CCNP Exam Prep Tips and Must Knows

Things You’ll Need to Know about Route Redistribution:

Configuring a Distribute List

• Define the traffic filtering or permit or deny routes using:
  • Access List
  • Route Map
• Configure a Distribute List to use he ACL or route map
  • Apply to inbound or outbound updates

Configuring a Prefix List

• Prefix lists match routes in part of an address space with a subnet mask that is longer or shorter than a set number
• For example:  R(config)#  ip prefix-list Test permit 10.8.0.0/16 le 22

Configuring a Route Map

• Route maps are complex access lists that allow conditions to be tested against a packet or route using the match command
• If the conditions match, actions can be taken to modify attributes of the packet or route.  These actions are specified by the set commands
• For example: 
• R(config)# route-map MYROUTEMAP permit 10
• R(config-route-map)# match ip address prefix-list Test
• R(config-route-map)# set interface Ethernet 0/0

Route Redistribution

• Routes learned by another routing protocol, static routes or directly connected routes can be redistributed into a routing protocol. For example:  EIGRP learned routes can be redistributed into the OSPF process
• Only routes learned by the router itself are redistributed

Seed Metrics

• Initial, or seed, metric for a route is derived from the directly connected router interface
• Default-metric command can be used to establish the seed metric for the routes or the metric can be specified when redistributing (e.g. via a route map)

Default Seed Metrics

• RIP – Infinity
• EIGRP – Infinity
• OSPF – 20 (except for BGP which is 1)
• BGP – BGP metric set it IGP metric value

Make sure you can configure:

• Route redistribution for all routing protocols
• One way redistribution with static route or default route
• Two way redistribution with route filtering
• Distribute Lists
• Prefix Lists
• Route Maps