The document provides an overview of data communication and networking in manufacturing systems. It discusses protocols, layered communication models like the ISO model, and physical network technologies. It introduces the TCP/IP model and motivations for the Internet, including universal connectivity and independence from physical networks. Key topics covered include IP addressing, packet formats, routing between networks, and Ethernet communication.

1. Data Communication & Networking in
Manufacturing System
Data Communication & Networking in
Manufacturing System
N. A. Sutisna
PLM Consultant, IBM Indonesia
Lecturer, President University

2. Chapter 5
Introduction to computer
communication networks
Chapter 5
Introduction to computer
communication networks
Data Communication & Networking in
Manufacturing System
Data Communication & Networking in
Manufacturing System

3. Protocol
 A protocol is a series of steps, involving two or more parties,
designed to accomplish a task
 Everyone involved in the protocol must know the protocol and
all of the steps to follow in advance
 Everyone in the protocol must agree to follow it
 The protocol must be unambiguous; each step must be well
defined and there must be no chance of a misunderstanding.
 The protocol must be complete; there must be a specified
action for every possible situation.

4. Communication Protocol Model
 A template to describe a protocol
 It has three components
 Address: naming
 Format: messages
 Behavior: rules Protocol Model
Address:
- how to name a partner
Format:
- specify the message formats
Rules:
- specify the behaviors of the
protocol
- what should be done when
something happens

5. Address:
phone number xxx-xxxx
Format:
English
Rules:
- dial when initiating
- pick up phone when
ringing
- ...
Phone conversation Protocol
Protocol Example: Phone

6. Can a single protocol do it all?
 Computer communication has to deal all sorts of problems
 Electrical/Optical signals/noise
 Errror detection and recovery
 medium control access
 message boundary
 routing, fragmentation
 flow control (net congestion)
 loss and duplicated messages
 synchronization
 representation
 application specific
 Yes. It can be done but
 how to develop in timely fashion (debug, verify and low cost)
 how to maintain it
 how to extend and evolve it

7. Layered Approach
 Divide and conquer
 partition into multiple layers of software
 each layer has clear programming interfaces
 each interface provides a service to adjacent layers
 each layer solves a limited set of problems
 each layer encapsulates the related details
 Pros
 reduce complexity, isolate changes, promote
manageability
 Cons
 efficiency

8. ISO Reference Model
 Not every layer is created equal
 physical and data link are hardware heavy
 network and transport are software heavy
 session and presentation are typically light layers
Some functions occurs in
multiple layers:
+ Error handling may be in
every layer
+ Flow control can be in
multiple layers
Layer Number Layer Name Problems to Be Solved
7 Application layer application specific (Lab #2)
6 Presentation layer data representation (XDR)
5 Session layer synchronization & dialog (client/server)
4 Transport layer reliable delivery of messages (sockets)
3 Network layer routing & fragmentation
2 Data link layer medium access control & framing
1 Physical layer signaling, physical connections

9. ISO vs. TCP/IPISO vs. TCP/IP
1. Physical
2.Data Link
3.Network
4.Transport
5.Session
6.Presentation
7.Application
Host to
network
Internet
Transport
Application

10. Physical layer protocols
 Highly physical network technology dependent
 Main tasks
 define the signaling protocol
 what is the meaning of 1s or 0s
 voltages or frequencies
 what is bad signals
 define the physical connections required
 RS232 connectors for RS232 serial line communication
 RJ45 or BNC connectors for Ethernet
 define the communication media
 define the network topology

11. Physical Network Technologies
 Circuit-switched network (CS)
 connection-oriented network
 establish connection before communication
 once communication established, a circuit line is
reserved for the communicating partners
 example: telephone network
 Packet-switched network (PS)
 store-forward based network
 packet sent from a node to another node
 the intermediate node stores the packet and decides to
forward to another node towards the destination
 no circuit line is reserved
 example: Ethernet

