TCP/IP Illustrated chapter 2

How many rules did RFC5952 come up with to help with the confusion of RFC4291's multiple representation of IPv6 addresses?

3

How many agreed-upon simplifications where standardized for expressing IPv6 addresses as of RFC4291

4

What is the fourth simplification standardized for expressing IPV6 addresses as of RFC4291

A conventional notation is adopted in which the low-order 32 bits of the IPv6 address can be written using dotted-quad notation. The IPv6 address ::0102:f001 is therefore equivalent to the address ::1.2.240.1. This is called an IPv4-compatible IPv6 address.

What is a unicast address?

A unicast address a single address made from subdiving IPv4 address chunks and is used to identify a single network interface of a computer attached to the Internet or to some private intranet

Describe an IPv4-mapped IPv6 address

An IPv4-mapped IPv6 address is when the address is proceeded by ::ffff:10.0.0.1

Are there anymore types of addesses beyond unicast addresses?

Beyond unicast addresses, other types of addresses do exist including broadcast, multicast, and anycast, which may refer to more than one interface, plus some special-purpose addresses.

What is the second simplification standardized for expressing IPV6 addresses as of RFC4291

Blocks of all zeros can be omitted and replaced by the notation ::

if colons are used to specify IPv6 addresses how do you specify port numbers?

Bracket characters, [ and ], are used to surround the IPv6 address. For example, the URL http://[2001:0db8:85a3:08d3:1319:8a2e:0370:7344]:443/ refers to port number 443 on IPv6 host 2001:0db8:85a3:08d3:1319:8a2e:0370:7344 using the HTTP/TCP/IPv6 protocols.

What is the third simplification standardized for expressing IPV6 addresses as of RFC4291

Embedded IPv4 addresses represented in the IPv6 format can use a form of hybrid notation in which the block immediately preceding the IPv4 portion of the address has the value ffff and the remaining part of the address is formatted using dotted-quad. For example, the IPv6 address ::ffff:10.0.0.1 represents the IPv4 address 10.0.0.1. This is called an IPv4-mapped IPv6 address.

What are the five classes named?

Here we see that the five classes are named A, B, C, D, and E. The A, B, and C class spaces were used for unicast addresses.

How are IP addresses grouped?

IP addresses are grouped by type and size.

What do IPv6 addresses look like?

In IPv6, addresses are 128 bits in length, four times larger than IPv4 addresses, and generally speaking, are less familiar to most users

What is the first rule that RFC5952 came up with to help with the confusion of RFC4291's multiple representation of IPv6 addresses?

Leading zeros must be suppressed (e.g., 2001:0db8::0022 becomes 2001:db8::22).

What is the first simplification standardized for expressing IPV6 addresses as of RFC4291

Leading zeros of a block need not be written.

Are IPv4 compatible addresses the same as IPv4-mapped addresses

No, IPv4-compatible addresses are not the same as IPv4-mapped addresses; they are compatible only in the sense that they can be written down or manipulated by software in a way similar to IPv4 addresses. This type of addressing was originally required for transition plans between IPv4 and IPv6 but is now no longer required [RFC4291].

What is the second rule that RFC5952 came up with to help with the confusion of RFC4291's multiple representation of IPv6 addresses?

The :: construct must be used to its maximum possible effect (most zeros suppressed) but not for only 16-bit blocks. If multiple blocks contain equal-length runs of zeros, the first is replaced with ::.

When was the decline of the classful approach to internet addressing and why was it declining?

The classful approach to Internet addressing lasted mostly intact for the first decade of the Internet's growth (to about the early 1980s). After that, it began to show its first signs of scaling problems—it was becoming too inconvenient to centrally coordinate the allocation of a new class A, B, or C network number every time a new network segment was added to the Internet. In addition, assigning class A and B network numbers tended to waste too many host numbers, whereas class C network numbers could not provide enough host numbers to many new sites.

What is the conventional notation adopted for IPV6 addresses?

The conventional notation adopted for IPv6 addresses is a series of four hexadecimal ("hex," or base-16) numbers called blocks or fields separated by colons.

Describe the dotted-quad notation of IPv4.

The dotted-quad notation consists of four decimal numbers separated by periods. Each such number is a non-negative integer in the range [0, 255] and represents one-quarter of the entire IP address.

What is the dotted-quad notation of IPv4 for?

The dotted-quad notation is simply a way of writing the whole IPv4 address—a 32-bit non-negative integer used throughout the Internet system—using convenient decimal numbers.

What is the third rule that RFC5952 came up with to help with the confusion of RFC4291's multiple representation of IPv6 addresses?

The hexadecimal digits a through f should be represented in lowercase.

What was the trade off for partitioning of IPV4 address spaces?

The partitioning of the address space involved five classes. Each class represented a different trade-off in the number of bits of a 32-bit IPv4 address devoted to the network number versus the number of bits devoted to the host number. The basic idea is that IPv4 address space was originally divided into five classes. Classes A, B, and C were used for assigning addresses to interfaces on the Internet (unicast addresses) and for some other special-case uses. The classes are defined by the first few bits in the address: 0 for class A, 10 for class B, 110 for class C, and so on. Class D addresses are for multicast use and class E addresses remain reserved.

What was the net number and host number?

When the Internet's address structure was originally defined, every unicast IP address had a network portion, to identify the network on which the interface using the IP address was to be found, and a host portion, used to identify the particular host on the network given in the network portion. Thus, some number of contiguous bits in the address became known as the net number, and remaining bits were known as the host number. At the time, most hosts had only a single network interface, so the terms interface address and host address were used somewhat interchangeably.

why was a partitioning devised for the IP address space?

With the realization that different networks might have different numbers of hosts, and that each host requires a unique IP address, a partitioning was devised wherein different-size allocation units of IP address space could be given out to different sites, based on their current and projected number of hosts.fingert

Are there many IPv4 unicast addresses?

Yes most of the addresses in IPv4 are unicast.

How did RFC5952 help with the confusion of RFC4291's multiple representation of IPv6 addresses?

[RFC5952] imposes some rules to narrow the range of options while remaining compatible with [RFC4291]. They are as follows

About how many addressescan fit in IPv6 address space?

around 340 trillion trillion trillion

About how many addresses can fit in IPv4 address space?

around 4.29 billion