[rbak-nsp] MPPP LCP keepalive ECHO's on SMS

[Arjan Van Der Oest]

Hi,

I'm trying to build a MPPP link with a Cisco 1921 with two ADSL HWICS towards an older SMS1800 (sw 6.1.4.16). All works fine, until I pull one of the ADSL lines. The cisco detects the ATM interface going down and tears down the corresponding PPP channel. The SMS however keeps thinking both channels are up and keeps trying to route traffic to both, resulting in packet loss. On the Cisco CPE I've configured a keep alive timer and it seems the SMS is responding to it:

debug from 1921:
001608: Aug 10 13:14:35.268: Vi2 LCP: O ECHOREQ [Open] id 126 len 12 magic 0xB76EB877
001609: Aug 10 13:14:35.268: Vi4 LCP: O ECHOREQ [Open] id 123 len 12 magic 0xB76F0D4C
001610: Aug 10 13:14:35.276: Vi2 LCP-FS: I ECHOREP [Open] id 126 len 12 magic 0x0885DBDE
001611: Aug 10 13:14:35.276: Vi2 LCP-FS: Received id 126, sent id 126, line up
001612: Aug 10 13:14:35.276: Vi4 LCP-FS: I ECHOREP [Open] id 123 len 12 magic 0x354CF0BA
001613: Aug 10 13:14:35.276: Vi4 LCP-FS: Received id 123, sent id 123, line up

However, a debug pop lcp on the SMS weirdly doesn't show any LCP ECHO's. Also, since I'm not seeing any ECHOREQ's coming in from the SMS I assume it's not sending them and hence it's not detecting the failed ATM pvc. I've been looking for a keepalive/echo configuration option on the SMS but wasn't able to find any.

Any suggestions?

-- 
Met vriendelijke groet,

Arjan van der Oest
Senior Network Engineer / Security Officer

Voiceworks BV - Editiestraat 29 - 1321 NG Almere
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