's very common that we send some additional data With the the real data. We want to deliver the real data is that one megabyte file, but I attach some other information Overhead is how much other information? so it's a measure of What extra do we need to make this work, but it's not the real useful data Bit hard to give Too many examples yet until we get into some real protocols later, but a couple here is Measured in bits so the overhead how many extra bits do we have to send? Some of you know about parody checks may be in computer hardware error detection schemes For every eight bits of data that I have I may add a two-bit parody check to make sure that Someone who gets that data can detect if there are any errors in that data It's used in computer hardware or in file systems to keep track of files, for example So there's eight bits of real data Plus an extra two bits to make sure that the data is delivered correctly We say those extra two bits of the overhead another example I send a chunk of data as a packet containing 1,000 bytes of real data and 50 bytes of additional data Often referred to as a header It's usually added at the start at the head of the real data The overhead is quite simply the extra additional data of 50 bytes So it's the extra stuff we need to send to get the real data to the destination Why do we need it? Well, we'll see many different cases to include addresses to include sequence numbers to do error Detection if something goes wrong for the receiver to be able to detect if there's errors We'll see those through the course Let's get to one more and then to through well throughput here. We are Data rate the rate at which the data is delivered from one point to another For example the data rate that I can send bits from my laptop to the access point is 54 million bits per second throughput is The rate at which useful data is delivered to the destination Let's go direct to some examples to explain I think You may know when you download a file from a website and the browser gives some feedback about the bits per second or the time it takes It may go up and down The download speed may vary over time and it's usually much lower than you expect or you hope Because often we know about the data rate the data rate of Wi-Fi is 54 megabits per second of your mobile phone 14 megabits per second of your home internet 24 megabits per second That's the data rate the rate at which we can send bits But there are overheads that always occur Plus there are things that may go wrong So another measure of performance is what's called throughput. It's the rate at which the real useful data gets delivered and It's less than the data rate Let's see if we can get an example I'm going to download it. I'm going to download a file from my computer Not in Japan anymore, but back to here from my computer from Where from the ICT web server? Okay, our course website is on the ICT. S I T T U A C T dot th Where is that web server? Anyone know it's a computer somewhere? Where is it? ICT Third floor of this building. Okay, it's downstairs a few few floors. It's just a PC sitting in there That's the ICT web server Let's download a file from it and see how fast it takes to download I've put a file there that I can Copy I think So W gets just a program that would download the file for me the web the address ICT web server domain and the file I created before is just some random data. Okay, it means nothing See if it works. It's downloading The file was 10 megabytes and This software downloads the file. It was 10 megabytes the file and it gives us what some summary Maybe here 2.36 megabytes per second. That's the throughput It is a measure of maybe Here there's maybe some approximations or some different calculations going on here that the timer is not that accurate 10 megabytes in 4.0 seconds Equates to 10 million bytes divided by 4.0 seconds 2.43 million bytes per second That's the calculation of throughput. The real data is the file The real useful data is the 10 megabytes the time it takes is four seconds So the throughput is simply 10 megabytes divided by four seconds or 2.43 megabytes per second million bytes per second Let's download again same file faster The throughput in this case it took 2.2 seconds Why? Same location the servers still downstairs same file same size Why I don't know the exact answer why? But note that it varies so throughput may vary under at different times the reason why in this case most likely is because in a computer network The speed depends not just upon you downloading, but what others may be doing at the same time Someone else may may have been downloading a file at the same time as the first case Therefore mine had to wait a little bit. It was slower. Whereas in the second instance Maybe no one else was downloading from the ICT web server and therefore mine was much faster I don't know unless I analyze that in depth, but the throughput First is the rate at which the real data is delivered It may vary over time and in fact is hard to predict how many megabits per second approximately of the faster one Megabits per second easy one How many megabits per second? Approximately 35 okay, so four times eight. This is note the uppercase B means bytes Lowercase B normally bits. So this is 4.4 megabytes per second times by eight so around 35 megabits per second I'm using my wired LAN, okay Downloaded by the wired LAN. Let's see if I can I'm going to add part unplug and If I can and switch to Wi-Fi Let's hope this works Now I'm downloading and I'm using the wireless link same file 10 megabytes took seven seconds 7.1 seconds 1.45 megabytes per second why is it slower? Why is it slower? Wi-Fi good Most likely again, we could we cannot know for sure but I guess that When I was using the wired link The maximum speed I could send was 100 megabits per second That's from here to the next device and then there's another device another link to go via When I'm using Wi-Fi the maximum I can send to this wireless access point here is 54 megabits per second But I know that there are many overheads involved Using Wi-Fi even though the data rate is 54 megabits per second the overheads practically mean The best you can get is about half of that and Later we'll do some calculations as to why but with wireless Best you'll get about half and even worse if many people are on their phones using the same Wi-Fi access point at the same time my Throughput will be even lower So it depends upon what others are doing So I guess that the reason this is slower is because the of the wireless access if I plug the wired land back in it Would go up again Let me go back to wired and do two more examples Sometimes these don't work as I plan, but we'll try Downloading a different file from Kazat Sart University. So also in Thailand So this is from KU Kazat Sart. So the other side of Bangkok I'm about three megabytes per second. So this is Before it was to a server downstairs