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[RPRWG] questions on RPR alternatives




Hi

I'm new to RPR, and I'm trying to understand its applications and 
compare it to other alternatives. I hope someone can help me with the 
following questions:

- What is the difference between 802.1w (when used on a ring) and 
802.17 in terms of the functionality provided?  At a high level, they 
both appear to support similar capabilties (at least in terms of 
protection, which appears to be the most important feature), so I'm 
trying to see whether I'm missing something here. (I understand that 
802.17 is defining a L2 protocol while 802.1w is a higher layer 
protocol.)

- What are the advantages of 802.17 over 802.1w as far as supporting 
dual counter-rotating ring topologies are concerned?

- From a cost point of view, would 802.1w have a cost advantage since 
Ethernet MAC/PHYs are readily available on the market and have high 
volumes? (I am aware of only one RPR-type MAC chip on the market from 
Conexant that supports Cisco's SRP.) 

- From a TTM point of view, 802.1w is probably nearer to completion as 
a standard since it is already on its 10th draft. Would 802.1w be a 
competitive alternative to 802.17?

- I guess a more general question to ask is: can the 
features/advantages that are targeted by 802.17 MAC be achieved just as 
well (in terms of both performance and cost) by using other 
standardized higher layer approaches. (For instance, another higher 
layer approach that comes to mind is the use of MPLS-TE to perhaps set 
up a primary LSP and a backup LSP on different rings, between each pair 
of nodes, where the rings are running Ethernet.)

Thank you.

Ravi
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Ravi Chandran
Data Access & Transport Group
Tellabs Operations, Inc.	phone : (219) 258-6410
3740 Edison Lakes Parkway	fax   : (219) 258-6446
Mishawaka, IN 46545		ravi.chandran@xxxxxxxxxxx
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