[Xorp-hackers] TCP sockets and packet splitting

[Victor Faion]

On Tue, Jun 9, 2009 at 08:31, Bruce Simpson <bms at incunabulum.net> wrote:

> Bruce Simpson wrote:
>
>> With most TCP/IP implementations, the MTU of the loopback interface will
>> be 65535 bytes. As you probably know already, the segment size used by a TCP
>> session is going to be negotiated upfront during the 3 way handshake.
>>
>
> Sorry, I meant to say 16384 bytes here (at least, that's the default in
> FreeBSD). It can usually be tweaked upwards.
>
> In any event, whilst the MTU of the loopback interface will affect XORP XRL
> IPC transport, the loopback MTU is *usually* sufficiently large not to cause
> problems with the socket4.xif, unless you are attempting to send IPv6
> jumbograms.
>
> cheers,
> BMS
>

Thanks for the reply, I was using TCP sockets with IPv4 packets, that's why
I thought XORP would handle the merging, but I saw the comment in
IoTcpUdpSocket::send():

	// We don't coalesce for TCP as well, but this could be changed in the
	// future if it improves performance.

I think the socket library should indicate to the programmer when it's going
to split the packet being sent.

Cheers,
Victor
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ICSI.Berkeley.EDU/pipermail/xorp-hackers/attachments/20090609/c9487823/attachment.html