Subject: [mpls-tp] MEF8/RFC4553 interworking

From: "Maarten Vissers" <[email-masked]>
Date: Mon, 16 Mar 2009 13:53:13 +0100

I have mentioned in previous emails that there is a need to interwork VLAN
and PW. Such interworking is required when a service has endpoints in both
Ethernet and MPLS domains. An example of such interworking necessity is the
interworking between MEF8 and RFC4553. MEF8 specifies the mapping of PDH
services (e.g. E1) into an EVC (Ethernet VLAN). RFC4553 specifies the
mapping of the same PDH services (e.g. E1) into a PW.

For the case an E1 service is to be provided between a UNI-N port at the
edge of an Ethernet network and a UNI-N port at the edge of a MPLS network,
then the E1 signal is carried in the Ethernet domain within a VLAN (EVC) and
in the MPLS domain within a PW.

There are now two alternatives to support this E1 service:
1) replace the RFC4553 function by a MEF8 function and carry the E1 as an
Ethernet service over an Ethernet PW in the MPLS domain and over an EVC in
the Ethernet domain.
2) introduce an MEF8<>RFC4553 IWF at the boundary between the Ethernet and
MPLS domains and interwork also the Ethernet and MPLS OAM to provide UNI-N
to UNI-N status and performance monitoring.

If we decide to use the MEF EVC layer as transport service layer in MPLS-TP,
then MPLS-TP will support the MEF8 encapsulation of PDH (e.g. E1) signals
and there is no longer an interworking issue with the PDH over EVC in
Ethernet domains. As interworking of MPLS-TP (and also Ethernet) with the
existing MPLS networks is important, there will be a need for an
RFC4553<>MEF8 type interworking function between MPLS domains and
MPLS-TP/Ethernet domains.

This MEF8/RFC4553 IWF will have to convert the MEF8 encapsulation into
RFC4553 encapsulation to pass through the data. In addition this IWF will
have to terminate the EVC OAM. Would it be possible to convert the ETH CCM
OAM into VCCV BFD so that there is at least a minimal continuity check
between the UNI-N ports in the MPLS domain and in the MPLS-TP/Ethernet
domains?

Regards,
Maarten

---

From: Jiang Yuan-long <[email-masked]>
Date: Tue, 17 Mar 2009 15:45:27 +0800

Hi, Maarten:
I think your last question is best covered by the following draft in PWE3 
WG:
http://www.ietf.org/internet-drafts/draft-ietf-pwe3-mpls-eth-oam-iwk-00.txt

Best regards,
Yuanlong

----- Original Message ----- 
From: "Maarten Vissers" <[email-masked]>
To: <[email-masked]>; <[email-masked]>
Sent: Monday, March 16, 2009 8:53 PM
Subject: [mpls-tp] MEF8/RFC4553 interworking

> _______________________________________________
> mpls-tp mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/mpls-tp