Address Allocation

Introduction

This document describes the IP address plan we will use for this set of workshop exercises.

Wherever possible the plan tries to replicate real life as closely as possible.

The IPv4 address space used in these exercises is from subnets of 100.64.0.0/10 which is an IPv4 Shared Address block. It must not be routed on the Internet.

Note that 2001:DB8::/32 is the IPv6 Documentation Address block. It must not be routed on the Internet.

And finally note that the 2001:10::/28 address block has been listed in the IANA special registry for future use. It must not be routed on the Internet.

If using these labs as inspiration for your own infrastructure design, please replace all instances of private, documentation, and unassigned address space with your own address blocks.

End-Site networks

If they are not a Regional Internet Registry member, end-site networks typically will receive a public IPv6 /48 and a very small public IPv4 block from their network operator.

We will use an IPv4 /24 for these exercises, reflecting the fact that in reality an end-site organisation will use a large private block like a /16 internally, NATed out into a small public IPv4 block like the /24 we are using here.

The list will continue in the same pattern if there are more groups.

Each group will then further partition their space as follows:

Where X is your group number (1,2,3...).

Prefixes for point-to-point links will be of length /31 for IPv4 and /127 for IPv6 (we will adopt the recommendations of RFC6164 for IPv6 inter-router links where we reserve a /64 for the link but subnet it as a /127). The point-to-point link for the server appliance will remain as a /30 for IPv4:

Router loopback address subnet masks will be /32 for IPv4 and /128 for IPv6:

The Group Server addressing is like this:

Note that the convention used here assigns the beginning of the IPv4 and IPv6 address space for use for infrastructure. This is generally a matter of choice: some network operators use the beginning of the space, others use the end of the space.

End User Provider Independent Space

For labs which configure IP address space for the end user network independent of the Group’s (aka ISP) block listed above, here are the address allocations for IPv4 and IPv6:

Transit Providers

Commercial network operators receive at minimum an IPv6 /32 from their regional internet registry. IPv4 allocations can range upwards from /22. We will use an IPv4 /16 for our exercises.

The point-to-point link addresses from Transit Providers 1 and 2 to the End-sites are listed next. Note that the Transit Providers will get the low address, and the end-site gets the high address in the subnet.

Note: The numbering started at the second /24 for the IPv4 point-to-point links to "end customers". The first /24 is kept for number infrastructure within the ISP, for example: loopbacks, internal point-to-point links, etc. The same applies to IPv6, where the first sixteen /64s were kept for loopbacks (the first /64) and internal point-to-point links (the next fifteen /64s).

The address for the point-to-point link between Regional ISP 1 and Regional ISP 2 is given in this table:

Internet Exchange Points (IXPs)

Internet Exchange Points do not have specific IP address needs outside of the peering LAN and the IXP Services infrastructure. The minimum allocation for an IXP would be a /24 for IPv4 and /64 for IPv6, so that the routers connecting to the IXP LAN have an IP address on that LAN. IXPs only need an ASN if they have a device known as a Route Server.

The address assignments for the IXP are documented here.

IXP

The IXP in this lab serves as the peering interconnection point between the six Groups. (An ASN is included for the Route Server at the IXP.)

And the address assignments made at the IXP are as follows:

Diagram

The following diagram shows the address plan as implemented in the lab topology.