From: Ido Schimmel <idosch@idosch.org>
To: Or Gerlitz <gerlitz.or@gmail.com>
Cc: David Ahern <dsahern@gmail.com>,
Linux Netdev List <netdev@vger.kernel.org>,
Roopa Prabhu <roopa@cumulusnetworks.com>,
Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
Ido Schimmel <idosch@mellanox.com>,
Tom Herbert <tom@herbertland.com>
Subject: Re: [PATCH RFC net-next 0/7] net/ipv6: Add support for path selection using hash of 5-tuple
Date: Tue, 13 Feb 2018 14:42:05 +0200 [thread overview]
Message-ID: <20180213124205.GB17908@splinter> (raw)
In-Reply-To: <CAJ3xEMhtpmcNRNH9p5a2=RHCPZq1HW_y6pnPF45UAFVeCDgang@mail.gmail.com>
On Tue, Feb 13, 2018 at 01:03:14PM +0200, Or Gerlitz wrote:
> On Tue, Feb 13, 2018 at 2:05 AM, David Ahern <dsahern@gmail.com> wrote:
> > Hardware supports multipath selection using the standard L4 5-tuple
> > instead of just L3 and the flow label. In addition, some network
> > operators prefer IPv6 path selection to use the 5-tuple.
>
> The HW supports using flow label and AFAIK that is the preferred approach
> by the community (?)
>
> > To that end, add support to IPv6 for multipath hash policy
>
> so a question comes up if/what are the disadvantaged
> to support 5-tuple. E.g Tom was commenting that such DPI is problematic
> when multiple IPv6 header extensions are used.
Tom is much more qualified to answer this, but I think the problem is
that the flow label isn't always set. Also, apparently some devices
change the flow label mid flow. See:
"At Fastly, this hashing is performed by an Ethernet switch ASIC, and to
avoid breakage, the IPv6 hashing function must not include the flow
label. As in IPv4, the hash function includes the source and destination
information in the L3 and L4 headers."
https://blog.apnic.net/2018/01/11/ipv6-flow-label-misuse-hashing/
https://www.youtube.com/watch?v=b0CRjOpnT7w
https://pc.nanog.org/static/published/meetings/NANOG71/1531/20171003_Jaeggli_Lightning_Talk_Ipv6_v1.pdf
next prev parent reply other threads:[~2018-02-13 12:42 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-13 0:05 [PATCH RFC net-next 0/7] net/ipv6: Add support for path selection using hash of 5-tuple David Ahern
2018-02-13 0:05 ` [PATCH RFC net-next 1/7] net/ipv4: Pass net to fib_multipath_hash instead of fib_info David Ahern
2018-02-13 0:05 ` [PATCH RFC net-next 2/7] net: Align ip_multipath_l3_keys and ip6_multipath_l3_keys David Ahern
2018-02-13 0:05 ` [PATCH RFC net-next 3/7] net/ipv6: Make rt6_multipath_hash similar to fib_multipath_hash David Ahern
2018-02-13 0:05 ` [PATCH RFC net-next 4/7] net: Rename NETEVENT_MULTIPATH_HASH_UPDATE David Ahern
2018-02-13 0:06 ` [PATCH RFC net-next 5/7] net/ipv6: Add support for path selection using hash of 5-tuple David Ahern
2018-02-13 20:31 ` Nicolas Dichtel
2018-02-13 20:35 ` David Ahern
2018-02-13 20:59 ` Nicolas Dichtel
2018-02-13 21:02 ` David Ahern
2018-02-13 21:21 ` Nicolas Dichtel
2018-02-21 16:22 ` Ido Schimmel
2018-02-21 17:54 ` David Ahern
2018-02-13 0:06 ` [PATCH RFC net-next 6/7] mlxsw: spectrum_router: Add support for ipv6 hash policy update David Ahern
2018-02-13 0:06 ` [PATCH RFC net-next 7/7] net: Remove unused get_hash_from_flow functions David Ahern
2018-02-13 11:03 ` [PATCH RFC net-next 0/7] net/ipv6: Add support for path selection using hash of 5-tuple Or Gerlitz
2018-02-13 12:42 ` Ido Schimmel [this message]
2018-02-13 13:16 ` Or Gerlitz
2018-02-14 22:45 ` Or Gerlitz
2018-02-13 15:21 ` David Ahern
2018-02-14 22:45 ` Or Gerlitz
2018-02-14 22:56 ` David Ahern
2018-02-18 10:40 ` Or Gerlitz
2018-02-13 12:32 ` Ido Schimmel
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