CCNA 新版（英文）D20S05L02.pps

© 2002, Cisco Systems, Inc. All rights reserved.
© 2002, Cisco Systems, Inc. All rights reserved.
2
Distance Vector Routing
Objectives
pleting this lesson, you will be able to:
Describe the features offered by distance vector routing protocols and give examples of each
Describe the issues associated with distance vector routing and identify solutions to those issues
Routers pass periodic copies of routing table to neighbor routers and accumulate distance vectors.
Distance Vector Routing Protocols
Routers discover the best path to destinations from each neighbor.
Sources of Information and Discovering Routes
Selecting the Best Route with Metrics
Updates proceed step-by-step from router to router.
Maintaining Routing Information
Each node maintains the distance from itself to each possible work.
Inconsistent Routing Entries
Slow convergence produces inconsistent routing.
Inconsistent Routing Entries (Cont.)
Router C concludes that the best path work is through router B.
Inconsistent Routing Entries (Cont.)