Learning by Doing: CISCO Certified Network ... - SCN Research

Troubleshooting in Action:
Now let’s see what happens to each of these troubleshooting outputs when you have
problems in your network.
Dialer interface shut down (layer 1)
No isdn cable connected (layer 1)
No dialer list (layer 2)
Incorrect dialer list (layer 2)
Incorrect spid (layer 2/3)
No ppp (layer 2/3)
Incorrect username/password (layer 2/3)
Missing username/password (layer 2/3)
Bad ip address/mask (layer 3)
The first thing you will want to do is “sh isdn status.” This will pin-point the layer where
your trouble lies.
Dialer interface shut down (layer 1)
Here, since we always start at layer 1 when troubleshooting, we want to check our cables
and interfaces. Debug dialer and debug dialer packets will show absolutely nothing if
you try to ping the other interface.
kissane#sh isdn status
Global ISDN Switchtype = basic-ni
ISDN BRI0/0 interface
dsl 0, interface ISDN Switchtype = basic-ni
Layer 1 Status:
DEACTIVATED
Layer 2 Status:
TEI = 64, Ces = 1, SAPI = 0, State = TEI_ASSIGNED
TEI = 65, Ces = 2, SAPI = 0, State = TEI_ASSIGNED
Spid Status:
TEI 64, ces = 1, state = 5(init)
spid1 configured, spid1 sent, spid1 valid
Endpoint ID Info: epsf = 0, usid = 70, tid = 1
TEI 65, ces = 2, state = 5(init)
spid2 configured, spid2 sent, spid2 valid
Endpoint ID Info: epsf = 0, usid = 70, tid = 2
Layer 3 Status:
0 Active Layer 3 Call(s)
Activated dsl 0 CCBs = 0
The Free Channel Mask: 0x80000003
Total Allocated ISDN CCBs = 0
432