EIGRP & OSPF Mutual Redistribution

There are two network types exist in this lab; EIGRP 100 and OSPF
Both internal and external routes will redistribute each other through R2 and R3.

Download complete GNS3 lab files from https://docs.google.com/leaf?id=0B889ogd4ltI2OWUwOTIxZjQtNGVmYS00M2FlLWI2MjEtZDI5MzVlNmRiYWVk&hl=en&authkey=CITduiY

Here is lab topology

The lab objectives are as follow;

The main point of this lab is how to block the routes from EIGRP network  pass through R2 and R3 not to inject back to EIGRP as external routes.
At the same time, how to prevent routes from OSPF network redistributed to EIGRP through R3 and R2 to inject back to OSPF as external routes.

All of the above two goals are achieve by using route-map and access-lists in both R2 and R3.

(1) Check R2's EIGRP to OSPF redistribution

router ospf 1
 log-adjacency-changes
 redistribute eigrp 100 subnets route-map EIGRP-TO-OSPF
 network 10.1.12.0 0.0.0.255 area 0

Let's check route-map EIGRP-TO-OSPF
------------------------
route-map EIGRP-TO-OSPF deny 5
 match tag 40
!
route-map EIGRP-TO-OSPF permit 10
 match ip address 1
 set metric 100
 set tag 10
!
route-map EIGRP-TO-OSPF permit 20
 match ip address 2
 set metric 200
 set tag 20
!
route-map EIGRP-TO-OSPF deny 30
 match ip address 3
!
route-map EIGRP-TO-OSPF permit 40
 set metric 300
 set tag 30
-----------------------------------------
Interstringly, match tag 40 is deny. Let's see detail of tag 40. Tag 40 is the redistribute routes from OSPF to EIGRP through R2 and R3.
All the access list used for redistrubtion of EIGRP to OSPF are using tag 10 for (10.4.0.0, 10.4.1.0), tag 20 (10.4.2.0, 10.4.3.0) and tag 30
for others.

access-list 1 permit 10.4.0.0 0.0.0.255
access-list 1 permit 10.4.1.0 0.0.0.255
access-list 2 permit 10.4.2.0 0.0.0.255
access-list 2 permit 10.4.3.0 0.0.0.255
access-list 3 permit 10.4.4.0 0.0.0.255
=====================

Route-map configuration for redistrubution from OSPF to EIGRP in R2 are as follow;

route-map OSPF-TO-EIGRP deny 5
 match tag 10 20 30
!
(* The above route-map is for blocking networks from EIGRP to injecting to network itself.)

route-map OSPF-TO-EIGRP permit 10
 set metric 400 20 255 1 1500
 set tag 40
---------------

router ospf 1
 log-adjacency-changes
 redistribute eigrp 100 subnets route-map EIGRP-TO-OSPF
 network 10.1.12.0 0.0.0.255 area 0


======================================================
Let's start in R3 configutation in detail. All of the route-maps and configurtation will be the same as in R2 as the lab demonstrate for mutual redistrubution.
Route configurations are as follow;

router eigrp 100
 redistribute ospf 1 route-map OSPF-TO-EIGRP
 network 10.1.23.0 0.0.0.255
 no auto-summary
!
router ospf 1
 log-adjacency-changes
 redistribute eigrp 100 subnets route-map EIGRP-TO-OSPF
 network 10.1.13.0 0.0.0.255 area 0
-------------------
Route-map configuation are as follow;

route-map EIGRP-TO-OSPF deny 5
 match tag 40
!
route-map EIGRP-TO-OSPF permit 10
 match ip address 1
 set metric 100
 set tag 10
!
route-map EIGRP-TO-OSPF permit 20
 match ip address 2
 set metric 200
 set tag 20
!
route-map EIGRP-TO-OSPF deny 30
 match ip address 3
!
route-map EIGRP-TO-OSPF permit 40
 set metric 300
 set tag 30
!
route-map OSPF-TO-EIGRP deny 5
 match tag 10 20 30
!
route-map OSPF-TO-EIGRP permit 10
 set metric 400 20 255 1 1500
 set tag 40

==========================================
Final goal of the lab can achive as follow;

To reach R1's loopback 10.1.0.0 network from R4, default path is R4-R2-R1. Instead of using this path, how to establish to achive as the path
R4-R2-R3-R1. The solution is to change the advertised EIGRP distance from 110 to 105.

Configuration in R2 is as follow;

router eigrp 100
 redistribute ospf 1 route-map OSPF-TO-EIGRP
 network 10.1.23.0 0.0.0.255
 network 10.1.24.0 0.0.0.255
 distance eigrp 90 105
 no auto-summary
======================

Checking whether routes are going as R4-R2-R3-R1 path using traceroute in R4 as follow;

R4#traceroute 10.1.0.1


Type escape sequence to abort.
Tracing the route to 10.1.0.1


  1 10.1.24.2 52 msec 32 msec 40 msec
  2 10.1.23.3 48 msec 32 msec 28 msec
  3 10.1.13.1 52 msec *  76 msec
=======================

Route in R2 are as follow.

