Subject: for PPP over ATM or PPPoE over ATM - which is more common - LLCencaps or VC multiplexing

From: "S.Rajesh Kumar" <[email-masked]>
Date: Tue, 6 Jun 2000 14:39:52 -0700 (PDT)

The PPP over AAL5 specification allows use of VC multiplexing or
LLC/SNAP encapsulation as an option. Which one is more prevalent?

For the solutions of PPPoE (PPP over Ethernet) carried over ATM VCs,
which of the two - LLC/SNAP encapsulation or VC multiplexing - is more
common?

Also - what do the Cisco and Redback boxes do? Leave this as a
configuration option? Or choose one particular way? If so, which one?

I would appreciate any pointers on these aspects
Thanks in advance for any pointers
Rajesh

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From: James Carlson <[email-masked]>
Date: Tue, 6 Jun 2000 19:55:04 -0400 (EDT)

> LLC/SNAP encapsulation as an option. Which one is more prevalent?

Does it matter?  If you're doing one, you should do both.  The big
difference between them is that LLC/SNAP can traverse Frame Relay /
ATM interworking units.  VC mux cannot.

(Also, just fyi, at least one VC mux implementation gets the header
wrong by including the HDLC Address and Control fields, despite what
RFC 2364 says.)

> configuration option? Or choose one particular way? If so, which

Both have configuration information on their web sites ...

You probably don't want to try to claim interoperability with these
boxes without purchasing a few for test.

-- 
James Carlson                                  <[email-masked]>
"PPP Design and Debugging" --- http://people.ne.mediaone.net/carlson/ppp