What does EVPN use lo identity which remote leaf device advertised the EVPN route?

What does EVPN use lo identity which remote leaf device advertised the EVPN route?
A . a route distinguisher value
B . a community tag
C . a route target value
D . a VRF target value

View Answer

Answer: A

Explanation:

EVPN uses a route distinguisher (RD) value to identify which remote leaf device advertised the EVPN route. An RD is a 64-bit value that is prepended to the EVPN NLRI to create a unique VPNv4 or VPNv6 prefix. The RD value is usually derived from the IP address of the PE that originates the EVPN route. By comparing the RD values of different EVPN routes, a PE can determine which remote PE advertised the route and which VRF the route belongs to.

The other options are incorrect because:

– B. a community tag is wrong because a community tag is an optional transitive BGP attribute that can be used to group destinations that share some common properties. A community tag does not identify the source of the EVPN route.

– C. a route target value is wrong because a route target (RT) value is an extended BGP community that is used to control the import and export of EVPN routes between VRFs. An RT value does not identify the source of the EVPN route.

– D. a VRF target value is wrong because there is no such thing as a VRF target value in EVPN. A VRF is a virtual routing and forwarding instance that isolates the IP traffic of different VPNs on a PE. A VRF does not have a target value associated with it.

References:

– EVPN Fundamentals

– RFC 9136 – IP Prefix Advertisement in Ethernet VPN (EVPN)

– EVPN Type-5 Routes: IP Prefix Advertisement

– Understanding EVPN Pure Type 5 Routes