Connect two router back to back via 2 pin copper wire.

[acbennyma]

Dear all,

I would like configure two router (e.g. 1921) back to back via a 2 pin copper wire.  Can I use HWIC-4SHDSL-E card to do it? What is the configuration I can use? Any sample configuration can be provided ?

Thanks!

[adnane dakna]

yes you can connect routers back to back  with E1 controller (E-Card ) using crosseover cable , the config is quite simple :

router1# config t

router1-config# card type e1 0 0      # after puting  this command router will create virtual serial interface for example s0/0.0

router1-config# int s0/0.0

router1-int# ip address 192.168.1.1 255.255.255.252

the same command is done for other router just change @IP =192.168.1.2

[acbennyma]

Sorry, I am using  HWIC-4SHDSL-E card. Then what will be the configuration?

[Giuseppe Larosa]

Hello Acbennyma,

one side has to act as CO side (central office)

see

http://www.cisco.com/en/US/tech/tk175/tk274/technologies_configuration_example09186a0080135834.shtml

Hope to help

Giuseppe

[acbennyma]

This connection just show a router act as a CO office. My real case is.

My two 1921 router with HWIC-4SHDSL-E card connected via a 2 pin copper wire. I want to set a bridge connection.

Any professional can give me a sample configuration. Thanks!

[Giuseppe Larosa]

Hello Acbennyma,

the example I have linked is for a back to back connection.

For the way xDSL work, to build a back to back connection one side has to act as CO because otherwise no link is possible.

It is not a matter of crossing wires to build the connection, the behaviour of one side has to change because it has to receive on a range of frequencies where the other side transmits and viceversa.

All modern xDSL use forms of DMT that is the use of subcarriers and the upstream and downstream direction uses two different subsets of these subcarriers (tones),

The normal setup is towards the central office so CO modems work in the opposite way in comparison to CPE modem side.

I hope it is more clear now

Hope to help

Giuseppe

[acbennyma]

Dear Giuseppe,

Thanks for your reply, however, my case is I have two site A & B and there is a 2 copper pin wire between these two site (without using DSL modem). That 's means I only can use two router use with HWIC-4SHDSL-E card to configured as bridge. Is it work ? I still need to use one router to act as CO and configure it as a bridge also ?

[Giuseppe Larosa]

Hello Acbennyma,

>> That 's means I only can use two router use with HWIC-4SHDSL-E card to configured as bridge. Is it work ?

The bridging action  is performed at OSI layer2 and it is a different matter, the use of CO on one side is required to accomodate OSI layer 1 needs (physical layer)

to be noted you cannot use an ADSL WIC for this job but only symmetric DSL types are suitable for this application

>>  I still need to use one router to act as CO and configure it as a bridge also ?

yes, you need one side to act as CO to accomodate physical layer needs for back to back connectivity.

Bridging comes later and it is the way you want to use the link.

Hope to help

Giuseppe