Lane - Cisco RJ-45-to-AUX Brochure

Scalability—ATM is highly flexible, accommodating a wide range of traffic types, traffic rates, and
communications applications.
An ATM network includes two types of devices: ATM switches and ATM endpoints. One type of ATM
interface, called a user−network interface (UNI), connects an ATM device to a switch; a second type, called a
network−to−network interface (NNI), connects an ATM switch to another ATM switch.
ATM has built−in support for Quality of Service (QoS), which is used to guarantee a level of service for
networks that use ATM. This guarantee includes bandwidth utilization and data throughput. This type of
service is critical when dealing with newer multimedia technologies.

LANE

LANE is a method used to provide backward compatibility to legacy Ethernet and Token Ring networks.
LANE makes an ATM interface look like an Ethernet or Token Ring network interface, so no modifications to
existing network drivers or applications need to be made to support ATM environments. LANE allows ATM
networks to emulate Media Access Control (MAC) broadcast networks. Before the implementation of LANE,
a proprietary emulation device was needed to connect ATM to a LAN topology.
ATM LANE works with a client/server architecture to create an emulated LAN (ELAN). An ELAN is very
similar to a VLAN, in that it limits local broadcasts and multicast traffic to the ELAN. LANE devices can be
either clients or servers. The LANE Emulation service (LE service) consists of several different components:
LAN Emulation Client (LEC)—Resides in every ATM device and provides a LAN interface to higher
layer protocols.
LAN Emulation Server (LES)—The centerpiece of the LANE architecture. A single LES is
responsible for address registry and resolution for an ELAN.
Broadcast and Unknown Server (BUS)—The means by which ATM provides broadcasting support
for an ELAN.
LAN Emulation Configuration Server (LECS)—Contains the database of LES/BUS pairs for all the
configured ELANs.
LANE is discussed in much more detail later in this chapter.
Nothing in ATM makes it easy to comprehend and learn. It defies a lot of what today's network
administrators have learned. Telling you that ATM is used as a backbone protocol in the network makes you
think that you do not need to worry about packet−based broadcast LANs trying to communicate with
cell−based ATM networks (which will be discussed in the following sections). In this chapter, I discuss how
to connect ATM—which is a connection−oriented, point−to−point protocol—to the Layer 2 addresses of the
broadcast domains in the LAN.
ATM is a difficult subject for most people, because they rarely are exposed to it on a day−to−day basis like
Ethernet or Token Ring. In today's networking environment, however, increased emphasis is being put on
integrating data, voice, and video in networks, and ATM is a driving force. No other protocol today has
ATM's ability to ensure timely delivery of packets based on their type. In addition, ATM can be used on both
LANs and WANs on almost any types of media, with speeds that can scale up to gigabits per second.
ATM—Easy to Learn?
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