Configuring Remote CAPI

This chapter provides procedures for configuring Remote Common Application Programming Interface (CAPI) support on a Cisco 700 series router.

CAPI is an application programming interface standard used to access ISDN equipment connected to Basic Rate Interfaces (BRIs) and Primary Rate Interfaces (PRIs). CAPI provides a standardized interface that allows application programs to use ISDN drivers and controllers. One application can use one or more controllers. Several applications can share one or more controllers.

CAPI provides a selection mechanism that supports applications that use different protocols at different protocol levels. CAPI also provides standardized network access by performing an abstraction from different protocol variables. All connection-related data, such as connection state, display messages, and so on, is available to the applications at any time.

The framing protocols supported by CAPI consist of High-Level Data Link Control (HDLC), HDLC inverted, bit-transparent (speech), and V.110 synchronous/asynchronous.

CAPI integrates the following data link and network layer protocols:

Link Access Procedure on the D channel (LAPD) in accordance with Q.921 for X.25 D-channel implementation
Point-to-Point Protocol (PPP)
ISO 8208 (X.25 DTE-DTE)
X.25 DCE, T.90NL, and T.30 (fax group 3)

CAPI and RVS-COM

The Cisco 700 series router supports the ISDN Device Control Protocol (ISDN-DCP) from RVS-COM. ISDN-DCP allows a workstation on the LAN to use legacy dial computer telephony integration (CTI) applications. These applications include fax transmitting and receiving and placing and receiving phone calls.

Using ISDN-DCP, the router acts as a DCP server. By default, the router listens for DCP messages on TCP port number 2578 (the Internet-assigned number for RVS-COM DCP) on its LAN port.

When the router receives a DCP message from a DCP client (connected to the LAN port of the router), the router processes the message and acts on it. The actions consist of sending confirmations to the DCP clients and sending ISDN packets through the router BRI port.

When the router receives a packet on its BRI port for one of the DCP clients, the router formats the packet as a DCP message and sends it to the corresponding client. The router supports all the DCP messages specified in the ISDN-DCP specification.

The router provides two 64-kbps B channels to CAPI clients. Each B channel can be configured separately to work in either HDLC mode or bit-transparent mode. For CAPI support, the higher layer protocols (B2 through B7) are transparent to the applications using these B channels.

The ISDN Core Engine of RVS-COM supports the following B channel protocols:

CAPI layer B1
- 64 kbps with HDLC framing
- 64-kbps bit-transparent operation with byte framing from the network
- T.30 modem for fax group 3
- Modem with full negotiation
CAPI layer B2
- X.75 SLP (ISO 7776) with V.42bis compression option (negotiated)
- V.120 with V.42bis compression option (negotiated)
- Transparent
- T.30 modem for fax group 3
- Modem with full negotiation
CAPI layer B3
- Transparent
- T.90NL with compatibility with T.70NL, according to T.90 Appendix II
- ISO 8208 (X.25 DTE-DTE) modulo 8 and windows size 2, no multiple logical connections
- T.30 for fax group 3
- Modem with full negotiation
T.30 for fax group 3 (SFF file format [default], sending and receiving up to 14400 bps with ECM option, modulations V.17, V.21, V.27ter, V.29)
Analog modem (sending and receiving up to 14400 bps with V.42 error correction and V.42bis compression option, modulations V.21, V.22, V.22bis, V.23, V.32, V.32bis)

Supported D-Channel Protocols

CAPI support is available only for the ISDN switch type Net3.

Supported Applications

ISDN-DCP supports CAPI and non-CAPI applications. Supported applications consist of those that use one or two B channels for data transfer, different HDLC-based protocols, Euro File transfer, or fax G4; also supported are applications that send bit-transparent data, such as A/Mu lay audio, fax G3, analog modem, or analog telephones.

Remote CAPI Router Commands

The commands used in this chapter have been added to the router user interface to support CAPI. Note that CAPI runs on a remote network device, not the router; the Cisco 700 series router enables remote CAPI applications.

Configuring the Cisco 700 Router as an RCAPI Server

This section describes how to configure the Cisco 700 series router to be an RCAPI server.

By default, RCAPI is disabled in the router. Enabling RCAPI causes the router to become an RCAPI server. When RCAPI is enabled, the router listens for incoming RCAPI messages from PCs connected on its LAN side. By default, the router listens for RCAPI messages on TCP port 2578.

Figure 6-1 illustrates the configuration used in this example. The PCs in the figure have RVS-COM software installed.

Figure 6-1: RCAPI Server Configuration Example

RCAPI Command Summary

Following is the command summary for configuring the RCAPI on the local Cisco 700 series router.

set rcapi on
set dir 5554000 
set rcapi 1 number 5554000
set rcapi server port 2578 
reboot

Verify the Configuration

You can use the command show rcapi status to see the status of RCAPI server, the clients that are in the listening state, and the status of RCAPI calls:

local-router> show rcapi status 
Rcapi Sever ON 
Rcapi Server Port 2578 
Rcapi Number(s) 5554000 
 
CLIENTSESSION-IDLISTENCONNECTION-IDTYPECALL-STATUS
------------------------------------------------------------------------
192.168.100.316777218ON

Table of Contents

Configuring Remote CAPI