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SHEFFIELD HALLAM UNIVERSITY. SCHOOL OF COMPUTING AND MANAGEMENT SCIENCES. Experiment 11: Configuration of a remote LAN connection via ISDN COMPUTER NETWORK EXPERIMENT TITLE Configuration of a remote LAN connection via ISDN AIM To understand the requirements for remote LAN connections. To understand the technologies behind network bridgeing and ISDN. OBJECTIVES 1. Understand the basic concepts of ISDN 2. Understand the basic concepts of Bridging 3. Applythis knowledge to make a remote LAN connection. PRE-REQUISITES You should be familiar with Microsoft Windows 95 You should have read the notes in the Appendix. EQUIPMENT REQUIRED 2 x 3COM Office Connect 530s 2 x ISDN points 1 Hub port A management console for the 3COM equipment ESSENTIAL READING http://support.3com.com/infodeli/tools/remote/ocremote/brouters/ocr5ug/index.htm Office Connec t 530 User Guide, Sections; Example of typical ISDN Network Applications, and Bridging and Routing Business Data Communications and Networking J. Fitzgerald, & A. Dennis, Wiley 1996. Routing 220-222, 336,337, ISDN pp308, 309 FURTHER READING http://www.timm.demon.co.uk/ UK ISDN Guide http://www.ziplink.net/~ralphb/ISDN/ ISDN Tutorial http://www.isocws.isoc.org/course/t4/introroute/index.htm ISOC IP Routing http://www.3com.com/products/dsheets/400318.html 3COM OfficeConnect® Remote Access Routers Mark Jacobi Updated Dec '99 REQUIREMENTS You are required to read the attached notes and necessary preparation before attempting the practical exercise You should provide solutions to the questions posed throughout the exercise You should document your research and procedures QUESTIONS 1. What is an IP mask? 2. Why is the ISDN1 LED lit almost permanently even when you are not sending messages using IP? 3. Why does the ISDN2 LED only occasionally light up? 4. How would you reduce the amount of time that the ISDN line is in use (and hence reduce the ISDN billing cost)? 5. How would you improve the security for the local and remote sites? SCENARIO The scenario for this experiment is that an organisation has a LAN situated at its local office. The organisation has a number of staff operating at remote sites that need to connect to the local office. All of these remote sites have ISDN connections, some have their own LAN's but this particular one has just a single PC that needs connecting. FIGURE 1. Remote access configuration LAN Local Office Remote Site Hub ISDN Bridge ISDN ISDN Bridge ISDN ISDN Router Other Sites ISDN Mark Jacobi Updated Dec '99 INSTALLING AND TESTING THE ISDN BRIDGE The ISDN Bridges that we will be using are 3COM Office Connect Remote 530s. These can be configured as either Bridges or Routers. You must read the essential reading references to ensure that you understand the reasons for the configuration used.1 STAGE 1: CONNECTING THE EQUIPMENT 3C530-ONE COM port on managemen t terminal ISDN LAN Hub /Switch 3C530-TWO ISDN PC Network Card The two bridges are lablelled 3C530-ONE and 3C530-TWO. Bridge ONE will be connected to the existing LAN via a hub/switch and bridge TWO will be connected to the remote PC. Both bridges use 10BaseT connectors for connecting to the network. The bridges are configured and monitored using a terminal emulator application installed on the management terminal PC. Windows 95 and NT have a tool called Hyperteminal installed which is suitable. A terminal called 3COM.ht has already been setup, but if this cannot be found create a new terminal setting the baud rate to 9600, 8 data bits, 1 stop bit, no parity. 1. Connect the bridges to the ISDN lines using the ISDN cables provided, note the ISDN numbers on the ISDN boxes. 2. Connect bridge ONE to the hub/switch using a free port and bridge TWO to the network card on the remote PC. Ensure that the correct socckets on the Bridges are used. 3. Ensure that the MDI/MDIX Switch on the rear of the bridges is in the IN position on the bridge ONE and OUT on bridge TWO. This implements the 10BASET crossover that is required. 4. Connect the serial port on bridge ONE to the COM 2 port on the management terminal PC. You will be configuring this bridge first. 1 http://support.3com.com/infodeli/tools/remote/ocremote/brouters/ocr5ug/index.htm Office Connec t 530 User Guide, Sections; Example of typical ISDN Network Applications, and Bridging and Routing Mark Jacobi Updated Dec '99 The Bridges should now have the PWR. LINK, and ISDN OK lights illuminated indicating that power is connected, the LAN link is up and the ISDN connection is live. 5. Startup the Manager terminal PC and boot into Windows 95 6. Select 3Com.ht from the Program - Accessories-Hyperterminals menu on the START button. 7. Press the RETURN key and you will be prompted to enter a password. Type PASSWORD in capitals. You have now started the Management System and can begin configuring the bridges. STAGE 2: SETTING UP AN IP BRIDGE Before configuring the bridge you must return the bridge to its factory default settings. You should already be at the Main menu on the Management System. Type CO STD and answer Y to confirm. The unit will restart and run through its self test procedure. 