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

[Judah Scott]

Yes what you see is correct behavior (for those MX DPCs).  I doubt it's a
cell size issue or you would see a saw-tooth.  Instead what you can infer is
that each of the 4 PFE's are limited to the packets-per-second they can
process depending on the transport type involved.  I.E. VPLS is really bad
at low packet sizes but pure L3 is good.

-J Scott


On Thu, Feb 18, 2010 at 5:08 PM, OBrien, Will <ObrienH at missouri.edu> wrote:

> We have been running 10G R cards exclusively in our pair of MX960s - so far
> we have had no issues with vpn tunnels coming in/out and we have many of
> them. We don't run voip over that particular connection either. In fact,
> we've really seen no problems with traffic going through them at all. We do
> run them exclusively at the edge of our network as border routers for I1 and
> I2 traffic.
>
> Typical I1 load is near a Gb and I2 usually has a few.
>
> Will
>
> On Feb 18, 2010, at 6:28 PM, Serge Vautour wrote:
>
> > 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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