Cisco 2521LF - 2521LF Router Uživatelský manuál stáhnout pdf (Strana 20)

6-39CSE: Networking Fundamentals — WAN Basics

www.cisco.com

EIGRP Convergence

Steps of convergence:

1. C detects link failure; has no FS, goes into active convergence

- No successor candidates present in topology database

2. C sends query to B and D to get logical successor

- Because no route with a lower feasible distance available

3. D’s response indicates no logical successor

4. B’s response indicates FS with higher feasible distance

5. C accepts new path and distance, adds route via B to table

6. Sends Flash update about higher metric, goes to D and B

- Only higher metric propagated in triggered update

Convergence time to F: approximately 2 seconds

6-40CSE: Networking Fundamentals — WAN Basics

www.cisco.com

OSPF Convergence

Steps of convergence:

1. C detects link failure; sends link -state advertisement, goes to D and B

- Topology change is detected, traffic forwarding suspended

2. All routers update topology database; copy LSA and flood to neighbors

- All devices have topological awareness

3. All routers run Dijkstra algorithm, generate new routing table

- Route via B in routing tables, traffic forwarding resumed

Convergence time to F: approximately 6 seconds

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Cisco 2521LF - 2521LF Router Uživatelský manuál Strana 20