OSPF does not inject external OSPF routes into BGP unless it is specifically instructed to do with the following command:
router bgp 3
redist ospf 3 match external 1 external 2
Normally you would not do this.
You should the nei dist-list xx out command to redist into any IGP,this will allow you to limit the networks into IGP.
router ospf 1
THE CCIE Book
redist bgp 200 dist-list 1 in
access-list 1 permit 172.16.0.0 0.0.255.255
16.10. IPX R EDISTRIBUTION
Manual Redistribution IPX EIGRP - NLSP
Ø *Automatic IPX Mutal Redistribution IPX EIGRP to IPX RIP
IPX RIP to NLSP
IPX RIP and Static Routes
Manual Redistribution IPX EIGRP - NLSP
Ø IPX EIGRP and IPX RIP Redistribution
Redistribution between IPX RIP and IPX EIGRP is automatic, use the no redistribute command to stop.
ipx router eigrp 100 no redistribute rip
Ø NLSP and IPX EIGRP Redistribtion ipx router eigrp 20
redistribute nlsp
!
ipx router nlsp
redistribute eigrp 20
16.11. FLSM AND VLSM
You will most definitely be asked to do some kind of redistribution between an FLSM protocol and a VLSM protocol, and you will be told you cannot use a static route, a default route, or a default network.
RIP will redistribute the 0.0.0.0 default network use the default-information originate command
IGRP does not distribute the 0.0.0.0 network use the ip default-network command, network must be classful, in routing table, and not on FLSM router.
ip classless must be configured on the FLSM router.
Ø RIPv2 Method
Create RIP routes with /25 mask, redistribute into OSPF with no subnets keyword.
Change to RIPv2 and see what happens. How can change RIP to RIPv2 make the routes appear / disappear?
Change RIP to version 2 that supports /28 networks.
Ø Static Method – RIP / IGRP OSPF ASBR
Create a static route to null0 on ASBR and redistribute static into IGRP.
THE CCIE Book
Ø Second OSPF Process Method – OSPF to RIP / IGRP
Use a second ospf process and redistribute your main process into your second and then use the summary-address command and redistribute the second process into igrp.
Ø Route-Map Method OSPF ASBR
router ospf 10
redistribute rip metric 10 subnets router rip
redistribute ospf 10 metric 2 route-map add-all route-map add-all permit 10
match ip address 1
access-list 1 permit 203.45.2.1 255.255.255.0
Ø Loopback Method OSPF – RIP / IGRP OSPF ASBR
OSPF /28 -> RIP /24 -> IGRP /24
Create a loopback on a router in the ospf domain other than the ASBR using the same subnet but with a /24 mask and then advertised that into ospf and all was well on the IGRP router.
You may be able to use the subnet-zero option to create the loopback.
Ø Summarize Method #1 OSPF ABR
Summarize route if the area in not connected to the same area as the ASBR.
If you use the area range command to summarize an area that is directly connected to the ASBR, the summarized route will not get "injected" into the RIP/IGRP domain.
OSPF ASBR
Summarize the network area 0 range on a router other than the ASBR, then the ASBR would have the summary in the routing table to redistribute.
For either of these summarization methods to work you must get the summary to the ASBR. The only way to do this is to have the ASBR be in another area.
Ø Summarize Method #2
To avoid the problems on a ASBR where the route must be external to summarize, you can redistributing connected into OSPF, the connected route appears as external, which is then subject to the summary-address command.
Redistribute connected using a route map with an access list to match only that route into OSPF (This makes the route EX external) and use a summary address to make it a /24 then redistribute OSPF to RIP.
An external routes will be injected
router ospf 10
redistribute connected route-map onlyloops subnets summary-address 173.16.24.1 0.0.0.3
summary-address 192.168.12.1 0.0.0.3
route-map onlyloops
match interface loop0 loop1
THE CCIE Book
int lo0
ip add 173.16.24.1 255.255.255.252 int lo1
ip add 192.168.12.1 255.255.255.252
16.12. M UTUAL R EDISTRIBUTION
This is when the same routing protocol is redistributed into two identical processes on different routers.
The AD can form a routing loop.
Route-tagging is great for mutual redistribution except for RIPv1 and IGRP.
Although route-maps do work, distribute-lists are more flexible.
To Solve this problem use:
Passive-interfaces Split-horizon
Distribute-list 1 out ospf 10
Ø RIP and OSPF (Dist-List) router ospf 10
redistribute rip metric 10 subnets router rip
redistribute ospf 10 metric 2 distribute-list 1 out ospf 10
Ø RIP and OSPF (Route-Map) Exmaple #1
router ospf 1
redistribute rip subnets metric 100 route-map r2o
router rip version 2
redistribute ospf 1 metric 2 route-map o2r
route-map r2o deny match tag 110
route-map r2o permit 20 set tag 120
route-map o2r deny match tag 120
route-map o2r permit 20 set tag 110
Example #2
route-map tagging deny 10 match tag 100
route-map tagging permit 20 set tag 100
router ospf 1
redistribute rip subnets metric 100 route-map tagging
router rip version 2
THE CCIE Book
redistribute ospf 1 metric 2 route-map tagging
The logic is that we can seperate the routes in OSPF domain as internal (no tag) and external (tag 100). Because tag in OSPF routes will not influence the routes in RIP2, vice versa, you can set both tag as 100. Harder to understand, though.
