|
Feature |
Product |
Release introduced |
|---|---|---|
|
Platform specific considerations for QoS behavior are documented in QoS Behavior Differences, which is in VOSS User Guide. |
||
|
Automatic QoS |
5420 Series |
Not Supported Use Auto-sense with IP Phone support instead |
|
5520 Series |
Not Supported Use Auto-sense with IP Phone support instead |
|
|
VSP 4450 Series |
VSP 4000 4.0 |
|
|
VSP 4900 Series |
VOSS 8.1 |
|
|
VSP 7200 Series |
VOSS 4.2.1 |
|
|
VSP 7400 Series |
VOSS 8.0 |
|
|
VSP 8200 Series |
VSP 8200 4.0 |
|
|
VSP 8400 Series |
VOSS 4.2 |
|
|
VSP 8600 Series |
VSP 8600 4.5 |
|
|
XA1400 Series |
VOSS 8.0.50 |
|
VoIP traffic requires low latency and jitter.
If you use edge routers, configure ingress ports as core ports to treat VoIP traffic appropriately. In this case, the system trusts QoS markings that apply to VoIP traffic, and the system does not re-mark QoS settings. However, if this configuration is not sufficient, you can also apply filters, route policies, or re-mark traffic.
Automatic QoS specifically supports converged voice deployments. Automatic QoS automatically recognizes the DSCP value voice applications can use, and associates these DSCP values with the proper queue.
When you use Automatic QoS, the system recognizes application traffic and prioritizes the traffic through the system. Automatic QoS offers a simplified and resource-efficient mechanism to prioritize application traffic within the network. Automatic QoS supersedes DiffServ mode configuration.
The following table shows the traffic types, the standard DSCP value, the specific Automatic QoS DSCP values, and the queue mappings for the Automatic QoS DSCP values.
|
Traffic type |
Automatic QoS DSCP value |
Queue |
|---|---|---|
|
VoIP data (Premium) |
0x2F (47) |
6 |
|
VoIP signaling (Platinum) |
0x29 (41) |
5 |
|
Video (Platinum) |
0x23 (35) |
5 |
|
Streaming (Gold) |
0x1B (27) |
4 |
The traffic that the system identifies, based on these DSCP values, receives preferential queuing treatment within the system and is re-marked for preferential downstream processing
The system associates additional filtering (ACL filters) to ensure that Auto-QOS DSCP values are honored no matter what the QOS configuration of the ingress is.
These additional filtering components target ingress traffic with the designated private DSCP values. After a match occurs, the system re-marks the traffic based on the application mode. Ingress traffic that is not marked with a recognized private DSCP value receives the same treatment as it receives without the Automatic QoS feature.
The switch activates Automatic QoS automatically; you cannot deactivate this feature but you can remap these DSCP values to use a different queue. The system displays a warning that these values should not be modified.
Switch:1(config)#qos ingressmap ds 47 2 DSCP values should not be modified. Do you want to continue ? (y/n) ? y
You do not need to configure individual QoS components across a variety of platforms. Automatic QoS applies end-to-end.
Important
For VSP 8600 Series switches, automatic QoS derives internal QoS based on DSCP and is honored for routed traffic only. For switched traffic, Automatic QoS does not work and falls back to deriving internal QoS based on VLAN .1p bits or uses the port‘s default QoS level.