A Introductory Overview of FDDI and ISDN Technologies.

1. FDDI and ISDN
-Vivek Jeena

2. Timeline : Presentation
• FDDI: What it is?
– Basic Principle’s
– Physical Properties
– Architectural Model
– SMT PMD Layer

3. 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.

4. 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

5. How Token Moves

6. FDDI: Architecture

7. 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.

8. 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

9. 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)

10. 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.

11. 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.

12. 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

13. ISDN: BRI
Use of 2B+1D channel
NT 1
ISDN Terminal Adapter
Phone Computer
ISDN BRI Line
2B +D
Network
Terminator

14. 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

15. 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

16. 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.HT
M#XTOCID14
• http://www.pacbell.com/products/business/fastrak/networking/isdn/info/isdn-
guide
• http://www.adtran.com/support/isu/mpfaq.html