Glossary

This glossary contains only definitions of new terms found in this book and are not in the Global Glossary. For definitions of other terms, see the Global Glossary at http://docs.sun.com:80/ab2/coll.417.1/GLOBALGLOSS/@Ab2TocView.

anycast address

An IP address that is assigned to more than one interface (typically belonging to different nodes), where a packet sent to an anycast address is routed to the nearest interface having that address, according to the routing protocol's measure of distance.

authentication header

An extension header that provides authentication and integrity (without confidentiality) to IPv6 datagrams.

autoconfiguration

The process of a host automatically configuring its interfaces in IPv6.

dual stack

In the context of IPv6 transition, a protocol stack that contains both IPv4 and IPv6, with the rest of the stack being identical.

encapsulating security header

An extension header that provides integrity and confidentiality to IPv6 datagrams.

encapsulation

The process of a header and payload being placed in the first packet, which is in turn placed in the second packet's payload.

firewall

Any device or software that protects an organization's private network or intranet from intrusion by external networks such as the Internet.

hop

A measure used to identify the number of routers that separate two hosts. If three routers separate a source and destination, the hosts are said to be three hops away from each other.

IPsec

The security architecture (IPsec) that provides protection for IP datagrams.

IPv4

Internet Protocol, version 4. Sometimes referred to as IP. This version supports a 32-bit address space.

IPv6

Internet Protocol, version 6. This version supports a 128-bit address space.

key management

The way in which you manage security associations.

link-local-use address

A designation used for addressing on a single link for purposes such as automatic address configuration.

local-use address

A unicast address that has only local routability scope (within the subnet or within a subscriber network), and can have a local or global uniqueness scope.

mobile IP

A node able to move from one link to another without changing the its IP address.

MTU

(maximum transmission unit) The size, given in octets, that can be transmitted over a link. For instance, the MTU of an Ethernet is 1500 octets.

multicast address

An IP address that identifies a group of interfaces in such a way that a packet sent to a multicast address is delivered to all of the interfaces in the group.

neighbor advertisement

A response to a neighbor solicitation message or the process of a node sending unsolicited neighbor advertisements to announce a link-layer address change.

neighbor discovery

An IP mechanism that enables hosts to locate routers that reside on an attached link.

neighbor solicitation

A solicitation sent by a node to determine the link-layer address of a neighbor, or to verify that a neighbor is still reachable by a cached link-layer address.

packet

A group of information that is transmitted as a unit over communications lines. Contains a header plus payload.

redirect

In a router, to inform a host of a better first-hop node to reach a particular destination.

router advertisement

The process of routers advertising their presence together with various link and Internet parameters, either periodically, or in response to a router solicitation message.

router discovery

The process of hosts locating routers that reside on an attached link.

router solicitation

The process of hosts requesting routers to generate router advertisements immediately, rather than at their next scheduled time.

SADB

(security associations database) A table that specifies cryptographic keys and algorithms used in the transmission of data.

security associations

(security associations) Associations that specify security properties from one host to another.

site-local-use address

A designation used for addressing on a single site.

SPI

(security parameters index) An integer that specifies the row in the SADB that a receiver should use to decrypt a received packet.

stateful autoconfiguration

The process of a host obtaining interface addresses and/or configuration information and parameters from a server.

stateless autoconfiguration

The process of a host generating its own addresses using a combination of locally available information and information advertised by routers.

tunneling

The mechanism by which IPv6 packets are placed inside IPv4 packets and routed through the IPv4 routers.

unicast address

An IP address that identifies a single interface.

VPN

(virtual private network) A single, secure, logical network that uses tunnels across a public network such as the Internet.