Subject: PPP frames on tunnel

From: Sridhar Malarothu <[email-masked]>
Date: Wed, 26 Jul 2000 23:38:32 +0530

Hi All,

    LAC before sending ppp frames on tunnel to LAC should strip of
the CRC, Link Framing and transperancy bytes, encapsulate them in L2TP
header. But what should be status of the PPP frames on tunnel, if send 
by LNS.
   
Best Regards
Sridhar

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From: "W. Mark Townsley" <[email-masked]>
Date: Wed, 26 Jul 2000 14:23:05 -0400

PPP framing of FFO3, unless ACFC is negotiated, should exist on packets
sent from the LNS and from the LAC.

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From: James Carlson <[email-masked]>
Date: Wed, 26 Jul 2000 14:41:18 -0400 (EDT)

> header. But what should be status of the PPP frames on tunnel, if send 

Data frames from the LNS should not have an appended CRC, framing, or
transparency bytes, and they should have L2TP headers.

Note that the leading FF 03 (the default values used for the HDLC
Address and Control fields on regular PPP links) must be included on
the tunneled frames, contrary to prior convention (such as described
in RFCs 1598, 1973, and 2364).  So, if you're coming from a regular
PPP over Frame Relay network into an L2TP tunnel, you'll have to add
those extra bytes on entry to the tunnel and remove them before going
into Frame Relay.

-- 
James Carlson, Internet Engineering       <[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
"PPP Design and Debugging" --- http://people.ne.mediaone.net/carlson/ppp