now. It's to a server on the other side of Bangkok. Okay, 20 30 kilometers away About three points or 3.6 megabytes per second Doesn't matter what the file is but I know that there's the same file on other servers in the world I'll download the same file from somewhere else This one's in Singapore Same file. Let's hope it connects There we go So this is from us to Singapore Well Singapore sending the file to here in Bangkok in fact, so You'll see it's it's going down. It's around. Oh, okay It goes up and down up and down Okay Many different factors impact on it here We averaged about one and a half before We got three and a half more than three and a half megabytes per second last one Same file, but in Australia ETA three minutes. Okay, we may not wait till the end Why? Why is it different? ping Okay, so one what's the difference? So we had Bangkok to Bangkok Bangkok to Singapore Bangkok to Australia actually the opposite direction Why is it what's different? I think most people can recognize the physical distance is different The delay may be different But many cases the delay doesn't matter the time to download a file once you get started Once the download starts doesn't depend much upon the delay Or the the distance it depends upon other factors many other factors. What's one of them? This one's still going. Okay, what what could be another factor that impacts upon the throughput anyone? Okay, if other people are accessing say the server at the same time the server needs to respond okay, so In many compute communication systems that the number of users using it at the same time Means the system slows down What else? Think about all of the links between my computer and the server the first link using white wired access is this cable going From my computer into the wall it goes up I'm pretty sure it goes direct into a device in the third floor and then that device has a cable direct into the server There are just two links between me and the server Sorry, this was a server in Kazat start. So there's another link. There's more links inside Thailand Whereas going to Australia the links are inside Thailand and then probably Australia down to Singapore and then most likely a Submarine cable Singapore down to Sydney or somewhere Okay, there are multiple links and then inside Australia to the destination The speed of those links may have a large impact upon the throughput the data rate of those links Generally if you have a sequence of links that you must use Your limit is the minimum of the data rates of all of those links Sometimes called the bottleneck link if my data passes through three links one is one megabit per second the second is 10 megabits per second and a third is 50 megabits per second the best that I can get is limited by one megabit per second link So the set of links and what are their data rates will impact upon my throughput today, we're just introducing these concepts over a A few of the lectures will see some more calculations of how to how to calculate throughput and Some more details of what would impact upon throughput Did we get to the end in a few seconds? Yes so Like the examples I just illustrated If I was downloading a 12 megabyte file from a website and it took 26 seconds Calculate the throughput how? Throughput is the rate at which useful data in this case the file is delivered to the destination and Here we'd really talk about the average throughput on average if we Take 26 seconds to send 12 megabytes on average. We're sending or receiving at 6 million bits per second how just File size divided by time We don't need that anymore What do we have? 26 our file was 12 megabytes which is Let's convert to bits Times by 8 is 96 megabits Or 96 million bits That's how much real or useful data. We have to deliver it took What do we say 26 seconds To download so we can say the throughput the rate at which That useful data was delivered. We're delivering 96 million bits in 26 seconds, which is whatever it was on our lecture slide. What was it? Six megabits per second approximately is that right? I don't think that's right is it? Doesn't sound right. What did I do wrong? 3.6 megabits per second Good 96 divided by 26 is three and a half or 3.6. Correct. Why is my lecture note say six? Because I made a mistake somewhere You can be better than me and use a calculator about 3.6 Megabits per second fix your lecture notes So it's just the total size that the total number of useful bits divided by the time it takes to deliver them the rate This one's easy to calculate if we know the total size and know the time it's just this division But in many cases in some networks, we may not know How long it takes we need to estimate what the throughput would be in advance So we need to look at overhead, but let's stick with this simple one for today Any questions on this calculation fix your lecture notes fix my error in there 3.6 not 6 We'll come back to it some other calculations later about throughput Do we have anything to finish? efficiency efficiency is related to throughput and overhead in general the fraction of time we spend using a resource for its intended purpose Come direct to this example Let's say my Wi-Fi link has a data rate of 54 megabits per second I know that when I buy the laptop and the access point the specifications say 54 megabits per second and when I Usually I can select and see. I don't know if it does this connection information Sorry, I'm on my wired link Ws it and I'll get there I can unplug Speed is at 2 megabits per second 5 megabits per second for my Wi-Fi up to 11 megabits per second The maximum it will go to is 54 here. It's not going to go there for me today because It changes depending upon the signal maybe and how strong the signal is for my laptop But if we have a data rate of 54 megabits per second But I download a file and I measure the throughput to be 20 megabits per second Then I could say the efficiency in that case of using the link is point three seven 20 divided by 54 you new check if I've got that calculation correct My data rate is the maximum speed at which I can send bits The throughput is the true speed at which I deliver real data So the efficiency is well what fraction of that maximum speed do I utilize? 20 out of 54 37% so in that case I'd say the efficiency of the link usage is 37% We'd like that to be as high as possible So this is just 20 divided by 54 another example Let's say I pay a thousand bar per month for my 10 megabit per second home internet access On average every month. I download at two megabits per second. Well, I'm 20% efficient I only use that resource on average 20% of the time We will use efficiency to compare different systems and to compare different protocols I think we'll stop there Next lecture when tomorrow we'll look at I'll try and find a few more examples of those metrics And then we'll look at delay come back to delay in a bit more depth do some more calculations