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5 — EVPN route types

EVPN carries several route types, each a different kind of announcement. You don't need all of them for lab 01, but knowing what each does is core knowledge (and classic interview fodder).

The five you should know

Type Name Carries Used for
1 Ethernet Auto-Discovery (A-D) per-ES / per-EVI info multihoming (ESI) — fast failover, aliasing
2 MAC/IP Advertisement a host's MAC (+ optional IP) behind a VTEP the workhorse — host reachability, ARP suppression
3 Inclusive Multicast (IMET) "I have this VNI" VTEP discovery + building the BUM flood list
4 Ethernet Segment which VTEPs share an ES multihoming — Designated Forwarder election
5 IP Prefix an IP prefix (not tied to a MAC) inter-subnet routing, L3VNI, external/summary routes

For the labs, focus on 2, 3, 5. Types 1 and 4 appear once you add multihoming.

Type-3 (IMET) — the first thing you see

When a VTEP has a VNI with an active member, it advertises a Type-3 route: "I participate in VNI 10100 — add me to the flood list for it." Every VTEP collects these to know who to replicate BUM traffic to (ingress replication, lesson 3).

Order matters: Type-3 is what appears first, before any host talks. In the lab, bgp.evpn.0 showed the two Type-3 routes (3:10.0.0.21:1::10100... and 3:10.0.0.22:1::10100...) as soon as the access port came up. A tunnel can't form until VTEPs discover each other via Type-3.

Type-2 (MAC/IP) — the workhorse

When a VTEP learns a local host (from a frame, ARP, or DHCP), it advertises a Type-2 route: "MAC aa🇧🇧cc — and IP 10.100.10.11 — is behind me (VTEP 10.0.0.22) in VNI 10100."

This one route does a lot: - Remote VTEPs install the MAC pointing at the tunnel to the origin VTEP. - The IP portion feeds ARP suppression — a leaf can answer ARP locally. - On a host move, a fresh Type-2 reconverges everything fast.

In the lab, show evpn database showed the Type-2 entries once the hosts pinged, and show ethernet-switching table flagged the remote MAC DR (Dynamic Remote) via the VXLAN tunnel.

Type-5 (IP Prefix) — routing, not bridging

Type-2 is about MACs (bridging within a subnet). Type-5 advertises an IP prefix with no MAC — used to route between subnets or to external destinations, via an L3VNI. You reach for Type-5 when you need inter-VNI routing, a default route to the internet, or route summarisation. (Later labs.)

A quick way to remember them

Type-3 = presence ("I'm here, I have this VNI"). Type-2 = endpoints ("this exact host is behind me"). Type-5 = routing ("reach this prefix through me").

Reading a route in show route table bgp.evpn.0

3:10.0.0.21:1::10100::10.0.0.21/248
│  └ RD      └ VNI  └ originator VTEP
└ route type (3 = IMET)
The leading number is the type. Learn to read that first digit — it tells you instantly what kind of announcement you're looking at.

Check yourself

  1. Which route type appears first, before any host sends traffic, and why?
  2. What two things does a single Type-2 route enable?
  3. When would you need a Type-5 route instead of a Type-2?
  4. In 2:10.0.0.22:1::10100::aa:c1:..., what does the leading 2 tell you?

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