[j-nsp] RFC2544 on Juniper MX960 10G ports

[Serge Vautour]

Hello,

We recently used a traffic generator to run RFC2544 tests against a Juniper MX960. The 1G ports work flawlessly. 0% packet loss at all frame sizes. 

The 10G ports  (4x10G "R" card) didn't do as well. They dropped up to 25% packets with certain small frames (ex: 70 byte frames). The packet loss goes away almost completely for frames larger than 100 bytes. Our SE tells us this is normal and is due to how the MX chops the frames up into 64 byte cells inside the PFE. The 4x10G cards have 4 separate PFEs (1 per 10G port) and each of them has 10G of bandwidth. 10G of small frames essentially creates more than 10G of traffic inside the PFE. That explanation may not be 100% correct but I think it paints the right picture.

Now the questions. Is this a problem on production networks with real world traffic? What about on VPN networks with alot of small frames like VoIP? Has anyone seen this problem creep it's head in production?

It seems very unlikely to me that a maxed 10Gbps link would carry 7.5Gbps of frame sizes less than 100 byte. I would expect larger frames to use up the majority of the bandwidth. Can anyone correlate this with real world traffic?

As usual, the help received on this distribution list is invaluable. Thanks in advance to anyone who replies.

Serge


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