Redistribution - Perplexing

Question:

I greet everyone.WS-C3560V2-24PS-S  Please be patient with me.  Here I am supposed to have a very basic network.

The configurations are as follows:

R1#

!

!

ip cef

!

!

interface Loopback0

ip address 2.2.2.2 255.255.255.255

!

!

interface FastEthernet0/0

ip address 10.0.0.1 255.255.255.0

speed 100

full-duplex

!

!

interface FastEthernet0/1

ip address 192.168.1.1 255.255.255.252

speed 100

full-duplex

!

!

router bgp 100

no synchronization

bgp log-neighbor-changes

network 2.2.2.2 mask 255.255.255.255

network 10.0.0.0 mask 255.255.255.0

network 192.168.1.0 mask 255.255.255.252

neighbor 192.168.1.2 remote-as 100

no auto-summary

!

!

end

*************************************************************************************

R2#

!

!

ip cef

!

!

interface Loopback0

ip address 3.3.3.3 255.255.255.255

!

!

interface Loopback1

ip address 6.6.6.6 255.255.255.255

!

!

interface FastEthernet0/0

ip address 192.168.1.2 255.255.255.252

speed 100

full-duplex

!

!

interface FastEthernet0/1

ip address 172.16.1.1 255.255.255.0

speed 100

full-duplex

!

!

router eigrp 45

redistribute bgp 100 metric 1000 100 255 1 1500

network 6.6.6.6 0.0.0.0

network 172.16.1.0 0.0.0.255

no auto-summary

!

!

router bgp 100

no synchronization

bgp log-neighbor-changes

network 3.3.3.3 mask 255.255.255.255

network 192.168.1.0 mask 255.255.255.252

redistribute eigrp 45

neighbor 192.168.1.1 remote-as 100

no auto-summary

!

!

end

*********************************************************************************************

R3#

!

!

ip cef

!

!

interface Loopback0

ip address 4.4.4.4 255.255.255.255

!

!

interface FastEthernet0/0

ip address 172.16.1.2 255.255.255.0

speed 100

full-duplex

!

!

router eigrp 45

network 4.4.4.4 0.0.0.0

network 172.16.1.0 0.0.0.255

!

!

end

******************************************************************************************************

The verifications are as follows:

R1#show ip route

!

!

     2.0.0.0/32 is subnetted, 1 subnets

C       2.2.2.2 is directly connected, Loopback0

     3.0.0.0/32 is subnetted, 1 subnets

B       3.3.3.3 [200/0] via 192.168.1.2, 00:04:57

     4.0.0.0/32 is subnetted, 1 subnets

B       4.4.4.4 [200/156160] via 172.16.1.2, 00:04:52

     6.0.0.0/32 is subnetted, 1 subnets

B       6.6.6.6 [200/0] via 192.168.1.2, 00:04:57

     172.16.0.0/24 is subnetted, 1 subnets

B       172.16.1.0 [200/0] via 192.168.1.2, 00:04:57

     10.0.0.0/24 is subnetted, 1 subnets

C       10.0.0.0 is directly connected, FastEthernet0/0

     192.168.1.0/30 is subnetted, 1 subnets

C       192.168.1.0 is directly connected, FastEthernet0/1

  

    No problems in this case.  I see all the routes to the remote subnets.

*****************************************************************************************************************

R2#show ip route

!

!

     2.0.0.0/32 is subnetted, 1 subnets

B       2.2.2.2 [200/0] via 192.168.1.1, 00:23:33

     3.0.0.0/32 is subnetted, 1 subnets

C       3.3.3.3 is directly connected, Loopback0

     4.0.0.0/32 is subnetted, 1 subnets

D       4.4.4.4 [90/156160] via 172.16.1.2, 00:23:49, FastEthernet0/1

     6.0.0.0/32 is subnetted, 1 subnets

C       6.6.6.6 is directly connected, Loopback1

     172.16.0.0/24 is subnetted, 1 subnets

C       172.16.1.0 is directly connected, FastEthernet0/1

     10.0.0.0/24 is subnetted, 1 subnets

B       10.0.0.0 [200/0] via 192.168.1.1, 00:23:35

     192.168.1.0/30 is subnetted, 1 subnets

C       192.168.1.0 is directly connected, FastEthernet0/0

This is okay, I see all the remote subnets.

************************************************************************************************************************

R3#show ip route

!

!

     3.0.0.0/32 is subnetted, 1 subnets

D EX    3.3.3.3 [170/2588160] via 172.16.1.1, 00:00:34, FastEthernet0/0

     4.0.0.0/32 is subnetted, 1 subnets

C       4.4.4.4 is directly connected, Loopback0

     6.0.0.0/32 is subnetted, 1 subnets

D       6.6.6.6 [90/156160] via 172.16.1.1, 00:00:34, FastEthernet0/0

     172.16.0.0/24 is subnetted, 1 subnets

C       172.16.1.0 is directly connected, FastEthernet0/0

     192.168.1.0/30 is subnetted, 1 subnets

D EX    192.168.1.0 [170/2588160] via 172.16.1.1, 00:00:36, FastEthernet0/0

As you can see, only two out of the four remote networks are in this routing table.  R2 simply redistributed the BGP networks that are directly connected to it.  What happened to the BGP networks that R2 learned from R1?  How come these BGP routes were not redistributed even though they are in R2's routing table?

Please, help in any way you can.

Answer:

Hello Jaighobahi,

you are on the right track about iBGP and IGP redistribution, you need also a command under router bgp to allow injection of iBGP routes into IGP redistribution. I'm sorry I have missed it in my first replay.

BGP by default provides a protection mechanism to avoid to overload the IGP database being BGP much more scalable,

This protection can be disabled with the commands below:

on R2:

router bgp 100

bgp redistribute-internal

BGP AS number and EIGRP AS number are different concepts and they don't need to be equal and this does not change the behaviour

see

http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_bgp/command/bgp-a1.html#wp4270480859

https://supportforums.cisco.com/docs/DOC-1575  WS-C3560V2-24PS-S Price