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How to Select WAN Hardware for Your Novell Product

Articles and Tips: article

Director of Engineering
Novell Labs

01 Dec 1996

Provides information to help you select appropriate hardware for your WAN connections.


To communicate over wide area networks (WANs), Novell products, such as NetWare 4.11, IntranetWare, MultiProtocol Router, NetWare Connect, and NetWare for SAA, need suitable WAN hardware.

This document contains information that will help you select appropriate hardware for your WAN connections. It is organized into the following sections:

  • A description of the various types of WAN drivers and hardware supported by Novell and how they are certified

  • A discussion of typical WAN applications, the relevant Novell products, and how to decide what type of WAN hardware you need

  • An explanation of how to read Novell Labs certification bulletins

  • A glossary of related technical terms

This document is adapted from the online version that can be found at the following location:

WAN Hardware and Certification

There are many types of wide area networks in use today, ranging from low- cost, low-speed solutions using modems and phone lines, through medium- speed networks based on Frame Relay, to high-speed networks based on T1 or faster leased lines. Because it is not possible to effectively integrate such a wide range of technologies with the same driver interface, Novell has created a number of interface specifications that are optimized for particular usage scenarios. These include:

  • The AIO (Asynchronous Input/Output) interface

  • The WAN-HSM(Hardware Specific Module) interface

  • The WAN-ODI (Open Data-link Interface) interface

  • The SDLC (Synchronous Data Link Control) interface

  • Modems/Communications products

Many of these interfaces can be used with more than one Novell product. For example, drivers written to the WAN-HSM specification can be used with IntranetWare, NetWare Connect, NetWare MultiProtocol Router, and NetWare for SAA. The actual type of link supported varies by product. IntranetWare, for example, could use a WAN-HSM driver/adapter for PPP, Frame Relay, or X.25; NetWare Connect could use the same driver and hardware with AIOPAD over X.25; and NetWare for SAA could use it for QLLC/X.25 or SDLC connections.

Novell Labs has produced a number of test specifications and specialized test software to verify that products conform to Novell's interfaces. Novell Labs works closely with hardware vendors to assist them in the development of driver software and in addressing any issues that arise during testing or from customer feedback.

As part of the certification, products are tested with major Novell products using a particular device driver interface. Although not all applicable Novell products are tested for a given certification, it is rare for there to be any problems with other Novell products when the test candidates pass certification with the major Novell products. Again, Novell Labs works closely with Novell technical support and with the hardware vendors to resolve any problems that may surface.

New products are added to the certification list regularly. You can view current bulletins on the Novell Labs web site at:

Certification bulletins can also be obtained from the Novell Labs Faxback server at 1-800-414-LABS or 801-861-2776.

The following table lists the classes of WAN drivers currently available and the common uses for the related hardware products. (Novell Labs produces a different type of certification bulletin for each class of driver listed here.)

AIO Adapters/Drivers

Dial-up connections for NetWare Connect, IntranetWare or MultiProtocol Router

Dial-up connections for GroupWise Async Gateway

WAN HSM Adapters/Drivers

Leased-line connections with IntranetWare or NetWare MultiProtocol Router using PPP

Frame Relay connections using IntranetWare or NetWare MultiProtocol Router

X.25 for IntanetWare or NetWare MultiProtocol Router

ISDN connections for IntranetWare or NetWare MultiProtocol Router

ISDN connections for NetWare Connect

X.25 for NetWare Connect using AIOPAD

X.25 for NetWare for SAA using QLLC

SDLC connections with NetWare for SAA

WAN ODI Adapters/Drivers

Leased line connections for IntranetWare or NetWare MultiProtocol Router using PPP

Frame Relay for IntranetWare or NetWare MultiProtocol Router

ISDN connections for IntranetWare or NetWare MultiProtocol Router

X.25 for NetWare MultiProtocol Router

X.25 over ISDN for IntranetWare or NetWare MultiProtocol Router, NetWare for SAA (QLLC) or NetWare Connect (AIOPAD)

SDLC Adapters/Drivers

Mainframe SDLC connections with NetWare for SAA 1.3 or 2.0

Communications Products

  • Modems, modem-like products such as client ISDN adapters and WAN products not covered by other classifications

Determining What Type of Driver and Hardware You Need

To decide what type of wide area networking hardware you need, you first need to consider the type of WAN link you will have and what it will be used for. Then you can check the table above to see which class of driver/hardware meets your needs. That, in turn, will tell you Novell Labs bulletin section to look in to find out what third-party products have been certified by Novell.

