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Cisco Bug: CSCsz51146 - TCP bad segment and sequence number in BGP raises CPU on SXI1 modular

Last Modified

Feb 23, 2018

Products (1)

  • Cisco IOS

Known Affected Releases


Description (partial)

Cisco WS-6509-Es running 12.2(33)SXI1 modular and BGP, gets into a state of receiving bad segment and sequence number from it's BGP peers.  This raises the CPU on device significantly.

MP_SW#sh proc cpu | ex 0.0
CPU utilization for five seconds: 58%/38%; one minute: 52%; five minutes: 60%
PID       5Sec    1Min     5Min Process
1         0.1%    0.3%     0.5% kernel                        
24599    39.6%   34.5%    40.3% ios-base                      
24620     0.6%    0.3%     0.4% raw_ip.proc                   
24622    15.6%   13.6%    16.7% tcp.proc                      
24624     2.7%    3.6%     2.0% iprouting.iosproc   


High CPU


Link flap or router reloads lead change in topology and trigger routing protocol update.
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