Subject: Re: FCS retention in PWE3

From: Stewart Bryant <[email-masked]>
Date: Mon, 01 Dec 2003 10:31:02 +0000

[email-masked] wrote:

> Stwart,
> 
> In general I agree with you.  But what you are actually saying 
> here is that we want independent OAM in each layer network (simply
> has to be independent....one reason being that we want the *same*
> OAM solution in the server irrespective of its client).  

Independent yes. Same depends on whether there are any differences
in the requirement that suggest otherwise, but I agree same would
be a good thing.

> But please note this:
> -	a PW is not a layer network, ie we do not network/switch PW entities;

I am not sure about this. Logically what we are doing is to recurse
back to a lower layer, over which we could run for example a new IGP.
In as much as we network/switch wires, we network/switch PWs.

> -	an LSP is a layer network, ie we do network/switch LSP entities;
> -	why can't we use Y.1711 OAM on the top level p2p LSP?

VCCV is the only method that has been formally accepted bt the PWE3
WG for further study. If you think that Y.1711 is more appropriate,
please write a draft explaining how this works in the PWE3 context and
why it is better. The WG will then decide the way forward through
our normal process.

> -	Y.1711 is sparse/simple/complete, ie all defects are defined 
         with entry-exit criteria and consequent actions.....it even
         defines availability and does so in order it can be used a
         single-ended way, ie behaviour of both directions can be
         observed from 1 end.

> -	MPLS and ATM OAM layer I/W is already defined in Y.1712.....
         and again its really simple.

         I thought that we were talking about Ethernet here?
> 
> None of this is done (and in some cases is not appropriate) for 
> the VCCV approach.    

I which case the VCCV team need to either provide these or explain
why they are not needed.

> 
> So what is wrong with this solution?

There is no WG draft describing the applicability of Y.1711 to PWE3.
If you want that solution, then you have to run the normal IETF
process to get it adopted, which will involve writing a draft,
getting it accepted by the WG, and going through a point by point
analysis of the advantages and disadvantages of Y.1711 and VCCV.

Regards

Stewart