The only way for a network infrastructure to recognize and prioritize the different data flows is if there is something in the data to identify the type of traffic. This can be done in many ways, some more intelligent than others. However, one sure way to alert the infrastructure is to tag the packets with predefined DSCP marking (which must be agreed upon and honored end-to-end in the network).
This task cannot be completed without proper planning and an agreement with the network team on which values to mark the different data types with. We also need to know which ports the different types of traffic will use. Once this is settled, it's time to configure servers and clients to tag the traffic.
There are at least three systems that we need to address: clients, domain servers, and non-domain servers (edge). The first two can have group policies assigned to them, but the third system must be edited through the local group policy.
The following are the steps to enable QoS system-wide:
- Launch PowerShell in an elevated administrative mode.
- Type the following command:
Set-CsMediaConfiguration -EnableQoS $true
Follow these steps to add Client Group Policies. Each type of traffic will need its own QoS policy. Here is the description of the first policy for the clients. Repeat the procedure for all the types of traffic to be tagged as follows:
- Log on to a server/client with administrative rights to the domain and with the group policy management tool available.
- Start the Group Policy Management window.
- Locate the container/OU where the new policy should be created.
- Right-click on the appropriate container and then select Create a GPO in this domain, and Link it here.
- Give the new policy a name and then click on OK.
- Right-click on the newly-created policy and then click on Edit.
- Expand Computer Configuration and Windows Settings.
- Right-click on Policy-Based QoS and click on Create new policy.
- Type a descriptive name for the new policy. Give it a descriptive name for later reference, for example,
Lync Audio QoS. - Select the Specify DSCP Value checkbox, and then select the assigned DSCP (46 for audio).
- Uncheck the Specify Outbound Throttle Rate checkbox.
- Click on Next.
- Click on Only applications with this executable name.
- Type
communicator.exe(the Lync client name). - Click on Next.
- Leave the source and destination as is (the default is all source/destination IP).
- Click on Next.
- Select TCP and UDP.
- Specify the source port number by selecting From this source port number or range. Enter the port range for the media type that you specified while planning.
- Click on Finish.
- Repeat steps 8 to 20 for all of the media types to tag.
- Save the GPO, and make sure that the Group Policy is applied to all of the clients where Lync is used.
Follow the same procedure to add policies to clients when applying to servers, with the following exception.
All server policies must be configured with the All programs and Source ports settings, and not with Only applications with this executable name as the client-side policies are.
Follow the same procedure to add policies to clients when applying to servers, with the following exceptions:
- The Edge Server cannot receive Group Policies from the domain. The configuration must be performed on the server in Local security Policy.
- All edge server policies must be configured with the All programs and Destination ports settings, and not with Only applications with this executable name as the client-side policies are.