Subject: [Pppext] PPPoE compression/encapsulation

From: Anandavel P <[email-masked]>
Date: Tue, 14 Dec 2004 18:06:48 +0530 (IST)

I have a query regarding PPPoE using Compression & encapsulation.

The compression and encription protocols often require the packets to be
delivered in sequence. In an IP network( over which a PPPoE session is
estabished ), packets could get delivered out of sequence. So how
does compression/encription work?

Is there anything i am missing?

Regards,
Anand.

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From: James Carlson <[email-masked]>
Date: Tue, 14 Dec 2004 09:59:05 -0500

Anandavel P writes:
> delivered in sequence.

Right.

> In an IP network( over which a PPPoE session is
> estabished ),

PPPoE runs over Ethernet, not IP.  Ethernet guarantees sequencing.

> packets could get delivered out of sequence. So how

Most of the algorithms involved either have their own sequence numbers
or have some mechanism for detecting a loss of sender/receiver
synchronization.  Even if there's reordering and loss, those
algorithms can generally deal with it.  (Though, of course, with a
performance penalty.)

> Is there anything i am missing?

Just that PPPoE doesn't run over IP, I think.

I wouldn't recommend running compression or encryption with PPPoE, as
these tend to magnify any errors that occur, but they should work as
specified.

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James Carlson, IP Systems Group?               <[email-masked]>
Sun Microsystems / 1 Network Drive         71.234W   Vox +1 781 442 2084
MS UBUR02-212 / Burlington MA 01803-2757   42.497N   Fax +1 781 442 1677