Using and Configuring Features Version 3.4

Configuring and Monitoring the Random Early Detection Feature

This chapter describes the commands provided by the Random Early Detection (RED) feature for configuring interfaces to randomly drop packets during congested conditions. It includes the following sections:

• "Accessing the Random Early Detection Configuration Prompt"
• "Random Early Detection Configuration Commands"
• "Accessing the Random Early Detection Monitoring Environment"
• "Random Early Detection Monitoring Commands"

Accessing the Random Early Detection Configuration Prompt

To enter RED configuration commands:

1. Enter talk 6 at the OPCON (*) prompt.
2. Enter feature red at the Config> prompt.

The RED Config> prompt displays. You may now enter RED configuration commands.

Random Early Detection Configuration Commands

These commands enable you to configure the RED options, which determine how packets are dropped during periods of congested traffic. This can prevent overflow and global resynchronization. Table 50 summarizes the RED configuration commands, and the rest of this topic describes them in detail. Enter the commands at the RED Config> prompt. Either enter the command and options on one line, or enter only the command and then respond to the prompts. To see a list of valid command options, enter the command with a question mark instead of options.

Table 50. Random Early Detection Configuration Commands

Command	Function
? (Help)	Displays all the commands available for this command level or lists the options for specific commands (if available). See "Getting Help".
Delete	Deletes a RED configuration record or interface record from a network device's SRAM.
Disable	Disables RED either in a network device or on a specific egress interface.
Enable	Enables RED either in a network device or on a specific egress interface.
List	Displays information about a network device's RED status and interface-related settings.
Set	Specifies RED settings for a specific interface on a network device.
Exit	Returns you to the previous command level. See "Exiting a Lower Level Environment".

Delete

Use the delete command to delete a RED configuration record for an interface from a network device's SRAM.

Syntax:  delete 

interface

interface

Prompts you for the interface number to delete.

Example:

RED Config> delete interface
Enter RED Interface number to delete [0]? 3
RED interface config record deleted 
 
 

Disable

Use the disable command to disable RED either for a network device or on a specific egress interface.

Syntax:  disable 

red

interface

red

Disables RED for a network device.

Example:

RED Config> disable red
RED disabled
 
 

interface

Disables RED on a specific egress interface.

Example:

RED Config> disable interface
Enter RED Interface number [0]? 2
RED interface disabled
 
 

Enable

Use the enable command to enable RED either for a network device or on a specific egress interface.

Syntax:  enable 

red

interface

red

Enables RED for a network device.

Example:

RED Config> enable red
RED enabled
 
 

interface

Enables RED on a specific egress interface.

Example:

RED Config> enable interface
Enter RED Interface number [0]? 2
RED interface enabled
 
 

List

Use the list command to display information about a network device's RED status and interface-related settings.

Syntax:  list 

all

all

Displays a network device's RED status.

Example:

RED Config>list all
 
        RED Status: Enabled
 
----------------------------------------------------
Status  Net If   qW   maxP   minT   maxT    initAvgQ
                             ------ %ofdevQ --------
----------------------------------------------------
Enable  6   PPP  4    1/512  70     100     60
 
 
Abbreviation:
 
qW = Queue Weight
minT = Minimum Threshold, maxT = Maximum Threshold
maxP = Maximum Drop Probability: 1 drop in 512 pkts
%ofdevQ = A percentage of the Maximum Device Queue
 

Set

Use the set command to specify RED settings for a specific interface on a network device.

Syntax:   set 

interface

interface number

Specifies the number of the interface for which to set RED options.

Default value: none

Example:

RED config>set interface
Enter RED Interface number [0]? [6]
RED Interface enabled
Exponential Maximum Packet Drop Probability (9 for 1/2e9) (5 - 10) [9]?
Advanced Setting (y/n)? [Yes]: yes
 
Maximum Device Queue = 5
Weight Factor (1 - 8) [4]?
Minimum Threshold value (% of the max device queue) (0 - 100) [70]?
Maximum Threshold value (% of the max device queue) (0 - 100) [100]?
Initial Average Queue Size (% of the max device queue) (0 - 100) [60]?
Accept input (y/n)? [Yes]: yes
 

Accessing the Random Early Detection Monitoring Environment

The console portion of the Random Early Detection feature enables you to view and manage RED-related settings. To access the RED monitoring environment enter talk 5 at the OPCON prompt (*):

   * t 5

Then, enter the following command at the + prompt:

   + feature red
   RED Console>
 
 

Random Early Detection Monitoring Commands

These commands enable you to view RED-related settings. Table 51 summarizes the RED monitoring commands and the rest of this section describes them. Enter the commands at the RED Console> prompt. Either enter the command and options on one line, or enter only the command and then respond to the prompts. To see a list of valid command options, enter the command with a question mark instead of options.

Table 51. RED Monitoring Commands

Command	Function
? (Help)	Displays all the commands available for this command level or lists the options for specific commands (if available). See "Getting Help".
Clear	Resets an interface's RED parameter settings.
List	Displays RED-enabled network device interface settings.
Exit	Returns you to the previous command level. See "Exiting a Lower Level Environment".

Clear

Use the clear command to reset an interface's RED parameter settings. The example in the description of the list command illustrates the results of the clear command.

Syntax:  clear 

interface-number

List

Use the list command to display information about RED-enabled network device interface settings.

Syntax:  list 

interface-number

interface-number

Lists the RED settings for the specified interface in a network device.

Example:

RED Console>list 6
--------------------------------------------------------------------------------------
Status  If    maxQ   avgQ   minT   maxT qW   maxP   pktCnt    pdpDepth  passCnt drpCnt
                           (dvQ)  (dvQ)     (pkt)   til drp     count     pkt    pkt
--------------------------------------------------------------------------------------
Enable   6       5      3      3      5  4  1/512    1:3787        285     4283      1
 
 
Abbreviations:
 
maxQ = Maximum Queue Length, avgQ = Average Queue Size
minT = Minimum Threshold, maxT = Maximum Threshold
dvQ = Device Queue, qW = Queue Weight
maxP = Maximum Drop Probability: 1 drop in 512 pkts
pktCnt til drp = Packet Count before a drop occurs
pdpDepth = Probability Drop Depth: 1 drop in 2048 depth count
 
RED Console>clear 6
 
RED Console>list 6
--------------------------------------------------------------------------------------
Status  If   maxQ   avgQ   minT   maxT  qW   maxP  pktCnt    pdpDepth  passCnt  drpCnt
                          (dvQ)  (dvQ)      (pkt)  til drp     count     pkt     pkt
--------------------------------------------------------------------------------------
Enable   6      5      3      3      5   4  1/512   1:3530   0         0        0
 
 
Abbreviations:
 
maxQ = Maximum Queue Length, avgQ = Average Queue Size
minT = Minimum Threshold, maxT = Maximum Threshold
dvQ = Device Queue, qW = Queue Weight
maxP = Maximum Drop Probability: 1 drop in 512 pkts
pdkCnt til drp = Packet Count before a drop occurs
pdpDepth = Probability drop Depth: 1 drop in 2048 depth count