Connecting

SSH to the netlab server:

$ ssh-keygen -R netlab.nanocat.net
$ ssh lab@netlab.nanocat.net

List and connect to the running containerlab devices:

$ list-devices
$ connect device-name

Diagram

Goal

• Practise the basics
• Review iBGP and eBGP
• Learn about Route Reflection

Configure the base network

• Configure PC1’s IP and default gateway
• Configure all link IP addresses and loopback0 interfaces
• Configure single-area OSPF inside the network to share loopback addresses
• Configure loopback10 on the ISP routers

Check:

• Can PC1 ping all loopback interfaces within AS65000?
• Can each ISP router ping its own lo10 address?

Configure eBGP

• Configure eBGP sessions between each ISP router and border router
• Configure the ISP routers to advertise their lo10 prefix
• Configure eBGP on the links between the ISP routers

Check:

• Can each border router ping all ISP routers’ lo10 addresses?
• Which path do the packets follow?
• Which routers are unreachable?

Configure iBGP

• When configuring iBGP, use the lo0 interfaces as the neighbor IPs
  • and add a neighbor x.x.x.x update-source lo0 too
• Configure iBGP sessions between your border routers
  • Because iBGP does not forward prefixes learned from other iBGP peers, you will need to create a full mesh.
• Configure iBGP sessions between the BRs and R5
• Announce 192.168.0.0/24 from R5

Check:

• Can PC1 ping the ISP routers’ lo10 addresses?

Configure a route-map to restrict what we advertise

• On all Border Routers:
  • Create a new ip prefix-list containing 192.168.0.0/24
  • Create a new route-map that allows this prefix-list
  • Apply this route-map to your eBGP sessions, to ensure that we control exactly what we will advertise

Configure your route-reflector

• Remove all iBGP sessions between your border routers
• Configure iBGP sessions between each border router and RR6 (using the route-reflector-client neighbor configuration on RR6)

Check:

• Can PC1 ping the ISP routers’ lo10 addresses?
• Which BGP next-hop does each BR learn?
• How does the routing table look on RR6?

Cheat Sheet

Configuring the PC with ip

ip address
ip address del xxx.xxx.xxx.xxx/xx dev eth1
ip address add 192.168.0.10/24 dev eth1
ip route
ip route del default
ip route add default via 192.168.0.1

Basis

!
ip routing
!
interface ethernet1
   no switchport
   ip address x.x.x.x/xx
!

Configuring BGP

!
router bgp 65000
   neighbor x.x.x.x remote-as xxxx
   neighbor y.y.y.y remote-as 65000
   neighbor y.y.y.y update-source loopback0
   network x.x.x.x/xx
!

Configuring a neighbor as a route-reflector-client

!
router bgp 65000
   neighbor x.x.x.x remote-as xxxx
   neighbor x.x.x.x update-source loopback0
   neighbor x.x.x.x route-reflector-client
!

Configuring OSPF

!
interface ethernet1
   ip ospf area 0
!
router ospf 100
!