I have two sites (A & B) connected using leased line as primary and ISDN30 as backup. The traffic flow is from Site-A to Site-B. ISDN30 provider use Alcatel ISDN switch in Site-A and Siemens ISDN switch in Site-B.
Following are setup in Site-A and Site-B routers.
- syslog (7)
- ip accounting of serial1/0:15 and dialer interface
- debug ppp authentication
- debug ppp negotiation
- debug isdn q921
- debug isdn q931
- debug dialer
- debug dialer packet
- leased line is monitored by WhatsUp
- leased line is monitored by MRTG
Configuration are okay and works according to the design that leased line is primary and ISDN30 is backup. Same configuration and rtouer model and connection setup is use in other sites without a problem.
According to ISDN provider, Site-B router ISDN30 is connecting to Site-A all 15 channels for 30 minutes and down for few seconds then connect again for 30 minutes all day long.
During the time ISDN30 provider sees the connection from the logs of their ISDN switch, I check the following;
- syslog >> no logs whatsoever about ISDN dialing or connecting
- snmp-trap messages >> no logs whatsoever about ISDN dialing or connecting
- show debug >> no logs whatsoever about ISDN dialing or connecting
- show ip accounting >> nothing
- show isdn active >> nothing
- show isdn history >> nothing
- MRTG >> doesn't show any break in leased line bandwidth utilization
- WhatsUp >> doesn't see leased line been down
- the routing table never change
- dialer interface is up/up (spoofing) >> normal
- serial1/0:15 is up/up (spoofing) >> normal
- serial1/0:0-14 and serial1/0:16-30 is down/down >> normal
- show isdn status
Global ISDN Switchtype = primary-net5
ISDN Serial1/0:15 interface
dsl 0, interface ISDN Switchtype = primary-net5
Layer 1 Status:
Layer 2 Status:
TEI = 0, Ces = 1, SAPI = 0, State = TEI_ASSIGNED
Layer 3 Status:
0 Active Layer 3 Call(s)
Active dsl 0 CCBs = 0
The Free Channel Mask: 0x00000000
Number of L2 Discards = 0, L2 Session ID = 10
Total Allocated ISDN CCBs = 0
Could it be a hardware or software problem of the router or ISDN switch in Site-B? Please advice the next step on identifying the root cause of the problem.
Cisco 2811 (revision 53.51) with 247808K/14336K bytes of memory.
2 FastEthernet interfaces
31 Serial interfaces
2 Serial(sync/async) interfaces
1 Channelized E1/PRI port
1 Virtual Private Network (VPN) Module
DRAM configuration is 64 bits wide with parity enabled.
Thank you for your reply. Yes you are right, the Serial1/0:15 and Dialer2 interface is up/up (spoofing) when it is enabled and the line is plugged, to masquerade it as up for it to include in the routing table.
What I don't understand is how come the telco detected 15 channels up when there is no data at all. Lets say that the ISDN dialed the remote site and gets authenticated/connected, but from what I understand, the B channel should be up only when there is data.
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