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NE40E V800R010C00 Feature Description - VPN 01

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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).
VPN ORF

VPN ORF

VPN outbound route filtering (ORF) enables VPNv4/VPNv6 peers to filter route target-MEM-network layer reachability information (RT-MEM-NLRI) on the BGP multi-service bearer framework.

ORF applies a local routing policy to the outbound interface of a peer so that the peer advertises only desired routes to the local device.

VPN ORF enables a PE to receive only desired routes, reducing pressure on the routing table capacity of the route reflector (RR) and autonomous system boundary router (ASBR).

Background

As networks develop, users keep increasing. The broadcast outbound policies used by carriers no longer meet user requirements because the routes that users desire vary. If the carrier maintains an export policy for each user, the O&M costs are extremely high. ORF allows users to receive only desired routes, without requiring the carrier to maintain an export policy for each user.

Related Concepts

  • RT-MEM-NLRI: VPN ORF routes
  • PE: provider edge
  • RR: route reflector
  • ASBR: autonomous system boundary router

Implementation

Each PE with VPN instances bound sends to BGP peers VPN ORF routes carrying the import route targets (IRTs) and the original AS number of desired routes, based on which the peers generate an export policy for the PE so that the PE receives only desired routes.

In Figure 7-44, if VPN ORF is disabled, the RR sends to PE3 all routes of VPN instances received from PE1. However, among these routes, PE3 only desires the routes with ERT 1:1. In addition, the RR sends to PE1 all routes of VPN instances received from PE3. However, among these routes, PE1 only desires the routes with ERT 1:1.
Figure 7-44  Basic usage scenario of VPN ORF

After VPN ORF is enabled, a BGP peer relationship is established in the VPN target address family view. As shown in Figure 7-44, a BGP peer relationship is established between the RR and PE1, and another BGP peer relationship is established between the RR and PE3. The BGP peers exchange VPN ORF routes. PE1 and PE3 each send VPN ORF routes carrying the IRTs of desired routes to the RR. Based on the received VPN ORF routes, the RR generates an export policy. In other words, before advertising BGP VPN routes, PE1 filters these routes based on the VPN ORF routes received from its peer.

In Figure 7-45, PE1, PE2, and PE3 are clients of the RR, VPN1 is bound to PE1 and PE2, and VPN2 is bound to PE3. If VPN ORF is disabled, PE1, PE2, and PE3 send routes with ERTs 1:1 and 2:2 to the RR. The RR reflects all routes to the PEs, and among the routes, PE1 and PE2 only accept the routes with ERT 1:1, and PE3 only accepts the routes with ERT 2:2.
Figure 7-45  Networking where a VPN RR has three clients

If VPN ORF is enabled, PE1, PE2, and PE3 send VPN ORF routes to the RR. The VPN ORF routes sent by PE1 and PE2 are the same. If the RR prefers the route sent by PE1 to the one sent by PE2, the RR reflects the route sent by PE1 and the route sent by PE3 to all clients. Then PE1 and PE2 learn the route with ERT 1:1, and PE3 learns the route with ERT 2:2.

Usage Scenario

VPN ORF applies to the following scenarios:

  • Intra-AS scenario where a VPN RR has clients
  • Inter-AS VPN scenario
  • Scenario where some routers do not support VPN ORF
  • Intra-AS scenario where an RR has clients and non-clients

Benefits

VPN ORF offers the following benefits:

  • Reduced bandwidth consumption

  • Reduced configuration workload

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Updated: 2018-07-04

Document ID: EDOC1100027166

Views: 42531

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