From: xander (xander@xxxxxx)
Date: Thu Apr 12 2001 - 07:27:46 GMT-3
Hello Phil,
Because OSPF has already have the same networks through OSPF, to avoid
making routing loops, due to AD(IGRP) is less than AD(OSPF),
they filter all networks being redistributer backward:
OSPF =} IGRP =} x(filter) - OSPF
P.S. Do not forget about BRI "on-demand" circuit. If you do not
block these routes, they bring BRI to flapping or always upping.
VP> All-
VP> I need some help in figuring out what this route map is doing.... R5 is the
VP> hub router in this excercise.R4 is a PtoP spoke runnning IGRP. R5 is runnin
g
VP> IGRP and OSPF and doing mutual redistribution between the two.
VP> Here is my head scratcher,........ The lab answer has route-map filter_igrp
VP> in its redistribution statement. Why? As I see it, none of these routes
VP> would be fed into IGRP anyway because of the different subnet mask than the
VP> IGRP is using,..... What am I overlooking?
VP> Anyone else run into this???????
VP> R5:
VP> router ospf 1
VP> redistribute igrp 1 metric 100 metric-type 1 subnets route-map filter_igrp
VP> network 137.20.25.2 0.0.0.0 area 2
VP> network 137.20.64.0 0.0.15.255 area 0
VP> network 137.20.100.32 0.0.0.31 area 1
VP> network 137.20.224.5 0.0.0.0 area 0
VP> network 137.20.240.1 0.0.0.0 area 0
VP> area 1 virtual-link 200.200.100.1
VP> area 1 virtual-link 137.20.33.33
VP> !
VP> router igrp 1
VP> redistribute ospf 1 metric 2000 100 255 1 1500
VP> passive-interface BRI0
VP> passive-interface Ethernet0
VP> passive-interface Serial0.1
VP> passive-interface Serial1
VP> network 137.20.0.0
VP> !
VP> ip classless
VP> ip route 137.20.81.0 255.255.255.0 137.20.86.1
VP> ip route 137.20.82.0 255.255.255.0 137.20.86.1
VP> no logging console
VP> access-list 1 permit 137.20.100.32 0.0.0.31
VP> access-list 1 permit 137.20.240.0 0.0.0.255
VP> access-list 1 permit 137.20.64.0 0.0.0.255
VP> access-list 1 permit 137.20.224.0 0.0.0.255
VP> access-list 2 permit any
VP> !
VP> route-map filter_igrp deny 10
VP> match ip address 1
VP> !
VP> route-map filter_igrp permit 20
VP> match ip address 2
VP> !
VP> R4:
VP> !
VP> !
VP> no ip domain-lookup
VP> !
VP> interface Ethernet0
VP> ip address 137.20.40.17 255.255.255.240
VP> !
VP> interface Serial0
VP> no ip address
VP> shutdown
VP> no fair-queue
VP> !
VP> interface Serial1
VP> ip address 137.20.200.18 255.255.255.240
VP> encapsulation frame-relay
VP> ip split-horizon
VP> keepalive 15
VP> clockrate 2000000
VP> frame-relay lmi-type ansi
VP> !
VP> router igrp 1
VP> network 137.20.0.0
VP> !
VP> ip classless
VP> ip default-network 200.200.200.0
VP> !
VP> Philip G. Virnoche CCNA
VP> Network Engineer - AT&T Wireless
VP> phone: 425.580.5239
VP> cell: 206.601.3134
VP> "HAM AND EGGS - A day's work for a chicken; A lifetime commitment for a
VP> pig."
-- WBW, xander mailto:xander@adt.ru CCNA, CCNP+VoiceAccess, CCIE first attempt in Brussels 19-20, April, 2001...
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