Default DOCSIS 1.0
ToS Overwrite
First Published: February
14, 2008
Last Updated: May
10, 2010
 Note |
Cisco IOS
Release 12.2(33)SCA and later releases integrate 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.
|
This document
describes the Default DOCSIS 1.0 ToS Overwrite feature for the Cisco Cable
Modem Termination System (CMTS). This feature eliminates the need to create
multiple QoS profiles in order to perform type of service (ToS) overwrite by
enabling a default ToS overwrite to be bound to all DOCSIS 1.0 Cable Modem (CM)
created profiles.
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.
Prerequisites for Default DOCSIS 1.0 ToS Overwrite
No special equipment or software is needed to use the Default DOCSIS 1.0 ToS Overwrite feature.
Restrictions for Default DOCSIS 1.0 ToS Overwrite
-
The Default DOCSIS 1.0 ToS Overwrite feature is only applicable to CMs running DOCSIS version 1.0.
-
Once the Default DOCSIS 1.0 ToS Overwrite feature is configured, all CMs will need to be reset in order for the effect to take place.
-
Once the Default DOCSIS 1.0 ToS Overwrite feature is configured, all CMs will display the default values that were configured. After which, overwrite values can only be changed by editing the QoS profiles.
Information About Default DOCSIS 1.0 ToS Overwrite
To configure the Default DOCSIS 1.0 ToS Overwrite feature, you should
understand the following topic:
Default DOCSIS 1.0
ToS Overwrite Overview
Currently, ToS overwrite requires the creation of
static cable QoS profiles, which are assigned ToS fields and are than
associated with 1.0 CMs. This implementation works well if only a few different
service types are offered.
However,
scalability issues arises when large numbers of service types are presented;
each requiring a static QoS profile in order to perform ToS overwrite.
The Default DOCSIS
1.0 ToS Overwrite feature eliminates the need to create multiple QoS profiles
in order to perform type-of-service (ToS) overwrite by automatically bounding
all DOCSIS 1.0 Cable Modem (CM) created profiles to a default ToS overwrite.
DOCSIS
Created by CableLabs, Data Over Cable Service Interface Specification (DOCSIS) defines the interface standards and requirements for all cable modems associated with high-speed data distribution over a cable television system network.
The DOCSIS architecture consists of the following two components:
-
Cable Modem (CM)
-
Cable Modem Termination System (CMTS)
Each of these components are situated at different locations, often with the CM located on a customer site and the CMTS on the service provider site, and communication between the CM and CMTS is conducted over cable through DOCSIS.
 Note |
Though there are several versions of DOCSIS available, the Default DOCSIS 1.0 ToS Overwrite feature is only applicable to CMs running DOCSIS 1.0.
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Type-of-Service (ToS)
Tools such as type-of-service (ToS) bits identification make it possible to isolate network traffic by the type of application being used. ToS capabilities can be further expanded to isolate network traffic down to the specific brands, by the interface used, by the user type and individual user identification, or by the site address.
How to Configure Default DOCSIS 1.0 ToS Overwrite
The tasks in this section enables the use of the Default DOCSIS 1.0 ToS Overwrite feature.
Enabling Default DOCSIS 1.0 ToS Overwrite
All CMs with a DOCSIS 1.0 configuration file currently have their ToS
overwrite default values are set to tos-and: 0xff and tos-or: 0x00. Since there
were previously no mechanism in the DOCSIS 1.0 configuration file to specify
the ToS overwrite, QoS profiles were created and assigned to the default ToS
overwrites.
The following procedures enable the Default DOCSIS 1.0 ToS Overwrite
feature, which will allow a default ToS overwrite to be bound to all CM created
profiles.
Before You Begin
There are no prerequisites for these procedures.
 Note |
- The Default DOCSIS 1.0
ToS Overwrite feature is only applicable to CMs running DOCSIS version 1.0.
- Once the Default DOCSIS
1.0 ToS Overwrite feature is configured, all CMs will need to be reset in order
for the effect to take place.
- Once the Default DOCSIS 1.0 ToS Overwrite feature is configured,
all CMs will display the default values that were configured. After which,
overwrite values can only be changed by editing the QoS profiles.
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| Command or Action | Purpose |
---|
Step 1 | enable
Example:
Router> enable
|
Enables privileged EXEC mode.
- Enter your password if prompted.
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Step 2 | configureterminal
Example:
Router# configure terminal
|
Enters global configuration mode.
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Step 3 | cable
default-tos-qos10
tos-overwrite
tos-and
tos-or
Example:
Router(config)# cable default-tos-qos10 tos-overwrite 0x1F 0xE0
|
Configures the ToS overwrite default value for the CM. This
default value will be bound to all future CM created profiles.
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Step 4 | end
Example:
Router(config-if)# end
|
Exits interface configuration mode and returns to privileged EXEC
mode.
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What to Do Next
After configuring the ToS overwrite default value, reset the CM using
the
clear
cable
modem
delete
command to allow the new ToS overwrite default value to take
effect.
Editing QoS
Profiles
Once the Default
DOCSIS 1.0 ToS Overwrite feature is configured, additional ToS overwrite values
can be changed by editing the QoS profiles.
| Command or Action | Purpose |
---|
Step 1 | enable
Example:
Router> enable
|
Enables
privileged EXEC mode.
- Enter your
password if prompted.
|
Step 2 | configureterminal
Example:
Router# configure terminal
|
Enters global
configuration mode.
|
Step 3 | cable
qos
profile {groupnum
|
ip-precedence |
guaranteed-upstream |
max-burst |
max-upstream |
max-downstream |
priority |
tos-overwrite |
value
Example:
Router(config)# cable qos profile 4 guaranteed-upstream 2
|
Configures
the QoS profile.
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Step 4 | end
Example:
Router(config-if)# end
|
Exits
interface configuration mode and returns to privileged EXEC mode.
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Additional References
The following sections provide references related to the Default DOCSIS 1.0 ToS Overwrite feature.
Standards
Standard
|
Title
|
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
MIB
|
MIBs Link
|
No new or modified MIBs are supported, and support for existing MIBs has not been modified by this feature.
|
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
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RFCs
RFC
|
Title
|
No new or modified RFCs are supported by this feature.
|
To locate and download Request for Comments (RFCs) and Internet Drafts, see the Internet Engineering Task Force (IETF) web site at the following URL:
http://www.ietf.org/index.html
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Technical Assistance
Description
|
Link
|
The Cisco Technical Support & Documentation website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, tools, and technical documentation. Registered Cisco.com users can log in from this page to access even more content.
|
http://www.cisco.com/cisco/web/support/index.html
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Feature
Information for Default DOCSIS 1.0 ToS Overwrite
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://www.cisco.com/go/cfn. An account on Cisco.com is not required.
 Note |
The table below 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.
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Table 1 Feature
Information for Default DOCSIS 1.0 ToS Overwrite
Feature
Name
|
Releases
|
Feature
Information
|
Default
DOCSIS 1.0 ToS Overwrite
|
12.3(17a)BC2
|
This
feature eliminates the need to create multiple QoS profiles in order to perform
type of service (ToS) overwrite by enabling a default ToS overwrite to be bound
to all DOCSIS 1.0 Cable Modem (CM) created profiles.
The cable
default-tos-qos10 tos-overwrite command was introduced by this feature.
|
Default
DOCSIS 1.0 ToS Overwrite
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12.2(33)SCD2
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The
priority of the QoS profile-2 is now configurable.
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