High CPU usage on Cisco 7604 RSP720-3C-GE IOS 12.33SRB1

Unanswered Question

Well, we have in subj mentioned hardware with line module X6724SFP+DFC3C, it works as our border - aggregates full views from 4 uplink providers and propagades it to mpls-core.

There is 30 ebgp/ibgp peers & 6 ip-ip tunnels.

Overall traffic-load is about 1,5Gb/sec.


Therewith cpu-load is about 90%!!!


CEF _is_ enabled )))


#show cef state

CEF Status:

RP instance

common CEF enabled

IPv4 CEF Status:

CEF enabled/running

dCEF enabled/running

CEF switching enabled/running

universal per-destination load sharing algorithm, id 3EA34FD7

IPv6 CEF Status:

CEF disabled/not running

dCEF disabled/not running

universal per-destination load sharing algorithm, id 3EA34FD7

RRP state:

I am standby RRP: no

RF Peer Presence: no

RF PeerComm reached: no

RF Progression blocked: never

Redundancy mode: sso(3)

CEF NSF sync: disabled/not running


CEF ISSU Status:

FIBHWIDB broker

No slots are ISSU capable.

FIBIDB broker

No slots are ISSU capable.

FIBHWIDB Subblock broker

No slots are ISSU capable.

FIBIDB Subblock broker

No slots are ISSU capable.

Adjacency update

No slots are ISSU capable.

IPv4 table broker

No slots are ISSU capable.

CEF push

No slots are ISSU capable.


#show logg

...

Apr 24 00:15:32: %CFIB-SP-7-CFIB_EXCEPTION: FIB TCAM exception, Some entries will be software switched

Apr 24 00:15:34: %CFIB-DFC4-7-CFIB_EXCEPTION: FIB TCAM exception, Some entries will be software switched

...


#show ip route summary

IP routing table name is default (0x0)

IP routing table maximum-paths is 32

Route Source Networks Subnets Replicates Overhead Memory (bytes)

connected 0 37 0 1924 6364

static 8 24 0 1700 5504

ospf 1 1 92 0 6324 17856

Intra-area: 17 Inter-area: 0 External-1: 0 External-2: 76

NSSA External-1: 0 NSSA External-2: 0

bgp 29648 129539 125567 0 13265512 43878232

External: 254935 Internal: 171 Local: 0

internal 3585 10635920

Total 133133 125720 0 13275460 54543876



Where should we seek for resolving?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4 (2 ratings)
Loading.
Sushil Kumar Katre Thu, 04/24/2008 - 05:37
User Badges:
  • Gold, 750 points or more

Hi,


The error that you are getting "CFIB-SP-7-CFIB_EXCEPTION" suggests that the amount of available space in the TCAM is exceeded which is resulting in high CPU. This is a FIB TCAM limitation.


Once TCAM is full, a flag will be set and FIB TCAM exception is received. This stops from adding new routes to the TCAM. Therefore, everything will be software switched. The removal of routes does not help resume hardware switching.


Once the TCAM enters the exception state,

the system must be reloaded to get out of that state. So try reloading the router.


The maximum routes that can be installed in TCAM is increased by the mls cef maximum-routes command.


-> Sushil

Actions

This Discussion