Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring HQoS (Rev.03)
Carrier Grade Ethernet Services and HQoS
© 2008 Foundry Networks, Inc.
Page 7 of 98
Normal QoS
Hierarchical QoS
Figure 3: Legacy ‘flat’ QoS vs. Hierarchical QoS Traffic Management
The HQoS capabilities are a critical component in providing “hard QoS” guaranties required by
current and next generation carrier Ethernet services (e.g. triple-play).
HQoS Specifications
•
Queuing
o
32K queues: 16K I 16K Egress.
o
Flexible per customer-site/service/EVC queues allocation:
Per forwarding class
Separate queues for unicast, multicast and broadcast traffic.
Up to 48 queues allocated per EVC: 24 i 24 egress.
Up to 512 queues per customer-site/service: 256 i 256 egress.
•
Hierarchical scheduling and shaping
o
2 levels of scheduling per customer-site/service: Queues
Æ
L2 schedules
Æ
L1 (root)
schedulers.
o
1K L2 schedulers with dual-rate shapers: 512 i 512 egress.
o
128 L1 schedulers with dual-rate shapers: 64 i 64 egress.
o
Each scheduler in the hierarchy supports the following programmable scheduling scheme:
o
2 priorities support (high/low) with strict priority scheduling.
o
Per priority – Dual Weighted Fair Queue (WFQ)
•
Congestion avoidance and buffer space allocation
o
WRED and buffer allocation per queue and per port.
HQoS Management
•
Policy-based HQoS configuration
o
Policy management model allows for flexible and extensive service SLA provisioning:
Multi-site