Subject: [SCTP]Congestion Control Parameters

From: Andrea Senatore <[email-masked]>
Date: Mon, 28 Oct 2002 10:38:48 +0100

Hi to all,
I have a confusion on Section 7.1 of RFC 2960......

<SNIP>
SCTP is designed to establish robust communication associations between 
two endpointeach of which may be reachableby more than one transport 
address. Potentially different addresses may lead to different data 
*paths* between the two endpoints, thus ideally one may need a 
*separate* set of congestion control parameters for each of the *paths*.
<SNIP>
......
<SNIP>
The sender keeps a separate congestion control parameter set for each of 
the destination address it can send to (*not* for each 
source-destination *pair* but for each *destination*).
<SNIP>

I don't understand.... "one need a *separate* set of congestion control 
parameters for each of the *path*, and then keeps this set *only* for 
each destination address". 
CWND, RTO, RTT, etc., depend upon used path and *not* upon destination 
address.
When host send packets through a different interface but at same 
destination address this parameters must change because the path change...

Best rgds

-- Andrea
========================================================
Andrea Senatore,     
Mail:    [email-masked],
Address: CoRiTeL c/o Università degli Studi di Salerno,
         Facoltà di Ingegneria,  via Ponte Don Melillo,
         84084 - FISCIANO (SA) - Italy
Tel:     +39 089 964012
Fax:     +39 089 964010
========================================================

---

From: Qiaobing Xie <[email-masked]>
Date: Mon, 28 Oct 2002 12:54:42 -0600

Andrea,

> *paths* between the two endpoints, thus ideally one may need a
                                          ^^^^^^^^^^^^^^^
Consider this a note for the future research on SCTP. Ideally, it makes
a lot of sense in theory that CC be performed on a per-path basis, but
no one knows how to achieve this without adding crippling complexity to
the protocol. So, the current SCTP per-dest-addr based CC is a design
compromise or simplification.

-Qiaobing