- FarLinX X25 Gateway -

An X.25 Gateway supporting XOT (X.25 over TCP/IP) and
TCP/IP to X.25 data format translation and connection routing

The FarLinX X25 Gateway datasheet, download from here, (PDF format).

Order Information
Product Name	Description		Product Code
FarLinX X25 Gateway-1	1 X.25 line Gateway supporting X.25 to XOT and X.25 to TCP/IP up to 1,000 sessions 1U rack mountable appliance. Low speed clock generation		FL2601
FarLinX X25 Gateway-2	2 X.25 line Gateway supporting X.25 to XOT and X.25 to TCP/IP up to 1,000 sessions 1U rack mountable appliance. Low and high speed clock generation		FL2602
FarLinX X25 Gateway-4	4 X.25 line Gateway supporting X.25 to XOT and X.25 to TCP/IP up to 1,000 sessions 1U rack mountable appliance. Low and high speed clock generation		FL2604
FarLinX X25 Gateway-8	8 X.25 line Gateway supporting X.25 to XOT and X.25 to TCP/IP up to 1,000 sessions 1U rack mountable appliance. Low and high speed clock generation		FL2608
POS Gateway Upgrade	POS Software upgrade to the FarLinX X25 Gateway range. Enhances the Gateway with Point Of Sale protocol handling including ISO 8583, APACS and SIBS		FL2610
Cable Options
UCR1		Single RS232C (V.24, X.21bis) DTE cable, male connector, 1.5 metres. External or Gateway generated clocks. see pinouts	FS6061
UCX1		Single X.21 (V.11, RS422) DTE cable, 1.5 metres, male connector. External or Gateway generated clocks. see pinouts	FS6062
UCV1		Single V.35 DTE cable, 1.5 metres, male connector. External generated clocks. see pinouts	FS6063
U530		Single RS-530 (EIA530) DTE cable, 1.5 metres, male connector. External or Gateway generated clocks. see pinouts	FS6064
UXD1		Single cable to connect direct to a Nortel DMS100 (NTFX35AA), 1.5 metres	FS6069
UX35C		Single V.35 special DCE cable, female connector, 1.5 metres. Gateway generated clocks.	FS6095

Overview

The FarLinX X25 Gateway product range is the third generation of X.25 Gateway products from FarSite, providing a very flexible powerful gateway for your X.25 migration needs at a very affordable cost.  It incorporates all the popular features of the previous product ranges with an improved browser interface and new comprehensive set of online statistics, connection logging and status change alert functions to put you in control.

Key Features

• TCP to X.25 data translation with a very wide variety of modes including: RFC1006, Cisco RBP, header stripping and parity conversion and many more
• TCP <-> X.25 routing including: fixed routes, dynamic routing and PAD routing
• Optional software upgrade to support the POS protocols APACS, ISO 8583 and SIBS
• Routing of calls between XOT (X.25 over TCP/IP) and multiple X.25 lines including X.25 to X.25 switching
  4 Models, equipped with between 1 to 8 X.25 lines with line speeds up to 2 Mbits/s
• High performance, non stop operation - over 2000 messages per second and up to 1000 SVC and PVC connections
• Dual Gateways providing automatic backup for resilience
• Graphical configuration via a Browser with SNMP alerts for critical events
• Activity logs with a configurable level of connection and data tracing
• Real time statistics of line performance, errors, connections and much more

The condition of the Gateway can be monitored from a browser with current line status, real time line and data statistics and real time active user activity available. There are also daily activity logs with a selectable level of detail, automatically archived on a daily basis. The SNMP support can provide alerts for a number of different conditions including critical events such as line down and line up.

Dual Gateway support is available such that 2 Gateways can share a common IP address to provide automatic switch over support for a range of conditions including X.25 line down and Gateway failure. Any such failures and switchover events will generate SNMP alerts so the network operator can instantly know what's happened.

The product can support protocols when the X.25 Host system treats the incoming X.25 data as a character stream. It can also convert the data when a header is used to describe the message payload within the TCP connections and remove this header on the X.25 virtual circuits. Data types supported include: RFC1006, Cisco RBP and special character delimiting. Dynamic routing is supported where the Client TCP application determines the X.25 address and call parameters used at the time the connection is established. XOT is supported so that the X.25 network can run over the top of an IP network. The Gateway can provide connectivity to several different Host systems at the same time with each can have different data conversion configurations.

This Gateway can be used in conjunction with ISODE's X.400 Server's to provide X.400 messaging over X.25.

Typical Applications

• Replacing a complete X.25 network by using FarLinX X25 Gateways to manage the X.25 connections over a
  TCP/IP network running XOT
• Reduce line costs by replacing expensive X.25 lines with a TCP/IP connection and conversion to X.25 at each terminating node
• Conversion of legacy X.25 connections and data for transfer over a TCP/IP network
• 4 or 8 port X.25 switch with migration and selective routing of X.25 traffic to TCP/IP networks
• Provides an X.25 Gateway to interface with X.400 Servers

Functional Overview - XOT and X.25 Switching

The FarLinX X25 Gateway provides a reliable means of routing connections between X.25 and XOT (X.25 over TCP/IP). Connections can be routed between X.25 lines and over XOT which is treated as another connection path. The connection routing module supports default routes, hunt groups, X.25 address translation, and routing commands with NUA wildcards for maximum flexibility.

