Cisco IOS CMTS Cable Software Configuration Guide, Release 12.2SC - Upstream Scheduler Mode for the Cisco CMTS Routers [Cisco uBR10000 Series Universal Broadband Routers]

Table Of Contents

Upstream Scheduler Mode for the Cisco CMTS Routers

Contents

Prerequisites for the Upstream Scheduler Mode for the Cisco CMTS Routers

Restrictions for Upstream Scheduler Mode for the Cisco CMTS Routers

Information About Upstream Scheduler Mode for the Cisco CMTS Routers

How to Configure Upstream Scheduler Modes

Troubleshooting Tips

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for Upstream Scheduler Mode for the Cisco CMTS Routers

Upstream Scheduler Mode for the Cisco CMTS Routers

Revised: November 10, 2008, Cisco IOS Release 12.2(33)SCA

First Published: Cisco IOS Release 12.3(13)BC

Note Cisco IOS Release 12.2(33)SCA 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. For the latest information on Cisco CMTS router support in Cisco IOS Release 12.2SC, refer to the Cross-Platform Release Notes for Cisco Universal Broadband Routers in Cisco IOS Release 12.2SC.

This document describes how to configure optional upstream scheduler modes.

With this feature, you are able to select Unsolicited Grant Services (UGS), Real Time Polling Service (rtPS) or Non-Real Time Polling Service (nrtPS) scheduling types, as well as packet-based or Time Divison Multiplex (TDM)-based scheduling. Low latency queueing (LLQ) emulates a packet-mode-like operation over the TDM infrastructure of DOCSIS. As such, the feature provides the typical tradeoff between packets and TDM: with LLQ, the user has more flexibility in defining service parameters for UGS, rtPS or nrtPS, but with no guarantee (other than statistical distribution) regarding parameters such as delay and jitter.

Finding Feature Information in This Module

Your Cisco IOS software release may not support all of the features documented in this module. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for Upstream Scheduler Mode for the Cisco CMTS Routers" section.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Contents

•Prerequisites for the Upstream Scheduler Mode for the Cisco CMTS Routers

•Restrictions for Upstream Scheduler Mode for the Cisco CMTS Routers

•Information About Upstream Scheduler Mode for the Cisco CMTS Routers

•How to Configure Upstream Scheduler Modes

•Additional References

Prerequisites for the Upstream Scheduler Mode for the Cisco CMTS Routers

The Upstream Scheduler Mode for the Cisco CMTS Routers feature is supported on the Cisco CMTS routers in Cisco IOS Release 12.3BC and 12.2SC. Table 1 shows the hardware compatibility prerequisites for this feature.

Table 1 Upstream Scheduler Mode for the Cisco CMTS Hardware Compatibility Matrix

CMTS Platform

Processor Engine

Cable Interface Cards

Cisco uBR10012 Universal Broadband Router

Cisco IOS Release 12.3(13)BC

•PRE

•PRE-1

•PRE-2

Cisco IOS Release 12.2(33)SCA

•PRE-2

Cisco IOS Release 12.3(13)BC

•Cisco uBR10-MC5X20S/U

Cisco IOS Release 12.2(33)SCA

•Cisco uBR10-MC5X20S/U/H

Cisco uBR7246VXR Universal Broadband Router

Cisco IOS Release 12.3(13)BC

•NPE-G1

Cisco IOS Release 12.2(33)SCA

•NPE-G1

•NPE-G2

Cisco IOS Release 12.3(13)BC

•Cisco uBR-MC28U/X

•Cisco uBR-MC16U/X

Cisco IOS Release 12.2(33)SCA

•Cisco uBR-MC28U/X

•Cisco uBR-MC16U/X

Cisco uBR7225VXR Universal Broadband Router

Cisco IOS Release 12.2(33)SCA

•NPE-G1

Cisco IOS Release 12.2(33)SCA

•Cisco uBR-E-28U

•Cisco uBR-E-16U

•Cisco uBR-MC28U/X

•Cisco uBR-MC16U/X

Restrictions for Upstream Scheduler Mode for the Cisco CMTS Routers

Note the following restrictions for this feature:

•To ensure proper operation, Call Admission Control (CAC) must be enabled. When the LLQ option is enabled, it is possible for the upstream path to be filled with so many calls that it becomes unusable, making voice quality unacceptable. CAC must be used to limit the number of calls to ensure acceptable voice quality, as well as to ensure traffic other than voice traffic.

•Even if CAC is not enabled, the default (DOCSIS) scheduling mode blocks traffic after a certain number of calls.

•Unsolicited Grant Services with Activity Detection (UGS-AD) is not supported by the LLQ scheduler mode but remains supported by the default DOCSIS scheduler mode.

Information About Upstream Scheduler Mode for the Cisco CMTS Routers

With UGS, a service flow is created that allows a cable modem to transmit fixed-size bursts of data at a guaranteed rate and with a guaranteed level of jitter by providing periodic transmission opportunities to the cable modem for fixed-sized frames. This kind of service flow is particularly suitable for VoIP applications.

With rtPS, a service flow is created that allows a periodic opportunity for a cable modem to request permission to transmit data by polling one cable modem for a bandwidth request, rather than all modems. This satisfies applications that have a requirement for real-time data transmission, and allows the cable modem to transmit data bursts of varying length. This kind of service flow is particularly suitable for MPEG VoIP.

With nrtPS, a service flow is created that allows a periodic opportunity for a cable modem to request permission to transmit data by polling one cable modem for a bandwidth request, rather than all modems. The data bursts may be of varying length. This kind of service flow is particularly suitable for non-interactive services such as file transfers.

