1. IEEE Standards, FDDI, Collision Free Protocols
Taranum Shaikh-45
Samidha Rane-40
Deepali Patil-34
Priyanka Warekar-57

2. IEEE
STANDARDS 802.3

3. IEEE 802.3 (Ethernet CSMA/CD)
The Institute of Electrical and Electronics Engineers (IEEE) publish widely accepted LAN- recommened standards
IEEE 802
IEEE 802.1
(Inter-networking)
IEEE 802.2
(LLC)
IEEE (Ethernet CSMA/CD)
IEEE (Token Bus)
IEEE (Token Ring)
IEEE 802.6
( DQDB )

4. ETHERNET : IEEE 802.3
To fully understand IEEE802.3 standard , it is important to understand where it fits in a layered design and how it relates to other topics.
Network operations mainly performed on lowest 3 layers of OSI model.
The Data Link Layer perform services for the network layer & assumes the existence of the physical layer.
The DDL is responsible for accurate communication between 2 nodes in a n/w.
This involves frame formats, error checking and flow control.
DDL further divided into 2 sublayers:
Logical Link control(LLC)
Medium Access Control(MAC)

5. Fig. Data Link Layer refinement
Network Layer
IEEE standard
LLC
Data link layer
IEEE standard
MAC
Physical Layer
Fig. Data Link Layer refinement

6. MEDIUM ACCESS SUBLAYER
Pure Aloha
Slotted Aloha
Carrier Sense Multiple Access (CSMA)
CSMA with Collision Detection

7. IEEE (CSMA/CD)
The best known scheme for controlling a LAN on bus structure is CSMA/CD.
Many people incorrectly use the name ‘Ethernet’ to refer all CSMA/CD protocols,even though it really refers to a specific product that implements stds.
ETHERNET:
- It is a type of cabling & signaling specification
- It uses a cable sharing process called CSMA/CD.
- The media access protocols deal with the data collisions that can occur when different nodes on the n/w attempt to send the data at the same time.
Advantages:
# Inexpensive way to get highspeed upto 100 Mbps.
# Supports various wiring technologies.
# Easy to install

8. DLL provides the logic to control the CSMA/CD network
DLL provides the logic to control the CSMA/CD network. Its functions are: Data Encapsulation / Decapculation: It provides source & destination address . Keeps track of error detection & error correction field Media Access Mgmt : It transmits frame into physical layer & receives from it. It provides buffers to frame. - Data Encoding / Decoding: At transmitting side it encodes binary data stream to self clocking code. At receiver side, it decodes to binary code. - Channel Access : Senses a carrier on channel indicating channel status. Detects collision on channel on transmission station.

9. Fig. Table IEEE 802.3 Cable Standards
Medium option
Transmission Media
Signaling Technique
Data rate (Mbp)
Max. seg. Length(m) 1
10Base5
Coaxial Cable
Baseband (Manchester) 10
500 2
10Base2
“ “
185 3
Unshielded Twisted pair
“ “
250 4
10BaseT
100 5
10Broad36
Broadband (DPSK)
3600 6
10BaseF
Fiber optics
Baseband
2000

10. Format of IEEE 802.3 CSMA/CD frame
preamble
SFD DA SA
length
LLC data
pad
FCS
Preamble:7-octet pattern of alternating 0 and 1’s
SFD:start frame delimeter
DA:destination address
Length:length of LLC data field
LLC Data:data unit supplied by LLC
Pad:octets added to ensure that the frame is of size appropriate for CD operation
FCS:frame check sequence

11. IEEE
STANDARDS 802.4

12. IEEE STANDARD 802.4:TOKEN BUS

13. TOKEN BUS
LAN standards
Arranged in a logical ring
Highest numbered station may send the first frame
Passes permission to its immediate neighbor
Used a special control frame called token

14. 90 50
120
400 75
PHYSICAL TOPOLOGY

15. 50
400 75
120 90
LOGICAL SEQUNCE OF TOKEN PROCESSING

16. TOKEN BUS FRAME FORMAT

17. IEEE
STANDARDS 802.5

18. IEEE STANDARD 802.5-TOKEN RING
a number of stations connected by transmission links in a ring topology. Information flows in one direction along the ring from source to destination and back to source.
Medium access control is provided by a small frame, the token, that circulates around the ring when all stations are idle. Only the station possessing the token is allowed to transmit at any given time.
Unidirectional ring
Stations
Ring
interface
Fig: A Ring Network

