Glossary (System Administration Guide, Volume 3)

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.

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

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

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

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

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

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

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.

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

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

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

The way in which you manage security associations.

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

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.

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

(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.

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.

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

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

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.

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

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

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

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

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

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

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

A designation used for addressing on a single site.

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

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

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

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

An IP address that identifies a single interface.

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