ANSI INCITS-342-2001 pdf download Information Technology – Fibre Channel – Backbone (FC-BB)
3.1.11 SR Flow Control: Selective Retransmission sliding window Flow Control Protocol applied between two BBW_ATM devices used for both flow control and error recovery.
3.1.12 WAN Interface: An interface which connects to a Wide Area Network; specifically, a port which connects to ATM or SONET/SDH.
3.2 ATM Definitions
3.2.1 AAL: ATM Adaptation Layer. A collection of standardized protocols that adapt user traffic to 48-octet payloads that can be placed in a cell-formatted stream. The AAL is subdivided into the Convergence Sublayer (CS) and the Segmentation and Reassembly (SAR) sublayer. There are currently four types of AALs: AAL1, AAL2, AAL3/4, and AAL5 to support the various service categories.
3.2.2 AAL5: AAL Type 5 and specified for use in BBW_ATM. Protocol Standard originally intended for variable bit rate traffic, which does not require source-destination timing relation, is now also used with applications that have constant bit rate traffic where source-destination timing relation is important.
3.2.3 AAL Service Categories: The ATM Forum has defined 5 Traffic Service Categories supported by the AALs: Constant Bit Rate (CBR), Variable Bit Rate-Real Time (VBR-RT), Variable Bit Rate-Non Real Time (VBR-NRT), Available Bit Rate (ABR), and Unspecified Bit Rate (UBR). VBR_NRT is the recommended service for FC-BB.
3.2.4 ATM: Asynchronous Transfer Mode. Broadband-ISDN standards defined by ITU-T and the ATM Forum.
3.2.5 ATM QoS Parameters: QoS is a term used to refer to the set of performance characteristics of the contracted ATM connection. Six QoS parameters are defined: Peak-to-peak Cell Delay Variation (CDV), Maximum Cell Transfer Delay (maxCTD), Cell Loss Ratio (CLR), Cell Error Ratio (CER), Severely Errored Cell Block Ratio (SECBR), Cell Misinsertion Rate (CMR).
3.2.6 ATM Traffic Descriptor: A term used to describe the traffic characteristics of an ATM connection. A Connection Traffic Descriptor includes a Source Traffic Descriptor, CDV Tolerance (CDVT), and a Conformance definition. A Source Traffic Descriptor is described by three parameters: Peak Cell Rate (PCR), Sustainable Cell Rate (SCR), Maximum Burst Size (MBS), and a Minimum Cell Rate (MCR).
3.2.7 Cell Loss Priority (CLP): A one-bit field in the ATM cell header specifying whether the cell is more (CLP=1) or less (CLP=0) likely to be discarded by an ATM network experiencing congestion.
3.2.8 Cell Loss Ratio (CLR): A QoS parameter that gives the ratio of lost cells to the total number of transmitted cells.
3.2.9 Connection Admission Control (CAC): Actions taken by the ATM network to accept or reject a connection request based on its QoS and traffic parameter requirements and then to route this connection across the network.
3.2.10 Convergence Sublayer Protocol Data Unit: The PDU used at the CS for passing information between the higher layers and the SAR (which is located below the CS, where the cell conversion takes place).
3.2.11 GCRA: Generic Cell Rate Algorithm is a method applied at the network side of the UNI to test the conformance of an ATM cell to its traffic contract.
ANSI INCITS-342-2001 pdf download
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