[e2e] overlay over TCP

[Randall Stewart]

Dan Wing wrote:
> 
> On Jan 21, 2005, at 12:15 PM, David P. Reed wrote:
> 
>> Dan Wing wrote:
>>
>>>
>>> Yes, combined with little market demand, as yet, for a NAT to handle 
>>> SCTP.
>>
>>
>> There is this chicken/egg problem.  If SCTP doesn't work over NATs it 
>> won't be used for applications where NATs are heavily used.   Then 
>> there won't be demand (at least no evidence of it).
> 
> 
> This egg was demonstrably cooked with IPsec, which had the same 
> problem.  IPsec "passthru" was implemented on nearly all vendor's 
> residential NATs at about the same time IPsec-over-UDP was beginning to 
> hit the market.  Passthru works by examining SPI's and simple mechanisms 
> have drawbacks (only one session through the NAT, or only one session to 
> a specific remote IP address, for example), and IPsec-over-UDP has even 
> more packet bloat than IPsec itself.
> 
> I expect DCCP, SCTP, and other new protocols will suffer the same 
> awkward deployment unless we (in the collective sense) improve the 
> situation with guidance from people familiar with those new protocols.  
> draft-xie-tsvwg-sctp-nat-00.txt is a move in the right direction, 
> although it seems NATting SCTP may well be complex.

It's not that complex.. and yes Cisco has had at least one
customer ask for it... Have they had lots .. no. The
reason being where Cisco currently makes money from
SCTP is inside the network. Most folks don't run their
SS7 over IP network where they want to have a NAT
to Global address cross over.

There are other places, as well, that Cisco makes money
from SCTP.. but again they are all "inside the network"
places...

However, that all being said, since Cisco does make
money from the protocol, and would benefit from
the M$ company producing SCTP with its O/S instead
having to place an add-on component.. encouraging
SCTP by making Cisco NAT's SCTP aware would help in
this.. after all someone must crack the egg :-D

(and yes Dan, we do ship a special internal version
  of SCTP for windows to some of our customers :o)

R

> 
>> There's a difference between "demand" (meaning actual use) and 
>> "demand" meaning I would ask and pay to use it if I thought I had any 
>> chance of getting it from the blind turkeys who sell things like NAT 
>> boxes.
>>
>> Reminds me of 1992 when a Nynex VP told me there was *no demand* for 
>> data connectivity between people working at home and their offices.  I 
>> pointed out that companies like DEC and MIT employed 10's of thousands 
>> of people who were using terminals to connect to computers at work.   
>> His response was that they had carefully analyzed measured data use 
>> and I was wrong.   I asked how they measured modems over home phone 
>> lines, thinking they could listen for modem tones or something, and he 
>> said (I'm not joking): "I thought that was illegal!"  It turns out 
>> that what they called "data" was a dedicated "data circuit" and that 
>> modems were "voice".
> 
> 
> :-)
> 
> -d
> 
> 


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