Huawei H12-821_V1.0 Questions Answers

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding LSA Filtering in OSPF and IS-IS:

The filter-policy command is used in OSPF and IS-IS to control which routing information isimported into the local routing tableoradvertised to other neighbors.

However, itcannot filter LSAs forwarded by neighbors. In OSPF and IS-IS, LSAs are always forwarded unchanged within the area to ensure all routers have a consistent link-state database.

Filtering only affects the routes that are installed into the local routing table or advertised to other areas or neighbors.

2. Why the Statement is False:

LSAs are forwarded without being filtered. This ensures link-state protocols maintain the same network topology view across the network.

The filter-policy import command only controls routes that are installed into the local routing table, not the forwarding of LSAs.

3. Summary:

The statement is FALSE because LSAs cannot be filtered by filter-policy import.

Huawei HCIA-Datacom Study Guide, Chapter "OSPF Route Filtering."

RFC 2328: OSPF Version 2, LSA Propagation Rules.

Inter-area route calculation in OSPF involves Summary LSAs (Type 3) for summarizing routes across areas and ASBR Summary LSAs (Type 4) for locating ASBRs. While Router LSAs and Network LSAs describe the internal structure of an area, they do not directly participate in inter-area route calculation. Thus, the statement that only Router, Network, and Summary LSAs are involved is false ​.

The IPv6 address 2001:0DBB:B8:0000:C030:0000:0000:09A0:CDEF can be compressed by removing leading zeros in each segment and collapsing consecutive zero groups into ::. The result is 2001:DBB:B8:0:C030::9A0:CDEF ​.

1 – Idle

2 – Connect

3 – OpenSent

4 – OpenConfirm

5 – Established

6 – Active

TheBGP finite state machinedefines how a BGP speaker transitions through various states when establishing and maintaining a BGP session. Below is the role of each state:

Idle (1)– BGP is waiting to start a connection. Initial state of the BGP process.

Connect (2)– BGP initiates a TCP connection to the peer.

OpenSent (3)– TCP connection is established; BGP sends an OPEN message and waits for one from the peer.

OpenConfirm (4)– BGP has received a valid OPEN message and is now expecting a KEEPALIVE.

Established (5)– BGP session is fully established; UPDATE messages can now be exchanged.

Active (6)– If the TCP connection fails in Connect state, BGP transitions to Active and will retry connection.

Reference from Huawei HCIP-Datacom-Core Technology Study Guide:

“BGP goes through the following states in order: Idle → Connect → Active → OpenSent → OpenConfirm → Established. The transition depends on the success or failure of TCP connection setup and BGP message exchanges.”

(Chapter: BGP Principles – Section: BGP State Machine)