RFC 3210 (rfc3210) - Page 2 of 8

Applicability Statement for Extensions to RSVP for LSP-Tunnels

RFC 3210        Applicability Statement for Extensions     December 2001


   submitted to the IETF MPLS working group.  It contains all the
   necessary objects, packet formats, and procedures required to
   establish and maintain explicit label switched paths (LSPs).
   Explicit LSPs are foundational to the traffic engineering application
   in MPLS based IP networks.  Besides the traffic engineering
   application, the RSVP-TE specification may have other uses within the
   Internet.

   This memo describes the applicability of the RSVP-TE specifications
   [1].  The protocol's principles of operation are highlighted, the
   network context for which it was developed is described, guidelines
   for deployment are offered, and known protocol limitations are
   indicated.

   This applicability statement concerns only the use of RSVP to set up
   unicast LSP-tunnels.  It is noted that not all of the features
   described in RFC 2205 [3] are required to support the instantiation
   and maintenance of LSP-tunnels.  Aspects related to the support of
   other features and capabilities of RSVP by an implementation that
   also supports LSP-tunnels are beyond the scope of this document.
   However, support of such additional features and capabilities should
   not introduce new security vulnerabilities in environments that only
   use RSVP to set up LSP-tunnels.

   This applicability statement does not preclude the use of other
   signaling and label distribution protocols for the traffic
   engineering application in MPLS based networks.  Service providers
   are free to deploy whatever signaling protocol that meets their
   needs.

   In particular, CR-LDP [6] and RSVP-TE [1] are two signaling protocols
   that perform similar functions in MPLS networks.  There is currently
   no consensus on which protocol is technically superior.  Therefore,
   network administrators should make a choice between the two based
   upon their needs and particular situation.

2.0 Technical Overview of Extensions to RSVP for LSP Tunnels

   The RSVP-TE specification extends the original RSVP protocol by
   giving it new capabilities that support the following functions in an
   MPLS domain:

     (1) downstream-on-demand label distribution
     (2) instantiation of explicit label switched paths
     (3) allocation of network resources (e.g., bandwidth) to
         explicit LSPs
     (4) rerouting of established LSP-tunnels in a smooth fashion
         using the concept of make-before-break



Awduche, et. al.             Informational