Re: [mpls-tp] [PWE3] Pseudo-wires: uni-directional o bi-directional?

Greg

I do not understand your point.

MS-PW S-PEs serve a purpose in breaking the PW into segments. If you do 
not need that decomposition in a network, there is nothing requiring 
their use. However we should not prohibit their use either, as there are 
scenarios whether this decomposition is of benefit.

If you need an existence proof of this point, remember that we initially 
designed SS-PW and needed to create MS-PW to address requirements of 
network operators that has deployed SS-PW.

Stewart

On 28/06/2010 15:01, Greg Mirsky wrote:
> Dear Sasha,
> I too find Stewart's explanation very useful for overall MPLS-TP. And 
> in this perspective perhaps the SS PW might be also referred as PW 
> section.
>
> Regards,
> Greg
>
> On Mon, Jun 28, 2010 at 8:56 AM, Alexander Vainshtein 
> <Alexander.Vainshtein@ecitele.com 
> <mailto:Alexander.Vainshtein@ecitele.com>> wrote:
>
>     Stewart,
>
>     Lots of thanks for a prompt and unambiguous response..
>
>     This issues looks like one more fine point of MPLS-TP-ese to me:
>     Does “co-routed” mean “co-routed in the immediate lower layer” or
>     “co-routed in all the underlying layers down to the duct”?
>
>     FWIW, I tend to agree with your interpretation: “co-routed” means
>     “co-routed in the immediate lower layer”, and hence PWs (both
>     single-segment and multi-segment) are co-routed bi-directional LSPs.
>
>     Regards,
>
>          Sasha
>
>     *From:* pwe3-bounces@ietf.org <mailto:pwe3-bounces@ietf.org>
>     [mailto:pwe3-bounces@ietf.org <mailto:pwe3-bounces@ietf.org>] *On
>     Behalf Of *Stewart Bryant
>     *Sent:* Monday, June 28, 2010 3:46 PM
>     *To:* pwe3@ietf.org <mailto:pwe3@ietf.org>
>
>     *Subject:* Re: [PWE3] Pseudo-wires: uni-directional o bi-directional?
>
>
>
>     It seems to me that PWs are associated bi-directional LSPs...
>
>     PWs are co-routed bi-directional since it is required that they go
>     through the same xPEs in each direction, and the xPEs knows about
>     the association of the two directional components.
>
>     Whether they run over co-routed bi-directional, or associated
>     bi-directional LSP is a deployment/applicability issue.
>
>     - Stewart
>
>
>
>
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