CN 6.0 Chapter 6

Data

1) Can be very greedy consuming a large portion of network capacity 2) Traffic can be smooth or bursty

Voice

1) Cannot be retransmitted if lost 2) Must receive a higher UDP priority 3) Traffic can be predictable and smooth 4) Does not consume a lot of network resources

Video

1) Without QoS and a significant amount of extra bandwidth capacity this traffic, typically degrades 2) Requires at least 384 Kbs of bandwidth 3) Traffic can be unpredictable, inconsistent, and bursty

Marking

Adding a value to the packet header.

802.1Q

An IEEE specification for implementing VLANs in Layer 2 switched networks.

Jitter

Caused by variations in delay.

Classification

Determines what class of traffic packets or frames belong to.

Queue

Holds packets in memory until resource become available to transmit them.

WRED Algorithm

Provides buffer management and allows TCP traffic to throttle back before buffers are exhausted.

Congestion Avoidance

Queuing and scheduling methods where excess traffic is buffered while it waits to be sent on an egress interface.

Traffic Shaping

Retains excess packets in a queue and then schedules the excess for later transmission over increments of time.

Code Delay

The fixed amount of time it takes to compress data at the source before transmitting to the first internetworking device.

Serialization Delay

The fixed amount of time it takes to transmit a frame from the NIC to the wire.

Bandwidth

The number of bits that can be transmitted in a single second.

Propagation Delay

The variable amount of time it takes for the frame to traverse the links between the source and destination.

Packet Loss

This happens when congestion occurs.

CoS Bits

Used to identify a Layer 2 QoS marking.

Congestion

When the demand for bandwidth exceeds the amount available.

Traffic Policing

When the traffic rate reaches the configured maximum rate, excess traffic is dropped.