1 / 41

Network Topology Discovery

Network Topology Discovery. Anirudha U Bodhanker Anshuman Tiwari. Road-Map. Motivation. Requirement. What is SNMP. Our Design. Problems and Challenges. Future Extension. References. Motivation. Client : Computer Center IIT- Bombay

shantell
Download Presentation

Network Topology Discovery

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Network Topology Discovery Anirudha U Bodhanker Anshuman Tiwari

  2. Road-Map • Motivation. • Requirement. • What is SNMP. • Our Design. • Problems and Challenges. • Future Extension. • References.

  3. Motivation • Client : Computer Center IIT- Bombay • Network Administrator wants to keep track of topology. • It becomes easy for a new person to understand the N/W layout of a particular organization. • N/W management does not remain dependent on a particular individual who is aware of the layout. • And Helps in Decision Making • Add or Remove network element. • Existing software's are very costly: eg HP Openview costs around 2 Lakhs.

  4. Requirement • Discover Topology of IITB network. • Differentiate between Layer2 and Layer3 switches. • Provide a Graphical Interface for User to see details.

  5. SNMPSimple Network Management Protocol • Definition: • A standard for gathering statistical data about network traffic and the behavior of network components. • How • SNMP uses management information bases ( MIBs ). • Versions • SNMPv1 ( RFC 1157). • SNMPv2 ( RFC 1905/6/7). • SNMPv3 ( RFC 1905/6/7 2571/72/73/74/75).

  6. How SNMP Query Agent Network Management station Query for mib Response TRAP

  7. MIB Management Information Base • Definition • a database of objects that is managed and used by network management protocol. • Structure of Database. • Tree structure is used . • MIB Browser.

  8. Design For Discovery • Approach • Step1 : Find out all Routers and Interconnection between them. • Step2 : Find All switches and end points. • Step3 : Find Interconnection between switches . • Step4 : Join End Points to respective switches.

  9. Router Discovery Algo. For each router in router_set { get ipRouteTable ; For each entry in ipRouteTable { if ( ipRouteType = indirect && ipRouteDest not_in(router_set) { Add Router to routerset ; Add router -> ipRouteDest to edge_set; } } }

  10. Modified Router Discovery Algo. For each router in router_set { get ipRouteTable ; get ipAddrTable add to interface_table; For each entry in ipRouteTable { if ( ipRouteType = indirect ) { swap ipRoutDest with its interface if exsits(nterface_table); if( ipRouteDest not_in(router_set) { Add Router to routerset ; } Add router -> ipRouteDest to edge_set; } } }

  11. Final Router Discovery Algo. For each router in router_set { if router exsits(interface table) { next; } get ipRouteTable ; get ipAddrTable add to interface_table; For each entry in ipRouteTable { if ( ipRouteType = indirect ) { swap ipRoutDest with its interface if exsits(nterface_table); if( ipRouteDest not_in(router_set) { Add Router to routerset ; } Add router -> ipRouteDest to edge_set; } } }

  12. S1 R1 1 2 S2 R2 3 S3 2 1 S4 2 S5 1 Switch Discovery 1 S11 = { R1 } S12 = {S2,S3,S4,S5,R2} S21 = {S1,R1} S22 = {R2} S23 = {S3,S4,S5} S31 = {S1,S2,R1,R2} S32 = {S4,S5} S41 = {S1,S2,S3,R1,R2} S42 = {S5} S51 = {S1,S2,S3,S4,R1,R2} 1 2 1 1

  13. Switch Interconnection Algo For each switch in switch_set { get dot1dTpFdbTable; if ipAdd is a switch & is only ip on that port { draw edge between them; } }

  14. We Discovered KReSIT

  15. But Aero Dissconnected

  16. Correct Switch Interconnection Algorithm. For each S in ST { For each ‘x’ in PT(S) { For each Ei in PAT(S,PT) { For each Ek in PAT(S,PT) other than Ei { If (Ek disconnects S and Ei) { //(S)x-a(Ei)b-y(Ek) delete Ek from S and S from Ek; delete PAT(Ek,y’) from PAT(S,x); delete PAT(s.x’) from PAT(Ek,y); apply same procedure to all entries in PAT(Ek,y’) and PAT(S,x’); } } } } }

  17. S1 R1 S2 R2 S3 1 S4 2 S5 1 Example 1 S11 = { R1 } S12 = {S2,S3,S4,S5,R2} S21 = {S1,R1} S22 = {R2} S23 = {S3,S4,S5} S31 = {S1,S2,R1,R2} S32 = {S4,S5} S41 = {S1,S2,S3,R1,R2} S42 = {S5} S51 = {S1,S2,S3,S4,R1,R2} 2 1 2 3 1 2

  18. S1 R1 S2 R2 S3 1 S4 2 S5 1 S1 disconnects S2 and R1 1 S11 = { R1 } S12 = {S2,S3,S4,S5,R2} S21 = {S1,R1} S22 = {R2} S23 = {S3,S4,S5} S31 = {S1,S2,R1,R2} S32 = {S4,S5} S41 = {S1,S2,S3,R1,R2} S42 = {S5} S51 = {S1,S2,S3,S4,R1,R2} 2 1 2 3 1 2

  19. S1 R1 S2 R2 S3 1 S4 2 S5 1 S2 disconnects S1 and S3 1 S11 = { R1 } S12 = {S2,S3,S4,S5,R2} S21 = {S1,R1} S22 = {R2} S23 = {S3,S4,S5} S31 = {S1,S2,R1,R2} S32 = {S4,S5} S41 = {S1,S2,S3,R1,R2} S42 = {S5} S51 = {S1,S2,S3,S4,R1,R2} 2 1 2 3 1 2

