Cisco SR2016T-NA Reference Manual page 323

Chapter 2 Cisco CMTS Configuration Commands
cable upstream fragment-force
To specify that a cable interface line card should fragment DOCSIS frames on an upstream when the
frame exceeds a particular size, use the cable upstream fragment-force command in cable interface
configuration mode. To disable the forcing of fragmentation, use the no form of this command.
Syntax Description n
fragment-threshold
number-of-fragments
Defaults fragment-threshold is 2000 bytes and number-of-fragments is 3
Command Modes
Interface configuration (cable interface only)
Command History Release
12.2(15)BC2
Usage Guidelines
DOCSIS 1.1 allows the CMTS to fragment DOCSIS frames to improve performance, especially in
networks that combine real-time traffic, such as voice, with data traffic. The cable upstream
fragment-force command allows you to specify the size of frames that should be fragmented, as well as
the number of fragments that should be created when fragmenting.
This command takes effect only when fragmentation has been enabled on the upstream using the
Tip
upstream fragmentation
the configuration of the
In the default configuration, the Cisco CMTS fragments DOCSIS frames that are 2,000 bytes or larger
in size, and it fragments these frames into three equally-sized fragments. Do not use a fragment size
greater than 2,000 bytes on the Cisco uBR-MC5X20S/U cable interface line cards, and do not use a
fragment size greater than 3,500 bytes on all other cable interface line cards, unless otherwise instructed
by a Cisco TAC engineer.
OL-1581-08
cable upstream n fragment-force [fragment-threshold [number-of-fragments] ]
no cable upstream n fragment-force
Specifies the upstream port number. Valid values start with 0 for the first
upstream port on the cable interface line card.
Number of bytes for the threshold at which DOCSIS frames are fragmented.
The valid range is 0 to 4000, with a default of 2000 bytes.
Number of fragments that the cable interface line card should create when
fragmenting DOCSIS frames. The card attempts to create this many equal-
sized fragments when fragmenting. The valid range is 1 to 10, with a default
of 3 fragments.
Modification
This command was introduced.
command (which is the default configuration). This command also supercedes
cable default-phy-burst
cable upstream fragment-force
command, if necessary.
Cisco Broadband Cable Command Reference Guide
cable
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