Cisco 7206 router question

[PouyaNasir]

Hi,

I have a Cisco 7206VXR Router with NPE-G1 with its PA-GE connected to 3x Gigabit module in a Cisco 12012 with PRP-1.

When my traffic exceeds 300Mbps 400Mbps I start seeing about 3% packet loss in the link and input errors (ignored) start increasing on the 7206 gigabit interface at the same time.

From what I gathered in my googling 7206VXR with G1 can support upto 600Mbps in each of its sides (slot 1,3,5 and slot 2,4,6). As I don't have any other interfaces on the same side of the said pa-ge, I don't see how this shoudl affect me. I tried changing the fiber patch cord, the PA-GE module, the slot it is installed, the gigabit interface on 12012 on the same module and also another module on 12012.

I'm running into a deadend here. Anyone has experience with gigabit traffic on 7206 or 12012?

P.S: Sorry for the bad English.

 

[VinceWhirlwind]

Don't overlook the possibility of your cabling being not up to scratch.

 

[PouyaNasir]

The cabling is just a 15m fiber patch cord, which I changed with another one with no result.

 

[VinceWhirlwind]

What grade fibre?

 

[PouyaNasir]

Its 9/125 µm single mode fiber patch cord.

 

[VinceWhirlwind]

I guess if I was having this problem, I would look at
- overdriving the laser receivers? Need attenuators?
- do a show int on each side to see what errors are being reported
- check your config for any throttling, QoS-related funniness.
- try a different pair of modules
- professionally test the fibre cabling

 

[PouyaNasir]

show int shows the following errors only on the 7206 side.

905376 input errors, 0 CRC, 0 frame, 2341 overrun, 903035 ignored

12012 shows no errors.

 

[VinceWhirlwind]

It looks like the 7206 can't handle what the 12012 can throw at it.

Where does the traffic coming from 12012-->7206 go from there? In other words are the egress interfaces from the 7206 maxed out?

Try a "show buffers".

Do a show proc cpu and see if the "ignored" errors increment when the CPU is maxed out.

Otherwise, maybe you can fiddle with the buffers to eke a bit more performance out of it:

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00800a7b80.shtml