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