12. Circuit connection
in out
In Out
3 2
4 1
Routing table
In Out
2 4
Routing table
In Out
2 4
Routing table
In Out
2 2
3 4
Routing table
Host A
Host B

13. Comparisons: CS and PS
Circuit-switched Packet-switched
line resource dedicated shared
performance guaranteed averaged
cost expensive less
adaptive routing not easy easy
switch device highly complex simple
reliability high higher
utilization low higher

14. Network Types by Scope
 WAN
 wide area network
 cross large span of space (continental)
 typically heterogeneous and low speed
 example: Internet
 MAN
 metro-area network
 regional scope (city-wide)
 LAN
 local area network
 limited scope (a couple of buildings)
 typically homogeneous & high speed
 example: Ethernet & Token ring

15. Network Transmission Medium
 Open air
 radio, microwaves, satellites, infrared
 noise signals, collision
 Optical
 clear signals, low power and high rate (Gbps)
 Copper wire
 Lower cost interfaces
 Bi-directional

16. Bus Network Topology
 Every nodes tap into a common medium
 Signals may collide with each other
 need to arbitrate who will get the bus
 capable of broadcasting message (one send & many listen)
 the common medium is the bottleneck
 single node failure causes no network failure
 the medium failure brings down the network
 Example: (old, 10BASE2, 10BASE5) Ethernet
common medium

17. Cable ModemCable Modem

18. Star Network Topology
 One node at the center as the master node
 Other nodes linked to the master as slaves
 slaves communicate via master
 easy to arbitrate among slaves (master decides)
 not scalable (the master is the bottleneck)
 normally for small networks or that requires predictable
performance
 master failure shutdowns the whole net
 Example: Ethernet, DSL
Master
slave
slave
slave
slave slave

19. Ring Network TopologyRing Network Topology
 Nodes are arranged in a ring
 One node receives from its predecessor &
sends to its successor
• arbitrate who can access the ring
• messages forwarded by each node
• sender deletes its messages from the ring
• the common ring is the single point of failure (complicated
connectors needed)

20. Mash Network TopologyMash Network Topology
 Nodes are arranged in grids
• each node can talk to its neighbors directly
• non-neighbor nodes needs store-and-forward for
communication

21. Hyper Network TopologyHyper Network Topology
 No restrictions on how to link the nodes
 Topology can adapt to individual organization
needs
Master
slave
slave
slave
slave slave

22. Data Link Layer Protocols
 Main tasks
 medium access control
 arbitrate who can use the transmission medium
 framing
 define the boundaries of a packet
 Physical technology dependent (like physical layer)
 typically implemented in hardware or firmware
 when you buy a network card, you get both physical
and data link layer protocols in the card

23. Introduction to Internet and
TCP/IP
Introduction to Internet and
TCP/IP
Data Communication & Networking in
Manufacturing System
Data Communication & Networking in
Manufacturing System

24. Motivations for Internet
 Observations:
 Different physical networks everywhere
 connection between limited hosts
 different needs for different technologies
 legacy networks
 Limited connectivity
 each physical technology has its limits
 Different technologies use different “languages”
 Need for a uniform virtual network
 universal connectivity
 every host speaks the same language independent of
physical networks

25. Virtual Network over Physical Networks
…...Ethernet Token Ring
ATM
(Asynchronous Transfer Mode)
Internet Protocol (Network layer)
Internet
Virtual network
Physical network
hosts

26. Design Goals of Internet
 A virtual (global) network
 independent of physical technologies
 independent of locations
 universal language
 Universal connectivity
 every host is equal no matter of
 its architecture and system origin
 its physical network attachment
 Scalable
 growth without limits
 Robust
 no single point of failure

27. Problems to be Solved
 Universal naming
 how to translate the universal name to local name
used by local physical network?
 Routing
 how to route IP packages among different local
networks to reach the destination?
 Fragmentation
 different physical networks use different package
sizes.
 how this should be handled?
 Error handling

