 | Copyright © 2009, Juniper Networks, Inc. All rights reserved. Trademark Notice. | |
An essential element of RSVP-based traffic engineering is the TED. The TED contains a complete list of all network nodes and links participating in traffic engineering, and a set of attributes each of those links can hold. (For more information about the TED, see Constrained-Path LSP Computation.) One of the most important link attributes is bandwidth.
Bandwidth availability on links changes quickly as RSVP LSPs are established and terminated. It is likely that the TED will develop inconsistencies relative to the real network. These inconsistencies cannot be fixed by increasing the rate of IGP updates.
Link availability can share the same inconsistency problem. A link that becomes unavailable can break all existing RSVP LSPs. However, its unavailability might not readily be known by the network.
When you configure the rsvp-error-hold-time statement, a source node (ingress of the RSVP LSPs) learns from the failures of its LSP by monitoring PathErr messages transmitted from downstream nodes. Information from the PathErr messages is incorporated into subsequent LSP computations, which can improve the accuracy and speed of LSP setup. Some PathErr messages are also used to update TED bandwidth information, reducing inconsistencies between the TED and the network.
You can control the frequency of IGP updates by using the update-threshold statement. See Configuring the RSVP Update Threshold on an Interface.
This section discusses the following topics:
| Copyright © 2009, Juniper Networks, Inc. All rights reserved. Trademark Notice. | |