19. Token Ring Operation Token Passing Method Priority and Reservation
When any station wants to send the frame , it seizes the token & transmit the frame to intended station.
Priority and Reservation
Station which wants to transmit the frame may reserve the token by entering its priority code in Access Control(AC) field of the token or data frame
Time Boundation
For each station, the token holding time is 10 milliseconds.
The Monitor Station
Monitor Station sets the timer on
If the token does not regenerate in the allotted time , it is assumed to be lost & then monitor station generates a new token.

20. Wire Center
Token ring has one difficulty that all stations have to be ON for passing token.
This problem is solved using Wire Center
Wire Center
Bypass relay
Fig: 4 Stations Connected via Wire Center

21. IEEE 802.5-Token Ring Frame Format
Token Frame Format
SD - Starting Delimiter
AC - Access Control
Four subfields
Priority bit field
Token bit field
Monitor bit field
Reservation bit field
ED - Ending Delimiter SD AC ED 1

22. Data Frame Format ~ FC Frame Control
Consist of two bit fields
First bit indicates type of information
Remaining seven bits contains information about token ring logic
Destination address & Source Address
Consists of physical address
Data
Contains data to transfer
Checksum
Used to detect errors
FS – Frame Status SD AC FC
Destination
Address
Source
Data
Checksum ED FS ~
or or No limit

23. IEEE
STANDARDS 802.6

24. IEEE STANDARD 802.6-DISTRIBUTED QUEUE BUS (DQDB) MAN
DQDB specification designed to be used in MAN
Architecture of DQDB
Direction of flow on Bus A
Bus A 1 2 3 N
Head
end
Bus B
Direction of flow on Bus B
Head
end

25. FIBER DISTRIBUTED DATA INTERFACE
FDDI
FIBER DISTRIBUTED DATA INTERFACE

26. FDDI Network that Data flows+
FDDI Network that Data flows

27. Same Network after the station has failed

28. FDDI Frame Format Byte >= 8 No limit Destination Address Source4 1 1
Preamble
Destination
Address
Source
Data
Checksum
Ending Delimiter
Frame control
Frame Status
Starting Delimiter

29. Destination Address(DA) and Source Address(SA):
Preamble:
-Preamble field is 8 bytes long. It is used to synchronize the receiver’s clock with sender’s clock.
Starting Delimiter(SD) and Ending Delimiter(ED):
- The starting delimiter and ending delimiter fields mark the frame boundaries.
Frame Control
-FC field defines the frame type (whether data or control frame).
Destination Address(DA) and Source Address(SA):
-DA and SA fields are 2 bytes or 6 bytes or 6 bytes of length and both are same as ……
Data
Checksum

30. COLLISION FREE PROTOCOLS

31. Collision Free Protocols
Bit-Map Protocol
Binary Countdown

32. A Bit- map protocol 8 Contention Slots 8 Contention Slots 1 2 3 4 5 6
Frames
Frames 1 2 3 4 5 6 7 1 2 3 4 5 6 7 1 1 1 1 3 7 1 1 1 5

33. A Bit- map protocol Reservation protocols.
Low numbered station must wait on average 1.5N slots.
At low loads only d/(d+N) efficient.
High numbered station must wait on average 0.5N slots.
At high loads d/(d+1) efficient.
N slots 1 2 3 4 5 6 7 d 1 4
N/2 slots 1 2 3 4 5 6 7 1 1 1 1 1 1 1 2 3 5 7

34. Binary Countdown Bit Time Station Result 1 2 3 0 0 1 0 0 1 0 0 1 0 0 11 2 3 1 1 1
Result 1 1

35. Binary Countdown It was used in data kit.
Higher numberes station have higher priority.
The channel efficiency is d/(d+ log2N)

36. Binary Countdown Mok and Ward(1979)
Variation of binary countdown using parallel interface
Virtual station numbers

37. C H D A G B E F 7 6 5 4 3 2 1 C H A G B E F D 7 6 5 4 3 2 1 Station
Priority 7 6 5 4 3 2 1
Station C H A G B E F D 7 6 5 4 3 2 1
Priority

38. THANK
YOU