28. Internet Architecture
 Internet: ‘‘the mother of all
networks’’
 THE network of (interconnected) networks
 Physical networks interconnected via gateways
 Gateway(router) is a host glues nets together
 attached to multiple nets
 forward IP packages between nets
Token Ring
Gateway
Ethernet
Other nets Gateway

29. IP Packet Format
 IP packet consists of header and data portions
IP header IP data portion
V HL type total length
Identification F frag. offset
TTL prot header cksum
Source IP address
Destination IP address
options if any
IP Header Format

30. IP Address
 IP address specifies a connection to a network instead
of a host
 IP address == NetID + HostID
 Dotted notation
 each byte in an IP address represented as a decimal
 bytes are separated with a period (.)
 example: 152.15.35.44
 Classes
0 8 16 24 31
0 NetID HostID
10 NetID HostID
110 NetID HostID
1110 Multicast address
11110 reserved for future use
class A
class B
class C
class D
class E

31. How do computers talk to each other
on an ethernet bus
 Each computer on the internet as a unique IP address.
 Each network interface (e.g. ethernet card) has a unique
address
 8.2.1.1 wants to send a message 8.2.1.3
 It yells “yaahoo, who is 8.1.2.3”
 Each computer listens to messages on the bus (collision detection
and resolution) for “yaahoo”
 8.2.1.3 replies to 00550DA2F5D82 “I am 02950JX2F5Y82”
 8.2.1.1 sends the message to 8.2.1.3.
8.2.1.1 8.2.1.2 8.2.1.3
00550DA2F5D82 02550JA2F5D82 02950JX2F5Y82

32. IP Routing
 Principles
 Route packages according to their destination IP net ID
 Forward packages hop by hop
 each gateway has the routing knowledge of its nearby
neighbors
 hosts route packages to gateway and gateway does the rest.
 Routing types
 direct routing
 If the destination net ID is the same as the local net ID, no
routing to gateway is needed and send the package via
underlying physical network
 indirect routing
 if the destination net ID is different from the local net ID, send
the package to an appropriate gateway.

33. IP Rules
 Fragmentation rules
 if underlying net size < packet size & not final dest
 break packet into small packets and send them
 if final dest is reached & packets are fragmented
 reassemble fragmental packets into original size
 Error rules
 if IP header is erroneous, drop/report it

34. Table-Driven IP Routing
 Each IP host has a IP routing table
 each entry associates a destination net ID with a
forwarding gateway
 each route has a performance metrics
 number of hops to reach the destination
Route table for 152.15.36.9
152.15.x.x
uncc
ncsu
152.15.254.254
163.29.x.x
163.29.10.88
152.15.36.9
152.15.35.1
net3
e0
Dest. Net ID Next hop host NIF
163.29 152.15.254.2
54
e0
Default 152.15.35.1 e0

35. Routes in an IP Routing Table
 Next-hop routes
 the destination is an IP net ID: a packages
addressed to any host in the net, send to the
associated gateway
 Host-specific routines
 the destination is a complete IP address: route all
packages to the specified host via the associated
gateway
 Default routes
 the catch all routing: all packages not specified by
the above, send the gateway associated with the
default route.
 the gateway associated with the default route is
called default gateway

36. Topology of the internet
net: 9.1.1.x
net: 8.2.1.x
9.1.1.3
net 1.1.1.x
net 2.1.1.x
net 3.1.1.x
9.1.1.2
9.1.1.4
9.1.1.1
8.2.1.1
8.2.1.2 8.2.1.3
8.2.1.4
d
c
b
a
1 2 3
4
hardware addresses

37. Sub-netting
 All hosts in a network must have the
same net work number
 As the number of networks grow, so
does the need for net work numbers
 Solution: subnet, divide the host name
portion of the IP address into subnet id
and the host
 Subnet mask and routing table.

