What is Quality of service [QoS]?
Quality of service (QoS) is the use of mechanisms or technologies that work on a network to control traffic and ensure the performance of critical applications with limited network capacity. It enables organizations to adjust their overall network traffic by prioritizing specific high-performance applications.
List out Quality of service [QoS] attributes in UMTS
| Attributes | Values | Description |
| Traffic Class | Conversational Streaming, Interactive, or Background | An indication of the type of traffic that the PDP context is expected to carry; the main difference between these classes is in terms of delay requirements |
| Maximum Bitrate | (kbps) | Maximum bitrate that is allowed for burst traffic; this is analogous to the p parameter in the token bucket algorithm in Sec. 2.3.2 |
| Guaranteed Bitrate | (kbps) | Sustained bitrate that the network will allow; this is analogous to the r parameter in the token bucket algorithm in Sec. 2.3.2 and with a b parameter equal to the Maximum SDU size PDP QoS attribute |
| Delivery Order | (y/n) | Whether in-sequence SDU delivery is required or not |
| Maximum SDU Size | (octets) | Maximum datagram size that can be transported (= MTU) |
| SDU Format Information | (bits) | List of possible SDU sizes; this information can be provided to the network in order to allow some optimizations |
| SDU Error Ratio | (float) | Maximum tolerable fraction of lost SDUs that the application can tolerate |
| Residual Bit Error Ratio | (float) | Maximum tolerable fraction of erroneous bits per SDUs that the application can tolerate |
| Delivery of Erroneous SDU’S | (y/n/-) | Whether to deliver SDUs that contain erroneous bits; some applications, such as video-telephony, are able to tolerate packets containing a few erroneous bits; the alternative of discarding entire packets with only a few erroneous bits is, in this case, much more detrimental to the overall quality |
| Transfer Delay | (ms) | Maximum Tolerable Delay |
| Traffic Handling priority | (integer) | As an Alternatively to specifying the bitrate attributes above, applications can just request traffic relative priorities |
| Allocation/Retention Priority | (integer) | When the access network becomes too loaded, it may be required to stop accepting some new PDP Contexts or to even discard existing ones; this value controls the relative priority of allocation and retention for PDP Contexts when this happens |
| Source Statistics Descriptor | (‘Speech’ / ‘ unknown) | Since speech has predictable traffic patterns, by indicating to the network that a PDP Context will be used for voice streams the network is able to better calculate the statistical multiplex gain, thus use resources more efficiently |
| Signaling Indication | (Yes/No) | Indicates if the SDUs to be transported are of signaling nature. This attribute is defined only for the Interactive traffic class. |
Quality of service [QOS] Classes in UMTS
| Traffic Class | Conversational class Real Time | Streaming class Real-Time | Interactive class Best Effort | Background class Best Effort |
| Fundamental characteristics | Preserve time relation (variation) between information entities of the stream – Conversational pattern (stringent and low delay ) | Preserve time relation (variation) between information entities of the stream | – Request response pattern -Preserve payload content | – Destination is not expecting the data within a certain time -Preserve payload content |
| Example of the application | Voice | streaming video | Web Browsing | Telemetry, emails |
Conclusion:
I hope this List out Quality of service [QoS] attributes in UMTS Answer would be useful for you. If it’s helped you then don’t forget to bookmark our site for more Question Paper Solutions. This Question has been Asked in the December 16 Question Paper of EXTC Branch – Mumbai University.
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