[j-nsp] mx960 to mx960 via ciena 6500 - mtu smaller in the middle

[Gert Doering]

Hi,

On Tue, Apr 17, 2018 at 12:34:18PM +0300, Saku Ytti wrote:
> On 17 April 2018 at 11:25, James Bensley <jwbensley at gmail.com> wrote:
> 
> > Also you say you have OSPF and LDP up but if you bring up BGP over
> > this link you may have issues. BGP packs UPDATE messages up to the TCP
> > MSS (derived from the link MTU). If you are carrying the full table
> 
> BGP messages are limited to 4096.

Which does not stop TCP from coalescing two messages into one 8 kbyte packet.

(As in "I have had a link that was transported over someone else's packet
network, and when they re-routed in an outage, I lost 8 bytes MTU, 
resulting in TCP failing across a 9200-minus-8-byte-link...")

gert
-- 
"If was one thing all people took for granted, was conviction that if you 
 feed honest figures into a computer, honest figures come out. Never doubted 
 it myself till I met a computer with a sense of humor."
                             Robert A. Heinlein, The Moon is a Harsh Mistress

Gert Doering - Munich, Germany                             gert at greenie.muc.de
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