Cabletron Systems 6500 - Manual (Page 95)

SmartSwitch 6500 User Guide 7-5
Traffic Management Traffic Management Capabilities
7.1.3 Queue Buffers
The SmartSwitch 6500 performs buffering using a shared-memory architecture. Buffer space is divided into queues
for each class of service. In turn, ports are allocated some portion of each of the service class queues. This allocation
is controlled on a per-port basis by the
porttrafficcongestion commands.
Qos is defined on an end-to-end basis in terms of cell loss ratio, cell transfer delay, and cell delay variation.
For example, enter the show porttrafficcongestion command to view current buffer utilization.
Smart6500 # show porttrafficcongestion
PortNumber(ALL) :
PortID QueueId ServiceClass MinIndex MinValue MaxIndex MaxValue
==============================================================================
CPU 1 CBR 10 64 15 1024
CPU 2 RTVBR 8 256 13 4096
CPU 3 NRTVBR 8 256 13 4096
CPU 4 ABR 8 256 12 8192
CPU 5 UBR 8 256 12 8192
PortID QueueId ServiceClass MinIndex MinValue MaxIndex MaxValue
==============================================================================
7A1 1 CBR 10 64 15 1024
7A1 2 RTVBR 8 256 13 4096
7A1 3 NRTVBR 8 256 13 4096
7A1 4 ABR 8 256 12 8192
7A1 5 UBR 8 256 12 8192
PortID QueueId ServiceClass MinIndex MinValue MaxIndex MaxValue
==============================================================================
7A2 1 CBR 10 64 15 1024
7A2 2 RTVBR 8 256 13 4096
7A2 3 NRTVBR 8 256 13 4096
7A2 4 ABR 8 256 12 8192
7A2 5 UBR 8 256 12 8192
PortID QueueId ServiceClass MinIndex MinValue MaxIndex MaxValue
==============================================================================
7A3 1 CBR 10 64 15 1024
7A3 2 RTVBR 8 256 13 4096
7A3 3 NRTVBR 8 256 13 4096
7A3 4 ABR 8 256 12 8192
7A3 5 UBR 8 256 12 8192
More(<space>/q)?:
MinValue and MaxValue are thresholds set on a per-queue, per-port basis and are measured in cells (53 bytes). The
MinValue threshold is the amount of buffer space guaranteed to a call of a particular service class on the corresponding
port. The MaxValue threshold is the maximum amount of buffer space that a call of a particular service class is allowed
on the corresponding port.
QoS corresponds to the queues as follows:
• Queue 1 — Constant Bit Rate (CBR)
• Queue 2 — Real Time Variable Bit Rate (rt-VBR)
• Queue 3 — Non-real time Variable Bit Rate (Nrt-VBR)
• Queue 4 — Available Bit Rate (ABR)