Evpn Multihoming Redundancy Group; Ethernet Segment Identifier; Lacp Bundling - Cisco Nexus 9000 Series Configuration Manual

Configuring VXLAN EVPN Multihoming
• EAD/ES: Ethernet Auto Discovery Route per ES that is also referred to as type-1 route. This route is
• EAD/EVI: Ethernet Auto Discovery Route per EVI that is also referred to as type-1 route. This route is
• ES: Ethernet Segment route that is also referred to as type-4 route. This route is used for DF election
• Aliasing: It is used for load balancing the traffic to all the connected switches for a given Ethernet
• Mass Withdrawal: It is used for fast convergence during the access failure scenarios using the type-1
• DF Election: It is used to prevent forwarding of the loops and the duplicates as only a single switch is
• Split Horizon: It is used to prevent forwarding of the loops and the duplicates for the BUM traffic. Only

EVPN Multihoming Redundancy Group

Consider the dually homed topology, where switches L1 and L2 are distributed anycast VXLAN gateways
that perform Integrated Routing and Bridging (IRB). Host H2 is connected to an access switch that is dually
homed to both L1 and L2.
The access switch is connected to L1 and L2 via a bundled pair of physical links. The switch is not aware that
the bundle is configured on two different devices on the other side. However, both L1 and L2 must be aware
that they are a part of the same bundle.
Note that there is no Multichassis EtherChannel Trunk (MCT) link between L1 and L2 switches and each
switch can have similar multiple bundle links that are shared with the same set of neighbors.
To make the switches L1 and L2 aware that they are a part of the same bundle link, the NX-OS software
utilizes the Ethernet Segment Identifier (ESI) and the system MAC address (system-mac) that is configured
under the interface (PO).

Ethernet Segment Identifier

EVPN introduces the concept of Ethernet Segment Identifier (ESI). Each switch is configured with a 10 byte
ESI value under the bundled link that they share with the multihomed neighbor. The ESI value can be manually
configured or auto-derived.

LACP Bundling

LACP can be turned ON for detecting ESI misconfigurations on the multihomed port channel bundle as LACP
sends the ESI configured MAC address value to the access switch. LACP is not mandated along with ESI. A
given ESI interface (PO) shares the same ESI ID across the VTEPs in the group.
used to converge the traffic faster during access failure scenarios. This route has Ethernet Tag of
0xFFFFFFFF.
used for aliasing and load balancing when the traffic only hashes to one of the switches. This route
cannot have Ethernet Tag value of 0xFFFFFF to differentiate it from the EAD/ES route.
for BUM traffic.
Segment using the type-1 EAD/EVI route. This is done irrespective of the switch where the hosts are
actually learned.
EAD/ES route.
allowed to decap and forward the traffic for a given Ethernet Segment.
the BUM traffic that originates from a remote site is allowed to be forwarded to a local site.
Cisco Nexus 9000 Series NX-OS VXLAN Configuration Guide, Release 7.x
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