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Re: [PWE3] draft-bryant-pwe3-packet-pw-02.txt
This is correct but could we not optimize this special mapping ?
-----Original Message-----
From: Andrew G. Malis [mailto:amalis at gmail.com]
Sent: maandag 16 november 2009 15:39
To: HENDERICKX Wim
Cc: stbryant at cisco.com; pwe3 at ietf.org
Subject: Re: [PWE3] draft-bryant-pwe3-packet-pw-02.txt
Wim,
It's still more efficient on the wire than a simulated Ethernet PW,
because you would have one less label (the protocol identifier), but
would add the Ethernet MAC header instead.
Cheers,
Andy
On Mon, Nov 16, 2009 at 9:03 AM, HENDERICKX Wim
<wim.henderickx at alcatel-lucent.be> wrote:
> Ok good, this is what I thought, the client LSP exist in the "client
> packet Network layer".
>
> Don't you think this is a huge stack for such a function. You could have
> 4-6 LBL(s) + CW (optionally). I understand this proposal re-uses
> existing functions defined in MPLS, but there are lot's of optimizations
> possible here -> we could combine FAT LBL, PID LBL, CW potentially.
>
> -----Original Message-----
> From: Stewart Bryant [mailto:stbryant at cisco.com]
> Sent: maandag 16 november 2009 14:49
> To: HENDERICKX Wim
> Cc: pwe3 at ietf.org
> Subject: Re: [PWE3] draft-bryant-pwe3-packet-pw-02.txt
>
>>
>>>
>>> WH> what I meant is this:
>>>
>>> -------- --------
>>> PE1-----| | | | --- PE3
>>> | LSR |------- PKT PW ------| LSR |
>>> | | | |
>>> PE2-----| | | |---- PE4
>>> -------- --------
>>>
>>> Assume PE1 has a LSP to PE3 and PE2 has an LSP to PE4, how is this
>>> distinguished on the PKT PW ?
>>>
>>>
>> SB> I am not sure what you have drawn there, but it is not what is
> shown
>>
>> in the draft. The pkt pw run between the PEs and is carried over the
>> LSPs. PWs are distinguished from each other at the PE via the PW
> label.
>>
>> WH> What I tried to draw is PE(s) attached to the device (drawn with
> the
>> box) which is performing the LSR function on a PKT PW to another
> device
>> (drawn with the box) which attaching PE(s).
>>
>> The question is if I have multiple LSPs from different PE(s) through
> the
>> PKT PW how are the distinguished. Do I need a separate PID LBL, a
>> separate PW, etc such that the LSR can make the correct LBL mappings.
>>
>>
> Wim
>
> Think of the PW as a point to point link between a pair of PEs. The PE
> chooses what traffic to sent over a given PW. The PE then pushes an MPLS
>
> label to identify the destination. The mid-point LSRs have no clue what
> is being carried over the LSP. The egress PE unwraps that packet and
> figures out what the payload is.
>
> RFC3985 applies to pkt pw as it does to any other PW.
>
> - Stewart
>
>
>
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