For example, suppose you have a small-scale NetWare Connect system to allow remote users to work from home or dial in and collect e-mail. In this scenario, you would probably want to have an asynchronous adapter in the server with four to eight voice modems attached. From the table above, you determine that an AIO adapter/driver best meets this need. You then know to look in the Novell Labs AIO driver section to get information about certified products.

The following sections describe some typical wide area network applications, and indicate the relevant Novell products and recommended types of drivers and hardware to use in each scenario.

Telecommuting or Remote User Dial-up Access

In this scenario, the most common solution is to use NetWare Connect with a bank of analog modems and an asynchronous adapter in the NetWare Connect server. These adapters can support from 2 to 128 ports at speeds up to 115.2 Kbps, and they use AIO drivers (look in the AIO drivers section for certified adapters). Most of these adapters are intelligent, meaning they off-load character processing from the host server to enable high-speed data transfer without high server usage.

Simple non-intelligent adapters, such as the built-in communication (COM) port, are only suitable for slower speeds up to 38.4Kbps (even less if you don't have a 16550 UART). For this you would use the AIOCOMX driver.

Systems with up to 8 ports are usually implemented on one board, while larger systems frequently use a single host adapter with external modules providing 8 or 16 ports each. The largest systems can handle up to 128 ports using only one slot in the server.

Note: An individual multiport adapter may be used simultaneously with more than oneproduct. For example, you could have NetWare Connect using six ports of an eight-port adapter, GroupWise Async Gateway using one port, and NetWare MultiProtocolRouter using the remaining port.

Novell Labs is currently certifying hardware that will provide similar access using ISDN. These adapters will be found under the WAN-HSM, WAN-ODI or CAPI certification areas, depending upon implementation.

Novell Labs has recently begun a modem certification program. The list of modems that NetWare Connect supports is constantly growing. If your modem is not currently supported, check back regularly for updates to the modem support files. Information and software for creating your own modem scripts is available on the Novell Labs web site ( modem.htm) and on CompuServe (GO NETWIRE).

LAN-to-LAN Communication Between Sites, or Between Branch Offices and Headquarters

You can set up LAN-to-LAN links between sites with IntranetWare or NetWare MultiProtocol Router, using adapters with either a WAN HSM or WAN ODI driver. The actual WAN protocol can be Frame Relay, X.25, PPP over leased-line, or ISDN.

Frame Relay is a common solution in the U.S. This type of connection can economically provide speeds from 56 Kbps to T1, and allow connection to multiple sites over one wire with good performance.

An adapter with a WAN-HSM driver requires that you also purchase the NetWare WAN Links add-on product to the NetWare MultiProtocol Router to support X.25 or Frame Relay. IntranetWare, NetWare MultiProtocol Router and NetWare Connect include PPP support for no additional charge. NetWare Connect and NetWare for SAA include X.25 support for no additional charge.

Hardware vendors of WAN-ODI drivers provide the software that implements the WAN protocol, usually on an intelligent board which can reduce server bandwidth. This can also provide improved performance and alternative capabilities beyond those found in the Novell WAN protocol software. These features may be significant if you are using the server to perform file/print and communications services simultaneously.

To ensure interoperability between vendors, Novell uses standard networking protocols and also collaborates with other industry leaders. For example, it is a common solution to use the Novell NetWare MultiProtocol Router in a branch office that communicates over a WAN link to a CiscoSystems, Bay Networks, or other hardware router at headquarters.

These adapters often work at up to T1 or E1 speeds and usually require an external CSU/DSU. Novell Labs does not certify CSU/DSUs because they are physical-layer devices which do not interact with the NetWare protocols.

