25 Aug
2008
25 Aug
'08
6:56 a.m.
On 25 aug 2008, at 12:27, Fernando Gont wrote:
IPv4 minimum MTU is 68 bytes,
That's kind of like "a human being can live without food for four to six weeks". It's not a recommendation.
536 is the minimum fragment re-assembly buffer size. Falling back to 536-byte packets does not guarantee that sessions will be kept up.
But: "PMTU black hole router detection is triggered on a TCP connection when TCP starts retransmitting full-sized segments with the DF flag set. TCP resets the PTMU for the connection to 536 bytes. Then, TCP retransmits its segments when the DF flag is clear."