The XOT and X.25 support features particularly fast switching times, 100s of calls a second can be established. This is particularly useful where calls are frequent or the system is prone to bursts of calls.

A mix of up to 1000 SVC or PVC sessions can be handled simultaneously over XOT and X.25 lines.

Simple example configuration showing an X.25 line at each end with the Network running XOT (X.25 of TCP/IP

Functional Overview - data packetization and routing between X.25 and TCP/IP

The Gateway provides connection establishment and data packetization services for general protocols to allow applications sending data over TCP/IP to interface to X.25 connected hosts and also routing facilities to select the appropriate Host from those available and maintains X.25 sessions to the Host as required.

A mix of up to 1000 SVC or PVC sessions can be handled simultaneously between TCP/IP and X.25.

Example network configuration using the FarLinX X25 Gateway to interlink the TCP/IP and X.25 networks

The Gateway listens on a number of TCP ports – one port per configured X.25 Host. When a client establishes a TCP connection to the Gateway, the Gateway sets up an X.25 virtual circuit to the appropriate Host. Once the end-to-end connection is complete, the messages can be transferred.

At the end of the transaction, if the terminal disconnects, the Gateway will clear the X.25 virtual circuit. Alternatively, if the Host clears the X.25 virtual circuit first, the Gateway will disconnect the TCP connection to the terminal.

An X.25 Switch function can switch X.25 calls between X.25 connections and permit selective filtering of calls to TCP.

TCP to X.25 data translation functions

The Gateway supports a wide range of TCP to X.25 data translation and connection functions, these include:

• Character stream
• ETX terminated messages
• Special character terminated messages (customisable)
• Message header conversion - types available 2 or 4 byte ASCII or Binary length representation
• Custom message header conversion
• RFC1006 - ISO Transport Class 0 protocol data units, using the RFC-1006 encapsulation on the TCP connection
• Cisco RBP - Record Boundary Preservation
• X.25 Parity conversion - the Gateway performs any required parity adjustments and removal on the x.25 connection

Many of the functions can be configured for the same connection for maximum flexibility.

Connection Routing and Address Mapping

The FarLinX X25 Gateway can support routes to 2,000 different X.25 hosts. Similarly, when using the called X.25 address as the routing key, incoming X.25 calls can be routed to thousands of different TCP/IP hosts.

When making connections to the X.25 network, the Gateway has the capability of mapping the source IP address to a calling X.25 address, thus allowing the destination X.25 host to identify the connection source uniquely.

The Dynamic routing option allows the X.25 address (NUA) and call parameters to be set by the remote application at the time each X.25 connection is established. X.25 packetisation information is passed to the application.

The main modes supported include:

• Statically defined routing
• DRPD - the Dynamic Routing Packetized Data format allows TCP connected applications to dynamically setup the X.25 connection
• X.25 Data Switching - allows X.25 devices to be interconnected via an IP network without the overheads associated with XOT
• PAD Routing - PAD or Dynamic routing may be employed to allow the TCP client application to specify the X.25 call parameters
  
  

Resilience Options

To permit network line redundancy, a FarLinX X25 Gateway may operate with two or more X.25 lines acting as a hunt group. Calls can optionally be routed over any active line connected to the Gateway so that if one line goes out of operation then the other lines can continue to be used automatically. Backup X.25 lines can also be configured.

Two Gateways can be used together as an Active and Standby pair sharing a single IP address. Should the active Gateway fail, the standby Gateway will automatically take over.

Statistics, event logging and SNMP

Statistics

The gateway maintains a comprehensive set of statistics and activity counts. This information can be used to indicate the total loads on the Gateway and also to give early warning of line performance problems even misconfigured systems elsewhere in the network. See a sample screen of some of the stats available on the right.

Logging

All connections setup through the Gateway can be logged. The logs are automatically saved on a daily basis, old logs can be displayed as required. The most recent connections/disconnections are displayed in a browser window.

SNMP

The Gateway supports SNMP alerts with 3 configurable levels. Alerts can be issued for SVCs connecting and disconnecting, PVC errors, connection routing errors, line up and line down events and many more events.

Configuration

The Gateway is configured from a Browser, IE and Firefox are supported. Access to the configuration is secured through a user name and password.

The Configuration Application allows all the features of the Gateway to be managed. The majority of configuration changes to the Gateway are made dynamically so continuous operation of the Gateway can be maintained. For example, where the configuration for one line is changed, only that line is restarted; other lines remain operational.

Configurations can be saved for later use.

The sample configuration screen on the right shows configuration of a remote host.

System Upgrades

Upgrades to the firmware can be remotely and securely uploaded to the device so that the latest revision levels can be used.

Maintenance Contract

FarSite recognises that this product is frequently used as a key component in networked systems and as such a guaranteed response to unexpected problems is required. A maintenance contract is available for the FarLinX X25 Gateway for priority service and rapid problem resolution.

All trademarks and registered trademarks are acknowledged.
Changes are periodically made to the information herein; these changes will be incorporated into new editions of the publication. FarSite Communications may make improvements and/or changes in the products and/or programs described in this publication at any time.

Last updated: 22-Apr-2008