Transcript ATM LAN Emulation

ATM LAN Emulation (LANE)
Trebea-Corda Cristian
Technical University,
Cluj-Napoca
LAN Emulation (LANE)
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What is LAN Emulation
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“…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
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Interconnectivity and transparency
Types of LANE connectivity
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All ATM connections
LAN to ATM
connections
LAN to LAN
connections (with
ATM backbone)
LAN emulated characteristics
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Connectionless Service
Multicast addresses
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Multicast MAC
MAC driver interfaces in ATM stations
Emulated LANs
Interconnection With Existing LANs
Architecture of LANE
Components of LANE
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LAN Emulation client software
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LAN Emulation Service
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Controlls an ATM interface
Three servers
Emulated LANs
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Ethernet/IEEE 802.3
Token Ring/IEEE 802.5
LANE Clients
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Role
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Ethernet/Token
Ring frames to
AAL5
Uses Virtual
Channel
Connections (VCC)
MAC for each ATM
interface
Application layer
Transport layer (e.g. TCP)
Network layer (e.g. IP)
LAN Emulation Client
ATM Adaptation Layer (AAL5)
ATM Layer
ATM Physical Layer
Switching and
bridging functions
LANE Client Protocol Elements
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Transmitted frames (with AAL5 frames)
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Ethernet II (DIX)
IEEE 802.2/IEEE 802.3 Ethernet
Token Ring
LANE Service
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Handles multiple LECs
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LUNI (LANE User Network Interface)
Three components
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LAN Emulation Configuration Service (LECS)
LAN Emulation Server (LES)
Broadcast/Unknown Server (BUS)
LANE Client Initialization
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Connect to LECS
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ILMI
Anycast address reserved for LECS
Use a special PVC, with VPI/VCI 0/17
Interact with LECS
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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
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Communication with LES
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Point-to-point connection (Control Direct VCC)
JOIN REQUEST control frame
JOIN RESPONSE control frame
Connection is maintained in point-tomultipoint list
LANE Client Initialization
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Communication with LES
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JOIN REQUEST
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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
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Communication with LES
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JOIN RESPONSE
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Similar fields with JOIN REQUEST
Mandatory fields
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Type of LAN
Maximum frame size
Name of ELAN
Assigns a LANE Client ID (LECID)
Connecting to the BUS
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LEC requests to the LES the ATM
broadcast address for all 1’s MAC
address
The reply is the BUS address
Address Resolution
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A LANE Client needs to know either
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The peer LANE Client ATM address
The proxy edge device ATM address
Steps of communication
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LE-ARP request to LES
The LES either forwards or responds with
the address
The connection is opened
Quick Sends and Flushing
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An alternative to LE-ARP is BUS
After broadcast, new connection can be
opened
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LE_FLUSH_REQUEST, path clear request
LE_FLUSH_RESPONSE, path cleared
Operating with Higher Layer Protocols
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After finding the peer MAC address
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Use BUS
Ask the LES the peer ATM, for connection
opening
IETF proposes ATMARP Server
Next Hop Resolution Protocol
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ATMs as non-broadcast multi-access
network (NBMA)
NHRP finds the ATM address of the best
next hop
Multiprotocol Over ATM
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MPOA device
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MPOA server
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Router containing MPOA server software
Shortcut
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ATM interface, LANE software, MPOA client
software
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
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http://www.cisco.com/univercd/cc/td/doc/product/software/ios113ed/1
13ed_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/cobd
en.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”