Wednesday, August 31, 2011

Broadband Modem Configuration

Let us learn how to go to the configuration settings of broadband modem, what is the difference between pppoe and bridge mode of connections.

If you want to become an expert in Data Network, then after learning some theory,
better you have to view the configuration settings of some working network equipments.
Here I have given the screenshots of configuration settings of a Broadband Modem ( utstarcom UT300R2U) which is connected to the landline broadband connection of BSNL India and the broadband is in working status. (in fact, this page was uploaded using that connection only).
Go through these settings to strengthen your network knowledge.
screenshots of configuration settings of a working broadband adsl modem of utstarcom ut300r2u
From the above screenshots what we have learnt is:

1. There are 7 connections running between my modem and the BSNL ISP. Out of these 7 connections, the very first connection is a PPPoE connection. The rest are Bridge connections.

PPPoE connection means, the modem is basically independent of my PC. My modem will directly talk to the ISP and get the public ip address(public ip is essential for Internet browsing).In the screenshot you will see the public ip address as Where as if you see the ip address of my pc (by going to command prompt and typing "ipconfig" command, you will see the ip address of my pc is which is a private ip address.
You should know the difference between PPPoE and Bridge mode. PPPoE connection means, modem is the master and the PCs are its slaves. Only the Modem will talk to the ISP and get the public ip address and keep it within the modem ( the pc will not know the public address.). But you are aware that browsing is done from the PC (not from the Modem).So PC needs an ip address. Forthis, the modem will give a private ip address to my pc using NAT.

Check the DHCP screenshot, you will see that the modem has been given to my pc. If another pc is connected to the modem, the modem may give to that pc. In essence what you should know is, in case of PPPoE connection, there will be only one PUBLIC ip address. That too, it will be WITH the modem. PC will have only the private ip addresses.

But in case of BRIDGE connection, modem behaves just as a bridge. that is in case of Bridge connection, PC is the master and Modem is just a slave. PC will directly to ISP equipments (mainly to BRAS(Broadband Remote Access Server) and get the public ip address from ISP.

If you want to know, whether your pc is working on PPPoE or Bridge, just type "ipconfig" command from the command prompt. If it is displaying a private ip address such as 192.168.1.x, then you are using pppoe connection. If it is showing a public ip address, then your pc is working in bridge mode. is that clear?

From the screenshot, you can find out my modem has 4 ethernet ports and 1 usb port. (check the diagnostics screen, you will find lines "Test Your ENet(1-4 Connection)=PASS, Test Your USB Connection=Down.). Which means, i am using my ethernet port and not the USB port. and it is working ok.