QoS and QoS Policies
118
Quality of Service Guide
3HE 11014 AAAC TQZZA Edition: 01
3.6.1.3 Ethernet Access Egress Queuing and Scheduling
Ethernet access egress queuing and scheduling is very similar to the Ethernet
access ingress behavior. Once the Ethernet pseudowire is terminated, traffic is
mapped to up to eight different forwarding classes per SAP. Mapping traffic to
different forwarding classes is performed based on the EXP bit settings of the
received Ethernet pseudowire by network ingress classification.
Queue-type and profile scheduling are both supported for Ethernet access egress
ports. If the queues are configured according to the tables and defaults described in
this guide (implying a default mode of operation), the configuration is as follows:
• CoS-8 to CoS-5 Expedited in-profile
• CoS-4 to CoS-1 Best Effort in-profile
• CoS-8 to CoS-5 Expedited out-of-profile
• CoS-4 to CoS-1 Best Effort out-of-profile
In this default configuration, for queue-type scheduling, CoS-8 to CoS-5 are serviced
by the Expedited scheduler, and CoS-4 to CoS-1 are serviced by the Best Effort
scheduler. This default mode of operation can be altered to better fit the operating
characteristics of certain SAPs.
With profile scheduling, the Ethernet frames can be either in-profile or out-of-profile,
and scheduling takes into account the state of the Ethernet frames in conjunction
with the configured CIR and PIR rates.
Scheduled nrt-VBR Weighted share (according to SIR) of port
bandwidth remaining after shaped traffic
has been exhausted
In the same WRR scheduler as UBR+
and UBR
Scheduled UBR+ Weighted share (according to MIR) of port
bandwidth remaining after shaped traffic
has been exhausted
In the same WRR scheduler as nrt-VBR
and UBR
Scheduled UBR Weighted share (with weight of 1) of port
bandwidth remaining after shaped traffic
has been exhausted
In the same WRR scheduler as nrt-VBR
and UBR+
Table 16 ATM Scheduling and Relative Priorities (Continued)
Flow type Transmission Rate Priority
To Next Page
Loading...
