WORKSHOPS

Turning Your NOS Into A Router

The recipe for a NOS-based router is simple: Take a Novell NetWare or Windows NT server, add the appropriate networking hardware, sprinkle in some routing software and presto, you've got a low-end router capable of handling several segments of traffic. We talked with companies like Cisco Systems, SourceCom Corp., Novell and Eicon Technology Corp. and took a hands-on look at solutions for turning your NetWare or NT server into a router. Based on your needs, the price range of routing on your server will run between free and about $2,500.

Turning a server into a router has several benefits and implications. You can use a software router to add WAN connectivity to a branch office, to segment existing LANs to reduce traffic load, and to bring different topologies and speeds together, such as FDDI, regular and Fast Ethernet, and Token-Ring networks. To add network segments or route between topologies you'll need an additional NIC card for your server. To add WAN connectivity you'll need either a modem or a synchronous serial adapter with an NT1 or CSU/DSU on the other end. In either case, you'll need some sort of routing solution to get the job done.

One-Stop Routing Novell NetWare 4.1 is your one-stop routing shop. All the pieces you need to do simple IP, IPX and AppleTalk routing are present right out of the box. It all starts with INE TCFG.NLM, the Internetworking configuration NLM. INETCFG takes over the networking aspects of your server by moving load and bind commands from the AUTO-EXEC.NCF file to SYS:ETC\ NETINFO.CFG. Administrators accustomed to editing their NCF files by hand will have to adjust to letting INETCFG do the work since INETCFG checksums the NETINFO.CFG file, and any edits done by ha nd are discarded by the NLM. We suggest backing up your AUTOEXEC.NCF and STARTUP.NCF files before starting.

Adding WAN connectivity to a NetWare router requires additional software. There are several routes to choose. The best by far is Novell's Multi-Protocol Router (MPR) v3.1. The MPR 3.1 adds support for source route bridging, up to 16 synchronous or asynchronous WAN connections, backup WAN support and optional add-on support for frame relay, X.25, SNA and ATM WAN products. MPR 3.1 also adds several useful administrative features, including advanced protocol filtering and remote-access via X-Windows.

Choosing a WAN connection will depend on your bandwidth needs. If e-mail and groupware applications are your primary interest, a 28.8-Kbps or ISDN modem can provide a small office with enough bandwidth to operate comfortably. If you plan regular file transfers or multimedia applications, we suggest frame relay with a T1 at the local loop for higher bandwidth. Although most PCs have high-speed serial ports capable of supp orting a modem or ISDN line, T1 connections will require a synchronous serial interface with a V.35 connection, as well as a CSU/DSU. Novell recommends at least a 60 MHz Pentium for a single WAN connection and two network segments. If Internet connectivity is part of your WAN plan, you will need to obtain a Class C address from your local Internet service provider.

To see just how much stress MPR puts on your server, we set up a six-PC network with two machines on Ethernet, four on Fast Ethernet and a 28.8-Kbps WAN connection to the main office. We took a NetWare 4.1 server running on a Compaq Prosignia P90 with 32 MB of RAM and added two Intel PRO/100b PCI LAN adapters to connect to our 10- and 100-Mbps hubs. Since we knew we were planning to add a WAN to our router, we immediately installed Multi-Protocol Router 3.1. The same process is used to configure the server as a router whether or not you choose to use MPR.

To configure routing under NetWare, use the INETCFG utilit y. The first time you loa d it, it will warn you that it must move all of the Internetworking commands to NETINFO.CFG. After you confirm the move, you will be presented with the Internetworking Configuration console.

From INETCFG you can review your adapter settings and add new adapters like your WAN board. Once you have added your interfaces, you need to bind the protocols you want routed to each interface. By selecting the protocols option in INETCFG, you can view, add and delete the various protocols supported on your LAN.

In the Office For our office LAN we routed TCP/IP and IPX across our 10- and 100-Mbps segment, and routed TCP/IP over the WAN link for e-mail and Internet access. Once you've successfully configured your protocols you can select which protocols you want routed, including IP, IPX, AppleTalk and source-route bridging, in addition to defining which routing information protocol you want to use, such as RIP, OSPF, EGP, NLSP or static routing.

To set up a WAN, use the WAN Call feature. Through INETCFG you can configure your synchronous or asynchronous ports for WAN connections. With NetWare MPR you can connect to a service provider, another MPR or any device which will support a PPP connection. With the optional WAN and SNA add-ons from Novell you can get online with frame-relay, X.25, ATM or SNA networks. You also can establish backup media for fault tolerance, in case your primary connection goes down. One feature we would like to have seen was multilink PPP load balancing. The current version of MPR supports only a single PPP channel, limiting ISDN connections to 64 Kbps and modem connections to a single line.

To test the loa d on our server we ran a copy of NetPerf (available at www.cup.hp.com/NetPerf) with the NetPerf server on our 100-Mbps segment and the client on our 10-Mbps segment. In addition to the LAN-to-LAN traffic, we established an FTP session over the 28.8-Kbps WAN connection. The LAN-to-LAN routing pushed our server from 15 percent to 25 percent load while routing about 8 Mbps of traffic . Adding in the 28.8-Kbps WAN routing took us to 31 percent CPU utilization.

Bus-mastering PCI cards will help greatly in keeping your CPU free for file and database serving. WAN connectivity will depend largely on how much traffic you push over the WAN and how smart your synchronous serial card is. Novell MPR also supports data compression over the WAN link to another Novell MPR. Novell warns that this sort of compression is best for links at 56 Kbps or below, as the compression adds significant overhead at higher speeds.

