Network topology & TCP/IP
Model
Cyber Security
Topology
• Topology refers to the layout of connected
devices on a network.
• Here, some logical layout of topology.
oMesh...
Network Topology
Mesh Topology
• Here every device has a point to point link to
every other device.
• Node 1 node must be connected with n-...
Mesh Topology
Advantages:
1. They use dedicated links so each link can only
carry its own data load. So traffic problem ca...
Mesh Topology
Mesh Topology
Mesh Topology
• Disadvantages:
1. The amount of cabling and the number of I/O ports
required are very large. Since every d...
Mesh Topology
• Applications:
1. Telephone Regional office.
2. WAN.(Wide Area Network).
Star Topology
• Here each device has a dedicated point-to-point link
to the central controller called “Hub”(Act as a
Excha...
Star Topology
Star Topology
Star Topology
• Advantages:
1. Less expensive then mesh since each device is
connected only to the hub.
2. Installation an...
Star Topology
• Disadvantages:
1. Even it requires less cabling then mesh when
compared with other topologies it still lar...
Applications
• Star topology used in Local Area Networks(LANs).
• High speed LAN often used STAR.
Bus Topology
• A bus topology is multipoint.
• Here one long cable act as a backbone to link all the
devices are connected...
Bus Topology
Bus Topology
Bus Topology
Bus Topology
Bus Topology
• A device want to communicate with other device on
the n/ws sends a broadcast message onto the wire all
othe...
Bus Topology
• Advantages:
1. Ease of installation
2. Less cabling
Disadvantages:
1. Difficult reconfiguration and fault i...
Bus Topology
• Applications:
• Most computer motherboard.
Ring Topology
• Here each device has a dedicated connection with two
devices on either side.
• The signal is passed in one...
Ring Topology
Ring Topology
Ring Topology
Ring Topology
• Advantages:
1. Easy to install.
2. Easy to reconfigure.
3. Fault identification is easy.
Disadvantages:
1....
Ring Topology
• Applications:
• Ring topologies are found in some office buildings or
school campuses.
• Today high speed ...
Tree Topology
• Alternatively referred to as a star bus topology.
• Tree topology is one of the most common network
setups...
Tree Topology
Hybrid Topology
• A network which contain all type of physical
structure and connected under a single backbone
channel.
Hybrid Topology
• a
TCP/IP protocol family
• IP : Internet Protocol
o UDP : User Datagram Protocol
• RTP, traceroute
o TCP : Transmission Cont...
OSI and Protocol Stack
OSI: Open Systems Interconnect
OSI Model TCP/IP Hierarchy Protocols
7th
Application Layer
6th
Prese...
Packet Encapsulation
 The data is sent down the protocol stack
 Each layer adds to the data by prepending headers
22Byte...
IP
• Responsible for end to end transmission
• Sends data in individual packets
• Maximum size of packet is determined by ...
IP addresses
• 4 bytes
o e.g. 163.1.125.98
o Each device normally gets one (or more)
o In theory there are about 4 billion...
IP Routing
• Routing Table
Destination IP address
IP address of a next-hop router
Flags
Network interface specification
Ap...
Applications of TCP
• Most things!
o HTTP, FTP, …
• Saves the application a lot of work, so used unless
there’s a good rea...
TCP implementation
• Connections are established using a three-way
handshake
• Data is divided up into packets by the oper...
TCP Packets
• Source + destination ports
• Sequence number (used to order packets)
• Acknowledgement number (used to verif...
TCP : Data transferHostClient
Send Packet 1
Start Timer
Retransmit Packet1
Start Timer
Packet should arrive
ACK should be ...
Thanks
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Computer Security

