Quality of Service for Voice on the Cisco uBR7200 Series Cable Router
Feature Overview
This feature describes the software enhancements that support quality of service (QoS) features for voice transmission over a DOCSIS cable network. These enhancements include improving support for
Delay/jitter requirements of real-time traffic typical of voice, video, and Fax traffic
Increase in per-modem data throughput,
New Media Access Control (MAC) scheduler
MAC messaging support to help support real-time response to your service requests
Benefits
This feature improves voice transmission over a DOCSIS cable network.
Restrictions
Baseline Privacy Interface (BPI) encryption is not supported when using dynamic Service IDs (SIDs).
Related Features and Technologies
Table 1 lists the IOS cable router features released in the IOS 12.0 timeframe.
Table 1 uBR7200 Series Cable Router Features Available Since 12.0 T
Available With:
Category
Feature
11.3(5)NA & 12.0(3)T
Cable Features
Feature Enhancements
11.3(6)NA
MC16 Modem Card
11.3(8)NA
Access List Support Enhancements
12.0(4)T
Downstream Channel ID Configuration
12.0(4)T
Multiple Service ID Support
12.0(4)T
Cable Modem and Host Subnet Addressing
12.0(5)T
Telephone Return
12.0(5)T
Time Server Functionality
12.0(7)T
Amplitude Averaging Compensation
12.0(7)XR
Cable Interface Bundling
12.0(7)XR
Enhanced Modem Status Display
12.0(7)XR
Show Interface Cable Command Verbose Enhancements
12.0(7)XR
IP Address Verification
12.0(7)XR
Registration Timeout Configuration
12.0(7)XR
Show Cable Modem Command Enhancements
12.0(7)XR
Modem Status Summary Enhancements
12.0(7)XR
Show Controller Command Enhancements
12.0(7)XR
Configuring Concatenation
12.0(7)XR
Virtual Private Network Support
12.0(7)XR
Blind Hopping Support on the MC16S Modem Card
12.0(7)XR
Signal-to-Noise Ratio Data Support
11.3(9)NA and 12.0(4)T
Cable QoS
QoS Profile Enforcement
12.0(4)T
Quality of Service for Voice
11.3(9)NA
Network Management
Upstream Traffic Shaping Feature
12.0(5)T
Enhanced-Spectrum Management
12.0(5)T
Downstream Rate Shaping with TOS bits
12.0(7)XR
Spectrum Management Using the MC16S Modem Card
12.0(7)XR
Downstream Test Signals Configuration
12.0(7)XR
Wireless Features
Point-to-Point Wireless Support
Related Documents
The uBR7200 series cable router is described in Voice, Video, and Home Applications Configuration Guide for Cisco IOS Release 12.0 and in the following online feature modules:
This section documents modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0T command reference publications.
cable qos profile
show cable qos profile
Note For show and more commands: Required information. When show or more commands are
documented for a feature, you must include the following standard text about the search and filter
functionality (introduced in Release 12.0(1)T) immediately after the bulleted list of commands.
In Cisco IOS Release 12.0(1)T or later releases, you can search and filter the output for show and more commands. This functionality is useful when you need to sort through large amounts of output, or if you want to exclude output that you do not need to see.
To use this functionality, enter a show or more command followed by the "pipe" character (|), one of the keywords begin, include, or exclude, and an expression that you want to search or filter on:
command| {begin | include | exclude}regular-expression
See the following example of the show atm vc command in which you want the command output to begin with the first line where the expression "PeakRate" appears:
show atm vc | begin PeakRate
For more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module CLI String Search.
cable qos profile
To configure a QoS profile, enter the cable qos profile global configuration command. To either set default values for profile group numbers 1 or 2 or remove the QoS profile if no specific parameters remain, enter the no form of this command.
QoS profile group number. Qos profiles 1 and 2 are required by the system. QoS profile 1 is used during registration, and QoS profile 2 is the default QoS profile. Both profiles are preconfigured and cannot be removed. However, you can modify these profiles.
grant-interval
The periodic interval in microseconds at which the cable modem (CM) wants to send the fixed-sized upstream MAC frames. It is used to compute the period in between constant bit rate (CBR) slots for the CM. Valid range is from 0 to 65535.
grant-size
The size of the DOCSIS MAC frame the CM wants periodically to send on the upstream transmission. This value in bytes does not include any PHY layer overhead. It includes the complete fixed MAC frame size starting from the frame control byte to the CRC of the protocol data unit (PDU). This parameter is used by the CMTS to set the size of the periodic CBR slot for the CM after adding the PHY overhead.
guaranteed-upstream
Guaranteed minimum upstream rate in kilobytes per second. Valid values are from 0 to 100000. Default value is 0 (no reserved rate).
ip-precedence
Bits in the TOS byte that enable you to configure individual data rate limits on a per modem basis. Valid values are from 0 to 7.
max-burst
Maximum upstream transmit burst size in bytes that the modem can send for any single transmit burst. Valid values are from 0 to 65535 bytes. Default value is 0 (no limit).
max-downstream
Maximum downstream data rate in kilobytes per second that a modem using this QoS profile receives. Valid values are from 0 to 100000. Default value is 0 (no downstream rate limit).
max-upstream
Maximum upstream data rate in kilobytes per second that a modem using this QoS profile receives. Valid values are from 0 to 255. Default value is 0 (no upstream rate limit).
name
QoS name string.
priority
Relative priority number assigned to upstream traffic by this QoS profile. Valid values are from 0 to 7 with 7 being the highest priority. Default value is 0.
privacy
Enables cable baseline privacy.
tos-overwrite
Overwrite the Type of Service (TOS) field in the IP datagrams received on the upstream before forwarding them downstream (or IP backbone). This parameter sets the hexadecimal mask bits to a hexadecimal value, thereby helping the CMTS identify datagrams for QoS on the backbone. Valid range is from 0x0 to 0xFF.
value
The value substituted for the TOS value. See tos_overwrite.
