The second rule for shortening IPv6 addresses is that you can use a double colon (::) to represent any single, contiguous string of two or more hextets (16-bit segments) consisting of all 0s. Table 4-2 illustrates the use of the double colon.
Colons separate the groups of 4-bit hexadecimal digits. The unofficial term for a section of four hexadecimal values is a hextet, similar to the term octet used in IPv4 addressing. An IPv6 address consists of eight hextets separated by colons. As Figure 4-1 illustrates, each hextet, with its four hexadecimal digits, is equivalent to 16 bits.
Each IPv6 address is made up of three parts: a 48-bit prefix received from a provider, a 16-bit site prefix, and the host portion, which is 64 bits. Figure 7.9 below shows you how the address is comprised: Providers have a larger /32 prefix from which they assign /48 prefixes to organizations.
IPv6 addresses are 128 bits in length and written as a string of hexadecimal digits. Every 4 bits can be represented by a single hexadecimal digit, for a total of 32 hexadecimal values (0 16 [0000 2] through f 16 [1111 2 ]).
:: can be used once in an IPv6 address to replace a consecutive blocks of zeroes. It can be any length of zeroes as long as it is greater than a single block. All zeroes in a single block can be represented by :0: instead of writing out all four zeroes.
IPv6 addresses are 128 bits in length. Eight 16-bit groups are divided by a colon (:). Double colons (::) represent only 0s. Leading zeros can be omitted in an IPv6 address.
An IPv6 address is split into two parts: a network and a node component. The network component is the first 64 bits of the address and is used for routing.
Because new addresses are generated regularly the addresses are marked as temporary . A device can have multiple privacy extension addresses if the system is still using an old address when a new address is being generated. The system will keep the old address for as long as necessary.
Representation of IPv6 Addresses. IPv6 addresses are 128 bits in length and written as a string of hexadecimal digits. Every 4 bits can be represented by a single hexadecimal digit, for a total of 32 hexadecimal values (016 [00002] through f16 [11112]).
An IPv6 address is broken into three different parts; the site prefix, the subnet ID, and the interface ID. These three components are identified by the position of the bits within the address. The first three fields in an IPv6 address make up the site prefix.
Explanation: There are three elements that make up an IPv6 global unicast address. A global routing prefix which is provided by an ISP, a subnet ID which is determined by the organization, and an interface ID which uniquely identifies the interface interface of a host.
The three types of IPv6 addresses are: unicast, anycast, and multicast. Unicast addresses identify a single interface. Anycast addresses identify a set of interfaces in such a way that a packet sent to an anycast address is delivered to a member of the set.
link-local IPv6 addressesTypically, link-local IPv6 addresses have “FE80” as the hexadecimal representation of the first 10 bits of the 128-bit IPv6 address, then the least-significant 64-bits of the address are the Interface Identifier (IID).
An IPv6 multicast address defines a group of devices known as a multicast group. IPv6 multicast addresses use the prefix ff00::/8, shown in Table 4-10, which is equivalent to the IPv4 multicast address 224.0. 0.0/4. A packet sent to a multicast group always has a unicast source address.
An IPv6 address is a 128-bit binary number assigned to a computer on a TCP/IP network. Some of the bits in the address represent the network segment; the other bits represent the host itself. IPv6 addresses are not case-sensitive.
In IPv6, addresses are expressed as a series of eight 4-character hexadecimal numbers, which represent 16 bits each (for a total of 128 bits).
An IP address consists of two parts, one identifying the network and one identifying the node, or host. To learn more about Network Certification, check out these courses. The Class of the address determines which part belongs to the network address and which part belongs to the node address.
IPv6 addresses are 128 bits in length and written as a string of hexadecimal digits. Every 4 bits can be represented by a single hexadecimal digit, for a total of 32 hexadecimal values (0 16 [0000 2] through f 16 [1111 2 ]). You will see later in this section how to possibly reduce the number of digits required to represent an IPv6 address. The alphanumeric characters used in hexadecimal are not case sensitive; therefore, uppercase and lowercase characters are equivalent. Although IPv6 address can be written in lowercase or uppercase, RFC 5952, A Recommendation for IPv6 Address Text Representation, recommends that IPv6 addresses be represented in lowercase.
In this chapter from IPv6 Fundamentals: A Straightforward Approach to Understanding IPv6, 2nd Edition, author Rick Graziani examines all the different types of IPv6 addresses in the unicast, multicast, and anycast categories.
The second rule for shortening IPv6 addresses is that you can use a double colon (::) to represent any single, contiguous string of two or more hextets (16-bit segments) consisting of all 0s . Table 4-2 illustrates the use of the double colon.
Colons separate the groups of 4-bit hexadecimal digits. The unofficial term for a section of four hexadecimal values is a hextet, similar to the term octet used in IPv4 addressing. An IPv6 address consists of eight hextets separated by colons.
The most obvious and recognizable difference between IPv4 and IPv6 is the IPv6 address. An IPv4 address is 32 bits and expressed in dotted-decimal notation, whereas an IPv6 address is 128 bits in length and written in hexadecimal. However, there are many other differences between the two protocol addresses. IPv6 includes new address types as well ...
The alphanumeric characters used in hexadecimal are not case sensitive; therefore, uppercase and lowercase characters are equivalent.
Although IPv6 address can be written in lowercase or uppercase, RFC 5952, A Recommendation for IPv6 Address Text Representation, recommends that IPv6 addresses be represented in lowercase.
Nobody could have predicted the exponential explosion in the growth of the Internet when it was first created.
You will not find Internet users all over the world using IPv4 one day and then switching to IPv6 the next. The change will take place over a number of years in a phased approach. You will find that the address allocation is done in batches of addresses using a combination of DNS and DHCP or DHCPv6 autoconfiguration scripts.
IPv6 uses a number of underlying protocols in order to function (much in the same way IPv4 does). Some are enhancements of already familiar protocols, such as DNS, CDP, and DHCP, but a key protocol is Neighbor Discovery Protocol, which will be covered in some detail due to its importance.
The mind-boggling amount of available IPv6 addresses actually negates the need to worry about address exhaustion. The CCNA exam requires an understanding of how to allocate IPv6 subnets to satisfy addressing for a LAN or WAN.
Please visit www.howtonetwork.com/ccnasimplified to take the free Chapter 7 exam.