rsvp reduction srefresh

Use rsvp reduction srefresh to enable summary refresh and reliable RSVP message delivery.

Use undo rsvp reduction srefresh to disable summary refresh and reliable RSVP message delivery.

Syntax

rsvp reduction srefresh [ reliability ]

undo rsvp reduction srefresh

Default

Summary refresh and reliable RSVP message delivery are disabled.

Views

Interface view

Predefined user roles

network-admin

Parameters

reliability: Enables reliable RSVP message delivery. If you do not specify this keyword, the command enables only the summary refresh feature.

Usage guidelines

RSVP sends Path and Resv messages with the same states and objects to maintain the path and reservation states at intervals (configured by the refresh interval command). These messages are collectively referred to as refresh messages. Refresh messages are used to synchronize the path and reservation states on RSVP neighbors and to recover from lost RSVP messages.

When multiple RSVP sessions exist on a network, the periodically sent refresh messages can cause network degradation. In this case, the refreshing interval of Path and Resv messages should not be too short. However, delay sensitive applications want to recover from lost RSVP messages through the refresh messages as soon as possible. In this case, the refreshing interval should not be too long. You can use the summary refresh (Srefresh) and the reliable RSVP message delivery features to find the appropriate balance.

Srefresh is implemented by adding a Message_ID object to a Path or Resv message to uniquely identify the message. To refresh Path and Resv states, RSVP does not need to send standard Path and Resv messages. Instead, it can send a summary refresh message at regular intervals (configured by the refresh interval command). The message carries a set of Message_ID objects that identify the Path and Resv states to be refreshed. The Srefresh feature reduces the number of refresh messages on the network and speeds up the refresh message processing.

Reliable RSVP message delivery requires the peer device to acknowledge each RSVP message received from the local device. If no acknowledgment is received, the local device retransmits the message.

To implement reliable RSVP message delivery, a node sends an RSVP message that includes a Message_ID object in which the ACK_Desired flag is set. The receiver needs to confirm the delivery by sending back a message that includes the Message_ID_ACK object. If the sender does not receive a Message_ID_ACK within the retransmission interval (Rf), it performs the following operations:

• Retransmits the message when Rf expire.

• Sets the next transmission interval to (1 + delta) × Rf.

The sender repeats this process until it receives the Message_ID_ACK before the retransmission time expires or it has transmitted the message three times.

The initial value of Rf is configured by the rsvp reduction retransmit interval command. The delta value is configured by the rsvp reduction retransmit increment command.

After the summary refresh is enabled, RSVP maintains the path and reservation states by sending Srefresh messages rather than standard refresh messages.

Examples

# On VLAN-interface 10, enable summary refresh and reliable RSVP message delivery.

<Sysname> system-view
[Sysname] interface vlan-interface 10
[Sysname-Vlan-interface10] rsvp reduction srefresh reliability

Related commands

refresh interval

rsvp reduction retransmit increment

rsvp reduction retransmit interval