Dial-up Links for LAN-to-LAN Access

IntranetWare and the NetWare MultiProtocol Router can use analog dial-up lines with modems and AIO adapters. The performance is limited by the speed of the link, but is adequate for low traffic or backup links. Novell Labs is now testing AIO drivers with IntranetWare and MPR 3.1 in addition to NetWare Connect, because these products now include specific support for asynch PPP or ISDN to be used as a backup link.

Dial-up Access for GroupWise Async Gateway

The GroupWise Async Gateway can use any AIO driver. It can share boards that are also being used by other applications such as NetWare Connect, although it does need a dedicated port. GroupWise is not currently used in Novell Labs' certification test suite, so it will not appear on the bulletins. Based on our experience, drivers certified for use with NetWare Connect will also work successfully with GroupWise.

SDLC Connection to IBM Mainframe

Novell's NetWare for SAA product can provide SDLC connectivity to integrate an IBM mainframe or AS/400 into the network. Two types of drivers can support this connection: adapters with WAN HSM drivers, or adapters with dedicated SDLC drivers. The previous version of NetWare for SAA (v 1.3b) supported only the dedicated SDLC type of driver. There are also specialized SDLC drivers and adapters that offer additional features to NetWare for SAA.

X.25 Connection to IBM Mainframe

Many WAN ODI drivers and almost all of the WAN HSM drivers also provide Qualified Link Level Control (QLLC)/X.25 support for connecting to IBM mainframes over a WAN.

ISDN Connections

ISDN is a relatively new technology in the U.S., but it is well established in Europe. Novell Labs is working with a number of vendors to provide ISDN solutions that integrate with their products. These may consist of adapters installed inside of the computer, or external terminal adapters that look and function very much like modems, but which interface to ISDN lines instead of analog phone lines.

Terminal adapters (commonly called TAs) can be used with any Novell product that works with a modem over analog phone lines. However, they may require the user to modify the AT commands in a similar fashion to those for modems. Terminal adapters can provide many features that will function with existing software. Multi-Link PPP, Bonding, V.120, and synchronous communication are common on these devices.

As the technology available for ISDN adapters has not yet had time to mature, there are many competing standards. Usually each country has its own flavor of ISDN with differing D-Channel protocols for dialing the call. Drivers frequently only support one protocol. For example, an adapter might only support AT&T switches used in the U.S. and not Siemens switches used in Germany. Some countries (such as the U.S.) have more than one standard. You will need to contact the vendor of the potential product to find out where it can be used.

There are also multiple ways of putting data onto the ISDN line. Novell encourages and supports the use of PPP over ISDN. In some countries it is common to use X.25 with ISDN, and vendors may use their own proprietary techniques. The recent bulletins for ISDN adapters contain information about the data encapsulation used and about the D-channel protocols supported. You should contact the hardware vendor for more information.

Because of these variations, not many interoperable solutions are available at the moment. Novell is encouraging developers to use the PPP protocol with ISDN in the manner defined by Novell. This would allow one vendor's product to communicate with another's. In the future, Novell Labs will be verifying this interoperability. Until then, you should verify interoperability from the vendor or use the same product at each end of the link.

Understanding Novell Labs Certification Bulletins

A Novell Labs Certification Bulletin shows that Novell has tested the hardware and driver with the indicated Novell products and certifies that the vendor product has met our specifications. An example bulletin is shown below.

Digi SYNC/570 (i)(MC) by Digi International Inc.

Date: 07 OCT 1996
Bulletin #: C-238
Faxback Document ID: #29754

     The Novell Labs Faxback can be reached at (801) 861-2776 or (800) 414-LABS.

Tested and Approved compatible as a WAN-HSM Adapter with the 
following Novell products:

Certified OS:
     NetWare (v4.10)
     NetWare (v4.11) (a component of IntranetWare)
     NetWare (v3.12)
     WAN-Extensions (v3.1)
     NetWare MultiProtocol Router (v3.0)
     NetWare MultiProtocol Router (v3.1)
     WAN-Extensions (v3.0)
     NetWare Connect (v2.0)
     NetWare for SAA (v2.0)


Driver File(s):

Digi International SYNC/570 (i) WAN Driver (v1.01)

      SYNC570.LAN    (55781         01 DEC 1995)

