COMNET III CACI

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B.2.2 UPC/NPC Compliance Now that we have explained the details of the GCRA, let us take a second look at the conformance functions specified by the ATM Forum. This section summarizes the relationship between the UPC/NPC cell tagging/discarding function and the GCRA. The conformance definition of a cell depends on two factors: • The service class and its QoS parameters • The CLP cell streams (CLP=0+1, CLP=0) The ATM Forum defines different conformance rules for all possible combinations of these factors. These are outlined below. B.2.2.1Constant Bit Rate Conformance Definition Recall that the QoS parameters for CBR traffic are PCR and CDVT(PCR). This implies two versions of conformance definitions: one considering only the CLP=0+1 stream and one considering the CLP=0+1 and CLP=0 streams. The first version measures the bursts of all cells using the GCRA with respect to the PCR. If a cell is found to be conforming, irrespective of the value of its CLP bit, it is transmitted. Otherwise, the cell is discarded immediately. This version of the conformance definition does not allow tagging of cells. Figure 37 illustrates this policy. GCRA using PCR(CLP=0+1) confirms not confirmed Transmit Discard Figure 37: Conformance Definition for CBR traffic using PCR(CLP=0+1) The second version used two GCRAs: one for the CLP=0+1 stream and one for the CLP=0 stream. The first measures the conformance with respect to the PCR of all cells (i.e. CLP=0+1). The second GCRA measures the conformance of cells with respect to the PCR of only the CLP=0 cells. The UPC/NCP function is outlined in Figure 38. 96
CLP value? 0 1 GCRA using PCR(CLP=0) GCRA using PCR(CLP=0+1) confirms not confirmed confirms not confirmed Transmit Tagging supported? Transmit Discard yes no GCRA using PCR(CLP=0+1) Discard confirms Transmit not confirmed Discard Figure 38: Conformance Definition for CBR traffic using PCR(CLP=0+1) and PCR(CLP=0) Note that the conformance definition version used for a particular traffic stream is defined in the source traffic descriptor of the traffic contract. Also, in order for a cell to be tagged, the source has to request tagging and the network has to support it. B.2.2.2Variable Bit Rate Conformance Definition Recall that the QoS parameters for VBR traffic are PCR, SCR, CDVT(PCR) and CDVT(SCR). This implies two versions of conformance definitions: one considering only the PCR CLP=0+1 stream in conjunction with the SCR CLP=0 stream, and one considering the PCR CLP=0+1 in conjunction with the SCR CLP=0 stream. The UPC/NCP functions are outlined in Figure 39 for the first version and in Figure 40 for the second version. 97
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COMNET III Application Notes: Model
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Appendices……………………
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2.2 Underlying Assumptions A number
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only those details which are signif
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Table 1 gives you an overview of th
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Network Interfaces Connection Admis
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3.2 Overview of COMNET III’s Mode
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To generate ATM traffic, you would
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3.2.3 Other Protocols over ATM The
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3.4 Modeling CBR Services A fundame
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UPC/NPC conformance for the CBR tra
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3.5 Modeling VBR Services To model
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Figure 5: VBR buffer limit. As illu
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The remarks made under the previous
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control parameters as well as to ex
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In order for the RM cells to indica
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3.7 Modeling UBR Services As descri
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For the FM functions, a distinction
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Bus Bus 1..n CPU Ports Ports Line C
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4. Example Applications In the firs
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The particular QoS parameters of in
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CBR AAL1 VBR AAL3/4 ABR AAL3/4 Basi
Page 45 and 46: After running the model under both
Page 47 and 48: 4.2 TCP/IP vs. ATM at the Desktop T
Page 49 and 50: Note that she has decided to reduce
Page 51 and 52: The voice mail traffic is given the
Page 53 and 54: 4.3 Modeling ATM LANE Networks This
Page 55 and 56: The model topology consists of a nu
Page 57 and 58: Connected to the LES is a single CO
Page 59 and 60: Figure 17 depicts a modified model
Page 61 and 62: To model this architecture, COMNET
Page 63 and 64: The OFF command is a global process
Page 65 and 66: The respective connection utilizati
Page 67 and 68: A. Perspectives on ATM - Brief Revi
Page 69 and 70: This integration of the different n
Page 71 and 72: available, or it will accept to est
Page 73 and 74: Version 4.0 of the ATM Forum’s tr
Page 75 and 76: A.3 The B-ISDN Protocol Reference M
Page 77 and 78: Class A B C D AAL Type AAL1 AAL2 AA
Page 79 and 80: Higher layer PDU (1-65535 bytes) Co
Page 81 and 82: Link 1 ATM Switch VCI = 1 Link 2 VP
Page 83 and 84: FDDI ATM Router ATM Switch Private
Page 85 and 86: Input Ports Output Ports Figure 30:
Page 87 and 88: In addition to the internal switchi
Page 89 and 90: B.1.1 Resource Management Policies
Page 91 and 92: Finally, the setup request is forwa
Page 93 and 94: intermediary node, the local CAC fu
Page 95: Arrival of a cell at time ta(k) X
Page 99 and 100: B.2.2.3 Available Bit Rate Conforma
Page 101 and 102: control scheme requires more compli
Page 103 and 104: B.3 Management Services We will now
Page 105 and 106: In the second dimension, the OAM ce
Page 107 and 108: • SECBR = Severely Errored Cell B
Page 109 and 110: Note that the node detecting the fa
Page 111 and 112: Glossary and Acronyms: The terms in
Page 113 and 114: NNI* nrt-VBR OAM cells PCR PDU* PT
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