piggyback a BW Request on a data packet. in .NET Print Code 128 Code Set A in .NET piggyback a BW Request on a data packet.

piggyback a BW Request on a data packet. generate, create ansi/aim code 128 none for .net projects Internatioanl Orgnization for Standardization Best Effort (BE) Service The Best Effort (BE) Service supports service flows that do not require QoS support. The SS issues its requests in a contention period. An SS that is granted a request via BE is allowed to "steal" bandwidth if it is in GPSS mode.

BE Service flow is allowed to piggyback a BW Request on a data packet. The standard details extensive signaling techniques and access mechanisms for each service flow, but the details of bandwidth allocation, scheduling, and reservation management intelligence are out of the standard"s scope and are left to be vendor specific. The ability to employ different combinations of these access mechanisms allows vendors to differentiate their products, tailor solutions to unique needs and users, optimize system performance, and use different bandwidth allocation algorithms while maintaining consistent interoperability.

For example, contention may be activated to avoid polling of SSs that have been inactive for a long period of time.. 7.4.4 Network Entry and Initialization An SS wishing to enter the network has to go through the following steps: 1. Scan for a downlink channel and establish synchronization with the BS. The SS can either recall the downlink channel from its memory or continuously scan possible channels of the downlink frequency band until it finds a valid downlink signal.

After it finds a downlink channel it needs to synchronize and attempt to acquire the channel control parameters for the downlink by searching for the DL-MAP sent by the BS. 2. Obtain transmit parameters.

The SS searches for an uplink Channel Descriptor message from the BS in order to retrieve the transmission parameters for a possible uplink channel. 3. Adjust local parameters (e.

g., transmit power) based on approved values or messages from the BS. 4.

Negotiate basic capabilities. The SS informs the BS of its basic capabilities by sending an appropriate message to the BS. The BS acknowledges this message.

5. Authorize SS and perform key exchange. The BS goes through a process of authorizing the SS to enter the network and exchanges security keys with the SS.

6. Perform registration. The BS sends additional management messages and the SS becomes managed by the BS.

7. Establish IP connectivity. The SS receives an IP address from the BS.

8. Establish time of day. The SS and BS need to have equal timing information.

9. Transfer operational parameters. The BS sends additional configuration information to the SS.

. < Day Day Up > < Day Day Up > 7.5 QoS Support The principal me chanism of IEEE 802.16 standard for providing QoS support is to associate a packet with a service flow. A service flow is a unidirectional flow of packets that provides a particular QoS.

The standard details the mechanisms of how to allocate bandwidth and how to send the BW Requests in each service flow as described in the previous section. To summarize, the service flows and the supported applications are listed below:. UGS Service flow .net vs 2010 code128b supports real-time applications with constant bit rate (CBR) such as voice over IP and circuit emulation. rtPS Service flow supports real-time applications with variable bit rate (VBR) such as streaming video and audio.

nrtPS Service flow supports non-real-time applications which require better service than BE, such as high-bandwidth FTP. BE Service flow supports applications that do not have any QoS requirements..

Each network app lication, first, has to register with the network. The network will associate the application with a service flow by assigning an unique Service Flow ID (SFID). All packets must be tagged with this assigned SFID in order for the network to provide the appropriate QoS.

When the application wants to send data packets, it is required to establish a connection with the network and receives a unique CID assigned by the network. Therefore, the IEEE 802.16 data packets include both CID and SFID.

Next we describe QoS support from the following two aspects: QoS provision and QoS mechanisms..
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