Default
No default behavior or values.
Command Mode
Global configuration
Command History
Release
Modification
11.3 NA
This command was introduced.
12.0(3)T
Command was included in the mainline release.
12.0(5)T
The ip-precedence keyword was added and the max-downstream range was increased.
12.0(7)XR
Output was reorganized and name, grant-size, and grant-interval parameters were added.
Example
See the following example to configure QoS profile 4 with guaranteed upstream of 2 kbps, maximum transmission burst of 2, an IP precedence of 7, a maximum downstream rate of 300 kbps, with a priority of 4, cable baseline privacy set, and a tos-overwrite mask and value byte (in hex) of 0x7:
Router(config)# cable qos profile 4 name Mondayqos
Configures permissions for updating the QoS table.
show cable qos profile
Displays QoS profiles.
show cable qos profile
To display QoS profiles, use the show cable qos profile privileged EXEC configuration command.
show cable qos profile qos profile index [verbose]
Syntax Description
qos profile index
(Optional) Displays the index of the QoS profile specified.
verbose
(Optional) Displays all details for the specified QoS profile index.
Command Mode
Privileged EXEC
Command History
Release
Modification
11.3(5(NA)
This command was introduced.
12.0(3)T
The command was included in the mainline release.
12.0(5)T
tos-overwrite option was added.
12.0(7)XR
verbose option was added.
Examples
The following example shows the full QoS table for profile 30:
router# show cable qos profile 30 verbose
Profile Index 30
Name test
Upstream Traffic Priority 7
Upstream Maximum Rate (bps) 6000000
Upstream Guaranteed Rate (bps) 60000000
Unsolicited Grant Size (bytes) 100
Unsolicited Grant Interval (usecs) 55000
Upstream Maximum Transmit Burst (bytes) 256
IP Type of Service Overwrite Mask 0x0
IP Type of Service Overwrite Value 0x0
Downstream Maximum Rate (bps) 100000000
Created By mgmt
Baseline Privacy Enabled yes
IP precedence rate limits
IP precedence 2
Rate Limit 100000
Table 2 describes the fields shown in the show cable qos profile displays.
Table 2 Show cable qos profile Command Field Descriptions
Field
Description
Profile Index
Profile number.
Name
The name string for this profile.
Upstream Traffic Priority
Priority level for upstream traffic.
Upstream Maximum Rate (bps)
Maximum upstream transmission rate in bits per second.
Upstream Guarantee Rate (bps)
Guaranteed minimum upstream rate in bits per second.
Unsolicited Grant Size (bytes)
Number of grant-size parameters in bytes. Grant Size is used by the CMTS to set the size of the periodic CBR slot for the CM after adding the PHY overhead.
Unsolicited Grant Interval (usecs)
Number of unsolicited grant intervals in microseconds. The grant-interval parameter is used to compute the period in between CBR slots for the CM.
Upstream Maximum Transmit Burst (bytes)
Maximum transmit burst size in bytes.
IP Type of Service Overwrite Mask
Hex value of the mask bits.
IP Type of Service Overwrite Value
Value of the mask byte. This is the value the CMTS will overwrite into the ToS field (after masking bits specified in the ToS-mask parameter) of the IP datagram before forwarding the datagram into IP backbone/downstream. The IP ToS overwrite feature helps to propagate cable access QoS onto the IP backbone.
Downstream Maximum Rate (bps)
Minimum upstream transmission rate in bits per second.
Created by
Identity of the profile creator.
Baseline Privacy Enabled
Reports yes if Baseline Privacy is enabled for this QoS profile. Reports no if Baseline Privacy is not enabled for this Qos profile.
IP Precedence rate limits
Value of the IP precedence and the transmission rate limit in bits per second.
Related Commands
Command
Description
cable qos permission
Sets permissions for updating QoS tables.
cable qos profile
Configures QoS profiles.
show cable qos permission
Displays the status of permissions for updating QoS tables.
Debug Commands
This section documents new debug commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0T command reference publications.
debug cable dynsrv
debug cable scheduler
debug cable dynsrv
To display debug messages for all dynamic MAC messages at the router, use the debug cable dynsrv privileged EXEC mode command. To stop debugging dynamic MAC messages, use the no form of this command.
[no] debug cable dynsrv
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command History
Release
Modification
12.0(7)XR
This command was introduced.
Examples
The following example shows the message you receive when you turn debugging on and off:
router# debug cable dynsrv
CMTS dynsrv debugging is on
router# no debug cable dynsrv
CMTS dynsrv debugging is off
Related Commands
Command
Description
debug cable scheduler
Displays debug messages for admission control activity and reception of unsolicited grants.
debug cable scheduler
To display debug messages for admission control activity and reception of unsolicited grants, use the debug cable scheduler privileged EXEC command. To stop debugging, use the no form of this command.
