KNOW YOUR LAN
Yours truly got an opportunity to interview Prof. Satyabrata Jit from the Electronics Department, the Chairman of the committee responsible for setting up the much talked about Wi-fi and the new LAN facilities in IIT (BHU). We got an amazing insight towards this project, the challenges the team faced through its course, the issues which remain, and about what other things are in line regarding these internet services. Let’s have a look at what insights he shared with us:
Q — What were the challenges which you and your team faced through the course of this project? And how did you manage to resolve them?
“The main problem was that initially we were confused whether we should go for Star Topology or for Cascade Topology. In the cascade topology, all the access switches are connected to the main switch or the Distribution Switch through the same line, and the users are directly connected to the access switches. Here, the speed is restricted, so we thought that even if the cost increases, we will go for the star topology. In the star topology, every hostel is provided with one distribution switch. Then, whatever access switches are there, they are directly run from the distribution switch. Here also, every user is connected directly to the access switches. The main purpose of this topology is that we can monitor the activities of each user. If someone is doing something unethical, then we can directly close their connection. The second thing is that there is no obstruction here like in cascade topology. The third purpose is that if one switch gets damaged in cascade topology then the whole connection will be closed. But in here, if one switch is malfunctioning, then only the users connected to it will suffer and the other portions will remain running. On these basis, we structured the network on star topology. star topology increases the cost, but is much faster. The previously existing network was based completely on cascade topology.
Second problem was that whether we should go for UTP (Unshielded Twisted Pair) cabling or Fibre Optic Cabling. UTP cabling is cheaper than fibre optics.
Another challenge that we faced that took a lot of time in discussions and deliberations was whether we will consider the 4-tier network system or the 3-tier network system. In the 4-tier system, the switches are placed in 4 stages (similarly, in 3-tier system, the switches are placed in 3 layers or stages). 4-tier system was the original system of BHU’s network, and upto 7, 8 or 9 hostels were connected to only 1 distribution switch. We initially planned to place 5 distribution switches for the entire IIT. But the problem was that if again somehow one distribution switch fails, and if we would have connected 8 hostels with that switch then all the 8 hostels would have suffered. So, we considered to go for 3-tier system and every hostel would get 1 distribution switch.
Thus, we adopted a 3-tier network system with star topology with fibre optics cabling from the core switch up to the access switches with one distribution switch for every main hostel. This network system is supposed to be very robust and highly efficient.”
Q — Being a completely new network, there are some expected problems which students of many hostels are facing. The connectivity wavers and the speed is also not as good as it was expected. Till when can we expect that these matters be sorted out?
“The problem is that before this new LAN came, 9 old hostels were upgraded by CISCO, and around 3 crore rupees were spent for it. Now, when we considered the new LAN, we didn’t include these 9 hostels as already 3 crores were invested there.
But that upgradation was 2 years old. Along with UTP cabling, they were also given fibre optic ports; both options were given to these hostels. But when these fibre optic ports were opened then due to the dust, almost all the ports got blocked. The thickness of fibre optic cables is less than one millimetre, so even a small speck of dirt can cause problems to the network. Since we shifted to complete fibre cabling, the old switches started malfunctioning.
We have already contacted the bidders regarding this and asked them to upgrade the switches. But it will take some time. There are certain protocols for this, complaint must be registered, then the complaint will be processed and then accordingly upgradation will take place. Engineers have been deployed to take care of these switches one by one, but it will take some time. Until the work is completed, the LAN will continue to malfunction. Possibly, in one month or so all the old switches will be upgraded and then these problems won’t be there.”
Q — The new Wi-fi routers have been installed in the hostels, but still students are facing difficulties with the network strength and speed. In some places, there is absolutely no connectivity. What steps will be taken to counter that?
“I want to make it very clear that the wi-fi which was created, it was not made for every room. To provide good wi-fi signal to every room is very difficult. In some rooms the signal strength will be very good and in some places the signal will be very weak, and this problem will remain. There is no solution at all.
The wi-fi runs at 2.4 GHz, and it has 3 frequency channels. Suppose you have 3 routers which are radiating signals. One router will send its signal in some area, and there will be some common region where signals from more than one routers are reaching. Now if all these 3 routers are emitting on different frequencies then there is no problem. Problem arises when we deploy the 4th router. Then its frequency will match with either one of the previous 3 routers. When frequency and phase matches, interference takes place in their common region (constructive interference, as well as destructive interference). What happens then is at some places the signal strength increases, and at some places the strength decreases.
We. cannot place the routers too far away, and if we place them too close then interference will take place. So, we have no direct solution where we can deploy the routers densely.
Another technology which exists is of 5 GHz, which has 16 frequency channels. But the problem here is that most of the previously existing machines like computers and mobiles that we have operate on 2.4 GHz, only the newer systems like the 7th generation laptops and newly-bought mobiles are compatible with this 5 GHz technology.
Only one solution remains which is to place one router in each room. The walls of rooms here are thick, so interference won’t cause much problems to the signal strength. But if we do that the cost will be extremely high.
So, these are some issues which remain with the wi-fi network.”
Q — In some hostels, like Morvi hostel, the wi-fi routers are not working at all. What about those routers?
“Those issues are being handled. All the feedback and complaints which I get, I forward them so that the people who need to take care of it do so. But the thing is that I cannot deploy too many engineers in one go. And when some people go to resolve the matter at one place, then it usually takes about 2 hours, so the next complaint which arrives remains attended.
All the issues will be sorted out in a sequential manner, but it will take some time. I have ordered the people in-charge to send at least 1 person to each hostel to make sure that the routers are working properly.”
Q — Could you please tell us about the other 1 Gbps bandwidth which is going to be introduced in the LAN system?
“At the present position, we have 1 Gbps Reliance line, and today (16th October) also 1 Gbps Vodafone line has been installed and tested. Currently it is running on 1 Gbps line only, but we are going to immediately start working on the second line and by tomorrow or day after tomorrow, we will be running on 2 Gbps bandwidth.”
Q — Regarding the CAIT Policy, you mentioned that with the help of star topology in the network, you will be able to individually monitor the activities of every user. So, is it right in assuming that the policy will be implemented very strictly?
“Yes, it will be strictly implemented. Whatever sites you are accessing, and whatever other activities you are doing, will be monitored and accordingly a logfile will be created. If someone is found doing something unethical, then it will be tolerated in the beginning for a couple of times. Warnings will be given, but if the offenses continue then strict disciplinary action will take place.
Why not to maintain some unethical part? If we are telling you not do something, then don’t do it. One thing which I want to tell all the students is not to use your own routers. We are noting all such activities of students.
YouTube is not banned, but that doesn’t mean you will watch movies all day. If you are using it to watch video lectures or something then it’s fine. If any student is using YouTube for 1 hour (per day) then that’s also fine. But the problem is that students are not coming to classes. They are very much present in the campus but are bunking classes. Internet is mainly for your academics, and students too should be aware of this and maintain some ethics while using the internet provided by the institute.”
