Specifications

OmniAccess 5510 USG - Release Notes
September 2010
WRED
WRED (Weighted Random Early Detection) is also a congestion avoidance technique. WRED
combines the capabilities of the RED algorithm with the IP precedence/DSCP feature to provide
preferential traffic handling of higher priority packets. It can selectively discard lower priority traffic
when the interface begins to get congested and provide differentiated performance characteristics for
different classes of service.
WRED can also be configured to ignore the IP precedence when making drop decisions so that non
weighted RED behavior is achieved. WRED can provide separate thresholds and weights for different
IP precedences, which can provide different quality of service with regard to packet dropping for
different packet types.
Priority Egress Scheduling
The process of identifying which packet is to be selected for further action.
Egress Shaping
Egress Shaping is the process of delaying packets before they go out to make the traffic confirm to a
configured maximum rate. The main intention of shaping the traffic is to define the traffic to flow
with in an envelop.
The main objective of the traffic shaper is to allow the traffic in to the network at a controlled rate
from different sources so that the network resources are optimally utilized for better performance.
Typically, this is achieved by applying a Token Bucket Filter at the egress of an interface. Tokens will
be generated per each flow at a sustained rate (configured as CIR) and are emptied as and when the
packets are transmitted.
DSCP/TOS Marking
DSCP refers to the 6 bits in the ToS byte in the IP header. Marking refers to setting the IP DSCP/IP
Precedence or ToS flags on the matched packet. This is used to select the Per Hop Behavior that a
packet experiences through the network.
Auto QoS (diffserv, voice)
Auto QoS is a feature that enables user to configure QoS on OmniAccess 5510 USG with minimal
effort. Normally, QoS configuration involve definition of class, match list association with the class,
definition of policy, class association with the policy and defining class traffic attributes like
bandwidth, police, shape, etc. This entire configuration might be cumbersome for user to configure.
Auto QoS commands creates QoS configuration - automatically classifies traffic, applies the required
traffic attributes for each of the classes based on the class needs. Auto QoS configuration also
automatically applies the policy on to the interface. These configurations are not editable.
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