[c-nsp] mpls hw limits on 7206

[Gert Doering]

Hi,

On Thu, Jun 29, 2006 at 02:36:42PM +0100, David Freedman wrote:
> Yes, if you are implementing ethernet L2VPNs and wish to allow your 
> customers to have the ability to carry standard "ip mtu" (1500B) inside 
> their ethernet frames, then steer clear of the following interface types 
> for the uplink to the core / other MPLS routers:
> 
> - PA-FE-TX
> - PA-2FE-TX
> - PA-FE-FX
> - IO/FE
> - IO/2-FE

Have you found evidence in the meantime that the 2FE boards (intel-based)
have the very same 1530-byte-problem as the FE boards (digital based)?

Rodney, can you comment on that?  As it seems to be a chipset issue, 
using a different chipset might change things...

BTW: is there a way to actually notice if this problem strikes?  I'm
asking because I recently set up an EoMPLS link that crosses a IO-2FE
board, configured to "mpls mtu 1530" on 12.2(18)S12 - and transporting
full-sized ethernet frames plus two labels (1518+4+4+18 = 1544 on-the-wire)
doesn't seem to cause any issues.  I regularily see about 90 Mbit/s of
TCP traffic go through, and if there is packet corruption, the TCP 
endpoints would certainly notice.

gert
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de