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

Forwarding Equivalence Class (FEC) is a key concept in MPLS (Multiprotocol Label Switching), where packets with the same forwarding characteristics are grouped into an FEC and assigned a label.

Correct Answers (Cannot be Used for FEC Allocation):

A. Fragment Offset – Incorrect as an FEC allocation standard

Fragment offset is used for reassembling fragmented IP packets at the receiver side.

It is not relevant for MPLS label assignment.

B. Application Protocol – Incorrect as an FEC allocation standard

MPLS does not classify packets based on application-layer protocols (e.g., HTTP, FTP).

It works mainly at Layer 2 and Layer 3.

Incorrect Answers (Valid FEC Allocation Standards):

C. Destination Address – Valid FEC allocation criterion

One of the most common MPLS FEC classifications.

Packets with the same destination are grouped into the same FEC.

D. Class of Service (CoS) – Valid FEC allocation criterion

MPLS uses CoS-based traffic classification (e.g., Exp bits in MPLS headers).

Different CoS levels can be mapped to different labels.

Reference from Huawei HCIE-Datacom Documentation:

Huawei MPLS Technology Guide – FEC and Label Assignment

HCIE-Datacom MPLS VPN Configuration Guide

The command output shows:

* > i before both networks, which means these routes are the preferred routes (*) and are learned via internal BGP (i).

Two networks are listed: 3002::3 and 3002::4, which means R1 does have these two routes in its BGP IPv6 routing table.

For 3002::4, the path origin shows 65001 i, which means this route originated from AS 65001 and was learned through IBGP.

The AS Path attribute is only shown for 3002::4, but both routes are clearly present.

Therefore, the correct conclusion is:

D. R1 has routes 3002::3/128 and 3002::4/128.

Comprehensive and Detailed In-Depth Explanation:

By default, OSPF does not automatically associate a domain ID with a process ID. The concept of " domain ID " is primarily used when redistributing routes between OSPF and BGP, particularly in MPLS VPN scenarios. The domain ID in OSPF helps maintain loop prevention and correct route advertisement between different OSPF domains. You can manually configure the domain ID using the domain-id command within the OSPF process view, but it is not inherently set to the process ID.