     10.0.0.0/8 is variably subnetted, 10 subnets, 2 masks
D EX    10.1.13.0/24 [105/6917120] via 10.1.23.3, 00:47:56, Serial1/1
C       10.1.12.0/24 is directly connected, Serial1/0
D       10.4.4.0/24 [90/2297856] via 10.1.24.4, 00:47:56, Serial1/2
D EX    10.1.0.1/32 [105/6917120] via 10.1.23.3, 00:47:54, Serial1/1
D       10.4.2.0/24 [90/2297856] via 10.1.24.4, 00:47:56, Serial1/2
D       10.4.3.0/24 [90/2297856] via 10.1.24.4, 00:47:56, Serial1/2
D       10.4.0.0/24 [90/2297856] via 10.1.24.4, 00:47:56, Serial1/2
D       10.4.1.0/24 [90/2297856] via 10.1.24.4, 00:47:56, Serial1/2
C       10.1.24.0/24 is directly connected, Serial1/2
C       10.1.23.0/24 is directly connected, Serial1/1
-------------------------
Route in R3 are as follow;

     10.0.0.0/8 is variably subnetted, 10 subnets, 2 masks
C       10.1.13.0/24 is directly connected, Serial1/0
O       10.1.12.0/24 [110/128] via 10.1.13.1, 00:48:27, Serial1/0
D       10.4.4.0/24 [90/2809856] via 10.1.23.2, 00:48:28, Serial1/1
O       10.1.0.1/32 [110/65] via 10.1.13.1, 00:48:27, Serial1/0
D       10.4.2.0/24 [90/2809856] via 10.1.23.2, 00:48:28, Serial1/1
D       10.4.3.0/24 [90/2809856] via 10.1.23.2, 00:48:28, Serial1/1
D       10.4.0.0/24 [90/2809856] via 10.1.23.2, 00:48:28, Serial1/1
D       10.4.1.0/24 [90/2809856] via 10.1.23.2, 00:48:28, Serial1/1
D       10.1.24.0/24 [90/2681856] via 10.1.23.2, 00:48:28, Serial1/1
C       10.1.23.0/24 is directly connected, Serial1/1
---------------------

Route in R4 (EIGRP) are as follow;

     10.0.0.0/8 is variably subnetted, 10 subnets, 2 masks
D EX    10.1.13.0/24 [170/7429120] via 10.1.24.2, 00:49:16, Serial1/0
D EX    10.1.12.0/24 [170/6917120] via 10.1.24.2, 00:49:16, Serial1/0
C       10.4.4.0/24 is directly connected, Loopback4
D EX    10.1.0.1/32 [170/7429120] via 10.1.24.2, 00:49:14, Serial1/0
C       10.4.2.0/24 is directly connected, Loopback2
C       10.4.3.0/24 is directly connected, Loopback3
C       10.4.0.0/24 is directly connected, Loopback0
C       10.4.1.0/24 is directly connected, Loopback1
C       10.1.24.0/24 is directly connected, Serial1/0
D       10.1.23.0/24 [90/2681856] via 10.1.24.2, 00:49:16, Serial1/0

-----------------------
Route in R1 (OSPF) are as follow. As there are two routes path receiving external routers, R2 and R3, two load balacing paths are found.

     10.0.0.0/24 is subnetted, 9 subnets
C       10.1.13.0 is directly connected, Serial1/1
C       10.1.12.0 is directly connected, Serial1/0
C       10.1.0.0 is directly connected, Loopback0
O E2    10.4.2.0 [110/200] via 10.1.13.3, 00:49:37, Serial1/1
                 [110/200] via 10.1.12.2, 00:49:37, Serial1/0
O E2    10.4.3.0 [110/200] via 10.1.13.3, 00:49:37, Serial1/1
                 [110/200] via 10.1.12.2, 00:49:37, Serial1/0
O E2    10.4.0.0 [110/100] via 10.1.13.3, 00:49:37, Serial1/1
                 [110/100] via 10.1.12.2, 00:49:37, Serial1/0
O E2    10.4.1.0 [110/100] via 10.1.13.3, 00:49:37, Serial1/1
                 [110/100] via 10.1.12.2, 00:49:37, Serial1/0
O E2    10.1.24.0 [110/300] via 10.1.12.2, 00:49:37, Serial1/0
                  [110/300] via 10.1.13.3, 00:49:37, Serial1/1
O E2    10.1.23.0 [110/300] via 10.1.12.2, 00:49:38, Serial1/0
                  [110/300] via 10.1.13.3, 00:49:38, Serial1/1

EIGRP Redistribution

This is the question from CCNP route exam which I got from Digitaltut. I have created as GNS3 file for practicing.