One advantage of NetWare over NT as a routing platform is FILTCFG. The FILTCFG NLM allows the administrator to configure protocol-level filters. The NT packages we looked at had no support for filtering. If you plan on routing IPX over your WAN , you'll quickly realize how much bandwid th NetWare eats up with maintenance traffic for NDS and service advertising. Installing filters can increase available bandwidth on a dedicated 56-Kbps line by up to 40 percent. FILTCFG comes with NetWare 4.1, while MPR 3.1 comes with a more advanced version which can deal with source-route bridging for Token-Ring shops.

If you want to add LAN routing to Windows NT Server, you can obtain a free service pack from Microsoft Corp. WAN connectivity may require extra hardware depending on where you are connecting to. The Microsoft Multi-Protocol Routing (MPR) service comes with a service to handle IP and IPX routing and RIP protocols, as well as a BootP/DH CP forwarding agent. The NetWare equivalent of this service is BOOTPFWD.NLM.

It's Easy LAN-to-LAN routing is accomplished by installing Service Pack 3 and the MPR software. After installing the Microsoft MPR and a second network card in your NT server, you will see a check box in the Advanced TCP/IP configur ation which allows you to enable routing. St atic routing information for IP and IPX can be configured using the route and ipxroute command line options, which are part of the Microsoft MPR upgrade package. Using these utilities you can view dynamic and static routing information. The route command is similar to the Unix route command, but has some quirks. To add permanent static routes to the system, you add the '-p' (permanent) option on the command line. You can also delete or change existing routes with this command.

Routing WAN traffic under Windows NT Server requires a serial device which presents itself to the NT networking layer as an adapter card. One such device is the CiscoPro 1120, an ISA synchronous serial card with drivers for NT and NetWare. The card supports between two and four WAN connections via a user-selectable V.35 or RS-232 interface. Eicon Technology Corp. makes a card called WAN Services for Windows NT which offers the same functionality.

To use the CP1120, you will need a s ynchronous adapter. We were able to configure a pair of CP1120s using U.S. Robotics' V.Everything modems. The Cisco software supports only synchronous connections and has no support for dialing the modem, so we had to program the modem to dial via pushing the front panel button. The Eicon software does support V.25 and AT-style dialing.

After configuring our modems, we upgraded our NT server to Service Pack 4, and installed the MPR patches from ftp.microsoft.com/bussys/ winnt/winntpublic /fixes/usa/nt351/ussp4/mpr. After installing RIP for IP and IPX, we installed and configured a port on the CP1120 to communicate using PPP over our 28.8-Kbps modem connection. Finally, in the advanced settings of the T CP/IP configuration menu, we enabled IP routing. By pushing a button on our 28.8-Kbps modem we were able to dial the WAN connection and communicate with another CP1120 on the other side of the link. With the USR V.Everything, you can program the modem to automatically redial on loss of carrier, but this is a serious drawback to using a dial-up line wit h the Cisco product.

Taking a Hit Windows NT took a slightly larger performance hit than NetWare while routing. Our P90 NT box climbed to about 35 percent utilization when routing 8.5 Mbps of traffic from our 10-Mbps segment to the 100-Mbps segment. Adding 28.8-Kbps WAN traffic made it climb to about 40 percent. Microsoft MPR has no support for filtering, making it a poor choice for an IPX WAN router. Microsoft recommends third-party filtering software if you need to provide filtering or firewall services on your NT router.

If you are looking for simple Internet access for a small office, there is another solution for your NT router. Using Microsoft's Remote Access Server, it's possible to turn NT into a low-end dial-up router to the Internet. Making RAS function as a router requires that you change the registry. We didn't test Microsoft Remote Access Server in this capacity, but it is well documented in the readme file that comes with Microsoft MPR .

Several companies make ISA and PCI cards whic h function as routers. Although products such as the CiscoPro 1120 use Windows NT to do its routing, others, such as SourceCom's InCarda, do all routing in silicon, leaving the host CPU free for more demanding tasks like database and e-mail serving. We took a brief look at the newest release of SourceCom's InCarda software which runs under Windows NT or 95 and DOS.

InCarda is available in ISA and PCI flavors and sets up in just minutes. The card is configured through a graphical interface which allows you to configure the general setup, routing and firewalling features of the card. After you have configured the card to route IP, IPX or both, you click a button a nd the microcode on the router is updated with your routing rules.

InCarda has a single 10Base-T interface and a DB-25 connector that can be used for V.35 or synchronous RS-232 operations; you can't dial a modem connected in this manner. It's capable of using any of the standard synchron ous interfaces plus it has support for public frame-rela y networks. For routing IPX networks, InCarda uses an IPX server, which provides static SAP services for a NetWare network, which allows you to cut WAN traffic by filtering RIP/SAP traffic on your IPX network. It uses RIP to route IP and IPX, or lets you define static routes. InCarda provides most of the functionality of the Windows NT MPR, but has the added liability that it can handle only a single Ethernet segment as its LAN connection.

If you're looking for a router on the cheap, InCarda also has a DOS command line interface and it can be run in any machine of 286 caliber or better. For a single point-to-point connection, two InCarda ISA cards and a pair of 286 computers make an inexpensive routing solution.

Joel Conover can be reached at jconover@nwc.com