2. You will then have to re-type the password, PASSWORD, to return to the Main menu. 1. The bridges have a Quick Configuration procedure for setting up basic connections. We will use these for simplicity. Each unit must also be allocated an IP address belonging to the same IP network as the LAN to which we are connecting. From the Main menu type QC to access the Quick Configuration menu. Type NA to setup the unit name and IP address. 4. Type 3C530-ONE for the Unit Name. 5. Type 143.52.57.60 for the unit's IP address. 6. Type 255.255.255.0 for the Unit LAN IP mask. 7. Leave the Network Type set at United Kingdom and the SPIDs, and Directory numbers blank, type ^E and then type SAVE to save these details. To check that the ISDN connection is OK perform a loopback test: 8. Type CO PO to monitor the status of the units ports. 9. Call the units own ISDN number by typing CALL 2761921. 3. If it works the ISDN1 and ISDN2 port's NAME fields will show "LOOPBACK!" and STAT "UP". Type CANC to cancel the call, and QC to return to the Quick Configuration menu. You can now setup the bridge to connet to an IP host on the same network. 11. Type IPB to setup the bridging parameters. 12. Type the ISDN number of the remote bridge, 2761468 13. leave the Call Type set at 64K unrestricted and IP address at the remote host set at Default. 14. Type ^E to submit. The unit will say 'Wait while learning'. It is now connecting to the other bridge and will create a table a learned devices. 15. Type SAVE . To view the address table type CO BR AD. 16. Type ^G to return to the main menu and type QUIT 10. Mark Jacobi Updated Dec '99 You must now setup the other Bridge. Move the manager terminal serial lead from bridge ONE to TWO. Press RETURN and enter the password PASSWORD Type CO STD and answer Y to confirm. The unit will restart and run through its self test procedure. 20. You will then have to re-type the password, PASSWORD, to return to the Main menu. 21. From the Main menu type QC to access the Quick Configuration menu. Type NA to setup the unit name and IP address. 22. Type 3C530-TWO for the Unit Name. 23. Type 143.52.57.61 for the unit's IP address. 24. Type 255.255.255.0 for the Unit LAN IP mask. 25. Leave the Network Type set at United Kingdom and the SPIDs blank, type ^E and then type SAVE to save these details. 17. 18. 19. To check that the ISDN connection is OK perform a loopback test: 26. Type CO PO to monitor the status of the units ports. 27. Call the units own ISDN number by typing CALL 2761468 If it works the ISDN1 and ISDN2 port's NAME fielsd will show "LOOPBACK!" and STAT "UP". 28. Type CANC to cancel the call, and QC to return to the Quick Configuration menu. You can now setup the bridge to connect to an IP host on the same network. Type IPB to setup the bridging parameters. Type the ISDN number of the remote bridge, 2761921 leave the Call Type set at 64K unrestricted and IP address at the remote host set at Default. 32. Type ^E to submit. The unit will say 'Wait while learning'. It is now connecting to the other bridge and will create a table a learned devices. To view this table type CO BR AD. You will be able to see addresses of all the devices that can be seen on the LAN 29. 30. 31. This quick configuration turns IP learning on and will build an Autocall entry after it has learned the ARP/IP entries. You can view the table of learned entries by typing CO IS AUTO. Once both units have learned the each other's ARP/IP entries an autocall will be placed based on traffic. When a workstation sends out ARP/IP packets the autocall entry will bring up the ISDN connection. If no data is being passed (based on the IDLE timeout set in the unit) the ISDN line will be dropped. When the unit detects data that needs to be passed the ISDN line will be re-established. 33. Type ^G to return to the main menu. Mark Jacobi Updated Dec '99 You have now setup the units for bridging and have connected the remote PC to the network. Obviously the local PC must support TCP/IP and have its own IP address, in this case it is 143.52.57.36 STAGE 3: TESTING THE IP CONNECTION Ensure that the remote PC has been correctly configured for TCP/IP networking. The network lab normally allocates IP addresses dynamically using the DHCP protocol.: 1. 2. 3. 4. 5. 6. Boot the remote PC into Windows 95, do not try to login to netware Select Start - Settings - Control Panel - Network to open the Network Setting window, and select the Protocols tab. Highlight TCP/IP and select Properties. Set the IP address for the PC. This can be found on a lable on the top of the tower case. Check the IP address is set to 143.52.57.125 and the subnet mask should be 255.255.255.0, the default gateway should be 143.52.57.2 select ok. Select the DNS tab an ensure the following settings are used (the computer name is also on the case label): Host cms-2413-25 Domain ac.uk DNS Search addresses 143.52.2.18 , 143.52.28.10 Reboot the machine into Windows 95 if you have made changes. You can also now login to the network using the netlab login id. The simplest way to test an IP connection is to use the PING command. This send a number of IP packets and gives the length of time that the destination took to respond. 7. 