Network

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This page contains information regarding our Lab Network...

Lab Network settings

The typical Lab IP settings in Windows (replace '81' with the IP of your machine) is given in the figure on the left.
Browser settings (shown here for Firefox, but similar for other browsers) is given in the figure on the right.

Lab ip settings.png

Right

Wireless network access

  • iiscwlan -- available around the campus -- Print the form available on SERC website and get it signed by your adviser.
    Submit this form at SERC to get access to this network
  • Wireless router access -- available in lab only (SP 2.23)

IP allocation

IP allocation table

Set up network for the first time on a new machine (PC)

  • Set the IP address, netmask, gateway and DNS servers as shown in the above figure
    Please ask someone for an IP address you can use!
    Check the address by using the ping command to ensure that it is not already in use.
  • In any browser (such as firefox, chrome or Internet explorer) set the appropriate proxy-settings as shown in the figure above


IISc network basics

This are my understanding of IISc's network.
Please drop me a mail if you find any mistake or if you feel that some of these details can be more accurate

  • The IP address allocation in IISc is done as follows:
    10.xxx.yyy.zzz
10 indicates LAN
xxx is the number allotted for a department (32 for ECE, 114 for CEDT (now DESE))
yyy is the number allotted to a lab/Professor (33 for our lab, 1 for VLSI lab in DESE, 40 for Prof. GB's lab)
zzz is the number allotted to a machine (some of these are reserved, 1 -- for gateway)
  • 10.xxx.yyy.1 -- is the gateway for all IP address in 10.xxx.yyy.*
  • A switch is needed to communicate between two machines (well almost always)
  • The switch for communicating between two IP addresses with the same 10.xxx.yyy.* (i.e. differing in only their zzz field) is normally located close by to the machine (such as the same room of neighboring room).
  • The switch for communicating between two IP addresses with different yyy is generally located at one location within the department.
    This generally inaccessible to all but a few.
  • The switch for communicating between two IP addresses with different xxx is located in SERC (not sure exactly where, but is managed by people from SERC).
  • Almost all connections to outside IISc IPs must go through the switch in SERC (this may not be completely true for people in DESE)

Debugging Network Issues

The network in our campus is known to frequently throw-up issues. Here are a series of steps you should try before calling for help.

  • Has the network worked with this login on this machine before?
    If not then please check the above description on getting internet to work for the first time!
  • Does anyone else have network connection in the lab?
    If so then, there is something that can be fixed by you.
    If not then, it is likely that the department or campus network is down -- there is little that you can do about this, but if it is worth your time, debug and make conclusions
  • Obtain your IP address using the commands
    "ipconfig" (for Windows)
    "ifconfig (for Linux)
    Let us say it is 10.xxx.yyy.zzz
  • ping a machine in the same lab (i.e with same 10.xxx.yyy.*)
    Does it reply? If so then your local switch is working
    If not, then check your ethernet cable (it may be loose or defective) or there could be an issue with your local switch
  • ping you gateway (10.xxx.yyy.1)
    If you receive a response then the department network is fine
    Else something's wrong with the connection between your machine and the gateway (i.e. the gateway itself may be down or your connection to it may be faulty). Ask someone from a neighbouring lab if they can ping their gateway. If they can and you can't, then contact the department network administrator (mostly during working hours -- unless you are fortunate to have a very dedicated admin :))
  • ping the machine to which you are interested in establishing a connection.
    If is responds, then the software that is trying to communicate to this has some issue.
    Else the machine is down (such machines usually have the appropriate firewall settings)
  • If internet is still not working, then you have either not setup the browser (as explained above) or the SERC server is down (low probability event) or the internet service provider is not functioning correctly.


SERC Network Information page

Click here