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Drawbacks to the PSTN

Although the PSTN is effective and does a good job at what it was built to do (that is, switch voice calls), many business drivers are striving to change it to a new network, whereby voice is an application on top of a data network. This is happening for several reasons Data has overtaken voice as the primary traffic on many networks built for voice. Data is now running on top of networks that were built to carry voice efficiently. Data has different characteristics, however, such as a variable...

ISUP Call Control Messages

Table 4-4 identifies the most important ISUP call control signaling messages. All ISUP signaling messages contain the ISUP message type parameter. Table 4-4 identifies the most important ISUP call control signaling messages. All ISUP signaling messages contain the ISUP message type parameter. Table 4-4. ISUP Messages and Message Types The ISUP call control message formats, including signaling parameters, optional and mandatory fields, and field lengths, are listed in Appendix A, ISUP Messages...

Figure 131 Open Packet Telephony Architecture

Signaling and Call Control Senxe Access Foncton Switch Boand Serv* Logc Erri-U-ErtdVbi 5eiVdes Connect Coring RiutJWl (MGCR 5GCP) Connect Coring RiutJWl (MGCR 5GCP) Cisco H End gints. Trunhing. Corporate. Residefifel an t Wetfe eafewys Cisco H End gints. Trunhing. Corporate. Residefifel an t Wetfe eafewys The VSC provides the following call control-plane functions in the Cisco OPT architecture (in the Media Gateway Control Protocol MGCP architecture, the VSC represents the MGC) The connection...

Packet Telephony Call Centers

In most call centers today, the largest costs are for the brick and mortar holding the building together. You can drastically cut the actual costs of renting a building, putting a phone at each desk, and purchasing the required infrastructure (call-routing technology, PCs, and so on) by using a Packet Telephony Call Center (PTCC). Each call center is different, but for many call centers, the ability to grow the business as needed (perhaps as discretely as one station at a time) is a great...

ITUT International Numbering Plan

ITU-T Recommendation E.164 specifies that a Country Code (CC), National Destination Code (NDC), and Subscriber Number (SN) be used to route a call to a specific subscriber. The CC consists of one, two, or three digits. The first digit (1-9) defines world numbering zones. A list of all the defined CCs is found in ITU-T Recommendation E.164 Annex A. NDC and SN vary in length based on the needs of the country. Neither one has more than 15 digits. Many other recommendations and specifications for...

Database Query Example

Database Query Example Figure

This example demonstrates the steps involved in making an 800 query. The example also shows ways you can use the TCAP protocol for transactions in the SS7 network. Figure 4-17 provides the network topology for this example. Figure 4-17. Network for 800 Database Query Example Figure 4-17. Network for 800 Database Query Example In this example, the analog subscriber connected to SSP1 places an 800 call. The following steps occur when the subscriber on SSP1 places the 800 call 1. When the...

Plain Old Telephone Service

Standard telephony service is commonly referred to as plain old telephone service (POTS). This service provides a dial tone to rotary and touch-tone telephones, as well as access to national and international carriers. Standard dialing devices such as 500-type telephones (rotary), 2500-type telephones (touch-tone), facsimiles, and modems are compatible with POTS. POTS evolved internationally to include the 911 emergency number service and operator services. The following additional features and...

Basic Call Setup and Teardown Example

This example demonstrates the steps involved in basic call setup and teardown. The example also shows ways you can use the ISUP protocol to connect and disconnect calls in the SS7 network. Figure 4-16 provides the network topology for this example. Figure 4-16. Network for Call Setup and Teardown Figure 4-16. Network for Call Setup and Teardown In this example, the analog subscriber connected to SSP1 places a call to the analog subscriber connected to SSP2. The following steps occur when the...

ISDN L2 and L3 Protocols

ISDN user-network interface L2 and L3 specifications also are referred to as Digital Subscriber Signaling System No. 1 (DSS1). L2 provides error-free and secure connections for two endpoints across the ISDN reference configuration. L3 provides the mechanism for call establishment, control, and access to services. The L2 protocol for ISDN is Q.920 921, and the L3 protocol is Q.930 931. Q.932 enables general procedures for accessing and controlling supplementary services. The specifications for...

V2l

V2L is a simple service in that it enables Internet users to place and receive phone calls through their ISP only when they are connected through their Internet connection (modem, cable, digital subscriber line DSL , and so on). In many V2L cases, the PC is actually assigned a valid E.164 number, although this is not a requirement. All the benefits of ICW also exist for V2L. One key additional benefit is that service providers can offer outbound traffic, which can, in turn, create significant...