ATM LAN Emulation (LANE)

Prof. Dr. Ing. Pusztai KalmanTechnical University,

Cluj-Napoca

LAN Emulation (LANE) What is LAN Emulation

“…makes an ATM interface look like one or more LAN interfaces” (CISCO LANE Overview)

Specified in LAN Emulation over ATM (ATM_FORUM 94-0035)

Approved in Feb 1995, as LE V 1.0 The reason and goals of LANE

Interconnectivity and transparency

Types of LANE connectivity All ATM

connections LAN to ATM

connections LAN to LAN

connections (with ATM backbone)

LAN emulated characteristics Connectionless Service Multicast addresses

Multicast MAC MAC driver interfaces in ATM

stations Emulated LANs Interconnection With Existing LANs

Architecture of LANE

Components of LANE LAN Emulation client software

Controlls an ATM interface LAN Emulation Service

Three servers Emulated LANs

Ethernet/IEEE 802.3 Token Ring/IEEE 802.5

LANE Clients Role

Ethernet/Token Ring frames to AAL5

Uses Virtual Channel Connections (VCC)

MAC for each ATM interface

Switching and bridging functions

Application layer

Transport layer (e.g. TCP)

Network layer (e.g. IP)

LAN Emulation Client

ATM Adaptation Layer (AAL5)

ATM Layer

ATM Physical Layer

LANE Client Protocol Elements Transmitted frames (with AAL5

frames) Ethernet II (DIX) IEEE 802.2/IEEE 802.3 Ethernet Token Ring

LANE Service Handles multiple LECs

LUNI (LANE User Network Interface) Three components

LAN Emulation Configuration Service (LECS) LAN Emulation Server (LES) Broadcast/Unknown Server (BUS)

LANE Client Initialization Connect to LECS

ILMI Anycast address reserved for LECS Use a special PVC, with VPI/VCI 0/17

Interact with LECS Send ATM and MAC address, LAN type and

supported frame size Receive LES address, LAN type and frame

size to be used

LANE Client Initialization Communication with LES

Point-to-point connection (Control Direct VCC)

JOIN REQUEST control frame JOIN RESPONSE control frame Connection is maintained in point-to-

multipoint list

LANE Client Initialization Communication with LES

JOIN REQUEST Client ATM and MAC addresses Type of LAN and maximum frame size to

be supported Indication if the client acts as proxy for

remote MACs (it is switch or edge device) The name of ELAN wished to join (if

known)

LANE Client Initialization Communication with LES

JOIN RESPONSE Similar fields with JOIN REQUEST Mandatory fields

Type of LAN Maximum frame size Name of ELAN

Assigns a LANE Client ID (LECID)

Connecting to the BUS LEC requests to the LES the ATM

broadcast address for all 1’s MAC address

The reply is the BUS address

Address Resolution A LANE Client needs to know either

The peer LANE Client ATM address The proxy edge device ATM address

Steps of communication LE-ARP request to LES The LES either forwards or responds

with the address The connection is opened

Quick Sends and Flushing An alternative to LE-ARP is BUS After broadcast, new connection

can be opened LE_FLUSH_REQUEST, path clear

request LE_FLUSH_RESPONSE, path cleared

Operating with Higher Layer Protocols

After finding the peer MAC address Use BUS Ask the LES the peer ATM, for

connection opening IETF proposes ATMARP Server

Next Hop Resolution Protocol ATMs as non-broadcast multi-

access network (NBMA) NHRP finds the ATM address of the

best next hop

Multiprotocol Over ATM MPOA device

ATM interface, LANE software, MPOA client software

MPOA server Router containing MPOA server software

Shortcut ATM VCC, used instead of the default path

A MPOA device requests shortcut information from a MPOA server

Shortcuts are opened only at steady traffic

References http://www.cisco.com/univercd/cc/td/doc/product/software/ios1

13ed/113ed_cr/switch_c/xcovlane.htm http://www.iphase.com/docs/whitepapers/lanemul.cfm http://www.rad.com/networks/1996/atmle/atmle.htm http://www.ece.wpi.edu/courses/ee535/hwk96/hwk5cd96/cobd

en/cobden.html http://www.protocols.com/pbook/lane.htm http://www.atmforum.org http://cell-relay.indiana.edu/cell-relay/ Dr. Sidnie Feit – “Wide Area High Speed Networks”