Evpn Operation - Cisco ASR 9000 Series Configuration Manuallines

EVPN Operation

control-plane based MAC learning in the core. In EVPN, PE's participating in the EVPN instances learn
customer MAC routes in Control-Plane using MP-BGP protocol. Control-plane MAC learning brings a number
of benefits that allow EVPN to address the VPLS shortcomings, including support for multi-homing with
per-flow load balancing.
The EVPN control-plane MAC learning has the following benefits:
• Eliminate flood and learn mechanism
• Fast-reroute, resiliency, and faster reconvergence when link to dual-homed server fails
• Enables load balancing of traffic to and from CEs that are multihomed to multiple PEs
The following EVPN modes are supported:
• Single homing - This enables you connect a customer edge (CE) device to one provider edge (PE) device.
• Multihoming - This enables you to connect a customer edge (CE) device to two or more provider edge
• Active-Active - In active-active mode, all the PEs attached to the particular Ethernet-Segment is allowed
EVPN Operation
At startup, PEs exchange EVPN routes in order to advertise the following:
• VPN membership: The PE discovers all remote PE members of a given EVI. In the case of a multicast
• Ethernet segment reachability: In multi-home scenarios, the PE auto-discovers remote PE and their
• Redundancy Group membership: PEs connected to the same Ethernet segment (multi-homing)
L2VPN and Ethernet Services Configuration Guide for Cisco ASR 9000 Series Routers, IOS XR Release 6.3.x
486
(PE) devices to provide 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.
to forward traffic to and from that Ethernet Segment.
ingress replication model, this information is used to build the PE's flood list associated with an EVI.
corresponding redundancy mode (all-active or single-active). In case of segment failures, PEs withdraw
the routes used at this stage in order to trigger fast convergence by signaling a MAC mass withdrawal
on remote PEs.
automatically discover each other and elect a Designated Forwarder (DF) that is responsible for forwarding
Broadcast, Unknown unicast and Multicast (BUM) traffic for a given EVI.
EVPN Features