Configuring two back to back ADSL Routers

Unanswered Question
Oct 14th, 2008

Hi

I have a Cisco 877 & 878 ADSL router. I need to configure them in a back to back configuration before they are sent out on site.


The problem is, I have never configured any adsl routers before. Does anyone have any config templates I could see ?


Regards


Mike



  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
Giuseppe Larosa Tue, 10/14/2008 - 01:12

Hello Mike,

ADSL interfaces are seen as ATM interfaces by the routers with some specific commands


SideA


interface ATM0/0

no ip address

no ip mroute-cache

no atm ilmi-keepalive

dsl operating-mode auto

int atm0/0.1 poin-to-point

ip address 10.10.10.1 255.255.255.252

pvc 0/35

enc aal5snap

protocol ip 10.10.10.2 broadcast


one side has to act as the CPE the other side has to behave as the CO central office


SideB:



interface ATM0/0

no ip address

no ip mroute-cache

no atm ilmi-keepalive

! here the difference to be CO

dsl equipment-type co ignore-error-duration 18

dsl operating-mode auto

int atm0/0.1 poin-to-point

ip address 10.10.10.2 255.255.255.252

pvc 0/35

enc aal5snap

protocol ip 10.10.10.1 broadcast


The protocol commands are needed to use a routing protocol


Hope to help

Giuseppe


thestagman Tue, 10/14/2008 - 01:28

Hi Giuseppe


Thanks for the config. However I have come across a little problem in that one of the Adsl routers the 878 does not seem to support ands ATM interface. The physical interface is labelled G-SHDSL.


So I'm connecting from a Physical ASDLoPOTS on an 877 router to a Physical port labelled G-SHDSL on the 878 Router..


Can yo help ?

Giuseppe Larosa Tue, 10/14/2008 - 01:42

Hello Mike,

I'm afraid they cannot match but try to do the following on the ADSL side:

interface atm 0/0


dsl operating-mode gshdsl symmetric annex A


A for US north america

B for Europe


if this command is not supported you have no chance to make them talk ADSL and G-SHDSL are different DSL standards.


see

http://www.cisco.com/en/US/docs/ios/bbdsl/command/reference/bba_01.html#wp1013692



Hope to help

Giuseppe




thestagman Tue, 10/14/2008 - 01:45

lol ... no wonder I can't get them working .


I have managed to get hold of another adsl 877 router and I will try your configuration.


Thanks


thestagman Tue, 10/14/2008 - 02:05

When I do a show int atm0 the interface is down down. It's not down to a cross over cable is it ? There is one command listed from your CO config that is not supported on mine. Please see below




This is the CO Router running 12.3(8r)YI4


interface ATM0

no ip address

no ip mroute-cache

no atm ilmi-keepalive

dsl operating-mode auto

!

interface ATM0.1 point-to-point

ip address 10.10.10.2 255.255.255.252

no snmp trap link-status

pvc 0/35

protocol ip 10.10.10.1 broadcast

encapsulation aal5snap


The command "dsl equipment-type co ignore-error-duration 18 " does not appear to be supported on this router.


********************************************


This is NON CO router running 12.3(8r)YI4


interface ATM0

no ip address

no ip mroute-cache

no atm ilmi-keepalive

dsl operating-mode auto

!

interface ATM0.1 point-to-point

ip address 10.10.10.1 255.255.255.252

no snmp trap link-status

pvc 0/35

protocol ip 10.10.10.2 broadcast

encapsulation aal5snap


thestagman Tue, 10/14/2008 - 03:47

I have just been informed by BT that you cannot connect two ADSL routers back to back as you need to go via aN ADSL Cloud


is this true ?

Giuseppe Larosa Tue, 10/14/2008 - 08:41

Hello Mike,

your CO router is not configured correctly:


int atm0/0

dsl equipment-type co ignore-error-duration 18


this is the command to tell the router to behave as CO modem (exchange downstream and upstream role)


Cisco routers can be connected back-to-back on ADSL links with the correct configuration.


Other devices may not be able to act as CO modem so BT advice can be helpful in that case.


Hope to help

Giuseppe


thestagman Tue, 10/14/2008 - 23:17

Hello Giuseppe


Thanks for the help. But both Cisco 877's I have do not support the command "dsl equipment-type co ignore-error-duration 18 "


I have looked and cannot find any similar commands. The IOS version on this CO router is 12.3(8r)YI4


Any ideas ?


thestagman Tue, 10/14/2008 - 23:25

It might be that the command dsl equipment-type co ignore-error-duration 18 " is not supported on 12.4(6)T7 and I may need to downgrade to 12.3 ?

Giuseppe Larosa Wed, 10/15/2008 - 06:55

Hello Mike,

I've given a look again at the command reference and the DSL equipment-type is supported only on

G.SHDSL WIC


http://www.cisco.com/en/US/docs/ios/bbdsl/command/reference/bba_01.html#wp1012887


So you need to make a pair of 877 with the other type of DSL interface the one that couldn't fit with ADSL in the first posts.


The command is supported in G.SHDSL WIC because that is a symmetric service same speed in both directions.


see the following document:


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


To be honest this is the same document suggested by Andrew in first post.


Sorry for the misleading suggestions I hope you have two routers with G.SHDSL interfaces.


Hope to help

Giuseppe


thestagman Mon, 10/20/2008 - 23:07

Hi thanks for that Giuseppe


Here's another for you or anyone out there reading this.


I have just been informed that one end of this adsl circuit will be a BT ADLS MAX line running up to 8mb and the other end will be a BT SHDSL line providing 1Mb of bandwidth.


Does the above sound right ? an ADSL and SHDLS at each end ??



Actions

This Discussion