selection without giving regard to the WAN. Remember that a network chain is no stronger than
its weakest link. Most designers ignore the carrier because, for the most part, what the carrier
does is beyond the designer's control. Designing a VoIP network for QoS is tough because the
network designer does not have control over all the elements. The designer has no control over
the service provider network. All this increases the significance of the importance of tweaking
the QoS parameter by an order of magnitude. Cisco provides QoS tools to give the network
designers what they need to control the bandwidth, delay, jitter, and packet loss that can
combine to deprive the network of a consistent level of voice quality.
backbone routers in a network do not necessarily perform the same operations, the configured
assignments for QoS should be expected to vary. To configure an IP network for real-time voice
traffic, consider the functions of both edge and backbone routers in the network.
configuration management, whereas backbone routers might be expected to perform congestion
management and congestion avoidance.
same level of quality that the user had in the original voice network.
town, the delay due to distance is hardly noticeable because the signals travel at the speed of
light. In a phone call to someone 100,000 miles away, the delay can be perceptible. The time