List of Figures

Chapter 3: Getting Around the Telecom Neighborhood

Figure 3-1: The network of LATA boundaries and LATA numbers for the U.S. is pretty complex.

Chapter 4: Understanding Dedicated Service Requirements

Figure 4-1: Hardware and cabling setup for a dedicated circuit.

Chapter 8: Ordering Dedicated Service

Figure 8-1: This is an example of TDM based on a stopwatch dictating the allotted time for each conversation.

Figure 8-2: Each of the 24 slots equals one DS-0 or channel on the T-1.

Figure 8-3: Standard configuration for ISDN, with 23 bearer channels and 1 data channel, which handles the overhead.

Figure 8-4: SS7 Link T1 with 24 voice channels and an autonomous SS7 link.

Chapter 9: Ordering Toll-Free Service

Figure 9-1: The standard RespOrg LOA document used for migrating toll-free numbers.

Chapter 10: Activating Your Dedicated Circuit and Toll-Free Numbers

Figure 10-1: This diagram of a dedicated circuit shows areas of responsibility.

Chapter 11: Maintaining Your Telecom Services

Figure 11-1: A switched outbound long-distance call.

Figure 11-2: A switched inbound long-distance call.

Figure 11-3: A switched local call.

Figure 11-4: Dialing someone else’s toll-free number.

Figure 11-5: Someone dialing your switched toll-free number.

Figure 11-6: Dedicated calling process.

Figure 11-7: Expanded view of a dedicated call.

Figure 11-8: Comparing the call types in diagram form.

Chapter 12: Troubleshooting Switched Network Issues

Figure 12-1: Validating your long-distance carrier.

Figure 12-2: Forcing a call over your long-distance carrier.

Figure 12-3: Dialing over another long-distance carrier.

Figure 12-4: Testing the local carrier and phone system.

Figure 12-5: Dialing your ring-to number locally.

Figure 12-6: Dialing your ring-to number through your long-distance carrier.

Figure 12-7: Dialing your ring-to number over another long-distance carrier.

Figure 12-8: Schematic of an international toll-free number.

Chapter 13: Troubleshooting Your Dedicated Circuits

Figure 13-1: The CSU is the first piece of hardware your carrier intrusively tests.

Figure 13-2: A comparison of straight-through and crossover cables.

Figure 13-3: Dedicated circuit testing: looping the NIU.

Figure 13-4: Inside wiring, including the T-1 jack.

Figure 13-5: Dedicated circuit testing: looping the T-1 jack.

Figure 13-6: Dedicated circuit testing: looping the CFA.

Figure 13-7: Crossing CSU cables.

Chapter 14: Transferring Data, Not Just Voice Content

Figure 14-1: A typical private line with two local loops and a long-haul portion between.

Figure 14-2: A private line network with four locations is likely to be too expensive and inefficient.

Figure 14-3: A frame relay network with four nodes. The dashed lines are individual permanent virtual circuits (PVCs).

Figure 14-4: How a typical permanent virtual circuit (PVC) is partitioned.

Figure 14-5: A standard MPLS network setup.

Chapter 15: Riding the Internet Wave: VoIP

Figure 15-1: Calls are transmitted using both the VoIP protocols and the TDM protocol.

Figure 15-2: The four paths of a typical VoIP call.

Figure 15-3: The voice portion of this call in the RTP stream is being sent to a media server. The signaling protocol never connects between either of the phones and the media server.

Figure 15-4: Bandwidth consumed by the EPS during a VoIP call.

Appendix: Making a Loopback Plug

Figure A-1: The pin configuration for a male RJ-45 plug.