Enterprise QoS Solution Reference Network Design Guide
Enterprise QoS Solution Reference Network Design Guide
Enterprise QoS Solution Reference Network Design Guide
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Catalyst 6500 PFC2/PFC3—<strong>QoS</strong> Considerations and <strong>Design</strong><br />
WS-X6502-10GE Catalyst 6500 10 GigabitEthernet Base<br />
Module (Requires OIM)<br />
WS-X6516A-GBIC Catalyst 6500 16-port GigabitEthernet<br />
Module (Fabric-enabled; Requires<br />
GBICs)<br />
WS-X6516-GBIC Catalyst 6500 16-port GigabitEthernet<br />
Module (Fabric-Enabled; Requires<br />
GBICs)<br />
WS-X6516-GE-TX Catalyst 6500 16-port GigabitEthernet<br />
Copper Module; (Crossbar-enabled)<br />
WS-X6524-100FX-MM Catalyst 6500 24-port 100FX MT-RJ<br />
Module (Fabric-enabled)<br />
WS-X6548-RJ-21 Catalyst 6500 48-port 10/100 RJ-21<br />
Module (Fabric-enabled)<br />
WS-X6548-RJ-45 Catalyst 6500 48-port 10/100 RJ-45<br />
Module (Crossbar-enabled)<br />
WS-X6548V-GE-TX Catalyst 6500 48-port 10/100/1000 Inline<br />
Power RJ-45 Module (Fabric-enabled)<br />
WS-X6548-GE-TX Catalyst 6500 48-port 10/100/1000 RJ-45<br />
Module (Fabric-enabled)<br />
WS-X6816-GBIC Catalyst 6500 16-port GigabitEthernet<br />
Module (Fabric-Enabled; Requires<br />
GBICs)<br />
2-102<br />
<strong>Enterprise</strong> <strong>QoS</strong> <strong>Solution</strong> <strong>Reference</strong> <strong>Network</strong> <strong>Design</strong> <strong>Guide</strong><br />
Chapter 2 Campus <strong>QoS</strong> <strong>Design</strong><br />
<strong>Design</strong> recommendations for each of these six main Catalyst 6500 queuing structures follow.<br />
Catalyst 6500—2Q2T Queuing and Dropping<br />
1P1Q8T 1P2Q1T 64MB per port<br />
1P1Q4T 1P2Q2T 1MB per port<br />
1P1Q4T 1P2Q2T 512KB per port<br />
1P1Q4T 1P2Q2T 512KB per port<br />
1P1Q0T 1P3Q1T 1MB per port<br />
1P1Q0T 1P3Q1T 1MB per port<br />
1P1Q0T 1P3Q1T 1MB per port<br />
1Q2T 1P2Q2T 1MB per 8 ports<br />
1Q2T 1P2Q2T 1MB per 8 ports<br />
1P1Q4T 1P2Q2T 512KB per port<br />
This section includes the following topics:<br />
Configuration<br />
Catalyst MLS <strong>QoS</strong> Verification Commands<br />
Linecards that only support 2Q2T queuing models have no provision for priority-queuing. Nonetheless,<br />
tuning the Weighted Round-Robin (WRR) weights and the queue sizes can help offset this limitation.<br />
For example, if Q1 is to service Scavenger/Bulk (CoS 1) and Best Effort (CoS 0) traffic, then assigning<br />
30% of the buffer space to the first queue is adequate; the remaining 70% can be assigned to Q2.<br />
The WRR weights can be set to the same ratio of 30:70 for servicing Q1:Q2.<br />
Since the 2Q2T model supports configurable Tail-Drop thresholds, these can be tuned to provide an<br />
additional layer of <strong>QoS</strong> granularity. For example, the first queue’s first threshold can be set at 40% to<br />
prevent Scavenger/Bulk traffic from dominating Q1. Similarly, the second queue’s first threshold can be<br />
set to 80% to always allow some room in the queue for VoIP. The second threshold of each queue should<br />
always be set to the tail of the queue (100%).<br />
Version 3.3
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