Network Terms "L"

Network Glossary and acronym's

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

.LOG file

Exchange 2007's database engine is referred to as the Extensible Storage Engine (ESE). ESE is a transactional database that writes information into RAM memory and into a log file. Once it is in the log file, it will be written to disk. There are a number of files used to store information:

An .edb file is located in the actual database itself. All of a user's messages, folders, public folders, contacts, appointment information, etc. is all stored on the .edb file. An .edb file size can exceed multiple GB.
A .log file is an ESE transaction log file. All .log files are 1 MB.
A .jrs file is a reserve log file which is used to commit any transactions that are still in memory in the event of the server running out of disk space. All .jrs files are 1 MB.
A .chk file is used to identify which log files have been committed to the database. The size of .chk file varies from 2-3 KB.

The ESE takes the following steps to write information into database files:

The ESE writes a message into memory RAM when it arrives at the server.
At the same time that information is written to RAM, it's written into the current .log file. All current log files are named E00.log. The information is written in a sequential format until the log file is full. When the log file is full, it will be renamed.
Once it has been committed to the log file, the information is written to the .edb file.
The checkpoint file is updated to indicate that the transaction log that has been committed to the database.

L2F (Layer 2 Forwarding Protocol)

L2F is a VPN protocol which offers no data encryption.

L2F was combined with PPTP, creating L2TP. Support for IPSec was added, and the result is a very versatile, nearly universally interoperable VPN protocol that provides solid authentication and reliable data encryption.

L2TP (Layer Two Tunneling Protocol)

L2TP (Layer 2 Tunneling Protocol) is the VPN protocol that typically employs IPSec as its data encryption mechanism. L2TP is the recommended VPN protocol to use on dial-up VPN connections.

L2TP was created by combining PPTP and L2F and adding in support for IPSec. The result is a very versatile, nearly universally interoperable VPN protocol that provides solid authentication and reliable data encryption.

LAN (Local area network)

A group of closely located computers or peripherals connected so that they can interact with each other as a network.

LAPM (Link Access Procedure for Modems)

A Data Link layer protocol called Link Access Procedure for Modems (LAPM) used by newer modems for error detection. LAPM is implemented in the modem hardware. LAPM is described by ITU's V.42 standard.

Layer 2 Forwarding Protocol (L2F)

L2F is a VPN protocol which offers no data encryption.

Layer 3 switch

A layer 3 switch operates at the Network layer reading the logical address and making forwarding and receiving decisions. Contrast this with most switches that operate at the Data Link layer which read the MAC address.

Layer Two Tunneling Protocol (L2TP)

L2TP (Layer 2 Tunneling Protocol) is the VPN protocol that typically employs IPSec as its data encryption mechanism. L2TP is the recommended VPN protocol to use on dial-up VPN connections.

Layered Service Provider (LSP)

A Layered Service Provider (LSP) distributes link-state information and defines the characteristics of an IS-IS router.

LCR (Local Continuous Replication)

Local Continuous Replication (LCR) is a cluster implementation which maintains a copy of the production storage group on a second set of disks that are connected to the same server using built-in asynchronous log shipping and log replay technology.

LDAP (Lightweight Directory Access Protocol)

A lightweight protocol that clients such as Outlook Express use to look up and search for addresses in an online directory. It also allows a user to add, edit, and delete information from the directory.

Lease

The period of time for which a dynamically assigned IP address remains valid for a DHCP client. Before the end of the lease, the client has to renew the lease or be assigned a new lease by DHCP.

Legacy streaming

Legacy streaming is the traditional method of backup for Exchange environments. When a legacy streaming backup is initiated:

The backup application will notify the database engine that a backup is being started.
The database engine creates a file that will be used as a marker that the backup is occurring.
The backup application freezes the database.
The backup application backs up the database.
The backup application copies the marker file which contains any additional transactions and log files which took place during the backup.

Licensing mode

The way you pay to use an application or operating system. You can choose Per Server or Per Seat licensing for Windows 2000.

Lightweight Directory Access Protocol (LDAP)

Line Printer Daemon (LPD)

A service residing on a UNIX print server that receives print jobs from clients using the LPR utility.

Line Printer Daemon/Line Print Remote (LPD/LPR)

LPD/LPR is the most widely-used cross platform print protocol. LPD/LPR establishes connection between printing devices and workstations. LPD is usually loaded on the printing device. LPR is usually loaded onto the client workstation.

Line Printer Queue (LPQ)

This utility obtains the status of a print queue on a host running the Line Printing Daemon (LPD) service.

Line Printer Remote (LPR)

A utility on a client that allows it to send print jobs to the Line Printer Daemon on the server.

