Subject: RE: draft-davari-pwe3-aal12-over-psn-01

From: Shahram Davari <[email-masked]>
Date: Wed, 12 Mar 2003 10:44:10 -0800

Sasha,

>AFAIK, draft-anavi does not discuss treatment of OAM/RM cells.
>But [ATM-ENCAP] and, by implication, draft-davari define such
>treatment in detail. As a consequence neither the cell transport 
>modes nor  the PDU mode defined in [ATM-ENCAP] and referenced 
>in draft-davari can guarantee a fixed number of  cells per 
>packet due to 
>the [ATM-ENCAP] requirement to send OAM/RM cells "in order" 
>and in separate packets. IMO, this makes [ATM-ENCAP]-compatible 
>"interpolation for lost packets" somewhat problematic - unless 
>you always send a single cell per packet.
>Did I miss something?
>>

Your comment is valid, however, it is valid only for PDU mode. Cell modes don't send OAM cells in separate packet. I guess one of the restrictions of PDU mode would be as following:

If the PEs don't have a synchronized clock (i.e, use adpative clock), then to transport AAL1 traffic, OAM cells should not be transmitted at ingress PE, or they may be transmitted between PW packets ( which could cause misordering of OAM cells).

Yours,
-Shahram