Firewall > QoS Mapping
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SonicOS Enhanced 4.0 Administrator Guide
section on page 479. SonicOS’s BWM is a perfectly effective solution for fully autonomous
private networks with sufficient bandwidth, but can become somewhat less effective as more
unknown external network elements and bandwidth contention are introduced. Refer to the
Example Scenario in the “Example Scenario” section on page 472 for a description of contention
issues.
To provide end-to-end QoS, business-class service providers are increasingly offering traffic
conditioning services on their IP networks. These services typically depend on the customer
premise equipment to classify and tag the traffic, generally using a standard marking method
such as DSCP. SonicOS Enhanced has the ability to DSCP mark traffic after classification, as
well as the ability to map 802.1p tags to DSCP tags for external network traversal and CoS
preservation. For VPN traffic, SonicOS can DSCP mark not only the internal (payload) packets,
but the external (encapsulating) packets as well so that QoS capable service providers can offer
QoS even on encrypted VPN traffic.
The actual conditioning method employed by service providers varies from one to the next, but
it generally involves a class-based queuing method such as Weighted Fair Queuing for
prioritizing traffic, as well a congestion avoidance method, such as tail-drop or Random Early
Detection.
802.1p and DSCP QoS
The following sections detail the 802.1p standard and DSCP QoS.