Link Access Procedure for Modems (LAPM)

Link state routing protocol

Routing algorithm in which each router broadcasts or multicasts information regarding the cost of reaching each of its neighbors to all nodes in the internetwork. Link state algorithms create a consistent view of the network and are therefore not prone to routing loops, but they achieve this at the cost of relatively greater computational difficulty and more widespread traffic (compared with distance vector routing algorithms). Compare with distance vector routing algorithm.

Linked mailbox

Linked mailboxes are used in environments in which there are multiple forests (known as resource forests). When a linked mailbox is created, a mailbox and a disabled user account are created in the forest which hosts the Exchange organization. Once the mailbox has been created, it is then linked or associated with a user account that resides in the second forest. In order to assign an account from the second forest to the mailbox, a trust relationship must exist between the domain that contains the Exchange server and the domain in which the user account resides.

Link-local Multicast Name Resolution (LLMNR)

Link-local Multicast Name Resolution (LLMNR) enables IP hosts to perform IP address-to-host name resolution without a DNS server. LLMNR is feature used in Zeroconf networking and is being developed by Microsoft.

Linux

A popular (freely-distributable open source) operating system that runs on multiple hardware platforms.

LLC (Logical Link Control)

In the OSI model, the Logical Link Control (LLC) layer is one of two sublayers of the Data-Link layer. The LLC manages traffic (flow and error control) over the physical medium.

LLMNR (Link-local Multicast Name Resolution)

LMHOSTS file

An ASCII text file that associates IP addresses to computer names outside the local subnet. In Windows 2000, the Lmhost file is located in systemroot \System32\Drivers\Etc. You must manually update the LMHOSTS file.

Load balancing

Load balancing is the capability of a router to distribute traffic over all of its network ports that are the same metric from the destination address.

Local area network (LAN)

A group of closely located computers or peripherals connected so that they can interact with each other as a network.

Local Continuous Replication (LCR)

Local GPO

A Group Policy Object (GPO) stored on the local computer. Every Windows 2000 computer has exactly one local GPO.

Local group

Groups used to provide users with permissions to access a network resource and to provide rights to perform system tasks.

Local Host

Addresses in the 127.0.0.0 range are reserved to refer to the local host (in other words "this" host or the host you're currently working at).

Local preference attribute

The local preference (type code 5) is a well-known discretionary BGP attribute that describes the preferred exit path from an AS. Local preferences are configured by assigning a number between 1 and 100; higher values representing higher preference over lower values.

Local routing table

A neighbor table contains a list of neighbors with which it has a BGP connection.

Local update sequence number

The USN of the local domain controller when an Active Directory update is made.

Local user accounts

User name and password information stored in the directory database of the local computer.

Local user profile

A profile stored on a user's local workstation.

Log file

A text file that contains detailed information about the backup procedures you perform with Windows Backup. Other processes, such as the Performance Monitor, also generate log files.

Log off

The process by which a user disconnects from a network and closes connections to mapped drives and printers.

Log on

The process by which a user gains access to a network by providing security credentials (usually a user name and password).

Logical Link Control (LLC)

In the OSI model, the Logical Link Control (LLC) layer is one of two sublayers of the Data-Link layer. The LLC manages traffic (flow and error control) over the physical medium.

Logoff script

A script that executes when a user logs off.

Logon script

A script that executes when a user logs on.

Long file name

A name for a file or folder that includes more characters than the standard MS-DOS 8.3 filename convention.

Loopback address

A reserved IP address, 127.0.0.1, that is used to perform loopback functions.

Loopback Processing Mode

A mode of processing Active Directory-based Group Policy Objects (GPOs) in which computer-specific settings replace or take precedence over user-specific settings.

LostAndFound container

An Active Directory container that holds objects that no longer have a valid parent container. For example, this could happen if an object is created on one domain controller while simultaneously the object's container is deleted or renamed on another domain controller.

Low-level disk formatting

A hard disk formatting process, usually performed by the disk manufacturer, that defines the basic physical structure of the disk. It runs a surface analysis to test the disk heads, defines sectors and assigns sector IDs, temporarily fills each sector, identifies bad sectors on the drive, and defines the interleave ratio.

LPD (Line Printer Daemon)

A service residing on a UNIX print server that receives print jobs from clients using the LPR utility.

LPD/LPR (Line Printer Daemon/Line Print Remote)

LPQ (Line Printer Queue)

This utility obtains the status of a print queue on a host running the Line Printing Daemon (LPD) service.

LPR (Line Printer Remote)

A utility on a client that allows it to send print jobs to the Line Printer Daemon on the server.

LSP (Layered Service Provider)

A Layered Service Provider (LSP) distributes link-state information and defines the characteristics of an IS-IS router.