Supported Modes for EVPN-VPWS
EVPN-VPWS supports the following modes:
-
Single-homed - Enables you to connect a customer edge (CE) device to one provider edge (PE) device.
-
Multi-homed - Enables you to connect a customer edge (CE) device to more than one provider edge (PE) device. Multihoming ensures redundant connectivity. The redundant PE device ensures that there is no traffic disruption when there is a network failure. Following are the types of multihoming:
-
Single-Active - In single-active mode only a single PE among a group of PEs attached to the particular Ethernet-Segment is allowed to forward traffic to and from that Ethernet Segment.
-
All-Active - In all-active mode all the PEs attached to the particular Ethernet-Segment is allowed to forward traffic to and from that Ethernet Segment.
-
Benefits of EVPN-VPWS
The following are the benefits of EVPN-VPWS:
-
Scalability is achieved without signaling pseudowires.
-
Ease of provisioning
-
Pseudowires (PWs) are not used.
-
Leverages BGP best path selection (optimal forwarding).
Prerequisites for EVPN-VPWS
-
Ensure BGP is configured for EVPN SAFI.
-
BGP session between PEs with 'address-family l2vpn evpn' to exchange EVPN routes.
Restrictions for EVPN-VPWS
-
The VPN ID is unique per router.
-
When specifying a list of route targets, they must be unique per PE (per BGP address-family).
-
On versions earlier than IOS XR release 7.0.x, MTU is not signaled and the MTU mismatch is ignored with no interoperability issues.
On versions later than IOS XR release 7.0.x, L3 MTU is advertised by default and the MTU mismatch is enforced by default. But this results in interoperability issues with IOS XR release 7.3.2, if transmit-l2-mtu is configured since L3 and L2 MTUs do not match. You can configure transmit-mtu-zero and ignore-mtu-mismatch commands to avoid this situation.
On versions later than IOS XR release 7.3.2, MTU of 0 is advertised by default, and the MTU mismatch is ignored by default. L2 MTU can be advertised using the transmit-l2-mtu command, and MTU mismatch can be enforced with enforce-mtu-mismatch command.