Huawei H12-891_V1.0 Exam With Confidence Using Practice Dumps

In MPLS (Multiprotocol Label Switching), Label Switching Routers (LSRs) handle packets based on FECs (Forwarding Equivalence Classes) and their positions in the label-switched path:

Ingress LSR: The entry point for labeled packets; it classifies packets into FECs and assigns the initial label.

Transit LSR: Intermediate routers that swap labels and forward packets along the LSP.

Egress LSR: The last router in the LSP that removes the label and forwards the packet normally.

An LSR cannot be both an ingress and a transit router for the same FEC, because an ingress LSR is defined as the starting point for that specific FEC ' s LSP. If it’s the ingress, it means the labeled path starts there, so it can ' t be in the middle (transit) of that same path.

Therefore, the statement is FALSE.

Comprehensive and Detailed In-Depth Explanation:

In the inter-AS MPLS VPN Option B solution:

Option B establishes a multi-hop eBGP connection between the ASBRs (ASBR-PE1 and ASBR-PE2) to exchange VPNv4 routes.

In this setup, the ASBRs exchange labeled VPNv4 routes via MP-BGP (Multiprotocol BGP).

The command:

[ASBR-PE1-bgp-af-vpnv4] undo peer 10.0.34.4 enable

is used to disable VPNv4 route exchange between the ASBR-PE1 and ASBR-PE2.

If this command is executed, ASBR-PE1 will not transmit VPNv4 routes to ASBR-PE2, breaking the inter-AS VPN connectivity.

Therefore, the statement is FALSE because ASBR-PE1 and ASBR-PE2 must exchange VPNv4 routes to maintain connectivity between the VPN sites across different ASes.

SRv6 Instruction Naming Conventions

SRv6 (Segment Routing over IPv6) uses segment identifiers (SIDs) with specific functions, indicated by instruction keywords:

✅ A. T: Searches a specified routing table to forward packets.

T (Table Lookup) → Performs a lookup in a specified routing table and forwards packets accordingly.

❌ B. M: Searches a Layer 2 forwarding table for unicast forwarding.

Incorrect! SRv6 does not use M for Layer 2 unicast forwarding.

✅ C. V: Searches a VPN instance routing table to forward packets.

V (VPN Routing Table Lookup) → Performs a lookup in a VPN instance (VRF) table for forwarding.

✅ D. X: Forwards packets through one or a group of specified Layer 3 interfaces.

X (Cross-connect forwarding) → Forwards packets via a specified Layer 3 interface or group of interfaces.

Reference from Huawei HCIE-Datacom Documentation:

Huawei SRv6 Configuration Guide – SRv6 SID Naming and Instruction Set

HCIE-Datacom Study Material – Segment Routing over IPv6 (SRv6) Functionality