Route-maps

• Can identify the subset of the routes to filter or change based on the route's prefix/length, and many other factors.
• Can make filtering choices.
• Can set different metric values with different routes.
• Can set different metric types for different OSPF routes.
• Can set route tags.

• Relies on the match command to identify routes.
• There are multiple match command options for redistribution:
  • match interface g 1/1
  • match 192.168.1.254 1
  • match 192.168.1.252 ACL-INGRESS
  • match 192.168.2.251 PREFIX-INGRESS
  • match ip next-hop ACL-EGRESS
  • match ip next-hop 2
  • match ip route-source ACL-INGRESS
  • match ip route-source {access-list-number | access-list-name}
  • match metric metric-value {+- deviation}
  • match route-type {internal | external [type-1 | Matches route type type-2] | level-1 | level-2}
  • match tag tag-value […tag-value]

• Set commands to change characteristics. There are multiple set command options for redistribution.
  • set metric metric-value
  • set metric bandwidth delay reliability load mtu
  • set metric-type {type-1 | type-2}
  • set tag tag-value

• To set the metric of a route-map entry, use set metric.
• Validation commands:
  • show ip eigrp topology
  • show ip ospf database [external | nssa-external]
  • show ip rip database
  • show ip route

router eigrp 100
    network 120.0.0.0
    redistribute connected  # Learns from interface #
!
access-list 1 permit 188.188.188.0 0.0.0.255
!
route-map INE permit 10
    match ip address 1
    set metric 1000 100 255 1 1500
!
route-map INE permit 20
    set metric 100000 50 255 1 1500
    set tag 999
!
show ip route eigrp  # Look for D EX #
!
show ip eigrp topology 120.120.120.0/24
# no tag shown #
!
access-list 2 permit 120.120.120.0 0.0.0.255
!
route-map TAG permit 10
    match ip address 2
    set tag 888
!
router eigrp 100
    network 120.120.120.0 0.0.0.255
# Can't apply a tag to an iEIGRP route #
!
access-list 2 permit 2.2.2.0 0.0.0.255
!
router eigrp 100
    redistribute connected route-map TAG
!
show ip eigrp topology 2.2.2.0/24
# Can see **Administrator tag is 888** now #
!
route-map TAG permit 20

# Now second statement in route-map will permit network 88.88.88.20, but not set a tag #

# Only redistribute eEIGRP routes with a tag of 888 #
route-map Match-External permit 10
    match tag 888
    match route-type external
!
route-map Match-External permit 20 # Capture everything else internal #
    match route-type internal
    set metric-type type-1
    set metric 77
!
route-map Match-External permit 30 # Capture everything else #
!
router ospf 1
    redistribute eigrp 100 route-map Match-External subnets

show ip route eigrp
show run router ospf
show ip route 2.2.2.0 # Has a tag of 888 #
show ip route 88.88.88.0 # Has no tag #
show ip route ospf

• The metric-type can only be changed for OSPF routes when they are being redistributed into the OSPF domain. Can only be done on the ASBR.
• The tag value is useful for preventing routing loops when there are multiple routers doing mutual route redistribution between two or more routing domains.

• Validation commands

show ip access-list
show ip prefix-list
show route-map
show ip eigrp topology table
show ip ospf database
show ip rip database
show ip route

• The distribute-list command refers to the direction, and to either an ACL or IP prefix-list, allowing the routes matched with a permit and filtering routes matched with a deny action.
• The distribute-list command can be configured to refer to the routing process from which routes are redistributed and cuase the router to filter routes taken from that process.