Octet

Say this first

Type 1, Ethernet auto-discovery, and type 4, Ethernet segment, support multihoming. Type 2, MAC/IP advertisement, carries host MACs and optionally their IPs. Type 3, inclusive multicast Ethernet tag, says a VTEP is in a VNI and how to send it BUM traffic. Type 5, IP prefix, carries subnets and external routes. In a typical VXLAN fabric, types 2, 3 and 5 do most of the work.

Go deeper

Type	Name	Carries	Used for
1	Ethernet auto-discovery	ESI, per segment and per EVI	Fast mass withdraw, aliasing, split horizon
2	MAC/IP advertisement	MAC, optional IP, L2VNI, optional L3VNI	Bridging, host routes, ARP suppression
3	Inclusive multicast Ethernet tag	Originating VTEP IP, VNI, replication type	BUM flood lists, VTEP discovery
4	Ethernet segment	ESI, originating VTEP	Finding peers on a segment, DF election
5	IP prefix	Prefix, L3VNI, router MAC	Subnets, external and inter-site routes

Types 6 to 8 handle IGMP and MLD proxy for selective multicast.

What they look like on NX-OS

Output

[2]:[0]:[0]:[48]:[0050.56a1.0011]:[0]:[0.0.0.0]/216        MAC only
[2]:[0]:[0]:[48]:[0050.56a1.0011]:[32]:[10.10.10.11]/272   MAC and IP
[3]:[0]:[32]:[10.0.1.11]/88                                VTEP 10.0.1.11 is in this VNI
[5]:[0]:[0]:[24]:[10.10.20.0]/224                          prefix 10.10.20.0/24

In a type 2 string the fields are type, ESI, Ethernet tag, MAC length, MAC, IP length, IP.

Standards

RFC 7432 (EVPN base), RFC 8365 (EVPN with VXLAN), RFC 9135 (integrated routing and bridging) and RFC 9136 (type 5 prefixes).

They will ask next

Which route builds the BUM flood list?
Type 3. If a VTEP misses another VTEP's type 3 route, BUM toward that VTEP silently stops.
Which route gives fast convergence when a multihomed link fails?
Type 1 per Ethernet segment. The leaf withdraws one route and remote VTEPs drop that next hop for every MAC on the segment at once, instead of waiting for thousands of type 2 withdrawals.

Traps

Mixing up type 3 and type 5.

How did you do?