Upstream Utilization Optimization on the Cisco CMTS Routers

First Published: May 12, 2008

Last Updated: December 17, 2009

The Upstream Utilization Optimization feature on the Cisco Cable Modem Termination System (CMTS) provides higher upstream throughput.


Note
Cisco IOS Release 12.2(33)SCB integrates support for this feature on the Cisco CMTS routers. This feature is also supported in Cisco IOS Release 12.3BC, and this document contains information that references many legacy documents related to Cisco IOS 12.3BC. In general, any references to Cisco IOS Release 12.3BC also apply to Cisco IOS Release 12.2SC.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http:/​/​tools.cisco.com/​ITDIT/​CFN/​. An account on http:/​/​www.cisco.com/​ is not required.

Contents

Prerequisites for Upstream Utilization Optimization

You must have Advanced Time Division Multiple Access (A-TDMA)-capable line cards.

For optimum performance, do the following:

  • Set the maximum upstream burst on the cable modem to a large number; for example, 28,000 bytes.
  • Set the maximum concatenation burst on the cable modem to a large number; for example, 28,000 bytes.
  • Set the cable modem upstream maximum traffic burst parameter to a large number (for example, zero means no limit) using the cable default-phy-burst command.

The Upstream Utilization Optimization feature is supported on the Cisco CMTS routers in Cisco IOS Release 12.3BC and 12.2SC. The table below shows the hardware compatibility prerequisites for this feature.

Table 1 Upstream Utilization Optimization Hardware Compatibility Matrix

CMTS Platform

Processor Engine

Cable Interface Cards

Cisco uBR10012 Universal Broadband Router

Cisco IOS Release 12.3(23)BC2

  • PRE-1
  • PRE-2

Cisco IOS Release 12.2(33)SCB

  • PRE-2
  • PRE-4

Cisco IOS Release 12.2(33)SCH and later releases

  • PRE5

Cisco IOS Release 12.3(23)BC2

  • Cisco uBR10-MC5X20S/U/H

Cisco IOS Release 12.2(33)SCB

  • Cisco uBR10-MC5X20S/U/H

Cisco uBR7200 Series Universal Broadband Routers

Cisco IOS Release 12.3(23)BC2

  • NPE-G1

Cisco IOS Release 12.2(33)SCB

  • NPE-G1
  • NPE-G2

Cisco IOS Release 12.3(23)BC 2

  • Cisco uBR-MC28U/X
  • Cisco uBR-MC16U/X

Cisco IOS Release 12.2(33)SCB

  • Cisco uBR-MC28U/X
  • Cisco uBR-MC16U/X

Cisco uBR7225VXR Universal Broadband Router

Cisco IOS Release 12.2(33)SCB

  • NPE-G1
  • NPE-G2

Cisco IOS Release 12.2(33)SCB

  • Cisco uBR-E-28U
  • Cisco uBR-E-16U
  • Cisco uBR-MC28U/X
  • Cisco uBR-MC16U/X

Information about Upstream Utilization Optimization

Upstream utilization optimization provides the following benefits and functions on a Cisco CMTS router:

  • Group configuration mode enables upstream utilization optimization eligibility on all cable modem upstream flows.
  • Local configuration mode enables upstream utilization optimization eligibility on a specific upstream, provides configuration of selective parameters, and provides that local configuration overrides any global configuration.

How to Configure Upstream Utilization Optimization

The following tasks describe how to configure the Upstream Utilization Optimization feature:

Configuring Upstream Utilization Optimization Globally

By default, the Upstream Utilization Optimization feature is turned off. To globally enable upstream utilization optimization, use the cable upstream rate-adapt command in global configuration mode. All upstream flows created after this feature is enabled globally are eligible to rate-adapt. Using the priority or rate option allows you to restrict upstream utilization optimization to service flows that meet or exceed specified levels for priority or rate.

     Command or ActionPurpose
    Step 1enable


    Example: 
    Router> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2configure terminal


    Example: 
    Router# configure terminal
     

    Enters global configuration mode.

     
    Step 3cable upstream rate-adapt [local | priority value | rate number]


    Example: 
    Router(config)# cable upstream rate-adapt priority 6
     

    Enables upstream utilization optimization globally on all upstream flows.

    • local—(Optional) Enables upstream utilization optimization eligibility and configuration for a specific upstream flow.
    • priority—(Optional) Enables upstream utilization optimization on flows that meet or exceed a configured priority. The valid range is 0–7.
    • rate—(Optional) Enables upstream utilization optimization on flows that meet or exceed a specified minimum max-rate. The valid range is 0–30000000.
     

    Configuring Upstream Utilization Optimization Locally Per Upstream

    To configure a specific local upstream for upstream utilization optimization, use the cable upstream rate-adapt command in cable interface configuration mode for a specified upstream flow. You can configure several parameters for specific local upstream utilization optimization. By default, upstream utilization optimization uses the global configuration. However, when rate-adapt is configured on a local upstream, the local configuration parameters override the global configuration parameters.

