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Glossary

SCALANCE WLC711

User Guide, V8.11, 07/2012, C79000-G8976-C260-03 A-3

DHCP Dynamic Host Configuration Protocol. A protocol for assigning dynamic IP addresses to

devices on a network. With dynamic addressing, a device can have a different IP address

every time it connects to the network. In some systems, the device's IP address can even

change while it is still connected. DHCP also supports a mix of static and dynamic IP

addresses.

DHCP consists of two components: a protocol for delivering host-specific configuration

parameters from a DHCP server to a host and a mechanism for allocation of network

addresses to hosts. (IETF RFC1531.)

Option 78 specifies the location of one or more SLP Directory Agents. Option 79 specifies

the list of scopes that a SLP Agent is configured to use.(RFC2610 - DHCP Options for

Service Location Protocol)

Directory Agent (DA) A method of organizing and locating the resources (such as printers, disk drives, databases,

e-mail directories, and schedulers) in a network. Using SLP, networking applications can

discover the existence, location and configuration of networked devices.

With Service Location Protocol, client applications are 'User Agents' and services are

advertised by 'Service Agents'. The User Agent issues a multicast 'Service Request'

(SrvRqst) on behalf of the client application, specifying the services required. The User

Agent will receive a Service Reply (SrvRply) specifying the location of all services in the

network which satisfy the request.

For larger networks, a third entity, called a 'Directory Agent', receives registrations from all

available Service Agents. A User Agent sends a unicast request for services to a Directory

Agent (if there is one) rather than to a Service Agent.

(SLP version 2, RFC2608, updating RFC2165)

Diversity antenna and

receiver

The AP has two antennae. Receive diversity refers to the ability of the AP to provide better

service to a device by receiving from the user on which ever of the two antennae is receiving

the cleanest signal. Transmit diversity refers to the ability of the AP to use its two antenna to

transmit on a specific antenna only, or on a alternate antennae. The antennae are called

diversity antennae because of this capability of the pair.

DNS Domain Name Server

DSSS Direct-Sequence Spread Spectrum. A transmission technology used in Local Area Wireless

Network (LAWN) transmissions where a data signal at the sending station is combined with

a higher data rate bit sequence, or chipping code, that divides the user data according to a

spreading ratio. The chipping code is a redundant bit pattern for each bit that is transmitted,

which increases the signal's resistance to interference. If one or more bits in the pattern are

damaged during transmission, the original data can be recovered due to the redundancy of

the transmission. (Compare FHSS)

DTIM DTIM delivery traffic indication message (in 802.11 standard)

Dynamic WEP The IEEE introduced the concept of user-based authentication using per-user encryption

keys to solve the scalability issues that surrounded static WEP. This resulted in the 802.1x

standard, which makes use of the IETF's Extensible Authentication Protocol (EAP), which

was originally designed for user authentication in dial-up networks. The 802.1x standard

supplemented the EAP protocol with a mechanism to send an encryption key to a Wireless

AP. These encryption keys are used as dynamic WEP keys, allowing traffic to each

individual user to be encrypted using a separate key.

Table A-1 Networking Terms and Abbreviations (continued)

Term Explanation

1 2 ... 468 469 470 471 472 473 474 475 476 477 478 ... 491 492

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