There are three OSPF areas including Area 0 and one EIGRP AS 100 networks.
Goal is try to reach R2's  s1/0 interface from R4.

The point to test in exam is how you understand about redistribution.
I'm not sure exactly about original exam  questsion but I have added Area 0 by myself. If not it doesn't make senese to reach to R2's s1/0 interface.

Download complete lab from here.
https://docs.google.com/leaf?id=0B889ogd4ltI2NWQ2NGFjMWYtOTUwMy00NDI3LTgzNWItNTRiNWZmZTRkMjkz&hl=en&authkey=CNeu1b4D

First thing to know is all OSPF areas 24 and 34 are already configured.
EIGRP 100 has configured in R4-R3-R5.

Two redistrubution points;
(1) From R3's s1/2 (EIGRP 100) to OSPF area 24
(2) From R5's f0/0 (EIGRP 100) to OSPF area 34

The main point to note is check the K values of s1/2 of R3 and fa0/0 of R5 before redstribution.
How to check? Use "sh interface s1/2"

R3#sh int s1/2
Serial1/2 is up, line protocol is up 
  Hardware is M4T
  Internet address is 192.168.3.3/24
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
--------------------------------
Here are the things to note. BW is 1544, Delay is 20000 usec (2000 msec), reliability is 255, load is 1 and MTU is 1500.
So, the command to redistrube is as follow;
redistribute ospf 1 metric 1544 2000 255 1 1500
==========
But, checking in R5's fa0/0 will get different value because of it's fast ethernet interface. Check it out.

R5#sh int fa0/0
FastEthernet0/0 is up, line protocol is up 
  Hardware is Gt96k FE, address is c001.0aaa.0000 (bia c001.0aaa.0000)
  Internet address is 192.168.4.5/24
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
------------------
As you see, K values are as follows;
MTU 1500, Bandwidth is 100000 , Delay is 10 msec, reliabiliy is 255 and load is 1.
------------
All know that EIGRP's metric value calculation is only K1 and K3. It means it is only account only bandwidth and delay.
Here is the command to use for redistrubtion of EIGRP routes to OSPF area 34;
redistribute ospf 1 metric 100000 10 255 1 1500
-------------
In the mean time, when redistrubtion of EIGRP routes, pay attendtion to whether E1 or E2 types.
In short, E1 means metric will increase along it paths but E2 has constant value.
-----------
How to check whether route is E1 or E2 type.
It's simple. If you don't type any metric type, default is E2. To redistribute as E1, type "metric-type 1"
-----------
Check how it increase if the metric-type set to E1 in R2 and R1.
In R2's route table, both E1 routes have feasible distance 21.

     1.0.0.0/32 is subnetted, 1 subnets
C       1.1.1.1 is directly connected, Loopback0
     5.0.0.0/32 is subnetted, 1 subnets
C       5.5.5.5 is directly connected, Loopback1
     172.16.0.0/24 is subnetted, 1 subnets
C       172.16.100.0 is directly connected, FastEthernet0/0
C    192.168.4.0/24 is directly connected, FastEthernet0/1
O E1 192.168.1.0/24 [110/21] via 192.168.4.5, 00:24:44, FastEthernet0/1
O E1 192.168.2.0/24 [110/21] via 192.168.4.5, 00:24:44, FastEthernet0/1
C    192.168.3.0/24 is directly connected, Serial1/0
------------------
Let's check in R1. Feasible distance increased from 21 to 22 due to Fast Ethernet interface between two routers.
Also take note that default cost  for all redistribute external route (in this case , it is EIGRP AS 100) to OSPF is 20. That's why, in R3, it is appearing as 21 and in R1, it is 22.

     1.0.0.0/32 is subnetted, 1 subnets
O       1.1.1.1 [110/2] via 172.16.100.2, 00:26:42, FastEthernet0/0
     5.0.0.0/32 is subnetted, 1 subnets
O       5.5.5.5 [110/2] via 172.16.100.2, 00:26:42, FastEthernet0/0
     172.16.0.0/24 is subnetted, 1 subnets
C       172.16.100.0 is directly connected, FastEthernet0/0
O IA 192.168.4.0/24 [110/2] via 172.16.100.2, 00:26:42, FastEthernet0/0
O E1 192.168.1.0/24 [110/22] via 172.16.100.2, 00:26:42, FastEthernet0/0
O E1 192.168.2.0/24 [110/22] via 172.16.100.2, 00:26:42, FastEthernet0/0
O IA 192.168.3.0/24 [110/65] via 172.16.100.2, 00:26:42, FastEthernet0/0