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Cisco Port Adapters

Voice Gateway Application for the Cisco 7200 Series

Application Note

Cisco 7200 Series Router
Voice Gateway

With its multiservice capabilities, the Cisco 7200 Series can be deployed as a voice gateway within a next-generation network architecture. Depending on customer need, we can visualize several application scenarios in providing voice-over-packet network solutions. We can apply these scenarios to several network architectures in which voice gateways providing the call control or bearer transport functions, or both. Scenarios, or applications, include:

  • Toll bypass

  • Traffic offload

  • Integrated access

Toll bypass is an application that allows customers to bypass the Public Switched Telephone Network (PSTN) comprising Time Division Multiplex (TDM)-based switches, and then utilize the packet network for long-distance (or toll) voice calls. Traffic offload allows exchange carriers to offload voice traffic from the PSTN by using the packet network. Integrated access allows enterprise customers to integrate voice and data into single data networks.

Cisco 7200 generally can be used as high-density voice gateway that fit into any of the above-mentioned applications.

Overview

The Cisco 7200VXR, with support for six port adapter slots, can be equipped with up to 20 T1s or 18 E1s, supporting voice-over-packet applications. The DS0 channel from a T1/E1 is switched into the Digital Signal Processor (DSP) to perform the TDM-to-packet conversion of the bearer information present on a DS0.

Two types of port adapters (which provide a T1/E1 interface) can be housed within the Cisco 7200: those with onboard DSPs and those without.

Port adapters without onboard DSPs share their DSPs with port adapters without onboard DSPs. The total number of calls that can be handled depends on the complexities of compression algorithms used with the coding/encoding (codec) functions. Port adapters with onboard DSPs are available in two forms:

  • PA-VXA-1TE1-24+ supports 1 T1

  • PA-VXB-2TE1-30+ supports 1 E1

  • PA-VXB-2TE1+ supports 2 T1s or 2 E1s (see below for limitations when using 2 E1s)

  • PA-VXC-2TE1+ supports 2 T1s or 2 E1s

These port adapters provide interfaces of up to two T1s or two E1s. The PA-VXB-2TE1+ can handle a maximum of 48 concurrent calls on either T1 or E1 configurations. The PA-VXC-2TE1+ can support up to a maximum of 120 calls. Port adapters without onboard DSPs can be ordered to support two, four, or eight T1s/E1s as shown below:

  • PA-MCX-2TE1 -> two T1s or two E1s

  • PA-MCX-4TE1 -> four T1s or four E1s

  • PA-MCX-8TE1 -> eight T1s or eight E1s

The following list identifies a few examples of sample configuration scenarios.

Examples

Cisco 7200 with Two T1s

To equip a Cisco 7200 with two voice T1s, the following port adapters must be used as follows:

  • Medium-complexity compression (i.e., codecs compliant to G.711, G726, G728, G729a, fax relay) -> one PA-VXB-2TE1+

  • High-complexity compression (i.e., codecs compliant to G.723) -> one PA-VXC-2TE1+

Cisco 7200 with Two E1s

To equip a Cisco 7200 with two E1s using the full 60 channels, a PA-VXC-2TE1+ must be used.

Cisco 7200 with Four T1s

To equip a Cisco 7200 with four T1s, the following port adapters must be used:

  • Medium-complexity compression (i.e., codecs compliant to G.711, G726, G728, G729a, fax relay)

  -> one PA-VXC-2TE1+ and one PA-MCX (any version), or
  -> two PA-VXB-2TE1+
  • High-complexity compression (i.e., codecs compliant to G.723) -> two PA-VXC-2TE1+.

Cisco 7200 with Four E1s

To equip a Cisco 7200 with four E1s, the following port adapters must be used:

  • Medium-complexity compression (i.e., codecs compliant to G.711, G726, G728, G729a, fax relay) -> one PA-VXC-2TE1+ and one PA-MCX (any version)

  • High-complexity compression (i.e., codecs compliant to G.723) -> two PA-VXC-2TE1+.

Cisco 7200 with Ten T1s

To equip a Cisco 7200 with ten T1s, the following port adapters must be used:

  • Medium-complexity compression (i.e., codecs compliant to G.711, G726, G728, G729a, fax relay)

  -> two PA-VXC-2TE1+, one PA-MCX-8TE1, or
  -> five PA-VXB-2TE1+
  • High-complexity compression (i.e., codecs compliant to G.723) -> four PA-VXC-2TE1+ and one PA-MCX (any version).

Cisco 7200 with Eight E1s

To equip a Cisco 7200 with eight E1s, the following port adapters must be used:

  • Medium-complexity compression (i.e., codecs compliant to G.711, G726, G728, G729a, fax relay) -> two PA-VXC-2TE1+ and one PA-MCX (4 or 8 ports version).

  • High-complexity compression (i.e., codecs compliant to G.723) -> four PA-VXC-2TE1+.

Cisco 7200 with 20 T1s

To equip a Cisco 7200 with 20 T1s, the following port adapters must be used:

  • Medium-complexity compression (i.e., codecs compliant to G.711, G726, G728, G729a, fax relay) -> four PA-VXC-2TE1+, two PA-MCX (providing at least 12 additional ports).

Cisco 7200 with 18 E1s

To equip a Cisco 7200 with 18 E1s, the following port adapters must be used:

  • Medium-complexity compression (i.e., codecs compliant to G.711, G726, G728, G729a) -> five PA-VXC-2TE1+ and one PA-MCX-8TE1.

Product Bundle Information

To facilitate ordering of the Cisco 7200 voice gateways at a lower price, Cisco offers the following bundle:

  • C7206VXR/VOICE/400, comprising a 7206VXR with NPE-400, Enhanced Digital Voice Port Adapter PA-VXC-2TE1+, and two-port 10/100 I/O Controller