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BRI and Serial link are up at the same time


Got a question about BRI interface

Is there any way to disable BRI interface manually when primary link is up?

I had a situation where both BRI and Serial link were up and running

i reset the primary BRI0/1/0 and now BRI sub-interfaces are showing down..but still primary bri int showing up up (spoofing).

what does spoofing means?

RouterA(config-if)#do sh int BRI0/1/0

BRI0/1/0 is up, line protocol is up (spoofing) >>>>>>>>>>>

Hardware is GT96K BRI with U interface (3086)

Description: circuit id 50.ibsd.515307

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

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

Encapsulation PPP, loopback not set

Keepalive set (10 sec)

Last input 00:00:28, output never, output hang never

Last clearing of "show interface" counters 6w3d

Input queue: 0/75/115/0 (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

296542 packets input, 1320737 bytes, 0 no buffer

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

115 input errors, 113 CRC, 0 frame, 0 overrun, 0 ignored, 104 abort

329534 packets output, 1582923 bytes, 0 underruns

0 output errors, 0 collisions, 2 interface resets

0 output buffer failures, 0 output buffers swapped out

RouterA(config-if)#do sh ip int brie

Interface IP-Address OK? Method Status Protocol

GigabitEthernet0/0 10.X.160.1 YES NVRAM up up

GigabitEthernet0/1 unassigned YES NVRAM administratively down down

Serial0/0/0 unassigned YES NVRAM up up

Serial0/0/0.1 10.X.252.21 YES NVRAM up up

BRI0/1/0 unassigned YES NVRAM up up

BRI0/1/0:1 unassigned YES unset down down >>> >>>

BRI0/1/0:2 unassigned YES unset down down >>>>>>

Dialer0 unassigned YES IPCP up up

Loopback0 10.X.3.169 YES NVRAM up up


Really appreaciate anyone's explanation.

Thanks in advance



Re: BRI and Serial link are up at the same time

To begin with the last question: The status as observed is in fact normal behaviour.

Spoofing is in other words "faked up". An interface that's inactive normally goes down which also causes all routes running over it to be dropped from the routing table. This status was implemented to allow dialers to keep their static routes also when the dialer was inactive. Check with the command "show dialer" to see if there is any undesired calling action.

Use an access-list to allow traffic to activate the dialer.



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