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Cisco Bug: CSCum08918 - BFD Fails to Establish Neighbor when running ISIS

Last Modified

Feb 19, 2018

Products (21)

  • Cisco ME 3600X Series Ethernet Access Switches
  • Cisco ASR 901-6CZ-F-D Router
  • Cisco ASR 901-6CZ-FS-D Router
  • Cisco ASR 901-4C-FT-D Router
  • Cisco ME 3600X-24TS-M Switch
  • Cisco ASR 901S-4SG-F-D Router
  • Cisco ASR 901-6CZ-F-A Router
  • Cisco ASR 901S-2SG-F-D Router
  • Cisco ASR 901S-2SG-F-AH Router
  • Cisco ASR 901-6CZ-FT-A Router
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Known Affected Releases

15.4(2)S

Description (partial)

Symptom:
After an interface flap or device reload, a BFD neighbor fails to establish. Protocols registered to BFD like ISIS may also fail to establish.

Conditions:
This symptom occurs with Cisco ME3600-cx platforms running ISIS with BFD. The issue can be seen with the <CmdBold>show platform ho-fpga tx-buffer-table detail <local discriminator(LD)><noCmdBold> command. With this command you can see the packet header of the BFD packet. The second line will show all 0s.
The <local discriminator (LD)> value of the BFD session can be obtained from ?show bfd neighbors?  command output and 
 LD value should be between 1- 512  for the hardware offload BFD session. 

me3600-cx#show bfd neighbors ipv4 10.1.1.1 details

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
10.1.1.1                              258/0          Down      Down      Gi0/5   << LD info >>
Session Host: Hardware
OurAddr: 10.1.1.2
Handle: 258
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3
Received MinRxInt: 0, Received Multiplier: 0
Holddown (hits): 0(0), Hello (hits): 1000(0)
Rx Count: 0
Tx Count: 1660045
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: ISIS CEF
Last packet: Version: 1                  - Diagnostic: 0
             State bit: AdminDown        - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 0               - Length: 0
             My Discr.: 0                - Your Discr.: 0
             Min tx interval: 0          - Min rx interval: 0
             Min Echo interval: 0
=======================
me3600-cx#show platform ho-fpga tx-buffer-table detail 258
Tx Buffer Table Entry: 258
---------------------------

Type: BFD_IPv4
Overload Ptr: 0x0000002A
Length: 72
CFE Header: 0x004C
Packet Header:
   0x0000002A004C0000
   0x0000000000000000      <<<<<<<<<<<<<<<<<<<<<<<<
   0x0000080045C00034
   0x00000000FF11A4F4
   0x0A0101020A010101
   0x0EC80EC800205FC9
   0x2048031800000101
   0x00000000000F4240
   0x000F42400000C350
   0x0000000000000000
   0x0000000000000000
   0x0000000000000000
   0x0000000000000000
   0x0000000000000000
   0x0000000000000000
   0x0000002A005BD0C2
=======================
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