       Command or ActionPurpose
      Step 1enable


      Example: 
      Router> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.
       
      Step 2configure terminal


      Example: 
      Router# configure terminal
       

      Enters global configuration mode.

       
      Step 3interface cable


      Example: 
      Router(config)#: interface cable 4/0/0
       

      Enters cable interface configuration mode.

       
      Step 4cable upstream port rate-adapt [bcs slots | duration millisecs | fcms-off | priority value | rate number]


      Example: 
      Router(config-if)# cable upstream 0 rate-adapt priority 6
       

      Enables upstream utilization optimization configuration on specific upstream flows.

      • bcs—(Optional) Specifies the number of broadcast contention minislots (BCS). MAPs that have gaps are filled with BCS. By default, 10 BCS slots are saved. You can override the default of 10 with a larger or smaller number. The valid range is 0–80. The default is 10.
      • duration—(Optional) Enables configuration of the duration of a flow rate-adapt in milliseconds. You can override the default of one second for rate-adapt grants to a flow. A larger or smaller duration can be chosen. The valid range is 0–2000.
      • fcms-off—(Optional) Enables an override to the default forced broadcast contention minislot that follows each filled MAP. By default, fcms is turned on.
      • priority—(Optional) Enables upstream utilization optimization on flows that meet or exceed a configured priority. This overrides a globally configured rate-adapt priority. The valid range is 0–7.
      • rate—(Optional) Enables upstream utilization optimization on flows that meet or exceed a specified minimum max-rate. This overrides a globally configured rate-adapt rate. The valid range is 0–30000000.

       

      Verifying Upstream Utilization Optimization Configuration

      To verify the cable upstream utilization optimization configuration for cable modem upstream, use the show commands described below.

      • To display upstream utilization optimization parameters, use the show cable rate-adapt command as shown in the following example. Global upstream utilization optimization is enabled, local upstream utilization optimization is disabled. The duration is 500 and there is no rate or priority configured. 

        router# show cable rate-adapt
show_cable_rate-adapt_command: Global:Enabled Local-Only:Disabled
:maps 500 flags 0x1 priority -1, rate -1 bcs 10 fcms On

      • To display the upstream utilization optimization settings and the parameters for a specific upstream, use the show interface cable upstream command as shown in the following example. On upstream 0, global and local upstream utilization optimization are enabled, the duration is 250, priority is 255, bcs is set to 0, rate is not configured, and the fcms feature is turned off. 

        router# show interface cable 8/0/0 upstream 0 rate-adapt
cmts_rate-adapt_show: Global:Enabled US[0]:Enabled
local:maps 250 pri 255, rate -1 bcs 0 (0) fcms Off

      • To display service identifier (SID) and upstream utilization optimization information for a service flow, use the show interface cable sid command with the counter and verbose options as shown in the following example. On 8/0/0, upstream utilization optimization is enabled, 35542 rate-adapt requests were received, and there was one piggy-back request received from the upstream. 

        router# show interface cable 8/0/0 sid counters verbose
Sid : 1
Request polls issued : 0
BWReqs {Cont,Pigg,RPoll,Other} : 7, 146975, 0, 0
No grant buf BW request drops : 0
Rate exceeded BW request drops : 0
Grants issued : 1264300
Packets received : 2199040
Bytes received : 3241369899
rate-adapt : Enabled
rate-adapt {rcvd, Consec-PB} : 35542, 1
Fragment reassembly completed : N/A
Fragment reassembly incomplete : N/A
Concatenated packets received : N/A
Queue-indicator bit statistics : 0 set, 0 granted
Good Codewords rx : 14615740
Corrected Codewords rx : 1
Uncorrectable Codewords rx : 0
Concatenated headers received : 146807
Fragmentation headers received : 1296069
Fragmentation headers discarded: 240

      Additional References

      The following sections provide references related to the Upstream Utilization Optimization feature on the Cisco CMTS routers.

      Related Documents

      Related Topic

      Document Title

      Cable commands

      Cisco IOS CMTS Cable Command Reference,

      http:/​/​www.cisco.com/​en/​US/​docs/​ios/​cable/​command/​reference/​cbl_​book.html

      Line card configuration information

      Software configuration information

      Technical Assistance

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      http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

      Feature Information for Upstream Utilization Optimization

      Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http:/​/​tools.cisco.com/​ITDIT/​CFN/​. An account on http:/​/​www.cisco.com/​ is not required.


      Note

      The below table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

      Table 2 Feature Information for Upstream Utilization Optimization

      Feature Name

      Releases

      Feature Information

      Upstream Utilization Optimization

      12.3(23)BC2

      This feature was introduced and provides increased upstream CM throughput.

      The following commands were introduced or modified:

      • cable upstream rate-adapt (global)
      • cable upstream rate-adapt (interface)
      • show cable rate-adapt
      • show interface cable sid
      • show interface cable upstream

      Upstream Utilization Optimization

      12.2(33)SCB

      This feature was integrated into Cisco IOS Release 12.2(33)SCB.