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

Reminder

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

upgrade

ME60 V800R010C10SPC500 Feature Description - WAN Access 01

This is ME60 V800R010C10SPC500 Feature Description - WAN Access
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).
Principles of IP FRR

Principles of IP FRR

Overview

Fast Reroute (FRR) functions when the lower layer (physical layer or data link layer) detects a fault. The lower layer reports the fault to the upper layer routing system and immediately forwards packets through a backup link.

If a link fails, FRR helps reduce the impact of the link failure on services transmitted on the link.

Background

On traditional IP networks, when a fault occurs at the lower layer of the forwarding link, the physical interface on the router goes Down. After the router detects the fault, it instructs the upper layer routing system to recalculate routes and then update routing information. The routing system takes several seconds to reselect an available route.

For services that are sensitive to packet loss and delay, a convergence time of several seconds is intolerable because it may lead to service interruptions. For example, the maximum convergence time tolerable for Voice over IP (VoIP) services is within milliseconds. IP FRR enables the forwarding system to detect a fault and then to take measures to restore services as soon as possible.

Classification and Implementation

IP FRR, which is designed for routes on IP networks, consists of public network IP FRR and VPN IP FRR.

  • Public network IP FRR: protects routers on the public network.

  • VPN IP FRR: protects Customer Edges (CEs).

NOTE:
The static routes that are imported between public and private networks do not support IP FRR.

IP FRR is implemented as follows:

  • IP FRR can be enabled or disabled using commands.

  • When optimal routes are selected from the routes discovered by routing protocols, a backup link is selected for each preferred primary link based on the protocol priority, and then the forwarding information of primary and backup links is provided for the forwarding engine.

Implementation of IP FRR Between Different Protocols

When IP FRR between different protocols is enabled, and optimal routes are selected from protocol routes, a backup link is selected for each preferred primary link based on the protocol priority, and then the forwarding information of primary and backup links is provided for the forwarding engine.

If the forwarding engine detects that the primary link is unavailable after IP FRR between different protocols is enabled, the system can use the backup link to forward traffic before the routes converge on the control plane.

Comparison Between IP FRR and Load Balancing

Table 2-4 Comparison between IP FRR and load balancing

Feature

Description

IP FRR

Implements FRR through a backed up route. IP FRR is applicable to networks where a master link and a backup link exist and load balancing is not configured.

Load balancing

Implements fast route switching through equal-cost routes and applies to the multi-link networking with load balancing.

Translation
Download
Updated: 2019-01-04

Document ID: EDOC1100059473

Views: 14387

Downloads: 10

Average rating:
This Document Applies to these Products
Related Documents
Related Version
Share
Previous Next