PathErr Messages

PathErr messages report a wide variety of problems by means of different code and subcode numbers. You can find a complete list of these PathErr messages in RFC 2205, Resource Reservation Protocol (RSVP), Version 1, Functional Specification and RFC 3209, RSVP-TE: Extensions to RSVP for LSP Tunnels.

When you configure the rsvp-error-hold-time statement, two categories of PathErr messages, which specifically represent link failures, are examined:

• Link bandwidth is low for this LSP: Requested bandwidth unavailable—code 1, subcode 2

  This type of PathErr message represents a global problem that affects all LSPs transiting the link. They indicate that the actual link bandwidth is lower than that required by the LSP, and that it is likely that the bandwidth information in the TED is an overestimate.

  When this type of error is received, the available link bandwidth is reduced in the local TED, affecting all future LSP computations.

• Link unavailable for this LSP:
  • Admission Control failure—code 1, any subcode except 2
  • Policy Control failures—code 2
  • Service Preempted—code 12
  • Routing problem—no route available toward destination—code 24, subcode 5

  These types of PathErr messages are generally pertinent to the specified LSP. The failure of this LSP does not necessarily imply that other LSPs could also fail. These errors can indicate maximum transfer unit (MTU) problems, service preemption (either manually initiated by the operator or by another LSP with a higher priority), that a next-hop link is down, that a next-hop neighbor is down, or service rejection because of policy considerations. It is best to route this particular LSP away from the link.

Copyright © 2008, Juniper Networks, Inc. All rights reserved. Trademark Notice.