H12-821_V1.0 Exam Dumps - Huawei HCIP-Datacom Questions and Answers

Comprehensive and Detailed In-Depth Explanation:

InIS-IS, routes are distributed differently based onrouter levels:

Level-1 (L1) routers→ Maintainspecific routes only within their own area.

Level-2 (L2) routers→ Maintainspecific routes for the entire network(inter-area routing).

Level-1-2 (L1/L2) routers→ Storeboth L1 and L2 routesand act asarea border routers.

In the diagram,R2 and R3 are L1/L2 routers, meaning they storespecific routes for both their area and other areas.

R1 is only an L1 router, meaning it only hasintra-area routes, andR7 is an L2-only router, meaning it does not store all specific routes.

Therefore,R2 and R3havespecific routesfor the entire network.

????Reference:Huawei HCIA-Datacom Study Guide, IS-IS Routing Levels and Route Distribution.

The sequence of steps for electing the root port in an STP (Spanning Tree Protocol) network is as follows:

Bridge ID Comparison: TheBridge ID(BID) is compared between the bridges in the network. A smaller value indicates a higher priority, meaning the bridge with the lowest Bridge ID is elected as the root bridge.

RPC (Root Path Cost) Comparison: The path cost to reach the root bridge is calculated. The router with the lowest Root Path Cost (RPC) to the root bridge will have a higher priority for the election of the root port.

Peer BID Comparison: If there is a tie in the Root Path Cost, thePeer BIDis compared. A smaller Peer BID indicates a higher priority. This step ensures that if two routers have the same RPC, the one with the lower Peer Bridge ID wins.

Local BID Comparison: If there is still a tie, theLocal BIDis compared. A smaller Local BID indicates a higher priority. This final step ensures that the router with the lowest local identifier is selected.

Bridge ID Comparison:The first step in electing the root port is comparing the Bridge IDs. The bridge with the lowestBridge IDbecomes theroot bridge. The Bridge ID is made up of thebridge priorityandMAC address. The root bridge is the center of the network for STP, and all other ports will calculate their paths based on this root.

HCIP-Datacom-Core Technology Training Material (STP Concepts and Election Process)​​.

RPC (Root Path Cost) Comparison:Once the root bridge is selected, the network needs to determine the best path to the root. Each port on a non-root bridge will calculate theRoot Path Cost (RPC), which is the cumulative cost of reaching the root bridge from that port. The root port is the one that has the lowest RPC, meaning it provides the best path to the root bridge.

Comprehensive and Detailed In-Depth Explanation:

IP Multicast vs. Broadcast:

A. TRUE→ Unlikebroadcast, which sends data toall hostsin a subnet,multicast only sends data to interested receivers,preventing flooding.

B. TRUE→Multicast optimizes bandwidth usageby sending asingle copy of data, which is thenreplicated at network routers only when necessary.

IP Multicast vs. Unicast:

C. FALSE→Multicast does not improve security; it may expose data to unintended receivers ifnot properly controlled.

D. FALSE→Multicast reduces the load on the sourcebecause asingle data stream serves multiple receiversinstead of sendingindividual unicast streams.

????Reference:Huawei HCIA-Datacom Study Guide, IP Multicast Principles and Benefits.

Comprehensive and Detailed Step-by-Step Explanation:

Portal Authentication:

Portal authentication uses a web-based mechanism where clients are redirected to a login page.

Communication between the access device and Portal server uses HTTP or HTTPS protocols.

Correct Statements:

Option A:HTTP or HTTPS is used for Portal authentication.

Option D:Portal protocol packets are transmitted overTCPfor reliable communication.

Incorrect Statements:

Option B:Port 2000 is not the default for processing Portal packets.

Option C:The default destination port for communication with the Portal server is not 50100.

Thedefault Hello intervalon an OSPF P2P (Point-to-Point) or Broadcast network is10 seconds, and thedefault Dead intervalis40 seconds.

The Dead interval is the time a router waits without receiving a Hello packet from a neighbor before declaring it down.

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

“For broadcast and P2P network types, the default Hello interval is 10 seconds and the Dead interval is 40 seconds.”

(Chapter: OSPF Interface Types – Section: OSPF Timers)

RSTP improves convergence by introducing changes to the BPDU handling mechanism and port roles. However, RSTP does not rely on a fixed timeout of four Hello intervals for negotiation failure. Instead, RSTP uses a more dynamic mechanism to detect topology changes. The other options describe valid RSTP improvements ​.

 LSA Lifetime and Deletion

The LS Age field in the LSA header tracks the age of an LSA. When the LS Age reaches its maximum value (3600 seconds), the LSA is marked for deletion. This ensures old or stale LSAs are removed from the network to maintain accurate routing information.

 HCIP-Datacom-Core Reference

Detailed explanation of LS Age behavior and LSA deletion processes can be found in the OSPF LSDB and LSA sections​​.

Comprehensive and Detailed In-Depth Explanation:

A. TRUE→ Firewalls maintainsession tableswith adefault session timeout; adjusting it depends onnetwork conditions.

B. FALSE→Fast session aging does not affect persistent connection sessions. Persistent connections (e.g., TCP keepalives)maintain sessionseven if aging settings change.

C. TRUE→ Sessionsmust be constantly matchedwith ongoing traffic to remainactive.

D. TRUE→ Evenwithout stateful inspection, the firewallcreates session entriesfornon-first packetsto maintaincontinuity of services.

????Reference:Huawei HCIA-Datacom Study Guide, Firewall Session Table Mechanism.

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 ​.

Comprehensive and Detailed Step-by-Step Explanation:

DHCP Configuration Issues:

Option C:The DHCP function isdisabled by defaulton Huawei devices. If the administrator forgets to enable it, clients cannot receive IP addresses.

Option D:DHCP uses broadcast messages, which do not traverse routers. If the clients and DHCP server are on different subnets, aDHCP relay agentmust be configured.

Other Options:

Option A:Multiple DHCP servers can coexist as long as their IP address pools do not overlap. This is unlikely to cause the problem.

Option B:STP does not affect DHCP operations unless it delays port activation, which is uncommon in this scenario.