The following shows an example of PE1 configuration that provides single-active multi-homing to CE2, as shown in Figure 1.
*A:PE1>config>service>system>bgp-evpn# info
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route-distinguisher 10.1.1.1:0
ethernet-segment "ESI2" create
esi 01:12:12:12:12:12:12:12:12:12
multi-homing single-active
service-carving
sdp 1
no shutdown
*A:PE1>config>redundancy>evpn-multi-homing# info
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boot-timer 120
es-activation-timer 10
*A:PE1>config>service>vpls# info
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description "evpn-mpls-service with single-active multihoming"
bgp
bgp-evpn
evi 10
mpls bgp 1
no shutdown
auto-bind-tunnel resolution any
spoke-sdp 1:1 create
exit
The PE2 example configuration for this scenario is as follows:
*A:PE1>config>service>system>bgp-evpn# info
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route-distinguisher 10.1.1.1:0
ethernet-segment "ESI2" create
esi 01:12:12:12:12:12:12:12:12:12
multi-homing single-active
service-carving
sdp 2
no shutdown
*A:PE1>config>redundancy>evpn-multi-homing# info
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boot-timer 120
es-activation-timer 10
*A:PE1>config>service>vpls# info
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description "evpn-mpls-service with single-active multihoming"
bgp
bgp-evpn
evi 10
mpls bgp 1
no shutdown
auto-bind-tunnel resolution any
spoke-sdp 2:1 create
exit
In single-active multi-homing, the non-DF PEs for a specified ESI block unicast and BUM traffic in both directions (upstream and downstream) on the object associated with the ESI. Other than that, single-active multi-homing is similar to all-active multi-homing with the following differences:
The ethernet-segment is configured for single-active: service>system>bgp-evpn>eth-seg>multi-homing single-active.
The advertisement of the ESI-label in an AD per-ESI is optional for single-active Ethernet-Segments. The user can control the no advertisement of the ESI label by using the service system bgp-evpn eth-seg multi-homing single-active no-esi-label command. By default, the ESI label is used for single-active ESs too.
For single-active multi-homing, the Ethernet-Segment can be associated with a port and sdp, as well as a lag-id, as shown in Figure 1, where:
port is used for single-active SAP redundancy without the need for lag.
sdp is used for single-active spoke SDP redundancy.
lag is used for single-active LAG redundancy
In this case, key, system-id, and system-priority must be different on the PEs that are part of the Ethernet-Segment).
For single-active multi-homing, when the PE is non-DF for the service, the SAPs/spoke SDPs on the Ethernet-Segment are down and show StandByForMHProtocol as the reason.
From a service perspective, single-active multi-homing can provide redundancy to CEs (MHD, Multi-Homed Devices) or networks (MHN, Multi-Homed Networks) with the following setup:
LAG with or without LACP
In this case, the multi-homed ports on the CE are part of the different LAGs (a LAG per multi-homed PE is used in the CE). The non-DF PE for each service can signal that the SAP is operationally down if eth-cfm fault-propagation-enable {use-if-tlv | suspend-ccm} is configured.
Regular Ethernet 802.1q/ad ports
In this case, the multi-homed ports on the CE/network are not part of any LAG. Eth-cfm can also be used for non-DF indication to the multi-homed device/network.
Active-standby PWs
In this case, the multi-homed CE/network is connected to the PEs through an MPLS network and an active/standby spoke SDP per service. The non-DF PE for each service makes use of the LDP PW status bits to signal that the spoke SDP is operationally down on the PE side.