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Community Member

2811-1811-ADSL connection issue

Dear All,

I need your assistance with a strange problem i have

in my company we have like 10 remote sites connecting to the Head office using fram relay connections

in these sites we have thefollowing design:

Main router 2811 that is connected using a serial v35 cable to te provider Modem,

Also on the interface FE0/0 a connection to the backbone switch on this site

on FE0/1 a connection to another router(1811) in "FE0" that acting as a firewall,

the 1811 is connected(FE1) to an ADSL modem and is acting as a backup line, using IPsec connection

so when you show the bgp sum on the 2811, you should see the two connections,

let us say something like the below: (this is the primary line connection that is connected to our Head office) (thei is the backup line connectionto the provider ADSL)

The problem is at 3 sites from the 10 sites i have

whever the ADSL flaps, the 2811 can not restore the backup line connection,

ad on sh bgp sum, the status of the backup connection turned to Active"which means it is not working"

and to restore the service again, i have to manually reboot the modem,

i changed the provider of the ADSL line at the  3 remote sites, also i changed the ADSL modem more than once

the provider do not deny the flap, but he is asking why do not the router restore the connection after the flap vanishes,

in the other 7 sites whenever the backup connection flaps, i check the 2811 log and see that the connection was down and is backup agian with no need to reboot theprovider ADSL modem ,

we checked the configuration and found them the same in all sites

the ADSL provider is not the same for the 3 sites,

any ideas how can we fix this issue?

Cisco Employee

Re: 2811-1811-ADSL connection issue

Hi Mohamed

The Bgp in in active state when he tries to establish a TCP session to his neighbor

debug ip tcp transaction should confirm that

If you cannot establish a TCP via this ADSL modem, first thing is to ping an address in the

aggregator of the Telco I bet that will already fail

My guess is that the DSL part probably negotiated but that the IP connectivity

is not establish yet, PPPox faling or if bridging arp issue ...


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