Chapter 1 About Solstice X.25

The information in this section is specific to the Solstice X.25 9.2 product. For general X.25 information, refer to Chapter 2, About X.25.

Overview

Figure 1-1 Solstice X.25 Overview

Solstice X.25 9.2 is an implementation of the ITU-T's (formerly CCITT) X.25 Recommendations, together with some other, related software. Using Solstice X.25 9.2, you can make connections to a Packet Switched Data Network (PSDN), and connect to remote devices that are running any standard-compliant implementation of X.25.

Figure 1-1 shows some of the ways you can use Solstice X.25 to make connections with remote devices:

• PAD calls from Sun workstations running Solstice X.25 to Sun workstations and servers running Solstice X.25, and to remote systems running other implementations of X.25.

• PAD calls from one X.25 device to another, from where the user can rlogin to a non-X.25 IP host.

• uucp connections with remote X.25 devices.

• IP routed between TCP/IP networks.

All of the connections shown in the diagram are made across the X.25 PSDN.

Solstice X.25 9.2 Features

This section summarizes the features provided by Solstice X.25 9.2.

New in this Release

Solstice X.25 9.2 offers the following new features:

• Updated software which now runs in either 64bit or 32bit mode.

• New LLC2 module which handles LAN plumbing and PPA assignment for applications which run directly over LLC2.

• The ability to specify the name of a a file containing PAD commands when using the pad command.

Feature Summary

In addition to the new features added to the current release, Solstice X.25 offers the following features:

• A user-friendly GUI based on Motif.

• HTML-based on-line help that provides x25tool specific information.

• A PAD Printer which makes it possible to print locally while logged in to a remote terminal.

• A Call Filtering module filters incoming calls based on specific criteria which are then stored in a configuration file. The criteria you can specify include X.121 address, time of day, call user data.

• The software allows for a total up to 32,763 virtual circuits distributed over any number of links (with a maximum of 4096 virtual circuits on any one line). Machine resources and the configuration of your X.25 network may constrain you to a smaller number.

• Maximum data rates of:

  • 2.048 Mbits per second on one HSI port

  • 1.544 Mbits per second on two HSI ports

  • 19.2 Kbits per second on SPARCstation CPU ports

• X.29 packet-mode host (PAD daemon) and X.3/X.28 virtual terminal (PAD) support.

• Encapsulation of IP packets in X.25 packets, as defined in RFC 1356.

• Address Extension Facility (AEF) for running OSI over X.25.

• Standard configuration file templates for major PSDNs.

• Domain Manager agent (formerly known as SunNet Manager agent).

• Security mechanism (through full or partial address specification) for incoming calls to PAD daemon.

• APIs: STREAMS-based Network Layer Interface and sockets module for backward compatibility with SunNet X.25 7.0.

• The X.25 Packet Layer includes:

  • Extended packet sequence numbering.

  • Large flow control windows (up to 127 packets) and large packet sizes: up to 1024 bytes over 1980-compliant X.25 networks, and up to 4096 bytes over 1984 and 1988 X.25 networks.

• Basic and extended frame sequence numbering for LAPB (1984 and 1988).

• ISO 8208 for DTE-to-DTE operation.

• LLC2 for running X.25 over a LAN (802.x or FDDI)

• Reverse charging, RPOA selection, flow control parameter negotiation, CUG selection, throughput class negotiation, and fast select on a per-call basis.

• Multiple physical links per system. You can have as many connections as serial ports and other resources allow.

• MultiLink Procedure enables more than one physical interface to be used to connect a DTE and a DCE. This allows load sharing and link failure recovery.

• The Data Link Provider Interface (DLPI) is a standard way of writing application programs directly above the datalink layer.

• A client-only implementation of X.32, which provides authentication and is most useful for dial-up calls.

• V.25bis allows Solstice X.25 to be used in dial-up configurations.

• Routing (automatic link selection) among multiple links.

• Configuration files. You can also configure Solstice X.25 9.2 by editing the configuration files delivered with the product. This allows users who do not have access to a Graphical User Interface such as the OpenWindows or Motif environments to carry out a full configuration of the X.25 software.

• The ability to connect to the Defense Data Network via X.25 Standard and Basic Service.

Components of the Solstice X.25 9.2 Product

The Solstice X.25 9.2 product contains the following components:

X.25 Packet Layer

Layer 3 of the ITU-T X.25 Recommendation is known as the X.25 Packet Layer. Sometimes this is shortened to just X.25.

