Can't find what you need?

• Ask the Community
• Create a Case
Reset Search



High BCMRX and MCMGR process causing network issues

« Go Back


TitleHigh BCMRX and MCMGR process causing network issues
In the "top" output, high BCMRX and MCMGR processes are seen.
In the "show l2stats" output,  number of packets lifted to CPU is high as highlighted below -
Switch # show l2stats
Bridge interface on VLAN <VLAN_NAME>:
Total number of packets to CPU = 154303.
Total number of packets learned = 1010.
Total number of IGMP control packets snooped = 178828.
Total number of IGMP data packets switched = 1040056.
Total number of MLD control packets snooped = 0.
Total number of MLD data packets switched = 0.

Possible multicast loop scenario.
Rogue user pumping multicast and broadcast traffic.
Narrow down the rogue user using the "show port statistics command" and check for "Rx Mcast" and "Rx Bcast" incrementing rapidly.
Switch # show port 1:1 statistics no
Port      Link       Tx Pkt     Tx Byte      Rx Pkt     Rx Byte      Rx Pkt      Rx Pkt      Tx Pkt      Tx Pkt
          State       Count       Count       Count       Count       Bcast       Mcast       Bcast       Mcast
========= ===== =========== =========== =========== =========== =========== =========== =========== ===========
1:1       A           11318       28513     1283674    78614110      193437     1064086       67858       27553
========= ===== =========== =========== =========== =========== =========== =========== =========== ===========
          > in Port indicates Port Display Name truncated past 8 characters
          > in Count indicates value exceeds column width. Use 'wide' option or '0' to clear.
          Link State: A-Active, R-Ready, NP-Port Not Present, L-Loopback

Arrest the traffic by disabling the port and check to see if BCMRX and MCMGR CPU usage drops.
Additional notes



Was this article helpful?



Please tell us how we can make this article more useful.

Characters Remaining: 255