TSO for IPv6 traffic

Network related discussions (including general TCP/IP stuff, routing, etc).

TSO for IPv6 traffic

Postby shreyasbforu » 20 Oct 2010, 23:36

Looking at the FreeBSD networking stack, TSO is not asked for outgoing IPv6 packets
http://fxr.watson.org/fxr/source/netinet/tcp_output.c#L1075

CSUM_TSO is not set for IPv6 packets going out even when driver advertises IFCAP_TSO6. Any reasons why TSO over IPv6 is not supported ?
OR
Any idea as to what work is involved in making this happen ?

Thanks in advance.
->Shreyas
shreyasbforu
Junior Member
 
Posts: 1
Joined: 20 Oct 2010, 23:32

Postby SirDice » 21 Oct 2010, 11:48

Andre wrote that TSO for IPv4 and IPv6 is always enabled or disabled together. But IPv6 currently lacks a pseudo-header checksum function and thus doesn't support TSO yet.

http://www.bsdunix.ch/serendipity/index.php?/archives/374-TCP-segmentation-offload-in-FreeBSD-Current.html
Senior UNIX Engineer at Unix Support Nederland
Experience is something you don't get until just after you need it.
User avatar
SirDice
Old Fart
 
Posts: 16185
Joined: 17 Nov 2008, 16:50
Location: Rotterdam, Netherlands

Postby phoenix » 21 Oct 2010, 15:36

Search the freebsd-current mailing list for this week, specifically a thread with subject "IPV6 Checksum offload and TSO6", for a dicsussion of this topic. It appears that hardware is available that supports these functions (Intel), but the network stack doesn't support the features yet. A couple of coders are considering working on this in November.
Freddie

Help for FreeBSD: Handbook, FAQ, man pages, mailing lists.
User avatar
phoenix
MFC'd
 
Posts: 3349
Joined: 17 Nov 2008, 05:43
Location: Kamloops, BC, Canada

Postby acheron » 21 Oct 2010, 15:38

acheron
Junior Member
 
Posts: 92
Joined: 18 Aug 2010, 11:37
Location: France


Return to Networking

Who is online

Users browsing this forum: No registered users and 2 guests