HCIE-Datacom Changed H12-891_V1.0 Questions

✅ Hypertext Transfer Protocol (HTTP) is an application-layer protocol used for:

Accessing web pages and hypermedia content.

Client-server communication over the internet.

Stateless communication with request-response architecture.

Key Features of HTTP:

Application Layer Protocol in the TCP/IP model.

Uses TCP (Port 80) and HTTPS (Port 443) for secure communication.

Supports REST APIs, web applications, and cloud services.

Reference from Huawei HCIE-Datacom Documentation:

Huawei Network Protocol Guide – HTTP and Web Services

HCIE-Datacom Study Material – Application Layer Protocols in TCP/IP Model

NETCONF defines datastores to manage device configurations:

running: Active configuration in use

candidate: Staging area for changes before applying

startup: Configuration loaded on reboot

NETCONF operations:

< commit > : Applies changes from candidate → running → ✅

< delete-config > : Deletes a specified datastore (e.g., startup) → ✅

< validate > : Validates syntax/logic in the candidate datastore → ✅

Statement D is incorrect: < commit > never submits config from startup to running — that’s handled automatically at boot time, not through NETCONF commands.

Correct answer: D

VXLAN Inter-Subnet Routing with Symmetric IRB

VXLAN supports inter-subnet routing using Integrated Routing and Bridging (IRB). In symmetric IRB, both ingress and egress VTEPs perform Layer 3 forwarding to ensure efficient packet forwarding across subnets.

✅ A. Both the ingress VTEP and egress VTEP forward packets based on the Layer 3 forwarding table.

In symmetric IRB, both ingress and egress VTEPs perform Layer 3 lookup and forwarding.

The ingress routes packets before encapsulating them in VXLAN, and the egress performs another Layer 3 lookup to determine final delivery.

✅ D. When VTEPs forward inter-subnet user communication packets, the VNI carried in the VXLAN header is the L3VNI.

L3VNI (Layer 3 VXLAN Network Identifier) is used for inter-subnet routing between VXLAN segments.

WRED (Weighted Random Early Detection) helps prevent congestion by randomly discarding packets before buffers are full.

Drop Probability Behavior:

Below lower threshold = 0% drop (packets pass normally).

Between lower & upper threshold = Progressively increasing drop probability.

Above upper threshold = 100% drop (probability = 1).

✅ Reference: Huawei HCIE-Datacom Guide - WRED Mechanism