Debugging Commands

Use the following commands to debug your configuration:

debug bri

debug isdn q921

debug isdn q931

debug isdn events

show isdn status bri

show controller bri

show interfaces bri

For more information about these commands, see the IOS documentation.

Configuring DID Interfaces

Direct Inward Dialing (DID) enables external callers to direct-dial an internal extension on your PBX, without operator assistance. This service makes use of DID trunks provided by the local central office (CO), which forward only the last three to five digits of a phone number to your PBX. If, for example, a company has a PBX with extensions 555-1000 through 555-1999, and an external caller dials 555-1234, the local CO forwards 234 to the PBX. The PBX then rings extension 234.

When this feature is configured, a voice-enabled Cisco router can receive calls from a DID trunk and connect them to the appropriate extensions.

The DID feature makes it seem that all extensions on a PBX have direct lines to the PSTN. This is accomplished without the expense associated with connecting each extension to the PSTN. Besides saving the cost of an operator, DID lets callers feel that they are calling specific individuals, rather than calling a large company.

Figure 23 shows a hypothetical topology in which a user connected to the PSTN (User A) dials various numbers; this user is then connected to the appropriate extensions on a PBX.

Figure 23 DID Support for Cisco 1760 Routers

User A

User B #456

PSTN

DID

VoFR,

E&M

VoATM,

 

 

 

 

or VoIP

 

 

FXS

 

FXS

 

User C #234

 

User D #345

Table 8

DID Support

 

 

35968

Number Dialed

Number Received

 

by User A

by Router

Extension Receiving Call

 

 

 

555-1234

234

User C

 

 

 

555-1345

345

User D

 

 

 

555-1456

456

User B

 

 

 

555-1678

678

No dial-peer match found; fast busy tone is played

 

 

 

29

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Cisco Systems 1760 quick start Configuring did Interfaces, Debugging Commands

1760 specifications

The Cisco Systems 1760 series routers are part of Cisco’s popular line of integrated services routers, designed primarily for small to medium-sized businesses and branch offices. The 1760 series was introduced to provide robust connectivity and routing solutions that facilitate secure and reliable networking. Aimed at offering flexibility, these routers integrate multiple functionalities to enhance operational performance.

One of the main features of the Cisco 1760 router is its modularity. It supports various interface and service modules that allow for customization based on specific networking needs. This modular design enables businesses to expand their networking capabilities over time without necessitating a complete hardware overhaul. The router typically comes equipped with two WAN slots and numerous interface options, including Fast Ethernet and serial interfaces.

The 1760 series routers also support advanced security features, providing businesses with a secure environment for their data transmissions. Built-in firewall capabilities, along with support for Virtual Private Network (VPN) protocols, ensure that sensitive information remains protected. Furthermore, the integration of IPsec and MPLS security features assists organizations in maintaining secure and scalable connections across diverse networks.

Another characteristic of the Cisco 1760 is its support for various technologies, including Quality of Service (QoS). QoS functionality allows network administrators to prioritize traffic, ensuring that critical applications receive the bandwidth they require while minimizing latency. This ability is particularly valuable in environments where voice, video, and essential data applications compete for resources.

The router’s ease of management is also noteworthy. With Cisco’s IOS (Internetwork Operating System), the 1760 provides a user-friendly interface allowing for straightforward configuration and monitoring. The simplicity in managing the network devices helps reduce the burden on IT personnel and enhances overall operational efficiency.

Further enhancing the router’s capabilities is its support for voice over IP (VoIP) applications, making it an ideal choice for organizations looking to implement modern telephony solutions. The ability to support multiple voice channels while maintaining adequate data throughput positions the 1760 as an attractive option for businesses transitioning to unified communications.

In summary, the Cisco Systems 1760 series routers exhibit a harmonious blend of modularity, robust security, traffic management, and VoIP support. They effectively meet the demands of modern networking environments, making them a reliable choice for organizations aiming to streamline operations while ensuring secure connectivity. With their adaptable design, these routers can serve as a powerful backbone for enterprise networking needs.