8. Open up the MS-DOS command prompt, Programs-Command Prompt Type ping 143.52.57.2 to send IP packets to the networks lab gateway router. There should be a reply from 143.52.57.2. If there is no response and the reply times out check the link firstly betwwen the remote PC and Bridge TWO by typeing ping 143.52.57.61 and then the ISDN connection by typeing ping 143.52.57.60. This should identify where the problem is. 9. Start Netscape Communicator and try some surfing to ensure that TCP/IP is working. You will need to login to Netware using the id netlab with no password. 10. On the Management Terminal type CO PO to monitor the ports while surfing or downloading. You can also monitor the ports by watching the LEDs on the Bridge front panel. 11. Type ST IS to monitor the ISDN stats. You could also try logging in to the netware network and monitor the stats. STAGE 4: FINISHING OFF When you have completed your investigations you must delete all entries made in the Management system by returning the unit to factory defaults. This will ensure that the Mark Jacobi Updated Dec '99 ISDN line is not used unneccessarily and that the next group can start the exercise from default settings. 1. Connect the Management system lead to Bridge ONE, enter the password then type CO STD and confirm your request with Y. The Bridge will reboot. 2. Connect the Management system lead to Bridge TWO, enter the password then type CO STD and confirm your request with Y. The Bridge will reboot. 3. Disconnect the cables from the bridge but leave attached at the other end. 4. On the remote PC, delete the host IP address from the TCP/IP settings window. Mark Jacobi Updated Dec '99 APPENDIX 1 NOTES: An introduction to Bridging and ISDN. Extract from Office Connect Remote User Guide, 3COM. In the modern business environment sharing information is crucial. Until now only large businesses could afford the high speed connections between offices to gain the networking advantage. The OfficeConnect Remote is designed to connect a LAN (Local Area Network) at one location with a number of other LANs at remote locations. The LAN could comprise any number of PCs, servers or other computing equipment, which in an office or small business environment are typically linked together using a centrally located Office Connect hub. In order to interconnect the hubs in different locations, the OfficeConnect Remote unit transmits information over a WAN (Wide Area Network) service provided by telephone carrier organizations. The most modern and efficient of these WAN services includes ISDN (Integrated Services Digital Network). This provides a high speed dialup facility to allow your OfficeConnect Remote to automatically and quickly dial remote offices, transmit your data between remote PCs just as speedily and then disconnect the call. You incur minimum ISDN telephone charges as calls are made only when needed. This is known as Dial on Demand. ISDN ISDN, (Integrated Services Digital Network), is a system of digital phone connections which has been available for over a decade. This system allows data to be transmitted simultaneously across the world using end-to-end digital connectivity. With ISDN, voice and data are carried by bearer channels (B channels) occupying a bandwidth of 64 kbps. A data channel (D channel) handles signaling at 16 kbps or 64 kbps, depending on the service type. There are two basic types of ISDN service: Basic Rate Interface (known as ISDN2 in the UK) and Primary Rate Interface (ISDN30). BRI consists of two 64 kbps B channels and one 16 kbps D channel for a total of 144 kbps. This basic service is intended to meet the needs of most individual users. PRI is intended for users with greater capacity requirements. Typically the channel structure is 30 B channels plus one 64 kbps D channel for a total of 1984 kbps. BRI is the connection type used in the labs. It is possible to operate 2 separate pieces of equipment accessed by 2 separate numbers, or to have the 2 channels aggregate to provide a single, higher data rate connection. Bridging Bridges and routers are used to connect networks together. The cost of connecting networks together is generally proportional to the distance over which the network extends and the amount of bandwidth required. Large amounts of bandwidth can be provided easily within a LAN by connecting different segments together with a local bridge. However, it becomes impractical and expensive to extend this bandwidth over larger distances, and it is, therefore, usual to interconnect local high speed networks using bridges or routers connecting over slower speed terrestrial and satellite links. Mark Jacobi Updated Dec '99 A bridge connects one or more LANs together. It examines each data frame received at a LAN port and forwards any frames that it assumes are for a destination device not connected to that LAN port. The bridge is able to do this by learning which devices are connected to each LAN port. A router learns much more about the networks connected to it and is able to be much more selective about the data it passes on to other networks and to which networks it transmits. By default routers reject or filter data unless it matches predefined attributes (for example specific protocols or destination network addresses). In large interconnected networks a router selects the best route for data to travel. Mark Jacobi Updated Dec '99