[c-nsp] Unknown Multicast Traffic cause High CPU

[Ramón Alvarez R.]

Hello,

 

We have a metrothernet customer using vlan 993, we are experimenting high
CPU usage by unknown multicast traffic coming from this vlan id 993 and this
expand over several switches on the network, but when we remove the vlan
from some pop sites the behavior stop. After that we add the vlan id, again,
and the behavior is normal.

 

We setup a multicast filter to this equipment but this issue is showing
every few days. The multicast filter is:

 

ip igmp profile 1

    range 224.0.0.0 239.255.255.255

 

interface FastEthernet2/30

 switchport access vlan 704

 switchport trunk encapsulation dot1q

 switchport trunk allowed vlan
100,199,269,270,291,292,378,379,474,475,535,536

 switchport trunk allowed vlan add
615-620,677,678,703-705,715-735,805,826,829

 switchport trunk allowed vlan add
856,864,867,869,890,916,922,943,958,992,993

 switchport trunk allowed vlan add
996,1108-1110,1120-1122,1183-1185,1353,1354

 switchport trunk allowed vlan add 1363,1364,1375,1376,2513,2514

 switchport mode trunk

 switchport nonegotiate

 no cdp enable

 spanning-tree portfast

 spanning-tree bpdufilter enable

 spanning-tree bpduguard enable

 ip igmp filter 1

 

 

SW_4503#sh processes cpu | e 0.0
CPU utilization for five seconds: 99%/0%; one minute: 98%; five minutes: 91%
 PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process 
  30  17955901802907757383        617 69.35% 68.33% 63.77%   0 Cat4k Mgmt
LoPri 
  71     7245976  48021324        150  2.00%  2.31%  2.12%   0 MRD

  72    42231304  74816636        564 23.11% 21.86% 20.34%   0 IGMPSN


SW_4503#sh ip igmp snooping mrouter                         
Vlan    ports
----    -----
 993    Fa2/30(dynamic), Gi3/2(dynamic)

 

SW_4503#sh run int fa2/30
Building configuration...

 

Current configuration : 681 bytes
!
interface FastEthernet2/30

 switchport access vlan 704
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan
100,199,269,270,291,292,378,379,474,475,535,536
 switchport trunk allowed vlan add
615-620,677,678,703-705,715-735,805,826,829
 switchport trunk allowed vlan add
856,864,867,869,890,916,922,943,958,992,993
 switchport trunk allowed vlan add
996,1108-1110,1120-1122,1183-1185,1353,1354
 switchport trunk allowed vlan add 1363,1364,1375,1376,2513,2514
 switchport mode trunk
 switchport nonegotiate
 no cdp enable
 spanning-tree portfast
 spanning-tree bpdufilter enable
 spanning-tree bpduguard enable
 ip igmp filter 1
end

 

SW_4503#conf ter
Enter configuration commands, one per line.  End with CNTL/Z.
SW_4503(config)#int fa2/30
SW_4503(config-if)# switchport trunk allowed vlan remove 993
SW_4503#
SW_4503#sh processes cpu | e 0.0   
CPU utilization for five seconds: 14%/0%; one minute: 82%; five minutes: 89%
 PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process 
  29  2352303324 512512734       4589  2.87%  3.54%  3.72%   0 Cat4k Mgmt
HiPri 
  30  17956380562907774138        617  8.63% 56.76% 61.92%   0 Cat4k Mgmt
LoPri 
  72    42246460  74829450        564  0.71% 17.40% 19.51%   0 IGMPSN

 115    41220440  58103914        709  0.47%  0.14%  0.12%   0 SNMP ENGINE