IES-1248-51 User’s Guide
Chapter 17 xDSL Profiles Setup
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17.3.1.3 Unspecified Bit Rate (UBR)
The Unspecified Bit Rate (UBR) ATM traffic class is similar to the ABR traffic class for
bursty data transfers. However, while ABR gives subscribers a set amount of bandwidth, UBR
doesn’t guarantee any bandwidth and only delivers traffic when the network has spare
bandwidth.
17.3.2 Traffic Parameters
These are the parameters that control the flow of ATM traffic.
17.3.2.1 Peak Cell Rate (PCR)
Peak Cell Rate (PCR) is the maximum rate at which the sender can send cells. This parameter
may be lower (but not higher) than the maximum line speed. 1 ATM cell is 53 bytes (424 bits),
so a maximum speed of 832Kbps gives a maximum PCR of 1962 cells/sec. This rate is not
guaranteed because it is dependent on the line speed.
17.3.2.2 Sustained Cell Rate (SCR)
Sustained Cell Rate (SCR) is the mean cell rate of each bursty traffic source. It specifies the
maximum average rate at which cells can be sent over the virtual connection. SCR may not be
greater than the PCR.
17.3.2.3 Maximum Burst Size (MBS)
Maximum Burst Size (MBS) is the maximum number of cells that can be sent at the PCR.
After MBS is reached, cell rates fall below SCR until cell rate averages to the SCR again. At
this time, more cells (up to the MBS) can be sent at the PCR again.
Note:
If the PCR, SCR or MBS is set to the default of “0”, the system will assign a
maximum value that correlates to your upstream line rate.
The following figure illustrates the relationship between PCR, SCR and MBS.
Summary of Contents for IES-1248-51
Page 1: ...IES 1248 51 ADSL2 IP DSLAM User s Guide Version 3 51 ABQ 1 3 2006 ...
Page 4: ...IES 1248 51 User s Guide 4 Interference Statements and Warnings ...
Page 22: ...IES 1248 51 User s Guide 22 Table of Contents Index 379 ...
Page 30: ...IES 1248 51 User s Guide 30 List of Figures ...
Page 34: ...IES 1248 51 User s Guide 34 List of Tables ...
Page 48: ...IES 1248 51 User s Guide 48 Chapter 2 Hardware Installation ...
Page 62: ...IES 1248 51 User s Guide 62 Chapter 4 MDF Connections ...
Page 73: ...IES 1248 51 User s Guide Chapter 7 Introducing the Web Configurator 73 Figure 29 Logout ...
Page 74: ...IES 1248 51 User s Guide 74 Chapter 7 Introducing the Web Configurator ...
Page 88: ...IES 1248 51 User s Guide 88 Chapter 9 Home and Port Statistics Screens ...
Page 90: ...IES 1248 51 User s Guide 90 Chapter 10 System Information Figure 44 System Info ...
Page 98: ...IES 1248 51 User s Guide 98 Chapter 12 User Account ...
Page 104: ...IES 1248 51 User s Guide 104 Chapter 13 Switch Setup ...
Page 106: ...IES 1248 51 User s Guide 106 Chapter 14 IP Setup ...
Page 126: ...IES 1248 51 User s Guide 126 Chapter 16 xDSL Port Setup ...
Page 140: ...IES 1248 51 User s Guide 140 Chapter 17 xDSL Profiles Setup ...
Page 154: ...IES 1248 51 User s Guide 154 Chapter 19 VLAN ...
Page 188: ...IES 1248 51 User s Guide 188 Chapter 28 2684 Routed Mode ...
Page 192: ...IES 1248 51 User s Guide 192 Chapter 30 Syslog ...
Page 210: ...IES 1248 51 User s Guide 210 Chapter 33 Alarm ...
Page 240: ...IES 1248 51 User s Guide 240 Chapter 38 Commands ...
Page 256: ...IES 1248 51 User s Guide 256 Chapter 40 Alarm Commands ...
Page 262: ...IES 1248 51 User s Guide 262 Chapter 41 DHCP Relay Commands ...
Page 282: ...IES 1248 51 User s Guide 282 Chapter 44 IGMP Commands ...
Page 286: ...IES 1248 51 User s Guide 286 Chapter 45 Packet Filter Commands ...
Page 292: ...IES 1248 51 User s Guide 292 Chapter 46 IP Commands ...
Page 302: ...IES 1248 51 User s Guide 302 Chapter 48 SNMP ...
Page 338: ...IES 1248 51 User s Guide 338 Chapter 49 ADSL Commands ...
Page 358: ...IES 1248 51 User s Guide 358 Chapter 50 Virtual Channel Management ...
Page 370: ...IES 1248 51 User s Guide 370 Chapter 51 Troubleshooting ...
Page 378: ...IES 1248 51 User s Guide 378 ...