7206 NPE-G2 - High CPU, Low Bandwidth - POS

Unanswered Question
Nov 4th, 2008

Hello,

I currently have 2 7206 VXR routers with NPE-G2's in them. One of them is running a POS OC3, doing about 125Mbps inbound with 1Mbps outbound. This is the termination point for en eBGP peer, with a 5 line ACL on the interface also. I am seeing close to 85% CPU usage on this router, which seems to be extremely high, with only 80Kpps going through the OC3. I was wondering if anyone has experienced this problem with POS interfaces with the 7206 NPE-G2, I am running cef.

To compare, our second 7206 has a GigE connection to another eBGP peer, which runs roughly 100Mbps inbound and 175Mbps outbound, same setup, just using a GigE interface, and the CPU usage is roughly 45%.

We shifted all of the OC3 Bandwidth over to the other 7206, by turning down that eBGP peer, and now that GigE connection runs at roughly 310Mbps inbound and 250Mpbs outbound, with 75% CPU.

My main concern is these NPE-G2's are supposed to be able to handle 800Mbps or so, and at 75% CPU, this seems to be untrue.

Has anyone seen similar problems with the G2's?

I have this problem too.
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Giuseppe Larosa Tue, 11/04/2008 - 09:26

Hello Jason,

there was a similar thread some time ago with a collegue that was seeing the same behaviour.

It looks like that NPE-G2 is better in using its built in GE ports then using a WAN PA like a POS PA where it has to go through the PCI bus.

Another thought is that there are two types of POS PA with the one that contains the 1OC3 in the name is the newer.

The older is end of sale since December 2006.

the PA-POS-OC3 is older:

http://www.cisco.com/en/US/products/hw/modules/ps2033/products_data_sheet09186a0080091c88.html

Packet over SONET/SDH Port Adapter for the Cisco 7200 and 7500

The PA-POS-OC3MM, PA-POS-OC3SML and PA-POS-OC3SMI are now End of Sales (EOS) as of July 31, 2006 for all supported platforms. For more details, please see product bulletin:

http://www.cisco.com/en/US/products/hw/modules/ps2033/prod_eol_notice0900aecd80224b94.html

the name was changed because now exist also the PA-POS-2OC3 with two ports.

So this is something to be checked

However forwarding performance is not the the most interesting feature in this device that is usually deployed as Route Reflector Server.

From tests I did on NPE-G1 I can also say that CPU load doesn't grow linearly with offerred traffic volume.

Marketing numbers are also half-duplex usually: so you cannot expect with 2,000,000 pps capacity to fill a GE with frames of 64 bytes in both direction (this is what we think is wire speed).

Hope to help

Giuseppe

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