ISDN Connection Management

Protocol Awareness

For Connection Management to be effective, each of the P840s must be aware of the protocols used within the data being transferred over the ISDN calls between them.

IP Client-Server sessions are established between devices located on the LANs that are routed by the P840 router. If the P840 is to manage the ISDN calls between the routed LANs, the P840s on each WAN end of the Client-Server session must be aware of the session and also must become actively involved in the maintenance of the session. When an ISDN call is suspended, both the Client and the Server must still believe that the session exists.

Suspension Process

The P840 maintains a table for each ISDN call made to a partner ISDN P840 in order to determine when the ISDN call should be suspended during Connection Management.

Any number of LAN sessions may be currently using the established ISDN call to transfer data between the client and the server. The P840 monitors the ISDN call for interesting traffic passed on each of the sessions currently using the ISDN call. If no interesting traffic is observed on the ISDN call for a period of time greater than the defined Idle Timer value, the ISDN call is suspended and disconnected. While the ISDN call is suspended, the P840 will monitor the LAN sessions for interesting traffic and re-establish the ISDN call when required.

A suspended ISDN call may only be re-established by the P840 initiating the suspension or by the partner P840 that was connected just prior to the call being suspended. This prevents other P840s from tying up the ISDN calls and interfering with the suspended calls.

ISDN calls may be connected and disconnected between the two P840s when required according to the suspension and re-activation of the ISDN calls. When all of the sessions using the call in the table have been closed, the call will be terminated and the ISDN B-channel becomes available for use to connect to a different ISDN P840. When the connection to the partner ISDN P840 is configured to use Auto-Call, the ISDN call will be suspended when there are no sessions in the table.

Interesting Traffic

Interesting Traffic is defined as normal interactive user data for a session. Certain data exchanged during a normal session is not considered to be interesting and usually is composed of keepalive messages, watchdog messages, and routing messages. Non-interesting data is handled differently when Connection Management is enabled.

Idle Timer

In order to determine the criteria for suspending an ISDN call, an Idle Timer is defined. The Idle Timer defines the period of time that LAN traffic is monitored to determine when the ISDN call will be put in suspension and disconnected. When Interesting Traffic is observed once again, the call is reconnected.

The Idle Timer is common to all ISDN calls and may be defined from 6 seconds to 5 minutes in 1 second increments. The Idle Timer may be disabled so that only the partner P840 determines when the ISDN call will be suspended.

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Perle Systems P840 manual Protocol Awareness, Suspension Process, Interesting Traffic, Idle Timer
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P840 specifications

Perle Systems is renowned for its high-performance networking hardware, and the Perle P840 model exemplifies this reputation with its advanced features and technologies. Designed for small to medium-sized enterprises, the P840 serves as a versatile and reliable solution for connectivity needs.

One of the main features of the Perle P840 is its robust network performance, supporting both Ethernet and serial connectivity. With support for RS-232, RS-422, and RS-485 interfaces, the P840 enables seamless integration of legacy devices into modern network architectures, allowing businesses to leverage existing infrastructure without the need for extensive upgrades.

The P840 also boasts advanced security features to protect sensitive data during transmission. It supports SSL encryption and VPN capabilities, ensuring that data travels securely across the network. Additionally, it implements strong authentication protocols, providing organizations with peace of mind knowing that their communications are safeguarded against potential threats.

Another standout characteristic of the P840 is its flexibility in configuration. It offers multiple port configurations, allowing for customization based on specific user needs. With options for both managed and unmanaged modes, the device can easily adapt to various network environments. This flexibility makes it suitable for diverse applications, including industrial automation, process control, and telecommunications.

The Perle P840 is designed for durability and reliability, featuring a rugged enclosure that can withstand demanding environments. Its solid-state components reduce the risk of failure, contributing to increased uptime and lower maintenance costs. Furthermore, the compact design allows for easy installation in tight spaces, making it a practical choice for various deployment scenarios.

In terms of management and monitoring, the P840 includes an intuitive web-based interface, enabling administrators to configure settings and monitor network performance effortlessly. SNMP support further enhances management capabilities, allowing for integration into larger network management systems.

Overall, the Perle P840 stands out as a powerful solution for enterprises seeking seamless connectivity, robust security, and flexibility in configuration. Its combination of advanced features and durable design makes it an ideal choice for industries requiring reliable serial and network connectivity in challenging environments. With the P840, businesses can build a resilient networking infrastructure that supports their growing demands while safeguarding their critical data.
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