[f-nsp] Multicast causing high CPU

[Alexey Kouznetsov]

Hello!

We got the problem with high CPU usage on our bigiron 8000 router managed
by:

SL 3: BxGMR4 M4 Management Module, SYSIF 2 (Mini GBIC), M4, ACTIVE
      Serial #:
8192 KB BRAM, SMC version 1, BM version 21
  512 KB PRAM(512K+0K) and 2048*8 CAM entries for DMA  8, version 0209
  512 KB PRAM(512K+0K) and shared CAM entries for DMA  9, version 0209
  512 KB PRAM(512K+0K) and 2048*8 CAM entries for DMA 10, version 0209
  512 KB PRAM(512K+0K) and shared CAM entries for DMA 11, version 0209

When MC traffic goes to near 80 MBit (with packet size about 1300 bytes) we
got near 100% CPU usage apd MC packet lost.

telnet at BigIron Router#show cp
74 percent busy, from 141995 sec ago
1 sec avg: 96 percent busy
5 sec avg: 97 percent busy
60 sec avg: 96 percent busy
300 sec avg: 96 percent busy

telnet at BigIron Router#show processes cpu
Process Name 5Sec(%) 1Min(%) 5Min(%) 15Min(%) Runtime(ms)
IP_M 69.22 83.14 80.04 71.83 95219021
rest counters here near to 0.

Currently this switch doing the MC routing and L2 switching to 7*8 GB ports.
Switching itself work withot problems. Routing of MC work perfect untill it
load CPU less then 70-80%. then packet lost and as far as thi is TV unusable
picture.
as far as I can see from  sh ip pim mcache

1    (x.x.y.194 224.0.x.16) in v11 (tag e6/8), cnt=28266
     upstream nbr is x.x.x.109 on v11 using ip route
     Sparse Mode, RPT=0 SPT=1 REG=0 MSDP Adv=0 MSDP Create=1
     L3 (SW) 1: tag e8/8(VL1018)
     fast=0 slow=1 pru=0 swL2=0 hwL2=0 tag graft 0L2C
     age=0s up-time=2m no fid, no flow,
2    (* 224.0.x.16) RP x.x.x.109, in NIL (NIL), cnt=2028
     RP is directly connected
     Sparse Mode, RPT=1 SPT=0 REG=0 MSDP Adv=0 MSDP Create=0
     L3 (SW) 1: tag e8/8(VL1018)
     fast=0 slow=1 pru=0 swL2=0 hwL2=0 tag graft 0L2C
     age=0s up-time=2m no fid, no flow,

switchig works in software, not hardware mode. path to 224.0.x.16 receiced
via msdp connection. MCast route to x.x.y.194 received via MBGP (but I tried
to make static route, both route and mroute to such address)

all mcast related config bellow.

ip multicast-routing

ip multicast-perf
ip show-subnet-length
ip igmp query-interval 120
ip igmp group-membership-time 240

no ip source-route
ip multicast passive
ip multicast filter
ip multicast hardware-drop

mcast-hw-replic-oar

router pim
rp-address х.х.х.1 0
hardware-drop

router msdp
msdp-peer х.х.х.2
ttl-threshold х.х.х.2 10

interface ve 1
ip address y.y.31.2/24
ip pim-sparse
!
interface ve 3
ip address y.y.1.2/24
ip pim-sparse

..
! This is intercase where MC come from
interface ve 11
ip address x.x.x.1/30
ip pim-sparse
ip pim border

I saw there mail from someone to create ve interface w/o IP address... in
this case such vlan does not receve MC at all. Also I tried to disable L2
mcast
no ip multicast
but no any changes seen.

Any ideas how to force HW MC routing ?

With best regards
/Alexey
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