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Practical Routers & Switches for Electrical Engineers

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Routers and switches are primary components of most networks and obviously internetworks. Routers are simultaneously the most complex component of networks and the most important. This workshop goes …

Routers and switches are primary components of most networks and obviously internetworks. Routers are simultaneously the most complex component of networks and the most important. This workshop goes through the basics of routers, routed and routing protocols and the basic rules to follow in building internetworks. If you are using any form of communication system or are applying modern PLCs/SCADA systems this workshop will give you the essential tools in working with networks. It is not an advanced workshop – but a hands-on one.

MORE INFORMATION: http://www.idc-online.com/content/practical-routers-switches-engineers-technicians-2

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  • 1. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Routers and Switches by Steve Mackay from Engineering Institute of Technology
  • 2. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare EIT Micro-Course Series • Every two weeks we present a 35 to 45 minute interactive course • Practical, useful with Q & A throughout • PID loop Tuning / Arc Flash Protection, Functional Safety, Troubleshooting conveyors presented so far • Upcoming: – Electrical Troubleshooting and much, much more….. • Go to: http://www.idc-online.com/slideshare • You get the recording and slides
  • 3. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Topics Attend this complimentary session and gain an understanding on how routers and switches operate based on the TCP/IP suite of protocols.
  • 4. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Topics • Detail how TCP/IP protocol works • How a router and switch operate • Examine Routing Basics • Simple Troubleshooting Tips
  • 5. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Why Bother ? Useful to understand how routers work so that you can more effectively design and troubleshoot your TCP/IP networks.
  • 6. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare 1.0 How TCP/IP Works
  • 7. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare The OSI Model OSI LAYER PROTOCOL IMPLEMENTATION ARPA LAYER APPLICATION File Transfere Electronic Mail Terminal Emulation File Transfer Client/Server Network Management PRESENTATION File Transfer Protocol (FTP) Simple Mail Transfer Protocol (SMTP) TELNET Protocol Trivial File Transfere Protocol (TFTP) Sun Microsystems. Network file Systems Protocol (NFS) Simple Network Management Protocol (SNMP) PROCESS AND APPLICATION SESSION MIL-STD 1780 RFC 959 MIL-STD 1781 RFC 821 MIL-STD 1782 RFC854 RFC 783 RFC's 1014, 1057 & 1094 RFC 1157 TRANSPORT Transmission Control Protocol (TCP) MIL-STD 1778 RFC 793 User Datagram Protocol (UDP) RFC 768 HOST TO HOST NETWORK Address Resolution ARP RFC 826 & RARP RFC 903 Internet Protocol (IP) MIL STD 1777 & RFC 791 Internet Control Message Protocol (ICMP) RFC 792 INTERNET DATA LINK Network Interface Cards: Ethernet, Token-Ring, ARCNET, MAN and WAN. RFC 894, 1042, 1201 and others NETWORK PHYSICAL Transmission Media: Twisted pair cable, Coaxial Cable, Fiber Optics, Wirless Media etc. etc. INTERFACE
  • 8. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare IP Protocol • Primarily for routing • Version 4 uses 32-bit address • Version 6 uses 128-bit address • IP is hierarchical vs MAC which is flat and unique for each node
  • 9. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare IP address Notation – The IP address consists of 32 bits, e.g. 11000000011001000110010000000001. – Four octets, which for ease of reference could be called a,b,c,d or w,x,y,z. We then convert each octet to decimal and write it thus: • w x y z • 11000000.01100100.01100100.00000001 • or • 192.100.100.1
  • 10. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare NetId and HostId • Two portions to IP address • Network ID (NetID) • Host ID (HostID)
  • 11. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Transmission Control Protocol • Connection oriented • Reliable • Establishes a session before data is transmitted • Significant overhead in processing and header
  • 12. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare TCP functions • Fragmentation • Data stream reconstruction • Receipt acknowledgement • Socket services for multiple connections • Packet verification and error control • Flow Control • Packet sequencing and reordering
  • 13. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Ports and Sockets • TCP needs to know which process on a particular machine the packet is destined for. • Done by port assignments • Specific port numbers are assigned by the IANA • Well know ports • IP address + Port number = socket • Thus three addresses are used: (MAC/IP/Port#)
  • 14. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 SOURCE PORT DESTINATION PORT SEQUENCE NUMBER ACKNOWLEDGEMENT NUMBER OFFSET RESERVED U A P R S F WINDOW CHECKSUM URGENT POINTER OPTIONS AND PADDING DATA TRANSMISSION CONTROL PROTOCOL (TCP) HEADER U URG Urgent Pointer Field iis Valid A ACK Acknowledgement is Valid P PSH This Segment Requests a Push R RST reset the Connection S SYN Synchronise Sequence Numbers F FIN Sender at the End of its Byte Stream
  • 15. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare TCP Header Format 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 SOURCE IP ADDRESS DESTINATION IP ADDRESS ZERO PTCL TCP LENGTH 12 Octets of a Pseudo Header
  • 16. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare User Datagram Protocol The format of Fields in a UDP Datagram 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 UDP SOURCE PORT UDP DESTINATION PORT UDP MESSAGE LENGTH UDP CHECKSUM DATA …..
  • 17. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare APPLICATION LAYER PROTOCOLS
  • 18. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare 2.0 How a Router and Switch Operate
  • 19. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Fundamentals • Routers are used to interconnect multiple networks. • Connected over wide geographical areas with WAN’s
  • 20. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare • Act of moving information across an Internet work from a source to a destination Routing
  • 21. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Routing metrics • Path length • Reliability • Delay • Bandwidth • Load • Communication cost
  • 22. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Components of Router • CPU and RAM • BIOS • Operating System (eg Cisco’s Internetwork Operating system) • Motherboard • I/O Ports
  • 23. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Two methods of Operation • Static routing • Dynamic Routing – Distance Vector – Link-state – Hybrids
  • 24. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Static Routing • Fixed static routes configured by network administrator. • Optimum routes are programmed in. • Good for security as ingress into yur network can be controlled.
