QOS How To

Questions and answers to service issues.
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maurice
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QOS How To

Post by maurice »


How to Tweak with QOS



- On the Internet and in other networks, QoS (Quality of Service) is the idea that transmission rates, error rates, and other characteristics can be measured, improved, and, to some extent, guaranteed in advance. QoS is of particular concern for the continuous transmission of high-bandwidth video and multimedia information. Transmitting this kind of content dependably is difficult in public networks using ordinary "best effort" protocols.
Using the Internet's Resource Reservation Protocol (RSVP), packets passing through a gateway host can be expedited based on policy and reservation criteria arranged in advance. Using ATM, which also lets a company or user preselect a level of quality in terms of service, QoS can be measured and guaranteed in terms of the average delay at a gateway, the variation in delay in a group of cells (cells are 53-byte transmission units), cell losses, and the transmission error rate.
The Common Open Policy Service (COPS) is a relatively new protocol that allows router and layer 3 switches to get QoS policy information from the network policy server.



Workstations have it by default.

You have to install the service QoS Packet Scheduler.
Routers/Switches you have to enable the service.
Servers you have to enable the service




Network Technologies and Support for QoS
QoS depends on support throughout the network. To achieve QoS from sender to receiver, all of the network elements through which a traffic flow passes — such as network interface cards, switches, routers, and bridges — must support QoS. If a network device along this path does not support QoS, the traffic flow receives the standard first-come, first-served treatment on that network segment.
Network technologies such as Frame Relay, asynchronous transfer mode (ATM), and the more traditional local area network (LAN) technologies (including Ethernet, Token Ring, and 802.11 wireless LAN) support QoS mechanisms. ATM, in particular, offers a high degree of support for QoS. Because ATM is a connection-oriented networking technology, it can establish a service contract that guarantees a specific quality of service and can allocate network resources. ATM enforces the service contract and allocates bandwidth at the hardware level. For more information about ATM QoS, see “How ATM Works.â€
Maurice
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