A router or server on the foreign network that the mobile node visits.

Any network other than the mobile node's home network.

A tunnel that starts at the home agent and terminates at the mobile node's care-of address.

An optional form of tunneling that can be supported by home agents, foreign agents, and mobile nodes. GRE enables a packet of any network-layer protocol to be encapsulated within a delivery packet of any other (or the same) network-layer protocol.

A number that is generated from a string of text. Hash functions are used to ensure that transmitted messages have not been tampered with. MD5 and SHA-1 are examples of one-way hash functions.

Keyed hashing method for message authentication. HMAC is used with an iterative cryptographic hash function, such as MD5 or SHA-1, in combination with a secret shared key. The cryptographic strength of HMAC depends on the properties of the underlying hash function.

An IP address that is assigned for an extended period to a mobile node. The address remains unchanged when the node is attached elsewhere on the Internet or an organization's network.

A router or server on the home network of a mobile node.

A network that has a network prefix that matches the network prefix of a mobile node's home address.

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

Internet Key Exchange. IKE automates the provision of authenticated keying material for IPsec security associations.

The Internet-standard protocol for tunneling IPv4 packets within IPv4 packets.

A communication facility or medium over which nodes can communicate at the link layer. The link layer is the layer immediately below IPv4/IPv6. Examples include Ethernets (simple or bridged) or ATM networks. One or more IPv4 subnet numbers or prefixes are assigned to an IP link. A subnet number or prefix cannot be assigned to more than one IP link. In ATM LANE, an IP link is a single emulated LAN. When you use ARP, the scope of the ARP protocol is a single IP link.

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 that is 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). This address also can have a local or global uniqueness scope.

An iterative cryptographic hash function that is used for message authentication, including digital signatures. The function was developed in 1991 by Rivest.

An optional form of IPv4 in IPv4 tunneling that can be supported by home agents, foreign agents, and mobile nodes. Minimal encapsulation has 8 or 12 bytes less of overhead than does IP-in-IP encapsulation.

A host or router that can change its point of attachment from one network to another network while maintaining all existing communications by using its IP home address.

Either a home agent or a foreign agent.

The association of a home address with a care-of address, along with the remaining lifetime of that association.

A collection of security measures, such as an authentication algorithm, between a pair of nodes, which are applied to Mobile IP protocol messages that are exchanged between the two nodes.