No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search


To have a better experience, please upgrade your IE browser.


Feature Description - MPLS 01

NE05E and NE08E V300R003C10SPC500

This is NE05E and NE08E V300R003C10SPC500 Feature Description - MPLS

Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
RSVP Summary Refresh

RSVP Summary Refresh

RSVP summary refresh (Srefresh) function enables a node to send digests of RSVP Refresh messages to maintain RSVP soft states and respond to RSVP soft state changes, which reduces signaling packets used to maintain the RSVP soft states and optimizes bandwidth allocation.


RSVP Refresh messages are used to synchronize path state block (PSB) and reservation state block (RSB) information between nodes. They can also be used to monitor the reachability between RSVP neighbors and maintain RSVP neighbor relationships. As the sizes of Path and Resv messages are larger, sending many messages to establish many CR-LSPs causes increased consumption of network resources. RSVP Srefresh can be used to address this problem.


RSVP Srefresh defines new objects based on the existing RSVP protocol:
  • Message_ID extension and retransmission extension

    The Srefresh extension builds on the Message_ID extension. According to the Message_ID extension mechanism defined in relevant standards, RSVP messages carry extended objects, including Message_ID and Message_ID_ACK objects. The two objects are used to confirm RSVP messages and support reliable RSVP message delivery.

    The Message_ID object can also be used to provide the RSVP retransmission mechanism. For example, a node initializes a retransmission interval as Rf seconds after it sends an RSVP message carrying the Message_ID object. If the node receives no ACK message within Rf seconds, the node retransmits an RSVP message after (1 + Delta) x Rf seconds. The Delta determines the increased rate of the transmission interval set by the sender. The node keeps retransmitting the message until it receives an ACK message or the retransmission times reach the threshold (called a retransmission increment value).

  • Summary Refresh extension

    The Summary Refresh extension supports Srefresh messages to update the RSVP status, without the transmission of standard Path or Resv messages.

    Each Srefresh message carries a Message_ID object. Each object contains multiple messages IDs, each of which identifies a Path or Resv state to be refreshed. If a CR-LSP changes, its message ID value increases.

    Only the state that was previously advertised by Path and Resv messages containing Message_ID objects can be refreshed using the Srefresh extension.

    After a node receives an Srefresh message, the node compares the Message_ID with that saved in a local state block. If they match, the node does not change the state. If the Message_ID is greater than that saved in the local state block, the node sends a NACK message to the sender, refreshes the PSB or RSB based on the Path or Resv message, and updates the Message_ID.

    Message_ID objects contain sequence numbers of Message_ID objects. If a CR-LSP changes, the associated Message_ID sequence number increases. When receiving an Srefresh message, the node compares the sequence number of the Message_ID with the sequence number of the Message_ID saved in the PSB. If they are the same, the node does not change the state; if the received sequence number is greater than the local one, the state has been updated.

Updated: 2019-01-14

Document ID: EDOC1100058933

Views: 11161

Downloads: 12

Average rating:
This Document Applies to these Products

Related Version

Related Documents

Previous Next