The variation in packet-to-packet latency. Jitter causes distortion in real-time signals such as audio and video data streams.
Kilobits per second. Equal to 1024 bits per second.
Locally Administered Address. In Ethernet and Token Ring networks, it is often possible to override the globally unique MAC address that comes encoded onto a NIC (the BIA). The new address created this way is called an LAA.
Local Area Network. A computer network confined to a relatively small geographical region such as a single building. The term blends gradually into the term Campus Area Network. However, as distances grow, it becomes increasingly difficult to use common LAN technology and the network tends to require the addition of long-haul technologies. At that point, it ceases to be considered a pure LAN.
See LEC.
See LECS.
See LES.
Local Area Network Emulation. LANE specifies a method for making an ATM network emulate the functioning of a large-scale LAN. To do this, it provides mechanisms for encapsulating LAN protocols, such as Ethernet, into the ATM cells. It also provides tools for creating and tearing down ATM virtual circuits (SVC) as they are required.
Local Area Transport. This very old nonroutable protocol was developed by Digital Equipment Corporation. It is primarily intended to provide terminal access to mainframe computers over bridged networks.
The time delay involved in sending a piece of information from one point on a network to another. Network latency includes only the transmission delays and does not consider any additional delays that take place within the end devices.
LAN Emulation Client. In an ATM LANE environment, the LEC is the edge device that performs the encapsulation and switching of LAN protocols into the ATM network. Usually an ATM switch contains a number of Ethernet or other LAN ports.
LAN Emulation Configuration Server. In an ATM LANE environment, this device keeps track of which devices belong to which ELAN. Usually just one LECS exists for each network, controlling all ELANs, although there could be a backup LECS.
Unfortunately, this term is often used negatively to refer to equipment or protocols that are not at the cutting edge of current technology. However, more accurately, it refers to equipment or protocols that include deprecated features that are difficult to support.
LAN Emulation Server. In an ATM LANE environment, this device controls the functioning of a particular ELAN. There is only one LES for each ELAN.
See LSA.
Logical Link Control. In the 802 protocol suite, a separate logical-link sublayer is defined in 802.2. This sublayer operates in conjunction with the various MAC sublayers, such as Ethernet and Token Ring, to create the Data Link Layer.
See LAN.
See LAA.
See LLC.
A logical port on a device that connects to the device itself. Loopback ports exist in the software of a device and provide a way to make a network connection from the device to itself without going onto the network. For routers in particular, it is useful for network management purposes because it provides a Layer 3 address that is always up regardless of which physical ports on the device are down.
Link State Advertisement. In Dynamic Routing Protocols that are based on a Link State Protocol, such as OSPF, individual routers do not distribute their entire routing tables (as do Distance Vector Protocols). Instead, they just distribute information about the states of their own links, plus the links of other devices they have heard about. This information is distributed by Link State Advertisements.