Cell Relay Archive

[Ramana Yarlagadda <ramana.yarlagadda@analog.com>]

Hi,



>In AAL2 type2 cell we have CRC-10 check for reliable dtmf/cas bits
>transport.
>Then, Why does triple redundancy being implemented?
>Without triple redundancy, at the receiving end, if it finds the
>received
>type-3 cell has got some error, then it can ask the transmitting end to
>resend it.
>Is there any other specific advantage of triple redundancy?
>Can someone throw some light on this

Basically all the control data is sent using the triple redundancy. AAL2 is 
used
for the voice. If there is cell loss of voice data,  the jitter buffer 
algorithms will
take care of this .

The control information is important so that's the reason why triple 
redundancy
in in place for control data. Triple redundancy is simple and very little 
over-head.
The  re-transmission mechanism is always complex , especailly with the hand-
shake mechanism you are talking about. ATM is a reliable tranmission mechanism
and i think the triple redundancy is good enough.

-cheers
-ramana