Configuring Bit-Error-Triggered EVPN L3VPN Route Switching

This section describes how to configure bit-error-triggered EVPN L3VPN route switching.

Context

In an EVPN L3VPN scenario in which an RSVP-TE tunnel with TE hot standby protection carries services and VPN FRR is configured, you can configure bit-error-triggered EVPN L3VPN route switching in addition to bit-error-triggered RSVP-TE tunnel switching. If the primary and backup CR-LSPs of the RSVP-TE tunnel are both in the excessive bit error rate (BER) state or the TE hot-standby tunnel fails, bit-error-triggered RSVP-TE tunnel switching may not be able to protect services against bit errors. In this case, bit-error-triggered EVPN L3VPN route switching can do so.

On the EVPN L3VPN H-VPN shown in Figure 1, RSVP-TE tunnels are established between the UPE and SPEs to carry services, and the tunnels work in hot-standby mode. VPN FRR is configured on the UPE. If the primary and backup CR-LSPs of the RSVP-TE tunnel are both in the excessive BER state or the TE hot-standby tunnel fails, bit-error-triggered RSVP-TE tunnel switching cannot protect traffic against bit errors. To resolve this problem, configure bit-error-triggered EVPN L3VPN route switching on the UPE and SPE1. This function triggers EVPN route convergence if a bit error event occurs, diverting traffic from the link that has encountered the bit error event.

Figure 1 Application scenario for bit-error-triggered EVPN L3VPN route switching

Pre-configuration Tasks

Before configuring bit-error-triggered EVPN L3VPN route switching, complete the following tasks:

Procedure

Configure the UPE to reroute traffic when a bit error event occurs.
1. Run system-view
  The system view is displayed.
2. Run bgp as-number
  The BGP view is displayed.
3. Run ipv4-family vpn-instance vpn-instance-name
  The BGP-VPN instance IPv4 address family view is displayed.
4. Run bestroute bit-error-detection
  The function is enabled to reroute traffic when a bit error event occurs.
5. Run commit
  The configuration is committed.
Configure SPE1 to adjust the local preference or MED values of the EVPN routes that it advertises to the NPE when a bit error event occurs.
1. Run system-view
  The system view is displayed.
2. Run bgp as-number
  The BGP view is displayed.
3. Run l2vpn-family evpn
  The BGP-EVPN address family view is displayed.
4. Run nexthop recursive-lookup bit-error-detection { med + med-adjust-value | local-preference - localpref-adjust-value }^* [ route-policy route-policy-name ]
  The function is configured to associate bit error events with the adjustment of EVPN route local preference or MED values.
5. Run commit
  The configuration is committed.