Glossary
GL-5
Cisco 10000 Series Router Software Configuration Guide
OL-2226-23
IETF
Internet Engineering Task Force. Task force consisting of over 80 working groups responsible for
developing Internet standards.
IGMP
Internet Group Management Protocol. Used by IP hosts to report their multicast group memberships to
an adjacent multicast router.
Internet
A collection of networks interconnected by a set of routers that allow them to function as a single, large
virtual network.
Internet Protocol
(IP)
The network layer protocol for the Internet protocol suite.
IRB
Integrated routing and bridging. A protocol that allows a router to act as both bridge and router on the
same interface. For broadband aggregation, we recommend using the routed bridge encapsulation
(RBE) protocol. See RBE.
IP
See Internet Protocol.
ISO
International Standards Organization. A voluntary, non-treaty organization founded in 1946,
responsible for creating international standards in many areas, including computers and
communications.
ISP
Internet service provider. A company that allows home and corporate users to connect to the Internet.
ITU-T
International Telecommunications Union, Standardization Sector. ITU-T is the telecommunication
standardization sector of ITU and is responsible for making technical recommendations about
telephone and data (including fax) communications systems for service providers and suppliers.
L
L2F
Layer 2 Forwarding. Protocol that supports the creation of secure virtual private dial-up networks over
the Internet.
L2TP
Layer 2 Tunnel Protocol. An Internet Engineering Task Force (IETF) standards track protocol defined
in RFC 2661 that provides tunneling of PPP. Based upon the best features of L2F and PPTP, L2TP
provides an industry-wide interoperable method of implementing VPDN.
LAC
L2TP access concentrator. A node that acts as one side of an L2TP tunnel endpoint and is a peer to the
L2TP network server (LNS). The LAC sits between an LNS and a remote system and forwards packets
to and from each. Packets sent from the LAC to the LNS requires tunneling with the L2TP protocol as
defined in this document. The connection from the LAC to the remote system is either local or a PPP
link.
LAN
Local area network. A limited distance (typically under a few kilometers or a couple of miles)
high-speed network (typically 4 to 100 Mbps) that supports many computers.
LCP
Link control protocol. Protocol that establishes, configures, and tests data-link connections for use by
PPP.
