Download - Fddi and isdn
FDDI and ISDN
-Vivek Jeena
Timeline : Presentation
• FDDI: What it is?
– Basic Principle’s
– Physical Properties
– Architectural Model
– SMT PMD Layer
FDDI: Introduction
• FDDI: Fiber Distributed Data Interface(ANSI) • October 1992: By JAMES HAMSTRA at SPERRY(Now
UNISYS)
• Fiber Optics: Edge of 100Mbps
• Uses IEEE802.4 timed token
• Logical topology : Ring Based token Network
• “Dual Ring of trees”
• Primary ( Clockwise) and Secondary(Anti-clock wise) Rings.
FDDI: Basic Principles
• Uses TOKEN: a special sequence of bits.
• Token Circulates in the ring.
• No Collisions.
• During transmission token is captured by a node
and released after transmission.
• STANDARD: Secondary ring is kept for backup
How Token Moves
FDDI: Architecture
FDDI: SMT Layer
• OSI-RM’s Physical and Part of Data Link Layer
• SMT: Station Management- MAC,PHY,PMD
• SMT : Process in FDDI Device.
• PMD : Physical Medium Dependent
• PMD: Deals with Type of Media Interconnection and Physical Characteristics.
• PHY: Media Independent functions, uses 4B/5B Encoding Standard.
FDDI:Pro’s and Con’s
• Con’s:
– Higher Cost and Maintenance
– Professionals are needed to troubleshoot
• Pro’s:
– Higher Bandwidth
– Lower Attenuation
– Difficult tapping
– No collisions
ISDN: Introduction
• Integrated Services Digital Network
• Simultaneous Transmission of voice, data over PSTN
• Circuit Switched Network(Voice and Data)
• Provide Access to Packet Switched Network(Data)
• Doesn't Use Specific Protocol eg Q.931(L1,L2 and L3 of OSI-RM Context is used)
ISDN : Channels
• B channels : bearer channels(64Kbps)
– Carry information
• D channel :Delta channel(16Kbps)
– Used for signaling purposes
– Entire bandwidth is not used for signaling purpose
– Excess of 9.6 Kbps is available for packet switched data transmission applications
– Climate control, security alarm system etc.
ISDN : Devices
• NT1/NT2-4 wire conventional wiring connecting 2 wire local loop.
• TA- Terminal adapter connects TE2 devices to ISDN.
• TE1-Terminal Equipment 1, Specialized ISDN devices.
• TE2- Non ISDN Devices.
ISDN : Services
• One is known as the Basic Rate Interface or BRI
– Used in homes.
• The other is known as the Primary Rate Interface or PRI
– Used in large businesses
ISDN: BRI Use of 2B+1D channel
NT 1
ISDN Terminal Adapter
Phone Computer
ISDN BRI Line
2B +D
Network Terminator
ISDN: PRI
• 23B+1D Channel
• Delivered over T1-1.544Mbps
• Aggregate speed of PRI from all 23 B channels and the single D Channel is computed as follows:
– 23 * 64 + 64 + xx = 1.544 Mbps
• A separate DSU/CSU converts digital data frames from the communications technology used on a local area network (LAN) into frames appropriate to a wide-area network (WAN) and vice versa
ISDN : Pros and Cons
• Cons: – Not "always-on". – Expensive, considering its speed. – Generally requires on-site installation by an engineer. – Intermittent connections, Requires additional
hardware, new wiring, Difficult to get installed, Limited availability etc
• Pros – Signaling – Speed. – Multiple access
Refrences
• Amit Shah and D.Ramakrishnan, FDDI: A HIGH SPEED NETWORK, PTR PRENTICE HALL, 1994
• Cisco:Networking Basics.
• Wikipedia.org
• HTTP://WWW.CISCO.COM/UNIVERCD/CC/TD/DOC/CISINTWK/ITO_DOC/FDDI.HTM#XTOCID14
• http://www.pacbell.com/products/business/fastrak/networking/isdn/info/isdn-guide
• http://www.adtran.com/support/isu/mpfaq.html