Originally published in the May 1995 issue of Advanced Systems.


NetWare to Unix (and back)

NetWare-Unix connectivity is fast becoming a problem of the past, even for enterprise system managers.

By Rawn Shah

The undisputed king of the PC LAN is Novell's NetWare family of products. However, it's only recently that Novell has taken a bold step toward integration of NetWare 4.x versions with the enterprise. Previously, limitations in the company's server software and communication protocols made this level of interconnectivity problematic.

NetWare 4.x, however, has not completely integrated the path from the PC client to the Unix host. We hope to uncover some of the tools and techniques currently used to develop this strategy for your enterprise.

Let's talk protocols
NetWare's enterprise problems begin at the very bottom in its communication protocols. IPX/SPX communications are based on the Xerox Networking System, which had been developed more than a decade ago when PC LANs were still quite separate from the enterprise. The Internet Packet eXchange (IPX) uses a 12-byte host address compared with the 4-byte addresses of the current version of IP. The 12-byte address consists of a 4-byte network identifier, a 6-byte host identifier, and a 2-byte socket address. And the host identifier is based on the network hardware address. For example, the 6-byte host-identifier address over Ethernet looks like 00:20:a9:0a:db:f3 (hexadecimal). IP, on the other hand, has a variable-length network, subnetwork, and host identifier, depending on the class of IP addresses in use. The IPX method makes it much easier to configure and install nodes on the network. IPX is used similarly to raw IP and User Datagram Protocol (UDP) for nonreliable, nonsequenced communications between hosts.

In the next networking level, NetWare's Sequenced Packet eXchange (SPX) and its successor, SPX II, are reliable-connection-oriented communications mechanisms similar to the Transmission Control Protocol (TCP) of the IP suite. SPX II removes some of the limitations for packet size in SPX and implements the sliding window protocol found in TCP to improve the performance of communications. Other NetWare protocols include the NetWare Core Protocol (NCP) used to deliver presentation and application-layer communications for file and print services, and the Service Advertising Protocol (SAP) to help locate services on the LAN. NCP provides the equivalent capabilities of the Unix Network File System (NFS) and Line Printer protocol (LPR) in one unit.

SAP has been replaced with the NetWare Directory Services (NDS) in NetWare 4.0, providing an X.500-like directory and location service for all network entities and objects. The IP suite does not have a single equivalent to SAP and NDS; the closest is the Domain Name Service (DNS), which maps network addresses into node names. Sun's Open Network Computing (ONC) Network Information Service (NIS) and NIS+ are even closer equivalents.

Still, Novell hasn't forgotten that PCs and Unix systems are becoming more mainstream and need to cooperate in a common environment. Over the years, Novell and others have released products that address related issues in products as an option to the NetWare server or as separate products completely.

Bridging the gap
Novell added a TCP/IP protocol stack to the base NetWare server package in 3.11 to accommodate low-level communications differences between it and common Unix-based networks. Novell added Flex/IP and the NFS NetWare Loadable Module (NLM) to fill the gaps of access to the common file-sharing mechanisms. Other companies, such as Firefox (San Jose, CA), Ipswitch (Wakefield, MA), and NetCon Business Systems (Edison, NJ), also developed their own TCP/IP stacks and gateway mechanisms that improve upon the standard Novell-supplied products.

Firefox's Nov*ix family of products combine several of Novell's products including LAN WorkPlace, NetWare NFS, and Novell TCP/IP into a manageable entity that can support numerous addresses over a single network interface on the NetWare server. Firefox even offers support for Internet applications for the World Wide Web, Gopher, and so on for NetWare clients. NetWare users need not install a separate IP stack to run these applications or wait for Novell to develop or integrate such products.

Ipswitch's Catipult NetWare-TCP/IP Gateway uses an independent PC as a gateway between the two communication protocols. Catipult runs on OS/2 to take advantage of the operating system's true multitasking and low cost. Catipult, like Nov*ix, also can run Windows Sockets (Winsock)-compatible applications unaltered over NetWare. However, Catipult does not offer NFS.