  20. S1 R1 S2 R2 S3 1 S4 2 S5 1 S2 disconnects S1 and R2 1 S11 = { R1 } S12 = {S2,S3,S4,S5,R2} S21 = {S1,R1} S22 = {R2} S23 = {S3,S4,S5} S31 = {S1,S2,R1,R2} S32 = {S4,S5} S41 = {S1,S2,S3,R1,R2} S42 = {S5} S51 = {S1,S2,S3,S4,R1,R2} 2 1 2 3 1 2

  21. S1 R1 S2 R2 S3 1 S4 2 S5 1 S2 disconnects S3 and R2 1 S11 = { R1 } S12 = {S2,S3,S4,S5,R2} S21 = {S1,R1} S22 = {R2} S23 = {S3,S4,S5} S31 = {S1,S2,R1,R2} S32 = {S4,S5} S41 = {S1,S2,S3,R1,R2} S42 = {S5} S51 = {S1,S2,S3,S4,R1,R2} 2 1 2 3 1 2

  22. S1 R1 S2 R2 S3 1 S4 2 S5 1 S3 disconnects S2 and S4 1 S11 = { R1 } S12 = {S2,S3,S4,S5,R2} S21 = {S1,R1} S22 = {R2} S23 = {S3,S4,S5} S31 = {S1,S2,R1,R2} S32 = {S4,S5} S41 = {S1,S2,S3,R1,R2} S42 = {S5} S51 = {S1,S2,S3,S4,R1,R2} 2 1 2 3 1 2

  23. S1 R1 S2 R2 S3 1 S4 2 S5 1 S4 disconnects S3 and S5 1 S11 = { R1 } S12 = {S2,S3,S4,S5,R2} S21 = {S1,R1} S22 = {R2} S23 = {S3,S4,S5} S31 = {S1,S2,R1,R2} S32 = {S4,S5} S41 = {S1,S2,S3,R1,R2} S42 = {S5} S51 = {S1,S2,S3,S4,R1,R2} 2 1 2 3 1 2

  24. S1 R1 1 2 S2 R2 3 S3 2 1 S4 2 S5 1 Final Switch Table 1 S11 = { R1 } S12 = {S2} S21 = {S1} S22 = {R2} S23 = {S3} S31 = {S2} S32 = {S4} S41 = {S3} S42 = {S5} S51 = {S4} 2 1

  25. Finally we Discovered Aero Connection

  26. Interface • Providing a Web interface. • Features • Display Tree Structure of devices. • Search for a IP in current database. • Get dynamic Information for a IP. • Display information of different interface of routers. • Graphical View For network.

  27. Problems Faced • Not unique Access Specifier Throughout IITB. • Not a common version for SNMP. • Different MAC address Format. • “0:40:d:c0:2f:69” • ”00 00 AA 61 DC 40” • “000086487cd9”

  28. Challenges • How To Differentiate between L2 and L3 switches. • Which Particular MIB objects to use for Required Information. • The Router/Switch Discovery Algorithms are not well defined in any paper.

  29. Protocol and Tools • SNMP protocol. • Perl (Backend). • PHP (Interface). • DOT ( Graphs ).

  30. Learn From Project • SNMP protocol. • How to work on project. • How generally network layout. • Details of PERL, PHP,DOT.

  31. Future Extension • Network Diagnostics • Analysis of traffic pattern. • Handling of Systems via Network. • More Advanced GUI.

  32. References • Douglas R. Mauro and Kevin J.Schmidt, "Essential SNMP" , O'REILLY. • Rose, M., and K. McCloghrie, "Structure and Identification of Management Information for TCP/IP-based Internets", RFC 1155, Performance Systems International and Hughes LAN Systems, May 1990. • Bruce Lowekamp, David R. O'Hallaron, Thomas R. Gross, " Topology Discovery for large ethernet Networks",Proceedings of SIGCOMM 2001. • Y Bejerano, Y Breitbart, M Garofalakis, R Rastogi , " Physical Topology Discovery for Large Multi-Subnet Networks", Proc. of IEEE INFOCOM, 2003.

  33. References (contd.) • McCloghrie, K., and M. Rose, "Management Information Base for Network Management of TCP/IP-based Internets", RFC 1156, Hughes A Systems and Performance Systems International, May1990. • Case, J., M. Fedor, M. Schoffstall, and J. Davin, “The Simple Network Management Protocol", RFC 1157, University of Tennessee at Knoxville, Performance Systems International, Performance Systems International, and the MIT Laboratory for Computer Science, May 1990. • Y Breitbart, M Garofalakis, B Jai, C Martin, R. Rastogi, Avi Silberschatz, "Topology Discovery in Heterogeneous IP Networks: The NetInventory System", IEEE/ACM Transactions on Networking (TON), 2004

  34. Thanks. 

  35. Difference between SNMP version • Version2 • Still in experimental phase. • some new mibs. • Version3 • future version. • strong authentication and private communication.

  36. Diffrence between L2 and L3 switch • Layer 2 switches forward traffic based on physical network addresses. • Layer 3 switches read network addresses more closely, identifying network locations as well as the physical device.

  37. Diffrence between Router and L3 switch • Packet-forwarding decisions based not only on physical address (such as MAC address) and IP address, but also on the application protocol being used.

  38. ipRouteTable Query • snmptable -v $specifier $ip ipRouteTable • $Specifier = “.anshuman.” / “.anirudha.” • $ip = ip for query. • ipRouteTable Format • ipRouteDest| • diffrentmetric(4) • ipRouteNextHop • ipRouteType (direct,indirect). • ipRouteProto.

More Related