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ATM LAN Emulation (LANE). Prof. Dr. Ing. Pusztai Kalman Technical 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 L AN Emulation over ATM (ATM_FORUM 94-0035)
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ATM LAN Emulation (LANE) Prof. Dr. Ing. Pusztai Kalman Technical 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
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
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/ios113ed/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/cobden/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”