topic Re: Cisco 1801 ATM and dialer config for BT business ADSL in Archive

Cisco 1801 ATM and dialer config for BT business ADSL

abieh — Mon, 12 May 2014 10:47:05 GMT

Hi everyone,

after an outage with BT at the Kingston exchange this weekend my cisco 1801 did not want to sync the adsl. I spoke to BT and got the usual, "everything is fine our end, have you checked your password" response. I tested with an old router and found that to sync. (modem just makes the clicking noise - CD flashes and PPP is not lit)

I did a "sh dsl interface atm 0" and found that the modem status was DMTDSL_DO_DOWN and the DSL Mode was unknow. I found on some of the forums it was suspected to be an issue with auto negotiation of the ADSL Mode on the ATM interface.

So I started changing the ATM0 interface from "dsl operating-mode auto" to :

- adsl2
- adsl2+
- ansi-dmt , and finally

- itu-dmt

Trying each for a a minute or so. (you can use "shut" and "no shut" to stop and start the ATM0 interface to speed up the process.)

Eventually it synced up with "dsl operating-mode itu-dmt" and all was fine again. I presume there was some equipment change which stopped supporting this feature.

For full reference below is my ATM and Dialer interface config which works as of 2014-05-12 10AM:

interface ATM0
description ADSL Connection to BTInternet
no ip address
no ip redirects
no ip unreachables
no ip proxy-arp
ip route-cache flow
no ip mroute-cache
atm vc-per-vp 64
no atm ilmi-keepalive
pvc 0/38
encapsulation aal5mux ppp dialer
dialer pool-member 1
!
dsl operating-mode itu-dmt
!

interface Dialer1
description $FW_OUTSIDE$
ip address 81.138.X.X 255.255.255.248
ip access-group FW_ACL in
no ip redirects
no ip unreachables
no ip proxy-arp
ip nat outside
ip inspect FW out
ip virtual-reassembly
encapsulation ppp
ip route-cache flow
dialer pool 1
dialer-group 1
ppp authentication chap pap callin
ppp chap hostname [Dxxxxxx@hgxx.btclick.com - your username]
ppp chap password 0 [YOUR PASSWORD]
ppp pap sent-username [Dxxxxxx@hgxx.btclick.com - your username] password 0 [YOUR PASSWORD]
!

Hope this helps someone

Abie

Re: Cisco 1801 ATM and dialer config for BT business ADSL

Ogami — Mon, 12 May 2014 14:49:25 GMT

Hi there,

Thanks for the info.

I've floated this post to the top of the board for future reference, in case anybody else has similar issues.

Re: Cisco 1801 ATM and dialer config for BT business ADSL

morgano — Tue, 01 Jul 2014 15:35:22 GMT

We have the same issue, we had a fault on our line in Cardiff on Saturday. By Monday the fault was resolved but our Vigor 120 can no longer connect. Modem is syncing but no stream. I assumed it was a hardware fault and replaced the unit with no luck.

We have the following modulation options:

T1.413
G.Lite
G.DMT
ADSL2(G.992.3)
ADSL2 annex M
ADSL2+(G.992.5)
ADSL2+ annex M
Multimode

It was functioning in Multimode prior to the fault but no longer. I've tried ADSL2+(G.992.5) this is the mode the BT Business hub is connecting with right now but it doesn't make any difference. I guess I can go through them but i'm not sure the other ones will work.

Anyone have any ideas?

Re: Cisco 1801 ATM and dialer config for BT business ADSL

morgano — Tue, 01 Jul 2014 15:33:42 GMT

Our setup is as follows:

Watchguard XTM 330 Firewall/Router connecting on PPPOE via the Draytek Vigor 120 which connects via PPPOA

Was working fine until Saturdays fault. Just like your original post, we can no longer connect.

Re: Cisco 1801 ATM and dialer config for BT business ADSL

morgano — Wed, 02 Jul 2014 11:07:18 GMT

Fear not, this was resolved. BT had removed the static IP's from our account, removing them from the PPPoA connection resolved it. We have new IP's now and everything is working as normal.