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Zorluk: ZorRouting Concepts and Dynamic Routing Protocols

A network architect is evaluating dynamic routing protocols for an enterprise environment with redundant paths. The architect needs to ensure optimal path selection and fast convergence using Interior Gateway Protocols (IGPs). Which of the following statements accurately describe the operational characteristics of OSPF and EIGRP? (Select TWO.)

  1. EIGRP calculates backup routes known as feasible successors and maintains them in its topology table to enable rapid failover without recalculating paths.Cevap
  2. B
    OSPF Link-State Advertisements (LSAs) bypass Layer 3 IP header processing and encapsulate directly into Layer 2 frames to achieve faster routing updates.
  3. OSPF routers construct a synchronized Link-State Database (LSDB) representing the network map and run the Shortest Path First algorithm to determine the shortest tree to every destination.Cevap
  4. D
    When internal hosts access the internet via dynamic NAT with overload (PAT), dynamic routing protocols install a static one-to-one mapping entry in the routing table for every private host.

Cevap

The statements correctly describing OSPF and EIGRP are: EIGRP maintains precalculated backup routes (feasible successors) in its topology table for fast convergence, and OSPF maintains a synchronized Link-State Database (LSDB) to compute shortest path trees using Dijkstra's algorithm.
EIGRP uses the DUAL algorithm to identify feasible successors in the topology table, guaranteeing loop-free backup routes for instantaneous failover. Additionally, OSPF routers build a synchronized Link-State Database (LSDB) within an area and run Dijkstra's SPF algorithm to calculate the shortest path to every destination subnetwork.

Adım Adım Çözüm

1
Analyze EIGRP convergence mechanisms.
EIGRP calculates primary routes (successors) and backup routes (feasible successors) stored in the topology table, enabling fast convergence via DUAL.
If the primary route fails, EIGRP immediately promotes the feasible successor without needing a full recalculation.
2
Analyze OSPF operation and OSI layer encapsulation.
OSPF is a link-state protocol using Dijkstra's algorithm over an identical LSDB, and its packets are encapsulated in IP (Layer 3) headers using protocol number 89.
OSPF is a Layer 3 protocol, not a Layer 2 frame-level protocol, and builds a complete map of the network within an area.
3
Evaluate NAT/PAT interaction with dynamic routing protocols.
PAT translates private sockets to public IP/port combinations at the edge device and does not inject static host routes into RIB tables via dynamic routing protocols.
Routing protocols manage network prefix reachability, whereas PAT manages address translation tables.

Anahtar Kavram

Link-State vs Distance-Vector / Advanced Distance-Vector Routing Protocol Operations
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Konular

Routing Concepts and Dynamic Routing Protocols

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