The MPLS WG Archive

[Curtis Villamizar <curtis@workhorse.fictitious.org>]

In message <NDBBJLCGILIAGFOMFFAPIEDNKEAB.bharathir@future.futsoft.com>, "Bharat
hi R" writes:
> Hi Vishwas,
> If my understanding is correct, "The Various levels of PSC" means PSC-1,
> PSC-2..PSC-4?
> If so then in PSC-2 label stack depth is 2 and PSC-3 means label stack of
> depth 3 and so on.
> If so then why it is restricted to 4 levels?
> Thanks & Regards,
> Bharathi


PSC-1 would be N+1, where N is the number of labels that already
exist.  For example, LSPs are already used with VPN label, LDP label,
MPLS/TE label with no hierarchy designation.  This would add up to 4
levels of hierarchy intended to improve scaling to whatever labels
already exist.  Also note that a PSC-3 LSP can contain an LSP with no
hierarchy designation, a PSC-1, a PSC-2, but not another PSC-3 or
anything higher in the hierarchy.  So PSC-3 does not mean 3 labels,
nor does it mean N+3.

Curtis