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.

 

IP Address Plan

End-Site networks

Typically end-site networks (such as Universities, Colleges, etc) will receive a public IPv6 /48 and a very small public IPv4 block from their network operator (be it an ISP and/or their NREN)

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 private IPv4 address space is included for completeness, but is not used in these exercises as we are focusing on the BGP and traffic engineering needs of Universities and NRENs.)

Group Public IPv4 Private IPv4 IPv6 AS Number
1 100.68.1.0/24 172.21.0.0/16 2001:DB8:1::/48 10
2 100.68.2.0/24 172.22.0.0/16 2001:DB8:2::/48 20
3 100.68.3.0/24 172.23.0.0/16 2001:DB8:3::/48 30
4 100.68.4.0/24 172.24.0.0/16 2001:DB8:4::/48 40
5 100.68.5.0/24 172.25.0.0/16 2001:DB8:5::/48 50
6 100.68.6.0/24 172.26.0.0/16 2001:DB8:6::/48 60

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

 

Subnetting for each Group

Each group will then further partition their space as follows (you will need to replace the ‘X’ with your group number):

Network IPv4 IPv6
Group address block 100.68.X.0/24 2001:DB8:X::/48
Infrastructure space 100.68.X.0/26 2001:DB8:X:0000::/50
Router loopbacks 100.68.X.0/28 2001:DB8:X:0000::/64
Point-to-point links 100.68.X.16/28 2001:DB8:X:0010::/60
End user space 1 100.68.X.64/26 2001:DB8:X:4000::/50
End user space 2 100.68.X.128/26 2001:DB8:X:8000::/50
End user space 3 100.68.X.192/26 2001:DB8:X:C000::/50

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

 

Prefixes for point-to-point links will be of length /30 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):

IPv4 IPv6 Description
100.68.X.16/30 2001:DB8:X:10::/127 P2P Core1 to Border2
100.68.X.20/30 2001:DB8:X:11::/127 P2P Core1 to Border1
100.68.X.24/30 2001:DB8:X:12::/127 P2P Border2 To Adjacent Group
100.68.X.28/30 2001:DB8:X:13::/127 P2P (spare)

Note that the convention for addressing point to point links is that the low address goes on the first named router and the high address goes on the second name router.

 

Loopback Addressing

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

IPv4 IPv6 Description
100.68.X.1/32 2001:DB8:X::1/128 BX1 Loopback
100.68.X.2/32 2001:DB8:X::2/128 BX2 Loopback
100.68.X.3/32 2001:DB8:X::3/128 CX1 Loopback

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.

 

Commercial Internet Service Providers (ISPs)

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.

ISP IPv4 IPv6 ASN
1 100.121.0.0/16 2001:18::/32 121
2 100.122.0.0/16 2001:19::/32 122

 

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

Group IPv4 IPv6
1 100.121.1.0/30 2001:18:0:10::/127
2 100.121.1.4/30 2001:18:0:11::/127
3 100.121.1.8/30 2001:18:0:12::/127
4 100.122.1.0/30 2001:19:0:10::/127
5 100.122.1.4/30 2001:19:0:11::/127
6 100.122.1.8/30 2001:19:0:12::/127

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).

 

Workshop Backbone LAN

The two ISPs are also connected to the workshop backbone network. The interface “FastEthernet 0/0” is connected to the backbone network, and the addressing is in this table.

ISP Workshop Backbone Address
1 10.10.0.235/24
2 10.10.0.236/24

The default gateway for both ISP routers on the workshop backbone network is 10.10.0.254.

 

National RENs (NRENs)

NRENs, like all network operators, receive at minimum an IPv6 /32 for their infrastructure. IPv4 allocations can range upwards from /22. We will use an IPv4 /16 for our exercises.

NREN IPv4 IPv6 ASN
1 100.101.0.0/16 2001:11::/32 101
2 100.102.0.0/16 2001:12::/32 102

 

The point-to-point link addresses from the NRENs to the Campuses are listed next. Note that the NREN will get the low address, and the end-site gets the high address in the subnet.

Group IPv4 IPv6
1 100.101.1.0/30 2001:11:0:10::/127
2 100.101.1.4/30 2001:11:0:11::/127
3 100.101.1.8/30 2001:11:0:12::/127
4 100.102.1.0/30 2001:12:0:10::/127
5 100.102.1.4/30 2001:12:0:11::/127
6 100.102.1.8/30 2001:12:0:12::/127

 

And finally we need addresses for the point-to-point links between the NRENs and ISPs. (As with previously, we keep the first /24 of IPv4 and first 16 /64s of IPv6 for the NREN's internal infrastructure.)

NREN - ISP IPv4 IPv6
1 100.101.2.0/30 2001:11:0:20::/127
2 100.102.2.0/30 2001:12:0:20::/127

 

Regional REN (RREN)

Regional RENs, like all network operators, receive at minimum an IPv6 /32 for their infrastructure. IPv4 allocations can range upwards from /22. We will use an IPv4 /16 for our exercises.

We only need one RREN for this lab:

RREN IPv4 IPv6 ASN
1 100.100.0.0/16 2001:10::/32 100

 

And we need addresses for the point-to-point links between the RREN and the NRENs. (As with previously, we keep the first /24 of IPv4 and first 16 /64s of IPv6 for the RREN's internal infrastructure.)

RREN-NREN IPv4 IPv6
1 100.100.1.0/30 2001:10:0:10::/127
2 100.100.1.4/30 2001:10:0:11::/127

 

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.

We have one IXP in this lab, serving as the peering interconnection point between the ISPs and the RREN. (An ASN is included for completeness.)

IPv4 IPv6 ASN
100.127.1.0/24 2001:DB8:FFFF:1::/64 65534

 

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

Peer IPv4 IPv6
ISP1 100.127.1.1 2001:DB8:FFFF:1::1
ISP2 100.127.1.2 2001:DB8:FFFF:1::2
RREN 100.127.1.3 2001:DB8:FFFF:1::3