Subject: [PWE3] VPLS draft and PWE3-Ethernet draft are too confused.

From: "Fengger" <[email-masked]>
Date: Sat, 31 Dec 2005 11:35:09 +0800

All,

It seems to me, throughout the [PWE3-Ethernet] draft, the description about
raw-mode and tagged-mode are often inconsistent.

Especially, compared it with the draft l2vpn-vpls-ldp-08, there are too much
inconsistency.

My confused points are:

1.       Does raw-mode PW exactly mean Ethernet PW and tagged mode PW
exactly mean Ethernet Vlan PW?

If it does, as I understand, Ethernet PW means port to port PW and Ethernet
Vlan PW means [port,vlan] to [port,vlan] PW.

Then as a consequence, raw-mode PW means port to port PW and tagged mode PW
means [port,vlan] to [port,vlan] PW.

It seems the [PWE3-Ethernet], section 4.1-4.2 has confirmed my this
understand.

But please read the draft l2vpn-vpls-ldp-08.txt, section 7 and section 8, it
seems that in the Ethernet PW(that's raw mode), 

The service delimiting(generally, it's the vlan tag) still be be used to
identify the customer and/or the particular SERVICE of that customer,

That means the service delimitor can be used to map into a PW, right? As a
consequence, in the raw mode, between port(on ingress PE) to port(on the
egress PE)

There can be more than one PW existed, right?

And more, in the l2vpn-vpls-ldp-08.txt, section 10, it says, if there are n
PE participated in a VPLS instance, there can be n*(n-1)/2 PWs in the full
mess case.

So I can conclude, there is only one PW between each PE pair.

2.       Certainly, maybe all the description is consistent actually. All
the confuse are caused by my misunderstanding. So I want to confirm some
points.

1)       Does the raw-mode or tagged mode PW have some certain relationship
with the hierarchy VPLS?

2)       Does the raw-mode only mean the service delimiting tag must not be
carried in the PW while the tagged-mode only mean the service delimiting tag
must be carried in the PW? 

Don't they mean anything else? Then why does in the [PWE3-Ethernet], section
4,1, it say: this mode(tagged mode) uses service-delimiting tags to map
input Ethernet frames to

Respective PWs.....", my understanding to it is: the tagged mode also means
the PW is determined by both port and vlan while the raw mode also means the
PW is determined

only by the port.

These days, I am almost crazy about these questions. Expect somebody help me
escape from this status.

Fengger

Software Engineer

SuZhou CentecNetworks Ltd.,Co

13906214156

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