dqdb - dronacharyaggn.dronacharya.info/itdept/downloads/questionbank... · distributed queue dual...
TRANSCRIPT
![Page 1: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/1.jpg)
DQDBDQDB
![Page 2: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/2.jpg)
INTRODUCTIONINTRODUCTION Distributed Queue Dual Bus (DQDB
IEEE 802.6) is defined for use onMANs and affects the media-access-control (MAC) sub layer.
DQDB uses a dual bus operating inopposite directions so that a node maytransmit and receive concurrently atspeeds between 50 Mbps up to 600Mbps.
![Page 3: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/3.jpg)
Technical DataTechnical Data Distance >= 200 km Medium : optical fiber Access Method : Timed Token
Passing Transmission Rate : 34 - 600 Mbit/s Maximum no. of stations : 512
![Page 4: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/4.jpg)
DQDB in OSIDQDB in OSI
![Page 5: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/5.jpg)
DQDB Buses and NodesDQDB Buses and Nodes
![Page 6: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/6.jpg)
Working of DQDBWorking of DQDB The Head of Bus (HOB)s act a slot
generators so that the bus is neverquiet.
Nodes are located logically adjacentto the bus and are promiscuousreaders. They read all slots that comeoff the bus but may not necessarilyalter any of the data.
Nodes may be passive readers or, inan active system, they may act asrepeaters so as to forestallattenuation.
![Page 7: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/7.jpg)
Working of DQDBWorking of DQDB If Node 2 wishes to send data in the
direction of Node 5 then it will use BusA. This implies that it must firstreserve a slot by placing a request onBus B.
If Node 2 wishes to send data in thedirection of Node 1 it must first reservea slot using Bus A and then send thedata on Bus B.
![Page 8: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/8.jpg)
DQDB Data Transmission
![Page 9: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/9.jpg)
Queues
![Page 10: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/10.jpg)
Distributed Queues
![Page 11: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/11.jpg)
Reservation Token
![Page 12: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/12.jpg)
DQDB OperationDQDB Operation The DQDB configuration is
independent of the number of nodesand of the distances involved makingDQDB ideal for high-speedtransmissions
DQDB uses 53-byte packets (52 databytes and one access control byte) fortransmissions called slots.
Slots from different nodes areintermingled in the network traffic.
![Page 13: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/13.jpg)
DQDB Rings
![Page 14: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/14.jpg)
DQDB Rings
![Page 15: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/15.jpg)
ApplicationsApplications DQDB provides both isochronous and
asynchronous service to its users. Isochronous services require fixed
bandwidth and bounded delay e.g.Digital voice and video.
Asynchronous services require dataservices e.g. file transfer, email etc.
![Page 16: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/16.jpg)
Scope of ResearchScope of Research Priority based algorithm for slot
allocation
![Page 17: DQDB - Dronacharyaggn.dronacharya.info/ITDept/Downloads/QuestionBank... · Distributed Queue Dual Bus (DQDB IEEE 802.6) is defined for use on MANs and affects the media-access-control](https://reader036.vdocuments.site/reader036/viewer/2022062414/5fb5cd9abfaea517bf32e6da/html5/thumbnails/17.jpg)
Assignment Assignment What are distributed queues in
DQDB?