Ping problem to Gigabit cards 77xx with large buffer size (-l option)

[Ph. de Saint-Georges]

Hello,

I just have discovered that all my HP DL380 Gigabit Nics (7781/7782) on DL380G3 and G4 don't answer to a ping test with larger packet size (> 25000) than default (32) ...

Using the following command ping x.x.x.x -l 50000, I always get a request timed out message

No special parameter has been used when configuring these cards. Last drivers have been applied

Windows 2003 server SP1
Network Utility 8.20.0.16
Driver 8.48.0.0

On the same network, HP 100TX Nics (3163 per exampe) on DL380G2 respond well to this kind of ping with packet as bigger as 50000...

Does anybody know why this happens? Is it normal?

Thanks in advance for help

Philippe

[Ivan Ferreira]

I think this is not normal, check your network statistics with netstat -s, also check your switch port statistics, ensure that they are negotiating correctly.

[Alan_152]

large packet sizes are going to fragment on an ethernet network. Your switches or routers might not be configured to handle frag'd packets. I don't remembet what the critical size is offhand (shame on me) but it is north of 15000.

But first, you may need to optimize your interfaces. Download a copy of DrTCP and use it to optimize things...