Ensure that the Border Gateway Protocol (BGP) and the IP or Multiprotocol Label Switching (MPLS) network is up and running
at the customer site that is connected to the provider site by more than one path (multihomed).
Ensure that the backup or alternate path has a unique next hop that is not the same as the next hop of the best path.
BGP PIC Implementation Considerations
BVI as a core is not supported.
For labelled BGP loopback peering, the system supports only one primary and one backup path. No support for BGP PIC multipath
PIC EDGE is supported for all services, such as IPv4, IPv6, VPNv4, VPNv6, 6PE, 6VPE, VPWS, VPLS, and EVPN.over labelled unicast
By default, without primary and backup path
installation in the hardware, IPv4, IPv6, 6PE (per-vrf), 6VPE
(per-vrf/per-ce), L3VPN (per-vrf/per-ce) has good convergence.
When the mode
is a per-prefix by default, BGP-PIC does not give good convergence, hence
you must do hardware-assisted PIC. For this, configure the cef
encap-sharing disable command in XR Config mode.
hardware-assisted BGP PIC that is configured using the cef encap-sharing
disable command, separate hardware resources (FEC/EEDB) are
allocated for every prefix. Cisco recommends you to make sure that the
router has sufficient hardware resources for the resource allocation.
This CLI reprograms the CEF completely and impacts traffic. We recommend that you do it in the maintenance window.
RP/0/RP0/CPU0:router(config)# router bgp 100
Specifies the autonomous system number and enters the BGP configuration mode, allowing you to configure the BGP routing process.
Configures extra paths selection mode for a prefix.
Use the additional-paths selection command with an appropriate route-policy to calculate backup paths and to enable Prefix-Independent Convergence (PIC) functionality.
The route-policy configuration is a prerequisite for configuring the additional-paths selection mode for a prefix. This is
an example route-policy configuration to use with additional-selection command:
set path-selection backup 1 install