Configuring the BGP Additional Paths feature
1. Enter system view. system-view
2. Enter BGP instance view. bgp as-number [ instance instance-name ]
3. Enter BGP VPNv4 address family view or BGP VPNv6 address family view.
Enter BGP VPNv4 address family view. address-family vpnv4
Enter BGP VPNv6 address family view. address-family vpnv6
4. Configure the BGP Additional Paths capabilities. peer { group-name | ipv6-address [ prefix-length ] } additional-paths
{ receive | send } *
By default, no BGP Additional Paths capabilities are configured.
5. Set the maximum number of Add-Path optimal routes that can be advertised to a peer or peer group. peer { group-name | ipv6-address [ prefix-length ] } advertise
additional-paths best number
By default, only one Add-Path optimal route can be advertised to a peer or peer group.
6. (Optional.) Set the optimal route selection delay timer.
route-select delay delay-value
By default, the optimal route selection delay timer is 0 seconds, which indicates that optimal route selection is not delayed.
Configuring the route recursion mode
About this task
After a PE receives a customer packet destined for an SRv6 SID, it forwards the packet according to the route recursion mode.
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SRv6 BE mode —This mode is also called SID-based forwarding mode. In this mode, the PE first encapsulates the End.DT4, End.DT6, or End.DT46 SID into the packet. Then, the PE searches the IPv6 routing table based on the SID encapsulated in the packet to forward the packet.
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SRv6 TE mode —This mode is also called SRv6 TE policy-based forwarding mode. In this mode, the PE first searches for a matching SRv6 TE policy based on the packet attributes.
Then, the PE adds an SRH to the packet. The SRH includes the End.DT4, End.DT6, or
End.DT46 SID and the SID list of the SRv6 TE policy. Finally, the PE forwards the encapsulated packet through the SRv6 TE policy. For more information, see "Configuring SRv6 TE policies."
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SRv6 TE and SRv6 BE hybrid mode —In this mode, the PE preferentially uses the SRv6 TE mode to forward the packet. If no SRv6 TE policy is available for the packet, the PE forwards the packet in SRv6 BE mode.
Prerequisites
To use the SRv6 TE mode or the SRv6 TE and SRv6 BE hybrid mode, you must configure a tunnel policy and SRv6 TE policy. For more information, see tunnel policy configuration in MPLS
Configuration Guide and "Configuring SRv6 TE policies."
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