Fddi

Topic to be presented:

FDDI (Fiber Distributed Data Interface ) By

Junaid Ali Siddiqui Deparment of Computer science UOP.

What FDDI is? 

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FDDI is a token-passing ring network similar to token ring , but running over a fiber-optic cable. Unlike Token Ring , FDDI allows several devices to transmit at once. A computer in FDDI can transmit as many frames as it can produce within predetermined time before letting the token go. FDDI uses a ring topology of multimode or single mode optical fiber transmission links.

Operating at 100 Mbps to span up to 200 km s

Deparment of Computer science UOP.

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It was produced by ANSI X3T9.5 committee. Permits up to 500 stations. Employs dual counter-rotating rings. The station which are connected to both the rings is known as class A stations Those stations which are connected to only one rings is known as class B stations

Deparment of Computer science UOP.

FDDI: Dual Token Ring A

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Copyright ©2000 The McGraw Hill Companies

Leon-Garcia & Widjaja: Communication Networks

Figure 6.62

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FDDI uses the token passing system in dual ring setting.

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One ring is called “Primary ring” other is called “Secondary ring” Traffic usually flows only on the primary ring. If the primary ring fails FDDI automatically reconfigures the network So the data flows onto Secondary ring in opposite direction.

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Deparment of Computer science UOP.

IEEE 802.5 and FDDI Differences      

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Token Ring Shielded twisted pair 4, 16 Mbps No reliability specified Differential Manchester Centralized clock Priority and Reservation bits All three token operations possible

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FDDI Optical Fiber 100 Mbps Reliability specified (dual ring) 4B/5B encoding Distributed clocking Timed Token Rotation Time Multi-token operation

Deparment of Computer science UOP.

More FDDI Details  

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FDDI Transmission on optical fiber requires ASK. The simplest case: coding is done via the absence or presence of a carrier signal {Intensity Modulation}. Specific 5-bit codeword patterns chosen to guarantee no more than three zeroes in a row to provide for adequate synchronization. 1300 nm wavelength specified. Normally, second ring is idle and used for redundancy for automatic repair (self-healing).

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CIRCUITE OF FDDI

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Deparment of Computer science UOP.

Lets see How it works!!!!!!

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Deparment of Computer science UOP.

Now if A Node stop Working.

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Deparment of Computer science UOP.

A MESSAGE HADEES NABVI(SAW.)

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Thanks!!! Have a nice day!!

Deparment of Computer science UOP.