Re: IPsec & Markers

"Michael C. Cambria" <[email protected]>
Newsgroups gmane.ietf.rddp
Message-ID <[email protected]>

Caitlin Bestler wrote:

> 
> On Oct 8, 2004, at 5:10 PM, Michael C. Cambria wrote:
> 
>>
>> In MPA, is there any reason why, just like what is allowed with CRC, one
>> cannot have a system administrator knob to disable the use of markers
>> when IPsec is being used?
>>
>> In fact, when I know I'm using IPsec, I rather not have to go through the
>> overhead of markers even when the remote peer sets the M bit in the
>> Request/Reply frame.
>>
>> Regards,
>> MikeC
>>
>>
> The Markers are to enable the receiving side to locate the start of
> MPA Frames even when TCP Segments are received out-of-order.

Out of order or "unaligned"?  When the entire FPDU fits in the TCP 
segment (e.g. aligned), I have no problem locating the start of MPA 
Frames, in (TCP sequence) order or not.

> Even with IPSEC enabled a received out-of-order TCP Segment
> is not necessarily an MPA Frame.  Without markers how would the
> receiver locate the MPA Frame boundary?

Sec 5.3 says "MPA MUST encapsulate the ULPDU such that there is exactly 
one ULPDU contained in one FPDU."  With IPsec, there will be no 
middlebox that can re-segment TCP segments.  What I put in the IPsec 
(e.g.) tunnel will come out the other end of the tunnel.

MikeC

-- 
Michael C. Cambria

email : [email protected]
  VoIP : sip:[email protected]
   FWD : sip:[email protected]
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.