Cabletron Systems 04-0053-01 manual EFCI, EPD, and RM Cell Marking

Traffic Management Traffic Management Capabilities

6.1.4EFCI, EPD, and RM Cell Marking

To control switch congestion, ATM SmartSwitches implement standard resource management cell (RM-cell) marking, explicit forward congestion indicator cell marking (with backward RM cell marking), and early packet discard (EPD). These congestion control schemes are triggered when the number of cells within shared memory reaches user-definable thresholds. Use the switchtrafficcongestion commands to view and set these thresholds.

For example, enter the show switchtrafficcongestion command.

SmartSwitch # show switchtrafficcongestion

Switch Traffic Congestion Parameters

==============================================================================

Low EPD Threshold	: 209715 cells
High EPD Threshold	: 104857 cells
CLP1 Discard Threshold	: 131072 cells
RM Cell Marking Enable	: OFF
EFCI Cell Marking Enable	: OFF
Explicit Rate Marking Enable	: OFF

SmartSwitch #

For most types of traffic, EPD triggering is tied to the low EPD threshold. Signaling traffic, however, is tied to the high EPD threshold; this assures that signaling packets are discarded only when congestion is most severe.

Use the set switchtrafficcongestion command to change thresholds for EPD and to enable or disable RM and EFCI cell marking. For example:

SmartSwitch # set switchtrafficcongestion

LowEPDWatermark(4096):

HighEPDWatermark(4096):

CLP1_DiscardWatermark(4096):

RMCellMarkingEnable(enable):

ExplicitRateMarkingEnable(enable) :

EFCIMarkingEnable(enable):

SmartSwitch #

SmartSwitch ATM User Guide 6-7