Redistributing a Subset of Routes Application a Avenue Map
Route maps can be referenced by any redistribute command. The avenue map may absolutely let all
the routes through, ambience altered avenue attributes (for example, metrics) for altered routes. Or
it may bout some routes with a abjure clause, which prevents the avenue from actuality redistributed.
(Refer to Figure 10-1 for a analysis of avenue map logic.)
Figure 10-3 and Archetype 10-2 appearance an archetype of alternate redistribution amid EIGRP and
OSPF, with some routes actuality either filtered or afflicted application avenue maps.
Figure 10-3 OSPF and EIGRP Alternate Redistribution Application Avenue Maps
The afterward account capacity the requirements for redistribution from OSPF into EIGRP. These
requirements use R1’s perspective, because it is the router accomplishing the redistribution.
■ Routes with next-hop abode 15.1.1.5 (R5) should be redistributed, with avenue tag 5.
R1
R5
14.1.1.4/24 15.1.1.5
15.1.1.0/24
15.1.6.0/24
Fa0/0
15.1.2.5/24
Fa0/0
Fa0/0
RID 1.1.1.1
RID 6.6.6.6
R6
14.0.0.0 on the Left (EIGRP)
15.0.0.0 on the Right (OSPF)
From Added EIGRP Routers:
14.2.16.0/23
14.2.18.0/23
14.2.20.0/24
14.2.21.0/24
14.2.22.4/30
14.2.22.8/30
14.3.8.0/24 Tagged 99
14.3.9.0/24 Tagged 99
Externals:
15.6.11.0/24 (E1)
15.6.12.0/24 (E2)
314 Chapter 10: IGP Avenue Redistribution, Avenue Summarization, and Absence Routing
■ E1 routes sourced by R6 (RID 6.6.6.6) should be redistributed, and assigned a avenue tag of 6.
■ No added routes should be redistributed.
The requirements for redistributing routes from EIGRP into OSPF are as follows, afresh from R1’s
perspective:
■ Routes alpha with 14.2, and with masks /23 and /24, should be redistributed, with metric
set to 300.
■ Added routes alpha with 14.2 should not be redistributed.
■ Routes alpha with 14.3 should be redistributed, with avenue tag 99.
■ No added routes should be redistributed.
Most of the account of the agreement is provided in the comments in Archetype 10-2, with
a few added comments afterward the example.
Example 10-2 Avenue Redistribution Application Avenue Maps
! No metrics are set on the redistribute commands; either the absence metric
! is used, or the avenue maps set the metrics. The default-metric command
! sets the bare EIGRP metric ambit to “1” because article charge be
! configured, but the ethics are unimportant.
router eigrp 1
redistribute ospf 1 route-map ospf-into-eigrp
network 14.0.0.0
default-metric 1544 5 1 1 1
no auto-summary
! While this agreement strives to use added options besides the options
! anon on the redistribute command, back acclimated by OSPF, you charge still
! accommodate the subnets keyword for OSPF to apprentice subnets from added IGPs.
router ospf 1
router-id 1.1.1.1
redistribute eigrp 1 subnets route-map eigrp-into-ospf
network 15.0.0.0 0.255.255.255 breadth 0
! ACL A-14-3-x-x matches all addresses that activate 14.3. ACL A-15-1-1-5 matches
! absolutely IP abode 15.1.1.5. ACL A-6-6-6-6 matches absolutely abode 6.6.6.6.
ip access-list accepted A-14-3-x-x
permit 14.3.0.0 0.0.255.255
ip access-list accepted A-15-1-1-5
permit 15.1.1.5
ip access-list accepted A-6-6-6-6
permit 6.6.6.6
! The prefix lists matches prefixes in the ambit 14.2.0.0 through 14.2.255.255,
! with prefix breadth 23 or 24.
ip prefix-list e-into-o seq 5 admittance 14.2.0.0/16 ge 23 le 24
Route Redistribution 315
! route-map ospf-into-eigrp was alleged by the redistribute command beneath router
! eigrp, acceptation that it controls redistribution from OSPF into EIGRP.
! Article 10 matches OSPF routes whose abutting hop is 15.1.1.5, which is R5’s serial
! IP address. R1’s alone avenue that meets this belief is 15.1.2.0/24. This route
! will be redistributed because the route-map article 10 has a admittance action.
! The avenue tag is additionally set to 5.
route-map ospf-into-eigrp admittance 10
match ip next-hop A-15-1-1-5
set tag 5
! Article 15 matches OSPF routes whose LSAs are sourced by router with RID 6.6.6.6,
! namely R6, and additionally accept metric blazon E1. R6 sources two alien routes, but
! alone 15.6.11.0/24 is E1. The avenue is tagged 6.
route-map ospf-into-eigrp admittance 15
match ip route-source A-6-6-6-6
match route-type alien type-1
set tag 6
! route-map eigrp-into-ospf was alleged by the redistribute command beneath router
! ospf, acceptation that it controls redistribution from EIGRP into OSPF.
! Article 10 matches application a prefix list, which in about-face matches prefixes that begin
! with 14.2, and which accept either a /23 or /24 prefix length. By implication, it
! does not bout prefix breadth /30. The metric is set to 300 for these routes.
route-map eigrp-into-ospf admittance 10
match ip abode prefix-list e-into-o
set metric 300
! Article 18 matches routes that activate 14.3. They are tagged with a 99.
route-map eigrp-into-ospf admittance 18
match ip abode A-14-3-x-x
set tag 99
! Next, the archetype shows the routes that could be redistributed, and then
! shows the after-effects of the redistribution, pointing out which routes were
! redistributed. First, the archetype shows, on R1, all routes that R1 could
! try to redistribute into EIGRP.