Any show commands to observe tags?
sho ip ospf database, last section has tagging. if you do debug ip rip database (v2) it shows tags of routes coming in and out. igrp doesn't understand tagging.
eigrp does, and i things its also some show ip eigrp database like command.
Ø IGRP and OSPF router igrp 100
passive-interface s 0
distribute-list 1 out ospf 10
access-list 1 deny 10.10.0.0 ! IGRP route redistrib into OSPF access-list 1 permit any
The dist-list need to be applied to all routers that could advertise the OSPF network back to the originating router.
IGRP ->OSPF R1
router ospf 200
netw 1.1.6.0 0.0.0.255 area 6 netw 1.1.1.0 0.0.0.255 area 0 netw 1.1.4.0 0.0.0.255 area 4 R2
router ospf 200
netw 1.1.2.0 0.0.0.255 area 4 netw 1.1.4.0 0.0.0.255 area 4 R3
router ospf 200
redist igrp 200 metric 1 metric-type 1 netw 1.1.6.0 0.0.0.255 area 6
router igrp 200
redist ospf 200 metric 125 1000 255 1 1500 netw 1.1.1.3.0
passive-interface serial 0 dist-list 1 out ospf 200
access-list 1 permit 1.1.1.0 0.0.0.255 access-list 1 permit 1.1.2.0 0.0.0.255
Ø Two-Way Redistribution Method 1:
OSPF – EIGRP router eigrp 10
redistribute ospf 1 match internal router ospf 1
redistribute eigrp 10 route-map Internal-Only route-map Internal-Only permit 10
match route-type internal
Method 2:
OSPF – EIGRP router eigrp 10
redistribute ospf 1 route-map OSPF1
THE CCIE Book
router ospf 1
redistribute eigrp 10 route-map EIGRP10 route-map OSPF1 deny 10
match tag 10
route-map OSPF1 permit 20 set tag 1
route-map EIGRP10 deny 10 match tag 1
route-map EIGRP10 permit 20 set tag 1
Two-Way with RIP
RIP does not support internal / external tags Use route filters / tags.
Ø RIP and IGRP router rip
redist igrp 200 route-map igrp-to-rip netw 192.168.3.0
router igrp 200
redist rip metric 10000 100 255 1 1500 netw 192.168.6.0
route-map igrp-to-rip permit 10 match ip address 1
set metric 1
route-map ipgr-to-rip permit 20 match ip addr 2
set metric 2
route-map igrp-to-rip permit 30 match ip addr 3
set metric 3
access-list 1 permit 192.168.6.0 0.0.0.255 access-list 2 permit 192.168.1.0 0.0.0.255 access-list 2 permit 192.168.4.0 0.0.0.255 access-list 3 permit 192.168.2.0 0.0.0.255
Ø IGRP / OSPF Mutual
access-list 1 permit 172.161.1.0 access-list 1 permit 172.16.2.0 access-list 1 permit 10.1.1.0 access-list 2 permit 172.16.20.0 access-list 2 permit 172.16.30.0 access-list 2 permit 10.20.30.0 router ospf 100
redistribute igrp 100 subnets distribute-list 1 out igrp 100 router igrp 100
redistribute ospf 100 metric 10000 1000 255 1 1500 distribute-list 2 out ospf 100
16.13. R EDISTRIBUTION S UMMARIES
Ø RIP
default-metric 5 router rip
THE CCIE Book
redist igrp 200 metric 5 redist eigrp 200 metric 5 redist ospf 1 metric 5
Ø IGRP / EIGRP Examples
Default-Metric default-metric 10000 100 255 1 1500
Connected redist connected metric 10000 100 255 1 1500 Static redist static metric 10000 100 255 1 1500 RIP redist rip metric 10000 100 255 1 1500 IGRP (Same AS) router eigrp 200
netw 1.1.1.0 router igrp 200 netw 1.1.6.0
IGRP (Diff AS) redist igrp 100 metric 10000 100 255 1 1500 OSPF redistribute ospf 128 56 1000 255 1 1500 IPX RIP Automatic
NLSP redistribute nlsp ? metric 56 1000 255 1 1500
Ø OSPF
Static redistribute static metric 50 metric-type 1 subnets Connected redistribute connected metric 50 metric-type 1 subnets RIP redistribute rip subnets metric-type 1 metric 12
IGRP/ EIGRP redistribute eigrp subnets metric-type 1 metric 12
Ø BGP
EIGRP redist eigrp 10 OSPF Internal redist ospf 3
OSPF External redist ospf 3 match external 1 external 2 Ø IPX EIGRP
IPX RIP ipx router eigrp 100 dist-list 800 in
NLSP ipx router eigrp 20 redistribute nlsp
Ø NLSP
EIGRP ipx router nlsp redistribute eigrp 20
Ø VLSM to FLSM Solutions:
RIPv2
Use a static route
Use a second OSPF Process Use a route-map
Use a loopback
Use a regular summarization (ABR, ASBR) Use a reverse summarization (ASBR)
16.14. T ROUBLESHOOTING R EDISTRIBUTION
Enable the appropriate routing protocol debugging tools to verify the routes are getting passed through the redistribution process.
Is there an FLSM/VLSM conflict in the route redistribution process?