H12-891_V1.0 Exam Dumps : HCIE-Datacom V1.0

BGP EVPN in VXLAN Tunneling

✅ A. MP_REACH_NLRI is used to carry routing information.

MP_REACH_NLRI (Multiprotocol Reachable Network Layer Reachability Information) is used in BGP updates to carry VXLAN reachability information.

✅ B. Several BGP EVPN routes are defined through BGP extension.

BGP EVPN introduces multiple route types, such as Type 2 (MAC/IP Advertisement), Type 3 (Inclusive Multicast), and Type 5 (IP Prefix Advertisement).

✅ D. MP_REACH_NLRI is used to carry the RT.

RT (Route Target) defines route import/export policies in VPN environments.

MP_REACH_NLRI carries the RT attribute in BGP EVPN updates.

❌ Incorrect Answer:

❌ C. MP_REACH_NLRI is used to carry the RD.

Wrong! The Route Distinguisher (RD) is carried inside BGP attributes, but not in MP_REACH_NLRI.

Reference from Huawei HCIE-Datacom Documentation:

Huawei VXLAN BGP EVPN Configuration Guide – BGP EVPN Route Types

HCIE-Datacom Training Material – VXLAN Dynamic Tunnel Establishment

Comprehensive and Detailed In-Depth Explanation:

BGP4+ (BGP for IPv6) uses the MP_REACH_NLRI (Multiprotocol Reachable Network Layer Reachability Information) attribute to advertise IPv6 routes. This attribute is part of BGP ' s multiprotocol extensions (RFC 2858), allowing BGP to support multiple address families, including IPv6.

MP_REACH_NLRI: Advertises reachable IPv6 prefixes along with next-hop information.

MP_UNREACH_NLRI: Used to withdraw previously advertised IPv6 routes.

Since IPv6 addresses are significantly different from IPv4 addresses in structure and length (128 bits), the traditional BGP update message format (which supports only IPv4) is insufficient. The MP_REACH_NLRI attribute solves this by carrying IPv6-specific information.

Huawei Open Programmability System (OPS) is a programmable network architecture that uses RESTful APIs. In RESTful operations:

GET → Retrieve data

PUT → Configure/replace the value of a managed object

POST → Create new resources or perform non-idempotent operations

PATCH → Partially update a resource

When configuring or updating the value of a managed object (fully replacing it), PUT is the correct method.

Exact Extract – Huawei OPS and RESTful API Guide:

“The PUT method is used to configure the value of a managed object, replacing the entire object if it exists.”