Best Answer: VPI is Virtual Path Identifier and VCI is Virtual Channel Identifier and are used by, and are specific to, the ISP and differ per country. Typically in the UK these are 0 and 38 respectively. PPPoE is Point-to-Point Protocol over Ethernet. PPP used to be the method dial-up modem ISPs used to bring TCP/IP and authentication over a telephone line. PPPoE is just a next generation of that using Ethernet lines. LLC is Logical Link Control, a means to transfer TCP/IP or IPX over a line. VC-MUX is Virtual Circuit Multiplexing and is an alternative to LLC but does much the same thing. So LLC or VC-MUX will be determined by the ISP in question. CHAP is Challenge Handshake Authentication Protocol and is used to securely authenticate the username / password account to sign-in to the ISP. Hope that sheds light on their purpose.Complete the installation for secondary DUW; at this stage do not connect theIDL and CPRI cable in-between DUW.2. Power on the secondary DUW3. Perform format c2 and d harddisk using hyperterminalEg. reload , formathd /c2, formathd /d4. Switch off the secondary DUW5. Connect you thin client to primary DUW ( Moshell and EM).Create new CV (i.e : Before_adding_DUW)6. Connect thin client to the primary DUW, open the EM, perform Export cabinetand site equipment, and do not perform the DELETE.7. At the exported cabinet.xml file , edit the climate system to Extended and radiobuilding block to RBB 12_1A and save the file. This edited cabinet file will beused later.8. Complete the cabling in-between Primary DUW to secondary DUW, do notpower on the secondary DUW at this stageRefer to below illustration for cabling between primary DUW and secondary DUW Thisexample is for RBS6601 main remote.For the RBS 6201, secondary DUW EC cable must be connected to port A5 at SHUand Port A5 must be enable.9. Connect EM and Moshell at the primary DUW10. Load the supplied modify scripts for adding second DUW by using EM ( Wizard)11. Switch on the 2nd DUW whenever the EM notify waiting for plug-in unit12. After successfully loaded the modify scripts, check the status of the DUW at EM / Moshell13. Create new CV and restart the nodeAt moshell give the command below.> cabx ( observe that 2nd DUW is in Standbywiriting14. Wait till 2nd DUW in Standby Ready status ( it will take 10mins to 20mins for the2nd . DUW to be in Standby Ready15. Once the Standby Ready achieved, make a new CV.16. Perform the Export and Delete at the Primary DUW.17. Load back the modified cabinet file by using EM(wizard).18. Load back the site equipment (Using wizard) and add the 3rd carrier at this stageby using wizard19. Make a new CV20. Check any alarm appeared and clear the alarms.21. Call OSS/RNC to do the necessary i.e, load back the parameter base lineon the newly node B configuration.22. Perform call test with OSS personnel.Note: For RBS 6201 please do necessary editing for cabinet and site equipmentparameter in example the number of PDU, climate type depend on the actual hardwareinstalled at the node.