Multi-chassis redundancy for a retail service is enabled with the SRRP and redundant interface configuration on the wholesale group interface parented by the forwarding subscriber interface. The multi-chassis state (active or standby) of the retail subscriber host is determined from the SRRP state (master/non-master) of the group interface that parents the SAP of the retail subscriber host. The retail service ID must be equal on both nodes.
Sample wholesale service configuration:
vprn 3000 customer 1 create
description "Wholesale service"
route-distinguisher 64500:3000
auto-bind-tunnel
resolution-filter
ldp
rsvp
exit
resolution filter
exit
vrf-target import target:64500:3000
redundant-interface "red-int-1" create
address 192.168.100.0/31
ip-mtu 1500
spoke-sdp 12:3000 create
no shutdown
exit
subscriber-interface "sub-int-1" create
address 10.1.1.253/24 gw-ip-address 10.1.1.254
address 10.1.2.253/24 gw-ip-address 10.1.2.254
group-interface "group-int-1-1" create
dhcp
--- snip ---
exit
redundant-interface "red-int-1"
sap 1/1/6:1.4001 create
description "SRRP 1 message path"
exit
srrp 1 create
message-path 1/1/6:1.4001
send-fib-population-packets outer-tag-only
no shutdown
exit
pppoe
--- snip ---
exit
exit
group-interface "group-int-1-2" create
dhcp
--- snip ---
exit
redundant-interface "red-int-1"
sap 1/1/6:2.4001 create
description "SRRP 2 message path"
exit
srrp 2 create
message-path 1/1/6:2.4001
priority 50
send-fib-population-packets outer-tag-only
no shutdown
exit
pppoe
--- snip ---
exit
exit
exit
no shutdown
exit
Sample retail service configuration:
vprn 3001 customer 1 create
description "Retail service"
route-distinguisher 64500:3001
auto-bind-tunnel
resolution-filter
ldp
rsvp
exit
resolution filter
exit
vrf-target target:64500:3001
subscriber-interface "sub-int-rt-3000-1" fwd-service 3000 fwd-subscriber-
interface "sub-int-1" create
address 10.1.11.253/24 gw-ip-address 10.1.11.254
address 10.1.12.253/24 gw-ip-address 10.1.12.254
dhcp
--- snip ---
exit
pppoe
--- snip ---
exit
exit
no shutdown
exit
Retail unnumbered host routes must be leaked in the wholesale service. Retail subscriber subnets and prefixes leaked in the wholesale service are needed to forward downstream shunted traffic over the redundant interface.
The address of an IPv4 unnumbered subscriber host (enabled with unnumbered {ip-int-name | ip-address} or allow-unmatching-subnets on the retail subscriber interface) is not contained in the subnets configured on the retail subscriber interface. The export of the IPv4 retail subscriber host routes to the wholesale service must be explicitly enabled with the export-host-routes command:
vprn 3001 customer 1 create
subscriber-interface "sub-int-rt-3000-1" fwd-service 3000 fwd-subscriber-
interface "sub-int-1" create
allow-unmatching-subnets
address 10.1.11.253/24 gw-ip-address 10.1.11.254
address 10.1.12.253/24 gw-ip-address 10.1.12.254
export-host-routes
--- snip ---
The address of an IPv6 unnumbered subscriber host (enabled with ipv6 allow-unmatching-prefixes on the retail subscriber interface) is not contained in the IPv6 prefixes configured on the retail subscriber interface. IPv6 retail subscriber host routes are automatically exported to the wholesale service.
Downstream traffic arriving on a standby node (SRRP backup state) must be shunted over the redundant interface. Downstream traffic shunting can be reduced by advertising the retail subscriber subnets and prefixes from the active node (SRRP master state) with a more favorable metric using routing policies. To make retail subscriber subnets and prefixes SRRP state-aware, they have to be configured to track an SRRP instance that is active on a group interface of the connected wholesale subscriber interface:
vprn 3001 customer 1 create
subscriber-interface "sub-int-rt-3000-1" fwd-service 3000 fwd-subscriber-
interface "sub-int-1" create
address 10.1.11.253/24 gw-ip-address 10.1.11.254 track-srrp 1
address 10.1.12.253/24 gw-ip-address 10.1.12.254 track-srrp 2
---snip---
ipv6
subscriber-prefixes
prefix 2001:db8:d001::/48 pd track-srrp 1
prefix 2001:db8:d002::/48 pd track-srrp 2
prefix 2001:db8:1:100::/56 wan-host track-srrp 1
prefix 2001:db8:1:200::/56 wan-host track-srrp 2
exit
exit
Multi-chassis redundancy is supported for IPoE (IPv4 and IPv6) and PPPoE (IPv4 and IPv6) retail subscriber hosts and sessions.
Overlapping addresses on retail subscriber interfaces (enabled with config>service>vprn>subscriber-interface>private-retail-subnets) can be used in combination with multi-chassis redundancy.
When the private-retail-subnets command is enabled, downstream traffic arriving at retail services on a standby node (SRRP backup state) is shunted over to the redundant interface on a wholesale service. On a redundant interface, the service that each frame belongs to is identified by the source MAC address of the frame that includes service ID of a retailer service.
The service ID of each retailer service is synchronized over MCS. Therefore, service IDs for the retailer VPRN must be the same in both nodes.
Traffic shunting in the overlapping address scenario is supported for downstream traffic only.