Information Technology Reference
In-Depth Information
Case Study: Deploying a Dual-Stack IPv4 and IPv6
Environment
This case study begins with a simple IPv4 network in a route-reflection environment. The
steps to deploy IPv6 in a dual-stack configuration are discussed, and configuration
examples are provided.
Initial IPv4 Network Topology
The initial IPv4 network is built using a route reflection environment. The network has three
core routers—R1, R2, and R3. They are route reflectors and have a full iBGP mesh. The
network also has three route reflector clients—R4, R5, and R6. The physical topology is
shown in Figure 12-4.
Figure 12-4 Physical Network Topology
R6
R1
R7
AS 65001
AS 65000
R3
R2
R4
R5
Each router has an IPv4 loopback address for the iBGP sessions. The addressing scheme
for the loopback addressing is 10.1.1. X /32, where X is the router number.
The IGP used for internal reachability for the BGP sessions is IS-IS. This IGP was chosen
because it can offer IPv6 functionality in an integrated fashion. The IS-IS routing protocol
does not run over IPv4 or IPv6, but directly over the data link. This allows IPv4 and IPv6
prefix information to be carried in the same protocol, with the network topology being built
independent from the IP version.
Initial Configurations
This section shows the initial IPv4 BGP configurations. These configurations provide the
foundation on which IPv6 is deployed in this case study. The configuration shown in
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