Perle Systems P840 2 ISDN Connection Management

2 ISDN Connection Management

In the world of ISDN the ability to decrease connection time is a financial bonus in the LAN interconnecting marketplace. If

ISDN connections can be controlled so that a mi nimum amount of cost is incurre d while full LAN interconnecti ng

functionality is retained, the overall cost for WAN communications can be minimized.

In many LAN protocols, the interchange of data is sporadic and frequently long periods of time exist betwe en successive data

transfers. If ISDN calls can be disconnected du ring the periods of inactive data transfers without the LAN connections being

aware of the disconnection, the ISDN call time and cost is reduced.

To accomplish this, the P840’s Connection Management function actively tracks all of the LAN connections and ma intains

them while the ISDN call is deactivated. When the LAN devices require the connection to exchange more data, the ISDN call

is reactivated so that the LAN data may be transferred.

During the periods of ISDN cal l disconnection (suspension), e ach end of the LAN connection must believe that the complete

connection still exists. The generation of the regular status inquiries and responses normally generated by the two devices

involved in the LAN connection is performed by the P840 ISDN bridge/router while the ISDN call is suspended.

Two types of Wide Area Network (WAN) topologies are supported w ith Connection Management

1. Two P840 routers connected.

2. Three P840 routers connected in a star configuration.

Connection Management is not functional when P840 routers are connected in a ring.

ISDN calls may be established according to the following connection methods:

1. Auto-Call

2. Address Connect

3. Manual call

4. Combination