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New Member

ISDN BRI backup problem

we have configure ISDB bri DDR for backup of primary serial link

following are the configurations

interface Serial0/0

description ---------To remote router 128K LL----------

ip address 192.168.100.1 255.255.255.0

encapsulation ppp

backup delay 10 30

backup interface BRI0/0

interface BRI0/0

no ip address

encapsulation ppp

dialer pool-member 1

dialer pool-member 2

isdn switch-type basic-net3

no keepalive

ppp authentication chap

interface Dialer1

description ------to remote router backup------

ip address 172.168.100.1 255.255.255.0

encapsulation ppp

dialer pool 1

dialer remote-name remoterouter

dialer-group 1

no keepalive

ppp authentication chap

but when primary goes down isdn is not dialing and bri port is not up
following output taken after primary serial interface goes down.
mainrouter#show interface bri 0/0
BRI0/0 is standby mode/disabled, line protocol is down
  Hardware is PQUICC BRI
  MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation PPP, loopback not set
  Last input 4d03h, output never, output hang never
  Last clearing of "show interface" counters 43w6d
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/1/16 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 48 kilobits/sec
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     90070 packets input, 446670 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     90077 packets output, 496689 bytes, 0 underruns
     0 output errors, 0 collisions, 332 interface resets
     0 output buffer failures, 0 output buffers swapped out
     180 carrier transitions
we have checked ISDN line it is working ok.
Please suggest what would be the causes ????

3 REPLIES
Hall of Fame Super Silver

Re: ISDN BRI backup problem

Hello Sunil,

have you added floating static routes using Dialer1 as outgoing interface?

also the backup command should point to Dialer1 instead of the BRI interface in order to complete the configuration, because you are using dialer interfaces and not BRI directly (legacy DDR)

see

http://www.cisco.com/en/US/docs/ios/dial/configuration/guide/dia_backup_profiles_ps6441_TSD_Products_Configuration_Guide_Chapter.html#wp1001008

you can troubleshoot the issue using the following debug:

terminal monitor

debug dialer

debug ppp neg

debug ppp auth

shut the primary link and try to ping an host on remote network

Hope to help

Giuseppe

New Member

Re: ISDN BRI backup problem

Hi Giuseppe

thanks for reply

I tried that solution but after I was remove backup interface bri 0/0 and pointing dialer as a backup interface, BRI interface changed down to up immediately and both serial and BRI interfaces were UP simultaneously.

But we want BRI as a backup and whenever primary serial will down then only BRI should UP.

After changing the setting followings are the outputs

Mainrouter#config t

Enter configuration commands, one per line.  End with CNTL/Z.

Mainrouter(config)#interface serial 0/0

Mainrouter(config-if)#no backup interface bri 0/0

Mainrouter(config-if)#backup interface dialer1

6)

Output

Command base-URL was: /level/15/exec/-

Complete URL was: /level/15/exec/-/show/interface/bri/0\/0/CR

Command was:  show interface bri 0/0

________________________________________

BRI0/0 is up, line protocol is up (spoofing)

  Hardware is PQUICC BRI

  MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation PPP, loopback not set

  Last input 00:00:07, output never, output hang never

  Last clearing of "show interface" counters 44w2d

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: weighted fair

  Output queue: 0/1000/64/0 (size/max total/threshold/drops)

     Conversations  0/1/16 (active/max active/max total)

     Reserved Conversations 0/0 (allocated/max allocated)

     Available Bandwidth 48 kilobits/sec

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     90160 packets input, 447137 bytes, 0 no buffer

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

     90168 packets output, 497216 bytes, 0 underruns

     0 output errors, 0 collisions, 338 interface resets

     0 output buffer failures, 0 output buffers swapped out

     187 carrier transitions

________________________________________

command completed.

7)

Mainrouter#config t

Enter configuration commands, one per line.  End with CNTL/Z.

Mainrouter(config)#interface serial 0/0

Mainrouter(config-if)#backup interface dialer1

Mainrouter(config-if)#no backup interface dialer1

Mainrouter(config-if)#backup interface bri 0/0

8)

Output

Command base-URL was: /level/15/exec/-

Complete URL was: /level/15/exec/-/show/interface/bri/0\/0/CR

Command was:  show interface bri 0/0

________________________________________

BRI0/0 is standby mode, line protocol is down

  Hardware is PQUICC BRI

  MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation PPP, loopback not set

  Last input 00:00:05, output never, output hang never

  Last clearing of "show interface" counters 44w2d

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: weighted fair

  Output queue: 0/1000/64/0 (size/max total/threshold/drops)

     Conversations  0/1/16 (active/max active/max total)

     Reserved Conversations 0/0 (allocated/max allocated)

     Available Bandwidth 48 kilobits/sec

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     90197 packets input, 447285 bytes, 0 no buffer

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

     90205 packets output, 497364 bytes, 0 underruns

     0 output errors, 0 collisions, 338 interface resets

     0 output buffer failures, 0 output buffers swapped out

     188 carrier transitions

________________________________________

command completed.

_______________________________________

Please refer the above output and sugget the same

Thanks in advance....

Hall of Fame Super Silver

Re: ISDN BRI backup problem

Hello Sunil,

the fact that BRI interface stays up is not a problem because it is the dialer interface that is in charge, the BRI has no IP address so it cannot be an alternate path for IP traffic alone.

if you see in previous post I had provided a link with an example that fits with your needs

so I recommend to use backup interface Dialer1 not BRI

Hope to help

Giuseppe

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