  • 25. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Three methods of dynamic routing • Distance vector • Link-state • Hybrids
  • 26. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Distance-vector routing • Periodically pass copies of their tables to immediate network neighbours. • Each recipient adds a distance vector to its table.
  • 27. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Advantages of distance-vector • Simple to configure/maintain and use. • RIP uses only distance to work out best route.
  • 28. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Drawbacks to Distance-vector • Some time to converge on new understanding of network. • Bandwidth and traffic levels can affect performance of network.
  • 29. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Link-state routing • Shortest path first protocols • Exchange of link-state advertisements (LSA) to other routers. • LSA’s are triggered by an event rather than running periodically.
  • 30. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Disadvantages of Link State • Flood the network during initial discovery process • Memory and processor intensive
  • 31. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Advantages • Gracefully weather effects of topology changes • Lower overheads as no time-driven updates • Better scalability for networks
  • 32. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Hybridized Routing • Use distance vector metrics • More accurate than conventional distance- vector protocols • Converge more rapidly than distance-vector but avoid overheads of link-state updates. • Best example is EIGRP.
  • 33. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Convergence • Whenever a change occurs in a network’s topology, all routers must develop a new understanding of new topology. • Routers take time to converge to the new consensus of what the topology is.
  • 34. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare 3.0 Routing Protocols
  • 35. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Routing Protocols • RIP and • RIP 2 • IGRP • OSPF
  • 36. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Routing Information Protocol • One of the oldest routing protocols. • RIP uses a special packet to collect and share information about distances. • RIP is a routing protocol; not a routed protocol (e.g. TCP/IP).
  • 37. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Operation of RIP • Routers periodically pass copies of their routing tables to immediate neighbours. • Each recipient adds a distance vector to the table and forwards the table to its immediate neighbours. • RIP uses as a metric the hop count. • RIP only records one route per destination (even if there are more).
  • 38. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Limitations of RIP (Routing Information Protocol) • Hop count restriction • Least hop path • High routing overhead • Routing flexibility is not allowed
  • 39. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare RIP Packet format
  • 40. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare RIP packet fields • Command • Version number • Zero • Address-Family Identifier (AFI) • Address • Metric
  • 41. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Routing table
  • 42. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Routing table Routing table provides: • Ultimate destination • Next hop on the way to that destination • A metric
  • 43. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Routing database • IP Address • Gateway • Distance • Route change flag • Timers
  • 44. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare RIP algorithm • Update • Propagation
  • 45. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare
  • 46. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare RIP-2 • Authentication • Subnet Masks • Next Hop IP Addresses • Multicasting RIP-2 messages
  • 47. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare IP RIP 2 packet
  • 48. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare IP RIP 2 packet format fields • Command • Version • Address-Family Identifier (AFI) • Route tag • IP address • Subnet mask • Next hop • Metric
  • 49. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Limitations of RIP-2 • 15-hop maximum • Counting to infinity (e.g. routing loop) • Static distance vector metrics • Lack of alternative routes (single routes)
  • 50. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Interior Gateway Routing Protocol (IGRP)
  • 51. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Goals of IGRP • Stable routing • Fast response to changes • Low overhead • Splitting traffic • Account error rates • Handle multiple types of service
  • 52. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Metrics • Hop count • Packet size (Maximum Transmission Unit - MTU) • Link’s bandwidth • Delay • Loading • Reliability
  • 53. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Formula - Metric • Metric = K * Bandwidth + (K2 * Bandwidth)/(256 - Load) + K3 * Delay • K1,K2 and K3 are weighting factors
  • 54. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Reliability added in... • Metric = Metric * [K5/(reliability +K4)
  • 55. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Limitations of IGRP • Does not include subnet mask information • Does not support the use of VLSM • Sends updates to the broadcast address
  • 56. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Open Shortest Path First (OSPF) • Link State Routing Protocol • Distance vector know nothing about topology of network • OSPF assign a “path cost” to routes • Divide reference bandwidth by circuits preconfigured bandwidth
  • 57. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Example of calculation • Cisco uses reference bandwith of 100MBps • 100 MBps circuit has an OSPF cost of 100/100 = 1 • A 1.544Mbps circuit has an OSPF cost of 100/1.544 = 65 • OSPF routers pick the lowest cost path (i.e. highest speed)
  • 58. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare 4. Simple Troubleshooting Tips
  • 59. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Network Troubleshooting • Knowledge of networking protocols • Understanding of networks’ topology and layout • Troubleshooting tools • Some luck ? Preferably not.
  • 60. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Network Troubleshooting (cont.) • Utilisation on the Ethernet network • Low utilisation but high errors • High number of packets but low data transfer
  • 61. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare TCP/IP Utility Programs for Troubleshooting • netstat • ping • traceroute • arp • ripquery
  • 62. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Example of the use of a few of the TCP/IP utilities together • ping • netstat-nr • Tracert (or traceroute)
  • 63. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Unreliable Connections • ping • tracert (or traceroute) • netstat • ping-f • netstat
  • 64. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Network Congestion • ping • tracert(or traceroute)
  • 65. www.eit.edu.au Technology Training that Workswww.idc-online.com/slideshare Thank You For Your Interest If you are interested in further training, please visit: http://www.idc-online.com/slideshare