Table of Contents
IPv6 Lab - Customer Connections
This series of small labs is going to focus on how to deploy IPv6 into a customer’s network. Several technologies will be examined, including:
- static configuration with static route
The lab has been set up to include a sample Customer router connected to the Access router for each Autonomous System. We will use this extended lab network to explore the different technologies. The lab topology is shown in the following diagram:
This first lab looks at how to set up a static configuration between network operator and the end-user. This is the traditional method the industry has used for years for IPv4, and is also used for IPv6 in the case of a dual-stack connection from operator to customer and within the customer’s own network.
Configuring the Customer Router
Before we start, each group needs to configure their customer router, to give it the basic configuration. We do exactly as we did at the start of these labs. To help you, the configuration steps are listed here. Consult the Lab Access Instructions to find out how to get to the console port of the Customer Router.
Name the router
Router> enable Router# config terminal Router(config)# hostname CustX
aaa new-model aaa authentication login default local aaa authentication enable default enable username v6cust secret cust-PW enable secret cust-EN service password-encryption line vty 0 4 transport preferred none line console 0 transport preferred none
no logging console logging buffered 8192 debugging
Disable DNS resolution
no ip domain-lookup
Activate IPv6 routing
Turn on IPv6 Routing and activate IPv6 CEF (not on by default in Cisco IOS)
ipv6 unicast-routing ipv6 cef
Disable source routing for IPv4 and IPv6
no ip source-route no ipv6 source-route
Path MTU Discovery
Enable Path MTU Discovery on the router - this is not enabled by default for connections to the control plane (but it is enabled by default now for BGP).
ip tcp path-mtu-discovery
Exit configuration mode and save
end write memory
Configuring Interfaces on Customer Router
Now that the basic configuration is in place, we need to configure the interface linking the Customer router to our Access router. Refer to the ip address plan for the lab to find out the point-to-point link addresses for both IPv4 and IPv6.
Here is a configuration example:
interface FastEthernet0/1 description P2P Link to ASX0 ip address 100.68.X.34 255.255.255.252 no ip directed-broadcast no ip redirects no ip proxy-arp ipv6 address 2001:DB8:X:20::1/127 ipv6 nd prefix default no-advertise ipv6 nd ra suppress all no shutdown !
Configuring Interfaces on Access Router
We also need to configure the interface on the Access router which connects to the Customer router. Again, referring to the address plan, here is a possible configuration example:
interface FastEthernet0/1 description P2P Link to CustX ip address 100.68.X.33 255.255.255.252 no ip directed-broadcast no ip redirects no ip proxy-arp ipv6 address 2001:DB8:X:20::0/127 ipv6 nd prefix default no-advertise ipv6 nd ra suppress all no shutdown !
Once the interfaces on both the Customer and Access routers have been configured, try and ping the other end - check both IPv4 and IPv6.
Adding a customer route
We previously set up simulated customer connection on the Access Router. We can now redo this, so that rather than pointing the static route at the Null0 interface, we can point it to the actual Customer router we have just configured.
First we delete the static routes we set up earlier:
no ip route 100.68.X.64 255.255.255.192 null0 ! no ipv6 route 2001:DB8:X:4000::/52 null0 !
And then we add the static routes on the Access router to point to the point-to-point link address on the Customer router:
ip route 100.68.X.64 255.255.255.192 100.68.X.34 ! ipv6 route 2001:DB8:X:4000::/52 2001:DB8:X:20::1 !
Once this has been configured, check that you can still see the customer IPv4 /26 and IPv6 /52 visible in the iBGP for the AS. Check on the Border, Peering and Core routers, and make sure the prefix is still visible. Use these commands:
show ip bgp show bgp ipv6 unicast
Default route on Customer Router
To complete the connectivity we need to set up a static default route (IPv4 and IPv6) on the Customer router pointing to the Access router. We also need to create a source anchor point for the address space we have assigned to the customer. The simplest way to do this is to route create a Loopback interface on the Customer router with a single IP address from IPv4 and IPv6 address blocks in question, and point the entire IPv4 and IPv6 blocks to the Null0 interface. This way we have a target to test connectivity to, as well as following best practices by Null routing any address space which is not in use.
Here is an example for the Customer router:
interface Loopback0 description Address anchor for Customer X ip address 100.68.X.64 255.255.255.255 ipv6 address 2001:DB8:X:4000::0/128 ! ip route 0.0.0.0 0.0.0.0 100.68.X.33 ip route 100.68.X.64 255.255.255.192 Null0 ! ipv6 route ::/0 2001:DB8:X:20:: ipv6 route 2001:DB8:X:4000::/52 Null0 !
With this in place it should be possible to reach the Internet from the Customer router. Check connectivity from:
- your AS towards the Customer router too, using the newly created Loopback interface as a target.
- our Customer router, using the newly created Loopback interface as the source, towards the Internet, e.g. to 188.8.131.52 for IPv4 and 2001:4860:4860::8888 for IPv6.
Note: Can you explain why, in the latter case, we are running the traceroute from the Loopback interface, and not using the default (which would be the point-to-point link to the network operator’s Access router)?
Once complete, make sure you save a copy of the configuration on the Access and Customer routers - simple copy and paste into a text document is easiest. We will need to revert to this configuration at a future stage in the lab.