Error 500 - Core dump - InetDaemon's Brain has performed a raw core dump of ATM

PHYSICAL CHARACTERISTICS

  • Hardware independent/Media transparent
  • Point-to-Point (not a broadcast protocol)
  • Asynchronous
  • Cell based (all cells same size, therefore easy to predict intervals between data)
  • Supports QoS
  • Interfaces specified for:
    • Encapsulates ISDN (CCITT Q.2391)
    • Encapsulates FRAME RELAY
    • SDH/SONET (AAL5) - Use as Physical layer (most commonly used)
    • IP (AAL5) -
    • DSx (AAL5) - Use as physical layer
    • SMDS

OSI MODEL RELATIONSHIPS

AAL 0

AAL 3/4 - Message Mode OR Streaming mode

OSI MODEL ATM Layers
NETWORK CBR | VBR | ABR | UBR | Signalling
Service Specific Convergence Sublayer Convergance Sublayer ATM Adaptation Layer
Common Part Convergence Sublayer
DATA LINK Segmentation and Reassembly
Asynchronous Transfer Mode
PHYSICAL Transmission Convergeance
Physical Medium Dependant

 

    • Service Access Point (SAP)
    • ATM Adaptation Layer
      • Convergance Sublayer (CS)
        • Service Specific Convergence Sublayer (SSCS)
        • Common Part Convergance Sublayer (CPCS)
      • Segmentation And Reassembly (SAR)
    • Service Access Point (SAP)

 

ATM FRAME FORMAT (53 Bytes)

  • 5 byte header (bits - purpose)
    • 4 - Generic Flow Control (binary 0000 as default - not defined in standards yet)
    • 8 - Virtual Path Identifier
    • 12- Virtual Channel Identifier
    • 3 - Payload Type Identifier
      PTI CELL USAGE ATM User-User
      Signalling
      Congestion
      Experienced
      000 User Data no 0
      001 User Data no 1
      010 User Data yes 0
      011 User Data Yes 1
      100 OAM F5 link - -
      101 OAM F5 end-to-end - -
      110 Resource Management - -
      111 Reserved - -
    • 1 - Cell Loss Priority [yes/no]
    • 8 - Header Error Check
  • 48 bytes - Payload

ATM NETWORK INTERFACES

  • User to Network (UNI)
    • Q.2931 - ISDN
    • FUNI - Frame Relay
  • Network to Network Interface (NNI)

ATM ADDRESSES

NSAP

  • IDP - Initial Domain Part
  • AFI - Authority Format Identifier
  • IDI - Initial Domain Identifier
  • DSP - Domain Specific Part

CLASS OF SERVICE

  • A - Constant bit rate - no delay
  • B - Constant bit rate - delay tolerant
  • C - Connection oriented variable bitrate - burst-rate
  • D - Connection-oriented & connectionless variable bitrate - burst-rate
  • X - ATM-raw

ATM ADAPTATION LAYER TYPES (AAL) and CLASS OF SERVICE (COS) TABLE

AAL CLASS TYPE NOTES
0 A CBR - Constant Bit Rate Connection oriented; Constant bit rate. Best suited for voice and video.
2 B VBR - Variable Bit Rate Connection oriented; variable bit rate. Best for delay insensitive applications such as packetized voice, video.
3/4 C ABR - Adjustable Bit Rate Connection oriented; adjustable bit rate traffic. Usable for network applications, but has high complexity/overhead.
5 D UBR - Unspecified Bit Rate Connectionless
  X    

CIRCUITS

  • Permanent Virtual Circuits
  • Switched Virtual Circuits

ATM-LANE

ELANs - Emulated LANs each with:

  • LAN Emulation Server (LES)
  • LAN Configuration Server (LECS)
  • Broadcast and Unknown Server (BUS)

 


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