Lab #1: Basic BGP Routing
In this lab we will be looking at the most basic BGP setup, showing BGP sending routing information between routers.
Table of Contents
- Lab Goals
- Network Layout
- Lab Procedures
- Solutions
- Clear Previous Configs
- Configure Local Interfaces
- Configure Loopback Interfaces
- Configure BGP
- Final Router Configs
In this lab, you will want to do the following:
- configure the interfaces with the ip's that match the diagram
- configure bgp on all three routers, using the AS's noted in the diagrem
- configure bgp such that all bgp routes are sent between routers
In this lab we will be working with three routers. The routers will
need to have two local /24 networks, as well as the /30 networks
linking the routers together.
The eaisest way to configure the router with the two local /24 networks
is by creating loopback interfaces for each of the networks. This
allows the /24's to be directly connected to the router, and prevents
you from having to rely on a router with two extra interfaces.
For the /30 interconnect networks, I suggest using fast Ethernet subinterface's, thus allowing you to only use one interface
per router.
The routers should be configured as such:
- Router A
- int fa0/1.10 192.168.1.1 255.255.255.252
- int loopback0 10.10.1.1 255.255.255.0
- int loopback1 10.10.2.1 255.255.255.0
- BGP AS10
- Router B
- int fa0/1.10 192.168.1.2 255.255.255.252
- int fa0/1.30 192.168.1.6 255.255.255.252
- int loopback0 10.20.1.1 255.255.255.0
- int loopback1 10.20.2.1 255.255.255.0
- BGP AS20
- Router C
- int fa0/1.30 192.168.1.5 255.255.255.252
- int loopback0 10.30.1.1 255.255.255.0
- int loopback1 10.30.2.1 255.255.255.0
- BGP AS30
These are the following procedures you should complete to finish this lab.
- Clear any configurations that might be currently on the routers.
-
First configure the routers interfaces and make sure that the routers
can ping their peers local interfaces, but not their peers remote
interfaces. The local interfaces should use the /30 networks.
- Q2.1 How do you configure the local interfaces?
- Q2.2 How do you configure interfaces with /30 networks
-
Create loopback with /24 networks. Make sure that you can ping each
routers local loopback networks, but not remote loopback networks.
- Q3.2 How do you create loopback networks?
-
Configure BGP on all three routers and advertise all loopback networks
to BGP. The interface networks should only be advertised by the Stub
routers (Router A and Router C). View the BGP routing tables to ensure
that all routers can see all the other networks and AS's. Make sure
that you can ping all the networks on all the routers.
- Q4.1 How do you configure BGP on your router?
- Q4.2 How do you advertise networks in BGP?
- Q4.3 What command should you use to all the routes in the BGP route table?
- Q4.4 What command would you use to clear all the routes in the BGP routing table?
These are the following configs and tests you should do to solve this lab.
There are two ways to clear the config on your router. The first method
is from the exec prompt, and the second is from the rmon(?) prompt.
| Clearing the router configs from the exec prompt |
4a01
erase startup-config
reload
|
| Clearing the router configs from the rmon(?) prompt |
4b01
o/r 0x2142
I
|
These basic steps create local subinterfaces on a single fast ethernet
interface. The routers should be connected to a switch that can handle
VLANing. This is how I like running a test network, if you configure
the interfaces differently, it will not change anything (as long as you
can ping everything).
| Router A config (adding local interfaces) |
4c01 conf t
4c02 hostname routerA
4c02 int fa0/1.10
4c03 ip address 192.168.1.1 255.255.255.252
4c04 encap dot1q 10
4c05 no shut
4c06 exit
4c07 exit
|
| Router B config (adding local interfaces) |
4d01 conf t
4d02 hostname routerB
4d02 int fa0/1.10
4d03 ip address 192.168.2.1 255.255.255.252
4d04 encap dot1q 10
4d05 no shut
4d06 exit
4d07 int fa0/1.30
4d08 ip address 192.168.6.1 255.255.255.252
4d09 encap dot1q 30
4d10 no shut
4d11 exit
4d12 exit
|
| Router C config (adding local interfaces) |
4e01 conf t
4e02 hostname routerC
4e02 int fa0/1.30
4e03 ip address 192.168.5.1 255.255.255.252
4e04 encap dot1q 30
4e05 no shut
4e06 exit
4e07 exit
|
Note that you should only be able to ping local interfaces to
the router. There should not be any other routing protocols available.
| Example of pinging (with only connected routes) from Router A |
4f01
show ip route
ping 192.168.1.1
ping 192.168.1.2
ping 192.168.1.5
|
Creating
loopback interfaces allows us to hang many netwroks directly off the
router for the purposes of this experiment. You will need to know how
to create loopbacks for other situations with BGP, so this is a great
way to introduce this concept.
