IPv6 Multi-homing (was IPv6 /64 links)

Mon Jun 25 19:20:22 UTC 2012

On Mon, Jun 25, 2012 at 1:09 PM, Douglas Otis <dotis at mail-abuse.org> wrote:
> On 6/25/12 7:54 AM, Owen DeLong wrote:
>> It would have been better if IETF had actually solved this instead
>> of punting on it when developing IPv6.
>
> The IETF offered a HA solution that operates at the transport level.
> The transport is SCTP

Hi Douglas,

SCTP proposes a solution to multihoming by multi-addressing each
server. Each address represents one of the leaf node's paths to the
Internet and if one fails an SCTP session can switch to the other.
Correct?

How does SCTP address the most immediate problem with multiaddressed
TCP servers: the client doesn't rapidly find a currently working
address from the set initially offered by A and AAAA DNS records. Is
there anything in the SCTP protocol for this? Or does it handle it
exactly the way TCP does (nothing at all in the API; app-controlled
timeout and round robin)?

Is the SCTP API drop-in compatible with TCP where a client can change
a parameter in a socket() call and expect it to try SCTP and promptly
fall back to TCP if no connection establishes? On the server side,
does it work like the IPv6 API where one socket accepts both
protocols? Or do the apps have to be redesigned to handle both SCTP
and TCP?

Regards,
Bill Herrin

-- 
William D. Herrin ................ herrin at dirtside.com  bill at herrin.us
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