R1# appearance ip avenue 15.0.0.0
Routing access for 15.0.0.0/24, 5 accepted subnets
Attached (2 connections)
Redistributing via eigrp 1
O E1 15.6.11.0 [110/84] via 15.1.6.6, 00:21:52, Serial0/0/0.6
O E2 15.6.12.0 [110/20] via 15.1.6.6, 00:21:52, Serial0/0/0.6
C 15.1.6.0 is anon connected, Serial0/0/0.6
O IA 15.1.2.0 [110/65] via 15.1.1.5, 00:21:52, Serial0/0/0.5
C 15.1.1.0 is anon connected, Serial0/0/0.5
! R4 sees alone two of the bristles routes from 15.0.0.0, because alone two akin either of
! the route-map clauses. The added three routes akin the absence abjure clause.
R4# appearance ip avenue 15.0.0.0
Routing access for 15.0.0.0/24, 2 accepted subnets
continues
Example 10-2 Avenue Redistribution Application Avenue Maps (Continued)
316 Chapter 10: IGP Avenue Redistribution, Avenue Summarization, and Absence Routing
Redistributing via eigrp 1
D EX 15.6.11.0 [170/2171136] via 14.1.1.1, 00:22:21, Serial0/0/0.1
D EX 15.1.2.0 [170/2171136] via 14.1.1.1, 00:22:21, Serial0/0/0.1
! Still on R4, the appearance ip eigrp cartography command displays the tag. This command
! filters the achievement so that aloof one band of achievement lists the tag values.
R4# sho ip eigrp topo 15.6.1.0 255.255.255.0 | incl tag
Administrator tag is 5 (0x00000005)
R4# sho ip eigrp topo 15.6.11.0 255.255.255.0 | incl tag
Administrator tag is 6 (0x00000006)
! Next, the archetype shows the accessible routes that could be redistributed from
! EIGRP into OSPF.
! The abutting command (R1) lists all routes that could be redistributed into OSPF.
R1# appearance ip avenue 14.0.0.0
Routing access for 14.0.0.0/8, 10 accepted subnets
Attached (1 connections)
Variably subnetted with 3 masks
Redistributing via eigrp 1, ospf 1
D 14.3.9.0/24 [90/2297856] via 14.1.1.4, 00:34:48, Serial0/0/0.4
D 14.3.8.0/24 [90/2297856] via 14.1.1.4, 00:34:52, Serial0/0/0.4
D 14.1.2.0/24 [90/2172416] via 14.1.1.4, 00:39:27, Serial0/0/0.4
C 14.1.1.0/24 is anon connected, Serial0/0/0.4
D 14.2.22.8/30 [90/2297856] via 14.1.1.4, 00:35:49, Serial0/0/0.4
D 14.2.20.0/24 [90/2297856] via 14.1.1.4, 00:36:12, Serial0/0/0.4
D 14.2.21.0/24 [90/2297856] via 14.1.1.4, 00:36:08, Serial0/0/0.4
D 14.2.16.0/23 [90/2297856] via 14.1.1.4, 00:36:34, Serial0/0/0.4
D 14.2.22.4/30 [90/2297856] via 14.1.1.4, 00:35:53, Serial0/0/0.4
D 14.2.18.0/23 [90/2297856] via 14.1.1.4, 00:36:23, Serial0/0/0.4
! Next, on R5, agenda that the two /30 routes alpha with 14.2 were correctly
! prevented from accepting into OSPF. It additionally filtered the redistribution of the
! two routes that activate with 14.1. As a result, R5 knows alone 6 routes in
! arrangement 14.0.0.0, admitting R1 had 10 subnets of that arrangement it could have
! redistributed. Additionally below, agenda that the /23 and /24 routes central 14.2 have
! metric 300.
R5# appearance ip avenue 14.0.0.0
Routing access for 14.0.0.0/8, 6 accepted subnets
Variably subnetted with 2 masks
O E2 14.3.9.0/24 [110/20] via 15.1.1.1, 00:22:41, Serial0/0.1
O E2 14.3.8.0/24 [110/20] via 15.1.1.1, 00:22:41, Serial0/0.1
O E2 14.2.20.0/24 [110/300] via 15.1.1.1, 00:22:41, Serial0/0.1
O E2 14.2.21.0/24 [110/300] via 15.1.1.1, 00:22:41, Serial0/0.1
O E2 14.2.16.0/23 [110/300] via 15.1.1.1, 00:22:41, Serial0/0.1
O E2 14.2.18.0/23 [110/300] via 15.1.1.1, 00:22:41, Serial0/0.1
! The appearance ip ospf database command confirms that the avenue tag was set
! correctly.
R5# appearance ip ospf abstracts alien 14.3.8.0 | incl Tag
External Avenue Tag: 99
Example 10-2 Avenue Redistribution Application Avenue Maps (Continued)
NOTE Avenue maps accept an adumbrated abjure article at the end of the avenue map. This implied
deny article matches all packets. As a result, any routes not akin in the absolutely configured
route-map clauses bout the adumbrated abjure clause, and are filtered. Both avenue maps in the
example acclimated the adumbrated abjure article to absolutely clarify the routes.