## IPv6 Drill 2

This post gives you an exercise with five different problems. Each begins with an expanded IPv6 Global Unicast Addresses (GUA). For each problem, start by abbreviating the address. Then find the IPv6 subnet ID (aka the prefix ID), both in expanded and abbreviated form. This post has both the questions and the answers – just click the items in the post to reveal.

IPv6 addresses take up a lot of space – as many as 32 hex digits. Devices help us humans by listing the abbreviated form of IPv6 addresses. However, it helps to think about IPv6 addresses in their unabbreviated (expanded) form – so you need to be skilled at mentally converting from expanded to abbreviated form.

Beyond basic address abbreviation and expansion, you need to be ready to perform other operations on IPv6 addresses, like these:

• Find the subnet (prefix) ID based on an address (both in abbreviated and expanded form.)
• Calculate the complete IPv6 address when using the EUI-64 process to build the address’s interface ID (IID) portion.

IPv6 addresses take up a lot of space – as many as 32 hex digits. Devices help us humans by listing the abbreviated form of IPv6 addresses. However, it helps to think about IPv6 addresses in their unabbreviated (expanded) form – so you need to be skilled at mentally converting from expanded to abbreviated form.

Beyond basic address abbreviation and expansion, you need to be ready to perform other operations on IPv6 addresses, like these:

• Find the subnet (prefix) ID based on an address (both in abbreviated and expanded form.)
• Calculate the complete IPv6 address when using the EUI-64 process to build the address’s interface ID (IID) portion.

# Instructions and Problems

Each problem listed in the following table shows an expanded IPv6 Global Unicast Address (GUA). For each problem, find these values:

1. The abbreviated version of the GUA
2. The expanded prefix ID, assuming a /64 prefix length
3. The abbreviated prefix ID

### Question Set:

 Problem # Expanded GUAs 1 2001:0db8:0020:0a00:b000:000c:00d0:0e00 2 2001:0db8:feed:beef:cafe:1234:0000:0010 3 3000:00ba:0a00:000b:0000:00f0:fe00:0001 4 3000:0dad:1000:2000:3000:0004:0000:0000 5 2001:0db8:0000:0000:0000:0000:0000:0bad

Click the tabs below to see the answer to each problem.

#### Problem 1

 Value Expanded GUA 2001:0db8:0020:0a00:b000:000c:00d0:0e00 Abbreviated GUA 2001:db8:20:a00:b000:c:d0:e00 Expanded Prefix 2001:0db8:0020:0a00:0000:0000:0000:0000/64 Abbreviated Prefix 2001:db8:20:a00::/64

#### Problem 2

 Value Expanded GUA 2001:0db8:feed:beef:cafe:1234:0000:0010 Abbreviated GUA 2001:db8:feed:beef:cafe:1234:0:10 Expanded Prefix 2001:0db8:feed:beef:0000:0000:0000:0000/64 Abbreviated Prefix 2001:db8:feed:beef::/64

#### Problem 3

 Value Expanded GUA 3000:00ba:0a00:000b:0000:00f0:fe00:0001 Abbreviated GUA 3000:ba:a00:b:0:f0:fe00:1 Expanded Prefix 3000:00ba:0a00:000b:0000:0000:0000:0000/64 Abbreviated Prefix 3000:ba:a00:b::/64

#### Problem 5

 Value Expanded GUA 2001:0db8:0000:0000:0000:0000:0000:0bad Abbreviated GUA 2001:db8::bad Expanded Prefix 2001:0db8:0000:0000:0000:0000:0000:0000 Abbreviated Prefix 2001:db8::/64

## More Config Labs from Same Book Part

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problem 2 the abbreviated GUA reads 2001:db8:feed:beef:cafe:1234:0:10
but shouldn’t it be
2001:db8:feed:beef:cafe:1234::10
???

Just to be complete…
The short answer is no, it’s only for 2 or more consecutive all 0s quartets that are correctly abbreviated to ::. See RFC 5952 section 4.2. So all the examples you asked about are correct as is.