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Cisco Bug: CSCsy96287 - Linestate not propagated to LC, serial intf stays up after receiving AIS

Last Modified

Jan 28, 2017

Products (1)

  • Cisco 12000 Series Routers

Known Affected Releases

12.0(32)S6r

Description (partial)

Symptoms: A customer experienced a single T1 flapping on controller 0/3/0. It 
would take between 2,500 and 3,000 path code violations and then drop and 
come back. It would do this about once every 15 minutes. Problems with our 
phones losing connectivity to a central call manager when a WAN circuit 
experiences a problem.

We use Multilink PPP to bundle three T1s for a 4.5-Mb circuit. If any one of 
the three T1s experiences even a minor issue, phones are resetting. However, 
we never lose Layer 3 connectivity. The edge router maintains its BGP peering 
across the Multilink PPP bundle, and none of our management applications ever 
sees a loss in connectivity.
  
We recently switched over to Multilink PPP from Multilink Frame due to a 
requirement by our MPLS provider. We did not have an issue using Multilink 
Frame; hence, we believe it is an issue with our configuration for Multilink 
PPP.
 
Conditions: This issue was first noticed in a 32S6r image, and some nodes 
running 32s11 showed similar symptoms.
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Bug Details Include

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  • Status
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