address binding --A mapping between the client's IP and hardware (MAC) addresses. The client's IP address may be configured by the administrator (manual address allocation) or assigned from a pool by the DHCP server (automatic address allocation). The binding also contains a lease expiration date. The default for the lease expiration date is one day.
address conflict --A duplication of use of the same IP address by two hosts. During address assignment, DHCP checks for conflicts using ping and gratuitous (ARP). If a conflict is detected, the address is removed from the pool. The address will not be assigned until the administrator resolves the conflict.
address pool --The range of IP addresses assigned by the DHCP server. Address pools are indexed by subnet number.
automatic address allocation --An address assignment method where a network administrator obtains an IP address for a client for a finite period of time or until the client explicitly relinquishes the address. Automatic allocation is particularly useful for assigning an address to a client that will be connected to the network only temporarily or for sharing a limited pool of IP addresses among a group of clients that do not need permanent IP addresses. Automatic allocation may also be a good choice for assigning an IP address to a new client being permanently connected to a network where IP addresses are sufficiently scarce that it is important to reclaim them when old clients are retired.
BOOTP --Bootstrap Protocol. A protocol that provides a method for a booting computer to find out its IP address and the location of the boot file with the rest of its parameters.
client --Any host requesting configuration parameters.
database--A collection of address pools and bindings.
database agent --Any host storing the DHCP bindings database, for example, a Trivial File Transfer Protocol (TFTP) server.
DHCP --Dynamic Host Configuration Protocol. A protocol that provides a mechanism for allocating IP addresses dynamically so that addresses can be reused when hosts no longer need them.
DNS --Domain Name System. A system used in the Internet for translating names of network nodes into addresses.
manual address allocation --An address assignment method that allocates an administratively assigned IP address to a host. Manual allocation allows DHCP to be used to eliminate the error-prone process of manually configuring hosts with IP addresses.
PWLAN --Public Wireless Local Area Network. A type of wireless LAN, often referred to as a hotspot, that anyone having a properly configured computer device can access.
relay agent --A router that forwards DHCP and BOOTP messages between a server and a client on different subnets.
server --Any host providing configuration parameters.
SSG --Service Selection Gateway. The Cisco IOS feature set that provides on-demand service enforcement within the Cisco network.