[c-nsp] 6500 SUP720 High Latency and Jitter issues

Tim Stevenson tstevens at cisco.com
Tue May 24 12:53:14 EDT 2005


If you are measuring latency by pinging the RP itself, then that is not a 
good indicator of network performance at all. Are you saying that pings 
*through* the 6500 see the latency as well? or just pings to the RP? Your 
original mail suggests customers are being impacted, so either their 
traffic is getting s/w switched, or the CPU has little/nothing to do w/it.

As long as the h/w is programmed correctly, the CPU can be at 100% and not 
effect latency through the system.

Are the customers that are seeing the problem the same ones that are being 
NATted?

Tim

At 07:59 AM 5/24/2005, Dan Benson pronounced:
>This router has been in place for about 3 weeks.  Load has increased in
>this period, we have not seen this issue untill the last 2 days.
>Nothing has changed on the BGP/OSPF config.  When I ping other devices
>on the LAN, I do not have any latency or loss.  This only seems to occur
>when we hit the RP.  Pinging a device on the LAN from either of our
>upstreams returns the same results.
>
>Lupi, Guy wrote:
>
> >Was this switch in the network prior to this issue occurring or is this
> >switch new?  Any configuration changes to the switch, BGP or OSPF?  If you
> >ping from an IP serviced by a directly connected interface to an IP serviced
> >by another directly connected interface do you see the same results?  How
> >about pings from the switch to an IP serviced by a directly connected
> >interface?
> >
> >-----Original Message-----
> >From: cisco-nsp-bounces at puck.nether.net
> >[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Dan Benson
> >Sent: Tuesday, May 24, 2005 10:17 AM
> >To: cisco-nsp at puck.nether.net
> >Subject: [c-nsp] 6500 SUP720 High Latency and Jitter issues
> >
> >Hello all, I am in dire need of some assistance with a new problem that has
> >started occurring in one of my networks.  We are seeing very high Latency
> >and Jitter traversing one of our 6509's that has a sup720 with the PFC3BXL
> >and a GIG or Ram.  This period occur every 10 to 15 seconds, and last for
> >about 2 seconds.  This is causing a massive amount of troubles for our
> >customers and I am at a loss as to what could be the cause.
> >
> >Hardware:
> >
> > Cisco 6509, Fan2, Sup720,PFC3BXL, 1GIGe of Ram, 1x8 port GBIC gige,
> >1x48 port FE.
> >
> >Config:
> >
> > IOS Version 12.2(18)SXD3, running 2 full BGP routing tables to ISP's VIA FE
> >and GIGe.  OSPF running for core network with 5 neighbors.  2 VLans with
> >ports assigned to them.  6 GRE tunnels for private access to other offsite
> >POPs.  NAT running with overload to a public VLAN interface.  Router CPU
> >average load is 50% per 24 hours, peaks around 60%, lows around 20%.  Mem
> >usage is at 20%.
> >
> >Issue:
> >
> >Every 5 to 15 seconds we are seeing pings like this traversing the box:
> >
> >64 bytes from 147.135.0.16: icmp_seq=2099 ttl=63 time=1.000 ms
> >64 bytes from 147.135.0.16: icmp_seq=2100 ttl=63 time=1.000 ms
> >64 bytes from 147.135.0.16: icmp_seq=2101 ttl=63 time=1.033 ms
> >64 bytes from 147.135.0.16: icmp_seq=2102 ttl=63 time=1.037 ms
> >64 bytes from 147.135.0.16: icmp_seq=2103 ttl=63 time=1.001 ms
> >64 bytes from 147.135.0.16: icmp_seq=2104 ttl=63 time=86.345 ms
> >64 bytes from 147.135.0.16: icmp_seq=2105 ttl=63 time=179.171 ms
> >64 bytes from 147.135.0.16: icmp_seq=2106 ttl=63 time=178.301 ms
> >64 bytes from 147.135.0.16: icmp_seq=2107 ttl=63 time=108.800 ms
> >64 bytes from 147.135.0.16: icmp_seq=2108 ttl=63 time=33.387 ms
> >64 bytes from 147.135.0.16: icmp_seq=2109 ttl=63 time=1.018 ms
> >64 bytes from 147.135.0.16: icmp_seq=2110 ttl=63 time=1.014 ms
> >64 bytes from 147.135.0.16: icmp_seq=2111 ttl=63 time=1.064 ms
> >64 bytes from 147.135.0.16: icmp_seq=2112 ttl=63 time=1.023 ms
> >64 bytes from 147.135.0.16: icmp_seq=2113 ttl=63 time=1.042 ms
> >
> >I am used to the 60 sec. ICMP de-pri BGP update CPU load pinging the box
> >directly, but I have never seen this effect devices on the far side of the
> >router.  Any input on this is greatly appreciated.  //db
> >
> >
> >
> >
> >
> >_______________________________________________
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> >
> >
> >
> >
>
>
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Tim Stevenson, tstevens at cisco.com
Routing & Switching CCIE #5561
Technical Marketing Engineer, Catalyst 6500
Cisco Systems, http://www.cisco.com
IP Phone: 408-526-6759
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