Hello miracle_david@yahoo.com ,
"IP access-lists" have different uses:
a) an "IP access-list" either standard or extended can be used to filter user traffic ( this is not possible with prefix-list)
b) an "IP access-list" can be used in route filtering and matching
The prefix-list have been introduced speclfically for route / prefix filtering they allow to match a range of prefixes within an address block this is not easy to implement with an IP extended ACL and not all routing protocols support this use of IP extended ACL.
Example:
ip prefix-list EXAMPLE permit 10.100.0.0/16 ge 20 le 24
This means all prefixes within 10.100.0.0/16 with prefix length between 20 and 24 are accepted:
10.100.128.0/17 is not a match
10.100.20.0/24 is a match
10.100.21.128/25 is not a match
10.100.0.0/23 is a match
A "route-map" is similar to an if then logic and allows to use match and set action in each "route-map" block/clause.
"Route-maps" are the most flexible way to implement route filtering in route redistribution and in other cases like applied to a "BGP neighbor" for example.
To be noted "route-maps" are also used to implement PBR policy based routing that moves beyond normal destination based routing.
An access-list or a prefix-list can be invoked in a match ip address statement in a "route-map" clause. The prefix list requires the use of the additional keyword prefix to be able to discriminate between named ACLs and prefix-lists.
route-map EXAMPLE permit 10
match ip address 101
route-map EXAMPLE permit 20
match ip address prefix EXAMPLE
Hope to help
Giuseppe
