Re: [mpls-tp] [PWE3] Proposal of using GAL for PW

Hi Huub and Luca,

I also support the use of GAL on the PW.  I think that this has two 
advantages:
It supports OAM in the PW with or without a CW.
As Luca and Huub point out below, it makes the OAM processing uniform for 
LSPs and PW, this gives the additional benefit of simplifying the task of 
detecting miss connections between LSPs and PWs (as pointed out by Neil 
Harrison).

Regards,

Malcolm

Huub van Helvoort <hhelvoort@chello.nl> 
Sent by: mpls-tp-bounces@ietf.org
01/07/2010 03:39 AM
Please respond to
hhelvoort@chello.nl

To
Luca Martini <lmartini@cisco.com>
cc
pwe3@ietf.org, mpls-tp@ietf.org
Subject
Re: [mpls-tp] [PWE3] Proposal of using GAL for PW

Ciao Luca,

You wrote:

> I have to disagree that there was any consensus about this issue.
> If anything , there was consensus that there is no written statement 
> that we must to use the CW in MPLS-TP.

I agree with this.

> At the end we needed more input from service providers that have 
> deployed PWs. The point is not whether there is hardware support for the 

> CW, but whether we even want to use it in many cases where it adds 
> absolutely no value. For example ATM PWs in cell mode , where it add 
> almost 10% overhead with no benefit. Another case where the CW is not 
> useful is the ethernet PW without network link load balancing, where we 
> add 4 bytes to every packet just to occasionally send a status , or OAM 
> message.
> 
> I would like to propose update the rfc5586 to allow the use of the GAL 
> in PWs without the CW.

I  support this

> This makes the use of the GAL very symmetric among PWs and MPLS-TP LSPs. 

> This makes it easy to process by hardware based implementations.

I agree, consistency is very important, it causes less mistakes
in maintaining a network., and also for implementations (HW and SW).

Best regards, Huub.

> Andrew G. Malis wrote:
>> Larry and Feng,
>>
>> This issue has previously been discussed at length by the working
>> group, both at the Anaheim meeting and by email, for example in emails
>> with the subject line "Possible Contradiction re use of GAL in
>> pwe3-static-pw-status". There was rough consensus that for MPLS-TP
>> applications and/or when PW OAM is desired, PW implementations are
>> mature enough (it has been 10 years now, after all) that the time has
>> come to require the implementation of the CW for all PWs, including
>> Ethernet.
>>
>> Cheers,
>> Andy
>>
>> On Wed, Jun 30, 2010 at 6:34 AM, HUANG Feng F
>> <Feng.f.Huang@alcatel-sbell.com.cn>  wrote:
>> 
>>> it is reasonable to support GAL in MPLS-TP PW OAM, it is more generic, 
because CW is an option RFC4448 for Ethernet over MPLS.
>>>
>>> 4.6.  The Control Word
>>>
>>> xxxx
>>>
>>>
>>> The features that the control word provides may not be needed for a
>>>    given Ethernet PW.  For example, ECMP may not be present or active 
on
>>>    a given MPLS network, strict frame sequencing may not be required,
>>>    etc.  If this is the case, the control word provides little value 
and
>>>    is therefore optional.  Early Ethernet PW implementations have been
>>>    deployed that do not include a control word or the ability to 
process
>>>    one if present.  To aid in backwards compatibility, future
>>>    implementations MUST be able to send and receive frames without the
>>>    control word present.
>>> xxxx
>>>
>>>
>>>
>>> B.R.
>>> Feng Huang
>>>
>>>
>>> -----Original Message-----
>>> From:pwe3-bounces@ietf.org  [mailto:pwe3-bounces@ietf.org] On Behalf 
Of Larry
>>> Sent: 2010年6月30日 17:38
>>> To:mpls-tp@ietf.org;pwe3@ietf.org
>>> Cc:lihan@chinamobile.com
>>> Subject: [PWE3] Proposal of using GAL for PW
>>>
>>> Dear all:
>>>
>>>      In section 4.2 in RFC5586, it is defined that GAL MUST NOT be 
used with PWs in MPLS-TP. The PWE3 control word [RFC4385] MUST be present 
when the ACH is used to realize the associated control channel.
>>>      In real application, a lot of MPLS and MPLS-TP equipments do not 
support control word. It is proposed to use the GAL to identify associated 
control channel in PW layer.
>>>
>>> Best regards,
>>>
>>>                  Han Li
>>>
>>> ********************************************************************
>>> Han Li, Ph.D
>>> China Mobile Research Institute
>>> Unit 2, 28 Xuanwumenxi Ave, Xuanwu District, Beijing 100053, China
>>> Fax: +86 10 63601087
>>> MOBILE: 13501093385
>>> ********************************************************************
>>>
>>> 
>> _______________________________________________
>> pwe3 mailing list
>> pwe3@ietf.org
>> https://www.ietf.org/mailman/listinfo/pwe3
>>
>> 
> 
> 
> 
> _______________________________________________
> mpls-tp mailing list
> mpls-tp@ietf.org
> https://www.ietf.org/mailman/listinfo/mpls-tp

-- 
================================================================
                  http://www.van-helvoort.eu/
================================================================
Always remember that you are unique...just like everyone else...
_______________________________________________
mpls-tp mailing list
mpls-tp@ietf.org
https://www.ietf.org/mailman/listinfo/mpls-tp