How to Configure Upstream Scheduler Modes

This section describes the configuration tasks that are most commonly performed when using the upstream scheduler modes feature on the Cisco CMTS platforms.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface cable x/y
or
interface cable x/y/z

4. cable upstream n scheduling type [ugs | rtps | nrtps] mode [llq | docsis]

5. cable upstream n scheduling type [ugs | rtps | nrtps] mode [llq | docsis]

6. end

DETAILED STEPS
Command or Action

Purpose

Step 1

enable
Example:

Router> enable

Enables privileged EXEC mode. Enter your password if prompted.

Step 2

configure terminal
Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interface cable x/y
or
interface cable x/y/z
Example:

Router(config)# interface cable 5/1
Router(config-if)#

Enters interface configuration mode for the specified cable interface.
Step 4
cable upstream n scheduling type [ugs | rtps | nrtps] mode [llq | docsis]
Example:

Router(config-if)# cable upstream 4 scheduling type ugs mode llq
Enables LLQ-type (packet-based) scheduling for UGS services, where n specifies the upstream port. Valid values start with 0 for the first upstream port on the cable interface line card.

Note Any combination of ugs, rtps, nrtps, llq, and docsis is allowed. The only default value is docsis.
Step 5
cable upstream n scheduling type [ugs | rtps | nrtps] mode [llq | docsis]
Example:

Router(config-if)# cable upstream 4 scheduling type rtps mode docsis
Enables standard DOCSIS (TDM-based) scheduling scheduling for rtPS services, where n specifies the upstream port. Valid values start with 0 for the first upstream port on the cable interface line card.

Note Any combination of ugs, rtps, nrtps, llq, and docsis is allowed. The only default value is docsis.
Step 6

end
Example:

Router(config-if)# end
Router#

Exits interface configuration mode and returns to privileged EXEC mode.
Troubleshooting Tips

To confirm whether the scheduler is operating in LLQ or DOCSIS, mode, use the show interface cable mac-scheduler command. A new queue is added when LLQ mode is enabled, as shown below.
Router# show interface cable 4/0 mac-scheduler 0
     DOCSIS 1.1 MAC scheduler for Cable4/0/U0
     Queue[Rng Polls] 0/128, 0 drops, max 1
     Queue[CIR Grants] 0/64, 0 drops, max 0
     Queue[BE(7) Grants] 0/64, 0 drops, max 0
     Queue[BE(6) Grants] 0/64, 0 drops, max 0
     Queue[BE(5) Grants] 0/64, 0 drops, max 0
     Queue[BE(4) Grants] 0/64, 0 drops, max 0
     Queue[BE(3) Grants] 0/64, 0 drops, max 0
     Queue[BE(2) Grants] 0/64, 0 drops, max 0
     Queue[BE(1) Grants] 0/64, 0 drops, max 0
     Queue[BE(0) Grants] 0/64, 0 drops, max 0
     Queue[LLQ Grants] 0/64, 0 drops, max 0   <--- This queue is added in LLQ mode.
     Req Slots 153607143, Req/Data Slots 0
     Init Mtn Slots 1305584, Stn Mtn Slots 145897
     Short Grant Slots 47, Long Grant Slots 2939
     ATDMA Short Grant Slots 0, ATDMA Long Grant Slots 0
     ATDMA UGS Grant Slots 0
     Awacs Slots 0
     Fragmentation count 3
     Fragmentation test disabled
     Avg upstream channel utilization : 0%
     Avg percent contention slots : 98%
     Avg percent initial ranging slots : 1%
     Avg percent minislots lost on late MAPs : 0%
     Sched Table Adm-State: Grants 0, Reqpolls 0, Util 1%
     UGS    : 0 SIDs, Reservation-level in bps 0
     UGS-AD : 0 SIDs, Reservation-level in bps 0
     RTPS   : 0 SIDs, Reservation-level in bps 0
     NRTPS  : 0 SIDs, Reservation-level in bps 0
     BE     : 2 SIDs, Reservation-level in bps 0
     r4k ticks in 1ms 131000
     Total scheduling events 0
     No search was needed 0
     Previous entry free 0
     Next entry free0
     Could not schedule 0
     Recovery failed 0
Curr time 8282 entry 90
Router#
Additional References

The following sections provide references related to the Cisco CMTS routers.

Related Documents

Related Topic

Document Title

Cisco CMTS command reference

Cisco IOS CMTS Cable Command Reference

http://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.html

Standards

Standard

Title

DOCSIS

Data-Over-Cable Service Interface Specifications, DOCSIS 2.0, Radio Frequency Interface Specification, CM-SP-RFIv2.0-I08-050408

MIBs

No new or modified MIBs are supported by this feature.

RFCs

No new or modified RFCs are supported by this feature.

Technical Assistance

Description

Link

The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

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

Feature Information for Upstream Scheduler Mode for the Cisco CMTS Routers

Table 2 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

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

Note Table 2 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Table 2 Feature Information for Upstream Scheduler Mode for the Cisco CMTS Routers

Feature Name

Releases

Feature Information

Upstream Scheduler Mode for the Cisco CMTS Routers

12.3(13)BC

This feature was introduced for all Cisco CMTS routers. The cable upstream scheduling type command was introduced.

Upstream Scheduler Mode for the Cisco CMTS Routers

12.2(33)SCA

This feature was integrated into Cisco IOS Releaswe 12.2(33)SCA. Support for the Cisco uBR7225VXR Universal Broadband Router was added.

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