| Router A config (adding loopback networks) |
4g01 conf t
4g01 int loopback 0
4g01 ip address 10.10.1.1 255.255.255.0
4g01 exit
4g01 int loopback 1
4g01 ip address 10.10.2.1 255.255.255.0
4g01 exit
4g01 exit
|
| Router B config (adding loopback networks) |
4h01 conf t
4h01 int loopback 0
4h01 ip address 10.20.1.1 255.255.255.0
4h01 exit
4h01 int loopback 1
4h01 ip address 10.20.2.1 255.255.255.0
4h01 exit
4h01 exit
|
| Router C config (adding loopback networks) |
4i01 conf t
4i01 int loopback 0
4i01 ip address 10.30.1.1 255.255.255.0
4i01 exit
4i01 int loopback 1
4i01 ip address 10.30.2.1 255.255.255.0
4i01 exit
4i01 exit
|
And now to test connectivity, from router A, ping the two local loopback networks.
| Testing loopback networks |
4j01
sh ip route
ping 10.10.1.1
ping 10.10.2.1
|
To
configure BGP, we will need to enable the BGP route process, give it an
AS number, define it's BGP neighors, and specify what networks to
advertise.
| Router A config (config bgp) |
4k01 conf t
4k02 router bgp 10
4k03 network 192.168.1.0 mask 255.255.255.252
4k04 network 10.10.1.0
4k05 network 10.10.2.0
4k06 neighbor 192.168.1.2 remote-as 20
4k07 exit
4k08 exit
|
| Router B config (config bgp) |
4l01 conf t
4l02 router bgp 20
4l03 network 10.20.1.0
4l04 network 10.20.2.0
4l05 neighbor 192.168.1.1 remote-as 10
4l06 neighbor 192.168.1.5 remote-as 30
4l07 exit
4l08 exit
|
| Router C config (config bgp) |
4m01 conf t
4m02 router bgp 30
4m03 network 192.168.1.4 mask 255.255.255.252
4m04 network 10.30.1.0
4m05 network 10.30.2.0
4m06 neighbor 192.168.1.6 remote-as 20
4m07 exit
4m08 exit
|
And now to test BGP and make sure that you can recieve all the routes, we can do the following from Router A.
| Testing BGP from Router A |
4n01
sh ip route
clear ip bgp
sh ip bgp
ping 10.10.1.1
ping 10.20.1.1
ping 10.30.1.1
|
When it's all said and done, these are the basic configs for each of the routers.
| Router A's complete config |
5a01
5a02 hostname routerA
5a03 !
5a04 int loopback 0
5a05 ip address 10.10.1.1 255.255.255.0
5a06 int loopback 1
5a07 ip address 10.10.2.1 255.255.255.0
5a08 !
5a09 int fa0/1.10
5a10 ip address 192.168.1.1 255.255.255.252
5a11 encap dot1q 10
5a12 no shut
5a13 !
5a14 router bgp 10
5a15 network 192.168.1.0 mask 255.255.255.252
5a16 network 10.10.1.0
5a17 network 10.10.2.0
5a18 neighbor 192.168.1.2 remote-as 20
|
| Router B's complete config |
5b01
5b02 hostname routerB
5b03 !
5b04 int loopback 0
5b05 ip address 10.20.1.1 255.255.255.0
5b06 int loopback 1
5b07 ip address 10.20.2.1 255.255.255.0
5b08 !
5b09 int fa0/1.10
5b10 ip address 192.168.2.1 255.255.255.252
5b11 encap dot1q 10
5b12 no shut
5b13 int fa0/1.30
5b14 ip address 192.168.6.1 255.255.255.252
5b15 encap dot1q 30
5b16 no shut
5b17 !
5b18 router bgp 20
5b19 network 10.20.1.0
5b20 network 10.20.2.0
5b21 neighbor 192.168.1.1 remote-as 10
5b22 neighbor 192.168.1.5 remote-as 30
|
| Router C's complete config |
5c01 hostname routerC
5c02 !
5c03 int loopback 0
5c04 ip address 10.30.1.1 255.255.255.0
5c05 int loopback 1
5c06 ip address 10.30.2.1 255.255.255.0
5c07 !
5c08 int fa0/1.30
5c09 ip address 192.168.5.1 255.255.255.252
5c10 encap dot1q 30
5c11 no shut
5c12 !
5c13 router bgp 30
5c14 network 192.168.1.4 mask 255.255.255.252
5c15 network 10.30.1.0
5c16 network 10.30.2.0
5c17 neighbor 192.168.1.6 remote-as 20
|
