RE: [AVT] CAS signalling events: draft-ietf-avt-rfc2833biscas-00.txt

["Oren Peleg" <OrenP at audiocodes.com>]

I have a problem with the ABCD state definition. The ABCD bits should
have a respective bit in the state regardless to the trunk framing
method. E.g. when on A & B are used & A=0 & B=1, the state may be 0x0100
up to 0x0111. The important issue here is that the bit in the state for
A, B, C & D is constant no matter what is the framing method. This way
if the framing method is different between sender & receiver, the biscas
still support it. Also may be recommended to duplicate the AB value to
the CD bits when only A & B are used. This will help some different
framing methods to be synced.

Regards,

Oren P.

-----Original Message-----
From: avt-bounces at ietf.org [mailto:avt-bounces at ietf.org] On Behalf Of
Tom Taylor
Sent: Sunday, February 06, 2005 9:53 PM
To: avt at ietf.org
Subject: [AVT] CAS signalling events:
draft-ietf-avt-rfc2833biscas-00.txt

I have just submitted draft-ietf-avt-rfc2833biscas-00.txt to capture the

trunk-oriented signalling events from RFC 2833, as modified in earlier
2833bis 
work.  There are some key deviations from the events as presented in 
draft-ietf-avt-rfc2833-05.txt.  These have to do with line event
signalling for 
signalling systems No. 5, R1, and R2, and the mapping of ABCD bits to
event codes. 
  The new mappings are my best attempt at consistency with published
documents.

The basic mapping of ABCD states to event codes was changed when I found
a 
PacketCable specification using some of those events from RFC 2833.  It
appeared 
that they assumed a mapping where the A bit is the high-order bit of a
4-bit 
state, where draft-ietf-avt-rfc2833-05.txt suggested that the A-bit
would be the 
low-order bit.  I changed the text to be consistent with the PacketCable
mapping. 
  However, the R2 line code mappings are a bit ugly as a result, with
the event 
codes differing for the same line state depending on whether analog or
digital 
line signalling is being used.

Could anyone who has used the ABCD events in the past look over the
document to 
see if it still works for them?

-- 
Tom Taylor
Carrier VoIP Standards Development
Nortel
Phone +1 613 763 1496  (ESN 393-1496)
E-mail: taylor at nortel.com

_______________________________________________
Audio/Video Transport Working Group
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_______________________________________________
Audio/Video Transport Working Group
avt at ietf.org
https://www1.ietf.org/mailman/listinfo/avt