LLC2

Logical Link Control Class 2. This provides the datalink layer for 802 LANs, such as Ethernet, Token Ring and FDDI.

LAPB

Link Access Procedure Balanced. This provides the datalink layer over WAN interfaces.

MLP

MultiLink Procedure. This provides the datalink layer allowing a DTE and a DCE to connect using more than one WAN interface.

EXPX

The driver for the SCiiExpress-X card used by the x86 version of the product.

Loopback

The driver for the loopback interface.

XTY

A pseudo-device that lets applications access the PAD software to make outgoing calls.

PAD Software

The Packet Assembler/Dissassembler software. This allows you to make PAD calls to remote machines that are running X.25.

PAD Daemon

The software that listens for incoming PAD calls and determines how they are to be treated.

PAD Printer

Printing is routed through an X.25 server, making it possible for a user to print to the local printer even if the user is logged in remotely.

XXX

The three ITU-T software implementation recommendations --X.3, X.28 and X29-- that control operation of the PAD. They are often referred to as the triple X standards.

IXE

Software providing an interface between IP, the Internet Protocol and the X.25 Packet Layer.

Domain Manager Agent

The Domain Manager agent (formerly known as SunNet Manager agent) allows access to the MIB through the RPC protocol.

SNMP Agent

The Simple Network Management Protocol (SNMP) agent allows access to the MIB through the SNMP.

Call Filtering Module

This optional facility enables the X.25 administration software to define a list of authorized remote stations.

The Solstice X.25 9.2 product, together with the software provided with the Solaris 2.x operating software, is enough to make full use of the facilities offered by X.25. You can also interwork with the other Sun products shown in Figure 1-2.

Standards Support

The X.25 Recommendations were first specified in 1976, and have subsequently been revised on a number of occastions. It is common to refer to versions of the X.25 Recommendation by the year in which they were issued--for example X.25(1984). The 1980, 1984 and 1988 versions are the most widely used.

Solstice X.25 supports the following features from the 1984 and 1988 X.25 recommendations:

• optional user facilities:

  • extended packet sequence numbering

  • one-way incoming and one-way outgoing logical channels

  • non-standard default packet and window sizes

  • default throughput classes assignment

  • flow control parameter negotiation

  • throughput class negotiation

  • CUG-related facilities

  • bilateral CUG-related facilities

  • fast select and fast select acceptance

  • reverse charging and reverse charging acceptance

  • local charging prevention

  • charging information

  • RPOA selection

  • incoming and outgoing calls barred

  • called line address modified notification

  • call redirection notification

  • call deflection

  • transit delay selection and indication

  • TOA/NPI address format

  • Network User Identifier (NUI)

  • protection

  • priority

• permanent virtual circuits

• two-way logical channels

• called and calling AEF

• expedited data negotiation

• minimum throughput class

• user data on Accept and Clear with Fast Select

• non-X.25 facilities (in Call Request and Call Accepted packets)

• programmable facilities field

• up to 32 bytes of interrupt data

• up to 109 bytes of facilities in Call Request and Call Accepted packets

• DTE-originated cause codes

• MLP

Solstice X.25 does not support:

• on-line facility registration

• the hunt group facility

How Solstice X.25 9.2 Interworks With Other Sun Products

Figure 1-2 How Solstice X.25 Interworks With Other Sun Products

Solaris System Software used with Solstice X.25

The Solstice X.25 9.2 product can be used in conjunction with the following software that is supplied as part of the Solaris 2.x system software:

IP

The Transmission Control Protocol/Internet Protocol. The TCP/IP protocol suite is the de facto standard for networking. IP, the Internet Protocol, can be run above X.25, creating a Wide Area Network using TCP/IP. This allows for the use of rlogin, ftp and other useful facilities. The TCP/IP protocol suite is delivered as part of the Solaris system software

Line Discipline

The standard STREAMS line discipline modules.

802.3

The Ethernet interface.

ZSH

The onboard serial port of a Sun workstation.

Products that Interwork with Solstice X.25

Solstice X.25 9.2 forms part of a complete networking solution. As such, it interworks with other products--both from Sun and from other vendors. You can use the following software, available from Sun Microsystems, with the Solstice X.25 9.2 product:

OSI

You can run the OSI protocol stack, using the Solstice X.25 9.2 product as the bottom 3 layers.

FDDI

You can run Solstice X.25 9.2 on an FDDI network.

HSI

This is the High Speed Interface, available from Sun Microsystems. This provides four WAN interfaces and allows for higher speeds and better performance than the onboard serial port.