NetEss7EdChapter06

subnet mask

A 32-bit dotted decimal number, consisting of a contiguous series of binary 1 digits followed by a contiguous series of binary 0 digits, that determines which part of an IP address is the network ID and which part is the host ID.

IPv4 address

A 32-bit dotted-decimal address containing a network ID, which specifies the network the computer is on, and a host ID, which uniquely identifies the computer on that network.

logical AND operation

A binary operation in which there are two operands; the result is 0 if either operand is 0 and 1 if both operands are 1.

tunneling

A common network protocol technique that allows transmitting a packet in a format that would otherwise be incompatible for the network architecture by encapsulating the packet in a compatible header format.

Classless Interdomain Routing (CIDR)

A method of IP addressing in which the network and host IDs are determined by a prefix number that specifies how many bits of the IP address are network bits ; the remaining bits are host bits.

CIDR notation

A method of expressing an IP address in the format A.B.C.D/n; n is the number of 1 bits in the subnet mask or the number of bits in the network ID. See also Classless Interdomain Routing (CIDR).

multicasting

A network communication in which a packet is addressed so that more than one destination can receive it.

Automatic Private IP Addressing (APIPA)

A private range of IP addresses assigned to an APIPA-enabled computer automatically when an IP address is requested via DHCP but no DHCP server responds to the request.

subnetting

A process that reallocates bits from an IP address's host portion to the network portion, creating multiple smaller address spaces. See also subnets.

supernetting

A process that reallocates bits from an IP address's network portion to the host portion, effectively combining smaller subnets into a larger supernet.

localhost

A reserved name that corresponds to the loopback address in an IP network. See also loopback address.

multihomed server

A server with two or more NICs, each attached to a different IP network. Each NIC is assigned a network connection and requires its own IP address.

Network Address Translation (NAT)

A service that translates a private IP address to a public IP address in packets destined for the Internet, and then translates the public IP address in the reply to the private address. Often used to allow using private IP addresses while connected to the Internet.

metric

A value assigned to the gateway based on the speed of the interface used to access the gateway.

IP prefix

A value used to express how many bits of an IP address are network ID bits. Usually expressed by a / symbol, as in 192.168.1.24/27; in this example, 27 is the IP prefix.

octet

An 8-bit value; a number from 0 to 255 that's one of the four numbers in a dotted decimal IP address.

link-local address

An IP address that can be used to communicate only on the local subnet. It can't be routed to other networks.

6to4

An IPv4-toIPv6 transition protocol that provides automatic tunneling of IPv6 traffic over an IPv4 network. It canhandle host-to-router or router-to-host tunneling but is most often used to create a router-to-router tunnel.

unique local IPv6 address

An address for devices on a private network that can't be routed on the Internet.

unicast address

An address in a unit of network data intended for a single destination device.

loopback address

An address that always refers to the local computer; in IPv4, it's 127.0.0.1, and in IPv6 it's ::1. This address is used to test TCP/IP functionality on the local computer.

multicast address

An address that identifies a group of computers running a multicast application.

anycast addresses

An address type used in IPv6 to allow a one-to-many relationship between source and desetination; the packet is delivered to only one of the possible destination computers.

Extended Unique Identifier (EUI)-64 interface ID

An autoconfigured IPv6 host address that uses the MAC address of the host plus an additional 16 bits.

Teredo

An automatic IPv6-over-IPv4 tunneling protocol that solves the problem of 6to4's requirement of a public IPv4 address and the inability to traverse NAT routers. See also 6to4.

Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)

An automatic tunneling protocol used to transmit IPv6 packets between dual IP layer hosts across an IPv4 network. See also dual IP layer architecture.

Port Address Translation (PAT)

An extension of NAT, a service that allows several hundred workstations to access the Internet with a single public Internet address by using Transport-layer port numbers to differentiate each host conversation. See also Network Address Translation (NAT).

link-local IPv6 address

Similar in function to the IPv4 APIPA addresses, link-local IPv6 addresses begin with fe80, are self-configuring, and can't be routed. See also Automatic Private IP Addressing (APIPA).

subnets

Subdivisions of an IP network address space.

broadcast domain

The bounds of a network that defines which devices must receive a packet that's broadcast by any other device; usually an IP subnet.

dual IP layer architecture

The current architecture of the IPv6 protocol in Windows, in which both IPv4 and IPv6 share the other componentsof the stack.

dotted decimal notation

The format for expressing an IPv4 address; it's four decimal numbers separated by periods.

address space

The number of addresses available in an IP network number that can be assigned to hosts.

classful addressing

The use of IP addresses with their default subnet masks according to their address class: A, B, or C.