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Computer Security

  1. 1. Network topology & TCP/IP Model Cyber Security
  2. 2. Topology • Topology refers to the layout of connected devices on a network. • Here, some logical layout of topology. oMesh oStar oBus oRing oTree and Hybrid
  3. 3. Network Topology
  4. 4. Mesh Topology • Here every device has a point to point link to every other device. • Node 1 node must be connected with n-1 nodes. • A fully connected mesh can have n(n-1)/2 physical channels to link n devices. • It must have n-1 I/O ports.
  5. 5. Mesh Topology Advantages: 1. They use dedicated links so each link can only carry its own data load. So traffic problem can be avoided. 2. It is robust. If any one link get damaged it cannot affect others. 3. It gives privacy and security.(Message travels along a dedicated link) 4. Fault identification and fault isolation are easy.
  6. 6. Mesh Topology
  7. 7. Mesh Topology
  8. 8. Mesh Topology • Disadvantages: 1. The amount of cabling and the number of I/O ports required are very large. Since every device is connected to each devices through dedicated links. 2. The sheer bulk of wiring is larger then the available space. 3. Hardware required to connected each device is highly expensive.
  9. 9. Mesh Topology • Applications: 1. Telephone Regional office. 2. WAN.(Wide Area Network).
  10. 10. Star Topology • Here each device has a dedicated point-to-point link to the central controller called “Hub”(Act as a Exchange). • There is no direct traffic between devices. • The transmission are occurred only through the central “hub”. • When device 1 wants to send data to device 2; First sends the data to hub. Which then relays the data to the other connected device.
  11. 11. Star Topology
  12. 12. Star Topology
  13. 13. Star Topology • Advantages: 1. Less expensive then mesh since each device is connected only to the hub. 2. Installation and configuration are easy. 3. Less cabling is need then mesh. 4. Robustness.(if one link fails, only that links is affected. All other links remain active) 5. Easy to fault identification & to remove parts. 6. No distruptions to the network then connecting(or) removing devices.
  14. 14. Star Topology • Disadvantages: 1. Even it requires less cabling then mesh when compared with other topologies it still large.(Ring or bus). 2. Dependency(whole n/w dependent on one single point(hub). When it goes down. The whole system is dead.
  15. 15. Applications • Star topology used in Local Area Networks(LANs). • High speed LAN often used STAR.
  16. 16. Bus Topology • A bus topology is multipoint. • Here one long cable act as a backbone to link all the devices are connected to the backbone by drop lines and taps. • Drop line- is the connection b/w the devices and the cable. • Tap- is the splitter that cut the main link. • This allows only one device to transmit at a time.
  17. 17. Bus Topology
  18. 18. Bus Topology
  19. 19. Bus Topology
  20. 20. Bus Topology
  21. 21. Bus Topology • A device want to communicate with other device on the n/ws sends a broadcast message onto the wire all other devices see. • But only the intended devices accepts and process the message.
  22. 22. Bus Topology • Advantages: 1. Ease of installation 2. Less cabling Disadvantages: 1. Difficult reconfiguration and fault isolation. 2. Difficult to add new devices. 3. Signal reflection at top can degradation in quality. 4. If any fault in backbone can stops all transmission.
  23. 23. Bus Topology • Applications: • Most computer motherboard.
  24. 24. Ring Topology • Here each device has a dedicated connection with two devices on either side. • The signal is passed in one direction from device to device until it reaches the destination and each device have repeater. • When one device received signals instead of intended another device, its repeater then regenerates the data and passes them along. • To add or delete a device requires changing only two connections.
  25. 25. Ring Topology
  26. 26. Ring Topology
  27. 27. Ring Topology
  28. 28. Ring Topology • Advantages: 1. Easy to install. 2. Easy to reconfigure. 3. Fault identification is easy. Disadvantages: 1. Unidirectional traffic. 2. Break in a single ring can break entire network.
  29. 29. Ring Topology • Applications: • Ring topologies are found in some office buildings or school campuses. • Today high speed LANs made this topology less popular.
  30. 30. Tree Topology • Alternatively referred to as a star bus topology. • Tree topology is one of the most common network setups that is similar to a bus topology and a star topology. • A tree topology connects multiple star networks to other star networks. Below is a visual example of a simple computer setup on a network using the star topology.
  31. 31. Tree Topology
  32. 32. Hybrid Topology • A network which contain all type of physical structure and connected under a single backbone channel.
  33. 33. Hybrid Topology • a
  34. 34. TCP/IP protocol family • IP : Internet Protocol o UDP : User Datagram Protocol • RTP, traceroute o TCP : Transmission Control Protocol • HTTP, FTP, ssh
  35. 35. OSI and Protocol Stack OSI: Open Systems Interconnect OSI Model TCP/IP Hierarchy Protocols 7th Application Layer 6th Presentation Layer 5th Session Layer 4th Transport Layer 3rd Network Layer 2nd Link Layer 1st Physical Layer Application Layer Transport Layer Network Layer Link Layer Link Layer : includes device driver and network interface card Network Layer : handles the movement of packets, i.e. Routing Transport Layer : provides a reliable flow of data between two hosts Application Layer : handles the details of the particular application
  36. 36. Packet Encapsulation  The data is sent down the protocol stack  Each layer adds to the data by prepending headers 22Bytes 20Bytes 20Bytes 4Bytes 64 to 1500 Bytes
  37. 37. IP • Responsible for end to end transmission • Sends data in individual packets • Maximum size of packet is determined by the networks o Fragmented if too large • Unreliable o Packets might be lost, corrupted, duplicated, delivered out of order
  38. 38. IP addresses • 4 bytes o e.g. 163.1.125.98 o Each device normally gets one (or more) o In theory there are about 4 billion available
  39. 39. IP Routing • Routing Table Destination IP address IP address of a next-hop router Flags Network interface specification Application Transport Network Link Application Transport Network Link Network Link Source Destination Router
  40. 40. Applications of TCP • Most things! o HTTP, FTP, … • Saves the application a lot of work, so used unless there’s a good reason not to
  41. 41. TCP implementation • Connections are established using a three-way handshake • Data is divided up into packets by the operating system • Packets are numbered, and received packets are acknowledged • Connections are explicitly closed o (or may abnormally terminate)
  42. 42. TCP Packets • Source + destination ports • Sequence number (used to order packets) • Acknowledgement number (used to verify packets are received)
  43. 43. TCP : Data transferHostClient Send Packet 1 Start Timer Retransmit Packet1 Start Timer Packet should arrive ACK should be sent ACK would normally Arrive at this time Receive Packet 1 Send AXK 1 Time Expires Receive ACK 1 Cancel Timer Packet Lost Timer Timer
  44. 44. Thanks

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