RSVP-TE Overview

path message label request message

RSVP-TE (Resource Reservation Protocol-Traffic Engineering)

RSVP-TE(Resource Reservation Protocol-Traffic Engineering) is the enhanced RSVP for MPLS. RSVP-TE is not a real routing protocol, but it works with routing protocols.

For RSVP-TE, bidirectional flow is required. To provide this, there must be two RSVP sessions. Because RSVP-TE is unidirectional.

RSVP-TE brings some benefits to MPLS. These benefits are:

Ability to define LSP paths, path choice by administrator.
Advanced cost calculation, not restricted to IGP cost values.
Rich set of traffic protection (secondary paths and fast reroute).
Ability to make resource reservation functionality.

RSVP-TE Main Characteristics

As we talked about before in LDP articles, there are also some main characteristics for RSVP-TE. Some of these characteristics are different than LDP. What are these characteristics? Let’s check:

– Downstream on demand : LSPs signalled when requested. ( This was unsolicited downstream in LDP, which send labels without any requests).

– Ordered control : Label distribution process follows a hierarchical order (Same as LDP).

– Conservative label retention : Labels are cleared if not needed. ( This was liberal label retention in LDP, which stores all the labels).

Lesson tags: rsvp-te, traffic engineering
Back to: JNCIS > MPLS
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