[j-nsp] Longest Match for LDP (RFC5283)

[adamv0025 at netconsultings.com]

> Of Krzysztof Szarkowicz
> Sent: Monday, July 30, 2018 8:51 PM
> To: James Bensley
> Cc: Juniper List
> Subject: Re: [j-nsp] Longest Match for LDP (RFC5283)
> 
> 
> > On 2018-Jul-30, at 17:13, James Bensley <jwbensley at gmail.com> wrote:
> >
> > On 30 July 2018 at 15:22, Krzysztof Szarkowicz <kszarkowicz at gmail.com>
> wrote:
> >> James,
> >>
> >> As mentioned in my earlier mail, you can use it even with DU. If ABR
> >> has
> >> 10000 /32 LDP FECs, you can configure LDP export policy on ABR to
> >> send only subset (e. g. 20 /32 FECs) to access.
> >>
> >> Saying that, typical deployment is with DoD, since typically access
> >> PEs (and not ABRs) have better knowledge which loop backs are needed.
> >> So, basically access PEs send the info to ABR, which loop backs are
> >> needed, and which loop backs are not needed via LDP DoD machinery.
> >
> > Hi Kryzstof,
> >
> > This was exactly my point:
> 
> I have seen a deployment, where services were deployed via some
> centralized provisioning system. Part of the service provisioning was to adjust
> the LDP export policy on ABR, since LDP DU was used (some access PEs didn’t
> supported LDP DoD in that deployment). So, if you have some devices
> without LDP DoD support, your only choice is LDP DU + policies :-).
> 
Or BGP-LU + policies,

One follow up question, 
What about the case, where the minimum set of /32 loopback routes and associated labels is simply beyond the capabilities of an access node.
Is there a possibility for such access node to rely on default route + label -where originator of such a labelled default-route is the local ABR(s) in "opt-B" role doing full IP lookup and then repackaging packets towards the actual NH please?


adam

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