Test Configuration:
Product/Model/Rev:Digi SYNC/570 (i)(MC)
Bus Type:         MCA (16-bit)
Serial Interface: RS-232, V.35, X.21, up to 5Mbps
Number of Ports:  2 or 4


Configuration Notes:

This product supports PPP, Frame Relay, and X.25 when used in conjunction 
with IntranetWare. It will also support X.25 in

conjunction with NetWare Connect and both X.25 and SDLC with NetWare for 
SAA. Please note the following exceptions to

the WAN-HSM interface specification. They are not considered by Novell Labs 
to cause significant limitations in its use:

   1) Does not support asynchronous PPP.
   2) Does not support PPP data compression. This is rectified by 
   version 2.0.5 or later, available from Digi.


Vendor Product Description:

Digi's SYNC/570 WAN Driver for NetWare is a Novell-compliant WAN-HSM driver 
that fully supports Novell's 
IntranetWare products and NetWare for SAA 2.0. Designed for the popular 
SYNC/570 product family of synchronous 
communications controllers, the driver supports up to 16 lines at baud 
rates up to 2Mbps for both ISA and Micro Channel 
systems. The SYNC/570 product family includes the two port SYNC/570 with 
RS-232 only, and the two and four port 
SYNC/570i with RS-232, V.35, X.21 and RS-530 interfaces. The driver is 
easily configured via INETCFG and fully supports 
Novell's IntranetWare and NetWare for SAA 2.0.

The term Tested and Approved applies only to the exact configuration 
documented in this bulletin. For more information 
regarding the specific test configuration, please contact:

Digi International Inc.
11001 Bren Road East
Minnetonka, MN 55343
VOICE: (612) 912-3444
FAX: (612) 912-4953

The bulletin lists which Novell products the vendor product was tested with, gives version details of the driver and adapter, and provides other significant information. In some cases, a product may not fully meet our specifications but still be a useful product. There are many ways of using WAN adapters and it may be of little consequence that an obscure feature is not supported. These exceptions are noted in the "Configuration Notes" section of the bulletin.

At the bottom of the bulletin is a description of the product provided by the vendor, along with information on how to contact them.


AIO (Asynchronous Input/Output) Driver. A type of driver used to integrate asynchronous adapters with Novell software. This interface is used by NetWare Connect, IntranetWare and NetWare MultiProtocol Router. It is also used by other products such as the GroupWise Async Gateway, PSERVER.NLM, and some third-party products.

AIOPAD. A module included in the NetWare Connect product to support client connectivity over X.25 networks using the X.3, X.28 and X.29 standards.

Baud. A measure of data rate used for serial ports and modems. Strictly speaking, it means "symbols per second" but common usage is interpreted as meaning "bits per second." All modern modems actually transmit more than one bit per symbol (up to 512 bits in some designs).

CAPI (Common ISDN API). An international API standard for ISDN which Novell supports. It originated in Germany, but IHVs from many other countries support it as well. In Novell products, a CAPI driver can be used anywhere an ISDN WAN HSM driver would be used.

CSU/DSU (Channel Service Unit/Data Service Unit). A piece of equipment which usually needs to be connected between the adapter and high speed lines coming from your provider. This equipment provides diagnostic, safety, and data framing for the connection.

Driver. A piece of software written by an adapter vendor that integrates the adapter with system software such as NetWare Connect or the NetWare MultiProtocol Router.

DS0. A 56 Kbps line. The actual line runs at 64 Kbps, but due to the signalling method only 56 Kbps is available. Frequently used for Frame Relay, PPP connections, or X.25.

E1. A high-speed data line running at 2.048 Mbps, provided by a European wide area service provider. E1 is frequently used for point to point links, but can also be used for Frame Relay or primary rate ISDN. The equivalent speed in U.S. networks is called T1 (1.544 Mbps).

Frame Relay. A networking service that allows multiple virtual circuits for moderate speeds of 56 Kbps to 1.544 Mbps (in the U.S.). Currently only permanent connections are available. You have to arrange to have the phone company set up the connections to different destinations when you order the service, although you can have multiple simultaneous connections on one physical wire. Frame Relay is similar to the X.25 protocol, but it has been simplified to work more effectively over modern high-speed WANs.

