Advanced QoS Settings
Applies To: Windows Server 2008 R2
Advanced Quality of Service (QoS) settings enable you to manage bandwidth consumption and the way in which the computer handles DSCP markings set by applications and services, as opposed to those set by Group Policy. Advanced QoS settings apply at the computer level only, whereas QoS policies can be applied at both the computer and user level.
Inbound TCP Traffic
The Throttle Rate in policy-based QoS settings enables you to manage the sending rate for outbound network traffic, but settings on the Inbound TCP Traffic tab control the bandwidth consumption for TCP traffic the computer receives. When you set a lower throughput level on the Inbound TCP Traffic tab, TCP limits the size of its advertised TCP receive window. The effect of this setting will be increased throughput rates and link utilization for TCP connections with higher bandwidths or latencies (bandwidth delay product). By default, the throughput level is set to its maximum (Level 3).
To change the throughput level, select the Specify the inbound TCP throughput level check box, and then select a throughput level according to the following table. The throughput level can be equal to or less than the maximum, depending on network conditions.
| Setting | Maximum throughput level |
|---|---|
Level 0 (minimum throughput) |
64 kilobytes (KB) |
Level 1 |
256 KB |
Level 2 |
1 megabyte (MB) |
Level 3 (maximum throughput) |
16 MB |
DSCP Marking Override
DSCP Marking Override blocks the ability of applications to specify, or mark, non-zero DSCP values. By default, applications and services can set non-zero DSCP values.
To override DSCP marking requests from applications and services, select the Control DSCP marking requests from applications check box, and then select Ignored. Applications and services that use QoS application programming interfaces (APIs) will have their DSCP values set to zero, and only QoS policies can set DSCP values.