Some Protocols, particularly those which experience issues with latency such as SIP and H.323, can benefit from Quality of Service (QoS) Marking. This enables network devices to prioritize marked traffic and pass these tags to internal and external networks, if the devices accept them.
Correctly configured QoS marking can improve throughput and latency for affected traffic in the same way as Bandwidth Management while also passing the configuration beyond the network. This article will describe how to map QoS as desired and how to apply the desired actions via access rules.
TIP: For more information regarding Quality of Service, such as how it works at the packet level, reference the SonicWall UTM Administration Guide available on mysonicwall.com.
Click Manage in the top navigation menu.
Navigate to Security Configuration | Firewall Settings | Quality of Service Mapping to examine the current mapping. This table provides two methods of QoS.
802.1p Class of Service is typically used for internal Layer 2 and some Layer 3 mapping. This marking typically will not survive being sent to the Public Internet and isn't universally supported.
DSCP Marking is used for Layer 2 and Layer 3 mapping. Not all networking devices or ISPs support DSCP Class of Service.
CAUTION: Regardless of Mapping, QoS is largely useless without support from internal networking devices and/or your Internet Service Provider.
NOTE: In order to successfully map QoS, it is required to know which Tags the network devices above and below the SonicWall on your network map use for Class of Service.
Edit the necessary Mapping as required by your network.
Navigate to Policies | Rules and configure any access rule which are required to have their traffic tagged or mapped.
On the access rule go to the QoS tab.
Set the DSCP and/or 802.1p Marking settings as required. This can include the following:
None - No action will be taken regarding this Marking. For DSCP this will set the Marking to 0, for 802.1p the Marking will be removed.
Preserve - Existing Markings will be unaltered.
Explicit - Set the Marking to the desired value.
Map - Change the Marking to the value set under QoS Mapping.