SPF Algorithm JN0-664 Practice Questions (Page 6)

Questions 26–28

1. 26application · medium

   In an OSPF network, two paths from router R1 to router R2 have identical total cost. The paths diverge at R1 and rejoin at R2, but one path passes through router R3 with a higher router ID than the other path's intermediate router R4. How does OSPF handle this situation?

   • AIt discards both paths and uses a default route
   • BIt selects the path through the router with the lower router ID
   • CIt selects the path through the router with the higher router ID
   • DIt installs both paths as ECMP next hops
   Reveal Solution Discussion Select an answer first
2. 27expert · hard

   During an SPF computation, a router has the following candidate list entries: Router A with cost 10, Router B with cost 15, and Router C with cost 20. The router moves Router A to the tree list. After examining Router A's neighbors, the router finds that Router B can now be reached with cost 12 (via Router A) instead of 15. What does the router do?

   • AMove Router B to the tree list immediately
   • BDiscard Router B from the candidate list
   • CUpdate Router B's cost in the candidate list to 12
   • DKeep Router B's cost at 15
   Reveal Solution Discussion Select an answer first
3. 28expert · hard

   An OSPF network has two equal-cost paths from router R1 to destination D. One path goes through router R2, and the other goes through router R3. The network operator wants to ensure that traffic is load-balanced across both paths. However, the operator also wants to avoid any possibility of micro-loops during a link failure. What should the operator consider?

   • AECMP inherently prevents micro-loops during link failures
   • BECMP provides load-balancing, but loop prevention during failure requires additional mechanisms like LFA or FRR
   • CThe operator should disable ECMP to prevent micro-loops
   • DThe operator should configure a higher router ID on one path to avoid loops
   Reveal Solution Discussion Select an answer first