NetCon lets you mount NetWare files on Unix hosts as native Unix filesystems. NetCon uses a new high-performance filesystem, which is compatible with NCP and provides bi-directional printing and file sharing between Unix and NetWare systems. NetCon runs on SunOS, Solaris 2.x, SCO, AIX 3.x, and NetWare 3.11 servers. A multiprocessing version, NetConMT, runs in the symmetrical-multiprocessing Solaris environment.

In the networked display world, Hummingbird Communications (Mountain View, CA) and VisionWare (Menlo Park, CA) have brought the X Window Systems to the NetWare environment. With their products, eXceed and Xvision, respectively, they have created X servers for PCs that communicate over the IPX protocols directly. Hummingbird is the leading PC X Windows software vendor internationally with a unique configuration utility built into the X server that allows control of remote PCs for installation, configuration, or modification of any software on the remote system. VisionWare also has many fine features and looks forward to a more closely integrated product soon -- VisionWare recently was acquired by the Santa Cruz Operation (SCO; Santa Cruz, CA), the leading PC Unix vendor.

Changing protocols
Yielding to the predominance of Unix on the enterprise server, Novell has introduced a partially IP-based NetWare server system, known as NetWare/IP. It uses IP protocol in place of a majority of IPX communications, except some of the NetWare Core Protocols (NCP) that still need IPX. The network continues in effect, to run two communications protocols, rather than one.

Unix servers also play the part of a NetWare server with products from several different vendors, all of whom have licensed the NetWare system. You can run NetWare servers for Data General's Aviion, HP's 9000, IBM's RS/6000, and Sun's Solaris and SunOS environments. NetWare client emulation under Unix is also available from Puzzle Systems (Morgan Hill, CA), NetCon (Edison, NJ), Novell, and NeXT (Mountain View, CA).

SunSoft (Chelmsford, MA) is leading the effort to bring Unix and NetWare closer together through their SolarNet product line. SunSoft's bold step beyond PC-NFS eases bi-directional integration. The first product, SolarNet PC-Admin, provides almost the same client software as SunSoft PC-NFSpro with the addition of a Sun-based allocation and management system. With SolarNet PC-X, users also can add X Window System to their stations. With SolarNet's NetWare file and print services, the first bi-directional step is available. We should expect to see even more in the future of this product line.

SunSoft also has licensed the TotalNET Advanced Server from Syntax (Seattle, WA), which integrates NetWare, LAN Manager, and AppleTalk servers into a single unit. TotalNET runs on Solaris 2.x (SPARC and x86), AIX, HP-UX, SCO Unix, Digital Ultrix, SGI IRIX, and Sequent PTX. The TotalAdmin utility is a group of administration tools that lets a network manager control all three servers from a single PC. In addition, the TotalBackup, TotalFax, and TotalMail utilities integrate core network applications. Syntax is the first to accomplish such uniformity across these three communications systems. No longer do we have to worry about bits and pieces and try to figure out how they fit together with the least amount of servicing.

Bold steps
Novell clearly has taken bold steps toward uniting Unix and NetWare systems. In the future, the promise of Novell's SuperNOS project to completely integrate NetWare and Unix at the operating system level is raising eyebrows from Unix vendors. The project means rewriting the entire operating system, possibly based on the French vendor Chorus Systems microkernel operating system known as Chorus.

In fact, recent developments have made the integration between NetWare and Unix become an issue of the past. Vendors are paying strict attention to the success of the PC LAN market and to companies like Novell and Microsoft. The fear of such developments that might upset the Unix market is causing a scramble for new ideas that will further integrate the enterprise.

About the author
Rawn Shah is a Unix and PC systems consultant with RTD Systems & Networking of Tucson, AZ. Reach him at rawn.shah@advanced.com. He is also the author of the PC-Mac TCP/IP & NFS FAQ.

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Last updated: 1 May 1995