ISDN (Integrated Services Digital Network). A form of wide area networking very popular in Europe and rapidly attracting support in the U.S. Normally provided as two 64 Kbps bearer channels plus one 16 Kbps signaling channel (2B+D). In the U.S., it is common to only support 56 Kbps because the signalling method used between telephone exchanges "steals" one bit out of every byte of data. Each B-Channel can be used for one voice channel or for data. Novell products use PPP as the networking protocol over ISDN.

Modem. A device for translating the signals coming from the serial port of your computer into a form suitable for transmission over phone lines. Modern modems conform to the V.34 specifi-cation which allows transmissions at 28,800 bits per second, or V.32 bis which allows transmissions at 14,400 bits per second.

PPP (Point-to-Point Protocol). A modern protocol related to SLIP (Serial Line Interface Protocol) for connection over leased lines or voice lines using modems. Commonly used by Internet Service Providers (ISPs) for dial-up access. NetWare Connect 2.0 uses this protocol for its remote node service.

SDLC (Synchronous Data Link Control). A communications protocol used for connectivity to IBM mainframe systems.

T1. A high-speed data line running at 1.544 Mbps, provided by U.S. wide area service providers. T1 is frequently used for point-to-point links. It can also be used for Frame Relay or primary rate ISDN. The equivalent speed in European networks is E1 (2.048 Mbps).

Terminal Adapter (TA). A digital modem that usually connects to the computer via a serial port and can then communicate over ISDN. It can be used just like an analog modem. Many modern devices also support PPP, Multi-Link PPP, bonding, async PPP-to-sync PPP conversion, and other features.

UART (Universal Asynchronous Receiver Transmitter). The active device in a PC or adapter that converts data into the proper format for transfer over a serial line.

The normal built-in communication ports (such as COM 1) are based on the 16450 integrated circuit. This device only has buffering for one byte of data, which will be lost if another byte arrives over the serial line before the software has read the first one.

An improved version of the UART is known as the 16550 (or 16650). This version has buffering for 16 (32) bytes of data, allowing higher-speed operation with appropriate driver software. Adapters often use similar enhanced integrated circuits, or they are intelligent adapters with an on-board processor.

WAN (Wide Area Network). A general term used to cover all long-distance networking, usually using services from a provider such as AT&T.

WAN-HSM (Hardware Specific Module) Driver. A type of driver for use with NetWare MultiProtocol Router, NetWare Connect, and NetWare for SAA. WAN protocol processing (X.25, PPP, Frame Relay, or SDLC) is performed in the server by Topology Specific Modules (TSMs) provided by Novell. The adapters can be relatively simple and inexpensive.

WAN-ODI (Open Data-link Interface) Driver. A general term for the WAN driver architecture used for NetWare MultiProtocol Router, NetWare Connect, and NetWare for SAA. Also used to mean a specific type of driver where the WAN protocol processing occurs within the hardware vendor's software, usually on an intelligent adapter with its own CPU. This can reduce server CPU bandwidth and potentially give higher perform-ance, though usually at a higher cost than adapters using WAN HSM drivers.

X.25. A mature packet-switching, networking protocol that is available worldwide and can be used with many different products. Because it is a packet-switched protocol, you can set up connections to different destinations at any time; it does not require the phone company to perform the operation.

X.25 supports multiple virtual circuits over the same link, so you can connect to many sites with only one physical wire. It has a large amount of error checking, but as a result tends to be slow.

X.25 can be used with Qualified Link Level Control (QLLC) for IBM environments or with X.3/X.28/ X.29 (known as a Triple-X PAD) for terminal emulation or PPPRNS. NetWare Connect includes the AIOPAD.NLM module to support this feature.

For More Information

If you have questions about the WAN driver certification process, contact Novell Labs at (408) 577-7201, or send e-mail to:

Novell Labs cannot answer technical support questions or respond to requests for general information regarding Novell products.

For more information about obtaining technical support, or to find out more about the Novell products mentioned in this document, visit Novell's web site:

Or call 1-800-NETWARE (638-9273), or contact your local Novell office.

* Originally published in Novell AppNotes


The origin of this information may be internal or external to Novell. While Novell makes all reasonable efforts to verify this information, Novell does not make explicit or implied claims to its validity.

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