Re: [mpls] entropy label indicator label indraft-kompella-mpls-entropy-label

[Yong Lucy <[e-mail]>]

Yes, Egress PE has its own reserved value.

Cheers,
Lucy

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]]
> Sent: Wednesday, July 28, 2010 2:48 AM
> To: Shane Amante
> Cc: Yong Lucy; [e-mail]
> Subject: Re: [mpls] entropy label indicator label indraft-kompella-mpls-
> entropy-label
> 
> 
> In message <[e-mail]>
> Shane Amante writes:
> >
> >
> > Lucy,
> >
> > On Jul 27, 2010, at 17:06 GMT+02:00, Yong Lucy wrote:
> > > Hi John,
> > > I don=92t get it. If egress LSR asks ingress LSR to place ELI on the =
> > stack, the ingress can insert a unique ELI label on the stack followed =
> > by entropy label. When packet arrives to egress LSR, the LSR will find =
> > ELI on the stack. Why is it important for egress LSP to allocate a value
> =
> > for ELI instead of using standardized value?
> >
> > I think John already answered this question, but I'll give it a try, as
> =
> > well.  It's really a design choice on the part of the co-authors, in an
> =
> > attempt to avoid asking the MPLS WG to allocate a reserved label from =
> > the very scarce reserved label space.  I would note that there are only
> =
> > 8 reserved MPLS label values that are currently unassigned:
> > =
> > http://www.iana.org/assignments/mpls-label-values/mpls-label-
> values.xhtml
> >
> > So, if we believe it's "sound engineering" to use an ELI instead of a =
> > reserved label -- certainly a judgement call -- then, I believe, we =
> > should NOT request a reserved label in order that future applications =
> > that have a legitimate use (or, said differently, may not be able to =
> > function properly without a reserved label value) have an ability to =
> > acquire one.
> >
> > -shane
> 
> 
> Whether it is reserved or not, the ingress needs to verify that the
> egress understands it so there is little additional change having the
> egress provide its own reserved value.  This avoids using a scarse
> resource for no good reason.
> 
> Curtis
>