[e2e] overlay over TCP

[Randall Stewart]

Joe Touch wrote:
> 
> 
> Armando L. Caro, Jr. wrote:
> 
>> On Wed, 19 Jan 2005, Joe Touch wrote:
>>
>>
>>> In particular, _if_ you're referring to PR-SCTP, please indicate where
>>> in the PR-SCTP RFC its use for unreliable, out-of-order messages is
>>> simply and clearly described. ;-)
>>
>>
>> For out-of-order messages, refer to Section 6.6 in RFC 2960. I think
>> this section is fairly clear.
>>
>> For unreliable messages, refer to Section in 3.5 and 3.6 in RFC 3758.  I
>> think this section is clear, given that the reader is familiar with SCTP
>> basics.
> 
> 
> Greek is clear to a Greek as well. ;-)

Hmm but we are all Geeks here does that count :-D
> 
> Sec 3.5 and 3.6 are obscure, if the intent is to describe something that 
> supports UDP-like semantics with TCp-like congestion control, such as is 
> referred to in passing near the end of Sec 1 (item #3) of that RFC.
> 
> As to the full set of reasons for which DCCP is preferable to PR-SCTP, 
> see sec 3.3.2 of the DCCP problem statement ID (where PR-SCTP is 
> referred to as U-SCTP).
Hmm.. is this an expired draft? I searched the ietf drafts
and I also looked off the DCCP wg page and can't find
this draft...

> 
> Note that item F2 in sec 3.5  of RFC 3758 also allows delaying outgoing 
> chunks for aggregation; DCCP does not appear to do that (any DCCP 
> experts like to chime in?)DCCP appers to correlate packets on the wire 
> with application writes and reads; the same is not necessarily true with 
> SCTP. There are substantial advantages to such correlation when 
> tunneling network layer packets over transport protocols. I think that's 
> what David Reed was referring to...
> 
That is a base feature of SCTP as well.. even though its reflected
in RFC3758. In the sockets API we call it SCTP_NODELAY (same
as in TCP) and it is basically an implemenation of nagel. Of
course it is also required that it be disableable... so if
one wants "no bundling" one turns SCTP_NODELAY off.. which
at least for the socket api in BSD is on by default.

R

-- 
Randall Stewart
803-345-0369 <or> 815-342-5222(cell)