arthi,
first a recap: this item on stitching was initiated in order to allow per "domain" control of end-to-end (contiguous) LSP, as part of a separate document, and not to extend its scope (unduly, in this case, see below) but mainly in order to have the set of all related protocol mechanisms within a specific document -
from this initial working assumption, it is clear that the segment must have the properties of the incoming end-to-end LSP which are determined among other by its switching type e.g. PSC-3 or TDM, the first requirement of LSP stitching is contiguity of the end-to-end LSP at the data plane level (after stitching operation) - and this by definition of the initial working assumption -
note: the only latitude which is left (for a given switching type e.g. PSC-2) is due to the properties of packet (PSC) networks that allows you stitch a segment having a larger Max Reservable Bandwidth and Unreserved Bandwidth (we would have equivalent latitude for other attributes but this is a local policy decision - which at the end is the sole purpose of this approach)
Here are some of the questions related to LSP stitching to start a
discussion on the usage of LSP stitching.
>1) Are the control plane signaling procedures for LSP stitching as
>described in this ID, (explicit request for LSP stitching on
>LSP segment, different label allocation rules; etc) REQUIRED to stitch
>packet LSPs in data plane ?
-> yes (beside manual config operation)
>2) Are the control plane signaling procedures for LSP stitching as
>described in this ID, (explicit request for LSP stitching on
>LSP segment, different label allocation rules; etc) REQUIRED to stitch
>non-packet LSPs in data plane ?
-> yes (beside manual config operation)
>3) If an e2e LSP crosses a region boundary (based on different TE
>link switching capabilities), then can I use LSP stitching -
>a) control plane procedures for packet LSPs
>b) data plane procedures for packet LSPs
>c) control plane procedures for non-packet LSPs
>d) data plane procedures for non-packet LSPs
-> no, when crossing a region boundary, you simply use a document named "draft-mpls-lsp-hierarchy-08.txt" which is in the RFC Editor queue, but this does not prevent from creating an LSP segment on top of an FA-LSP (see below)
>4) If the switching type of an e2e LSP is different from that of an LSP
>segment, can I use LSP stitching -
>a) control plane procedures for packet LSPs
>b) data plane procedures for packet LSPs
>c) control plane procedures for non-packet LSPs
>d) data plane procedures for non-packet LSPs
-> no, in this case progression of the end-to-end LSP establishment, implies that the LSP segment must fulfil a set of constraints carried as part of the incoming end-to-end LSP request, in this case one has to create an LSP segment (with a switching type equal to the incoming end-to-end LSP switching type) over that FA (i.e. referred here above to the LSP segment with a different Switching Type)
>Note that although 3) and 4) appear to be the same, the reason I have
>them as different questions is that in one case the TE link switching
>capability is examined and in the other case the Generalized Label Request
>is examined.
-> what it appears to me is that this discussion mixes the issue of the operation describing the stitching operations at the domain boundaries from the LSP segment creation itself i.e. an LSP segment can indeed be an FA link inherited from the creation of an (intra-domain) FA-LSP -