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Re: [RPRWG] MAC Question


hopefully I will not step on anyone's toes in giving this 

there are multiple approaches to this issue and there are 
trade-offs with each. However, everyone agrees on destination
stripping of uni-cast packets and the need to allow multiple 
nodes on the ring to transmit simultaneously. Also, 
no one is (yet) proposing a token mechanism similar to 

some people support a store and forward paradign on the ring
where all packets are completely buffered on the transit 

there are at least 2 camps using the term cut-through to mean 
somewhat different things. they do agree on begining to 
transmit a transit packet as soon as possible. The difference
is in the definition of as soon as possible and the size 
requirement on the transit buffer.



Ray Zeisz wrote:
> I am following the .17 group from afar, but I have a question:
> Is it acceptable for each node in the ring to buffer up an entire packet
> before forwarding it to its neighbor?  Would the latency be to great if this
> were done?  Or is the .17 direction more along the lines of 802.5 where only
> a few bits in each ring node are buffered...just enough to detect a token
> and set a bit to claim it.
> Ray
> Ray Zeisz
> Technology Advisor
> LVL7 Systems
> (919) 865-2735

Michael Takefman              tak@xxxxxxxxx
Manager HW Engineering,       Cisco Systems
Chair IEEE 802.17 Stds WG
2000 Innovation Dr, Ottawa, Canada, K2K 3E8
voice: 613-271-3399       fax: 613-271-4867