BGP Configuration Part Deux

BGP configuration part 2

Advertising networks.

Now since I have been working only with IGP’s normally the network command in a IGP would do two things

Form a neighbor relationship and advertise the routes for that network.

With BGP Neighbors are statically defined, so by typing in the neighbor x.x.x.x remote-as will statically define a neighbor.

To send out a network advertisement it must be done like this.

With Debugging on.

r2(config)#router bgp 6400

r2(config-router)#network 100.2.2.0 mask 255.255.255.0

r2(config-router)#

*Mar  1 08:31:13.029: BGP: Applying map to find origin for 100.2.2.0/24

*Mar  1 08:31:13.037: BGP: Applying map to find origin for 100.2.2.0/24

*Mar  1 08:31:13.041: BGP: Applying map to find origin for 100.2.2.0/24

View from R3

r4#sh ip bgp

BGP table version is 7, local router ID is 4.4.4.4

Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,

r RIB-failure, S Stale

Origin codes: i – IGP, e – EGP, ? – incomplete

Network          Next Hop            Metric LocPrf Weight Path

*> 100.2.2.0/24     2.2.2.2                  0             0 6400 i

A view from R3

r3#sh ip bgp

BGP table version is 1, local router ID is 3.3.3.3

Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,

r RIB-failure, S Stale

Origin codes: i – IGP, e – EGP, ? – incomplete

Network          Next Hop            Metric LocPrf Weight Path

* i100.2.2.0/24     2.2.2.2                  0    100      0 6400 i

r3#ping 10.2.2.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.2.2.1, timeout is 2 seconds:

…..

Success rate is 0 percent (0/5)

This will not Ping?????

Since Eigrp Router does not Have BGP running it will NOT route that packet since it has no idea where 10.2.2.1 is.

BGP Synchronization is turned on by default on most IOS versions.

Synchronization – > Do not use or advertise a route learned with IBGP until the same route has been learned from IGP

Also judging by the next hop address which is the Loopback interface of 2.2.2.2

With Ebgp it will change the next hop address from where it originated from.  So what I will have to do is tell R3 to use R4 as the next hop…. The way I will do that is the following….

r4(config-router)#neighbor 3.3.3.3 next-hop-self

moving to R3

r3#sh ip bgp

BGP table version is 2, local router ID is 3.3.3.3

Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,

r RIB-failure, S Stale

Origin codes: i – IGP, e – EGP, ? – incomplete

Network          Next Hop            Metric LocPrf Weight Path

*>i100.2.2.0/24     4.4.4.4                  0    100      0 6400 i

> Indicating it is the best route and will be installed on the routing table.

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