38. Intranet example: home networkingIntranet example: home networking
Router
PC
PC
PC
Broadband
provider
Internet
Internet IP
Address
Intranet IP
address
Intranet IP
address
Intranet IP
address
Intranet IP
address

39. PPP protocol (phone dialin)
 Computer (client) dials to a modem.
 Computer on the other (ISP server) end
is on the internet.
 The ISP server assigns an ip address for
the dialing computer
 All messages send from the client are
routed by the isp host to the rest of the
internet.

40. DHCP protocol (most ethernet)
 Client sends a message (on the local
bus) to a DHCP server requesting an IP
address for the session
 DHCP server assigns an ip address

41. IP Fragmentation
 IP packages are broken to fit underlying physical network
when a package is sent
 locations of fragmentation
 original package sender
 gateways that forward the package
 IP packages are reassembled at the final destination
gateway
fragment
net 1 net 2
assemble

42. IP Fragmentation Example
IP header 800 bytes 800 bytes 250 bytes
Original IP datagram
IP header
(fragment 1)
IP header
(fragment 2)
IP header
(fragment 3)
800 bytes
800 bytes
250 bytes
Fragment 1 (offset 0)
Fragment 2 (offset 800)
Fragment 3 (offset 1600)
fragmentation

43. ISO vs. TCP/IPISO vs. TCP/IP
1. Physical
2.Data Link
3.Network
4.Transport
5.Session
6.Presentation
7.Application
Host to
network
Internet
Transport
Application

44. Transport Layer
 Why do we need a transport layer?
 Network layer provides delivery only
 from a host to a host
 in a best effort fashion
 Users want to transport data
 from application to application
 in a reliable delivery
 Transport layer fits the gap between user needs and IP
messaging
 provide communication endpoint for applications
 deliver messages reliably

45. Problems to Be Solved in Transportation
layer
 Missing packets
 Duplicated packets
 Out of order packets
 Flow control
 Synchronization

46. Reliable Delivery via Unreliable
Networks
 Missing packet
 acknowledge and timeout
 retransmission
 Duplicate messages
 sequencing packets
 Out of order messages
 sequencing packets
 Flow control
 wait and stop
 window-sliding
 Synchronization
 hand shaking

47. Transport Protocols in TCP/IP
 User Datagram Protocol (UDP)
 provide communication endpoint for applications
 best effort delivery of messages (packets)
 message boundary is observed
 the protocol embedded in Internet Datagram sockets
 Transmission Control Protocol (TCP)
 provide communication endpoint for applications
 reliable delivery via connection-based
communication
 no message boundary between packages
 the protocol embedded in Internet Stream sockets

48. Establish a TCP Connection
 Three way handshaking
application 1 application 2
TCPpack p;
p.codebit=SYN;
p.seq_no = x; p.winsize=S1;
send (p);
tcp_state=SYNSENT;
receive(p);
p.ack = p.seq_no + 1;
p.seq_no = x++;
send(p);
tcp_state=ESTABLISHED
syn+x
TCPpack pack;
tcp_state=LISEN;
receive(pack);
pack.ack=pack.seq_no+1
pack.seq_no = y; pack.winsize=S2;
send(pack);
tcp_state=ESTABLISHED;
syn+ack+y
ack

49. Denial of service attacksDenial of service attacks
 Exploits the TCP session establishment
protocol.
 An attacker will send syn, but never sends
ack. This type of attack is also called “sync
flood”.
 Synchronized attacks launched on multiple
(often victim) machines.

50. TCP Retransmission
 Sender
 is free to divide user stream data in packets
 expects an ack for each packet sent
 starts a timer when a packet is sent
 upon an ack reception, advances seq_no expected
 upon a timer expiration, resends the packet
 Receiver
 sends an ack whenever a packet is received
 deletes the packet if it duplicated
 is free to pass acknowledged packets to user
 is forced to pass to user the data when receives a
PUSH