Re: [Time] MEP and maintenance domain boundary

Qin Wu <> Wed, 02 July 2014 03:19 UTC

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From: Qin Wu <>
To: Yuji Tochio <>
Thread-Topic: [Time] MEP and maintenance domain boundary
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Date: Wed, 2 Jul 2014 03:19:40 +0000
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Subject: Re: [Time] MEP and maintenance domain boundary
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Hi, Yuji:
Thanks for pointing me to the relevant references. I will read.
I see how MEL is used in slide 36 associated with RFC5317.
It looks MEL is used to identify which part of network the fault happens, e.g.,
MEL x: Carrier1;
MEL y: Carrier1, Region 1;
MEL z: Carrier1, Region 2;
Regarding you are saying “MEL is considered for Ethernet OAM but not for MPLS(-TP)”
I am a little bit consumed, Isn’t Ethernet OAM has already been integrated into MPLS-TP?
What am I missing?

发件人: Yuji Tochio []
发送时间: 2014年7月2日 8:26
收件人: Qin Wu
主题: Re: [Time] MEP and maintenance domain boundary

Hi Qin,

(2014/07/01 20:42), Qin Wu wrote:

Regarding RFC6371, why the IETF insisted on using only
one maintenance level (MEL) per maintenance entity (ME) in MPLS-TP OAM?
Why multiple MELs per ME is not allowed? Do we need to relax this restriction defined by RFC6371?
If I uses both Ethernet OAM and IP OAM in the same maintenance entity, do I need to allow two MELs per ME?
Or the layer the OAM is applied has nothing to do with MEL?

The reason of single MEL per ME (LSP) can be found in RFC 5317 and RFC 5860.
The slidew 33 - 38 as attached to RFC 5317 will help you.
Note that MEL is considered for Ethernet OAM but not for MPLS(-TP).

And I recommend you should read draft-ietf-mpls-tp-temporal-hitless-psm for your concern.

Regards, Yuji