Subject: [Tsvwg] SCTP - Multihoming capability

From: "Ganesh Raaja, Natarajan" <[email-masked]>
Date: Mon, 28 Jan 2008 16:58:47 +0530

Hello,

I have a doubt in handling of INIT/INIT ACK message, with respect to,
multi-homing aspect of SCTP protocol.

Host 'A' gets an INIT message from host 'B'. Host B has furnished '5' IP
addresses in the INIT chunk for multi homing support. 

But host A has been configured to support a maximum of '3' peer IP
addresses for performance reasons. What is the desired behavior out of
the following?

(i)                   Get the first 3 IP addresses in the array out of 5
and proceed with the association.

(ii)                 Reject the INIT since host A has no capability to
support 5 peer IP addresses for multi-homing. 

If the option (ii) is selected, what is the error code/response to be
sent back to the peer, so that he will understand the real cause of
denial of association request?

(iii)                Any other options to handle this?

I am unable to find any discussion similar to this in the RFC.

Thanks in Advance.

Thanks,

Ganesh.

---

From: Michael Tuexen <[email-masked]>
Date: Mon, 28 Jan 2008 12:53:49 +0100

Hi Ganesh,

see my comments in-line.

Best regards
Michael

On Jan 28, 2008, at 12:28 PM, Ganesh Raaja, Natarajan wrote:

> Hello,
>
> I have a doubt in handling of INIT/INIT ACK message, with respect  
> to, multi-homing aspect of SCTP protocol.
>
> Host ‘A’ gets an INIT message from host ‘B’. Host B has furnished  
> ‘5’ IP addresses in the INIT chunk for multi homing support.
> But host A has been configured to support a maximum of ‘3’ peer IP  
> addresses for performance reasons. What is the desired behavior out  
> of the following?
>
> (i)                   Get the first 3 IP addresses in the array out  
> of 5 and proceed with the association.
This does not work. Since B has no indication which addresses A  
choses, it will receive an
ABORT after sending a packet with a source address A forgot. So the  
association will break
in the middle of the conversation... That is why
>
> (ii)                 Reject the INIT since host A has no capability  
> to support 5 peer IP addresses for multi-homing.
>
> If the option (ii) is selected, what is the error code/response to  
> be sent back to the peer, so that he will understand the real cause  
> of denial of association request?
I would send back an ABORT with error cause "Out of Resources".