Thus spake "Loureiro, Rodrigo - (Bra)" <rodrigo.loureiro@attla.com>
> Does anyone know what is the maximum datagram a Cisco MP-iBGP peer
> can send to a neighbor ?
The MTU, of course.
> I checked in many Cisco sources, but i could not get a precise response.
> RFC 1771 says that the maximum datagram size should be 4096 bytes.
The section you misread is:
"Messages are sent over a reliable transport protocol connection. A message
is processed only after it is entirely received. The maximum message size
is 4096 octets."
BGP messages are passed over TCP/179; how TCP chops up those messages into
segments is a function of the TCP stack, not the BGP implementation.
> Also, i found in "sh ip bgp neighbor" output the following line:
"Datagrams
> (max data segment is 536 bytes)".
Okay, TCP has for some reason negotiated a MSS of 536, which means a maximum
datagram size of 576, assuming you're using IPv4 and there are no IP or TCP
options present.
> And this message appeared in other code versions. Can i consider this
value
> as the maximum datagram size in Cisco´s implementation ?
Not if you want to be safe.
S
This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:13:21 EDT