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Configuring Asynchronous Connections with the NetWare MultiProtocol Router 3.0 Software

Articles and Tips: article

BEN CRUZ
Product Marketing Engineer
Network Infrastructure Division

JOE GERVAIS
Product Manager
Network Infrastructure Division

01 Jul 1995


This Application Note introduces the new asynchronous point-to-point protocol (PPP) support within the NetWare MultiProtocol Router 3.0 product family. This async PPP support allows users to route traffic over low-cost, dial-up analog lines with common high-speed modems, or over ISDN circuits with external terminal adapters. It presents concepts that are necessary to understand when configuring permanent asynchronous connections, followed by detailed instructions on how to configure such a connection. Additional concepts relating to the configuration of an on-demand asynchronous connection are then presented. The AppNote concludes with an example of how to convert a previously-configured permanent connection to an on-demand asynchronous connection.

Introduction

The NetWare MultiProtocol Router™ 3.0 product family includes asynchronous point-to-point protocol (PPP) support. This NetWare Link/PPP™ software allows users to route traffic over low-cost, dial- up analog lines with common high-speed modems, or over ISDN circuits with external terminal adapters.

This Application Note presents concepts that are necessary to understand when configuring permanent asynchronous connec-tions, followed by detailed instructions on how to configure such a connection. It then presents additional concepts relating to the configuration of an on-demand asynchronous connection. The AppNote concludes with an example of how to convert a previously-configured permanent connection to an on-demand asynchronous connection.

This AppNote assumes basic familiarity with IP and IPX routing. The examples used will show IPX™ (Internetwork Packet Exchange™) and IP routing over asynchronous connections.

Asynchronous WAN Connections

The NetWare MultiProtocol Router software supports two basic types of asynchronous WAN connections: permanent and on- demand (see Figure 1).

Permanent calls can be specified for switched or dial- up circuits, as well as for leased lines. If the connection fails, it is retried at periodic intervals. This type of connection is typically used when the cost of full- time connectivity is not an issue, such as in the case of two buildings in the same city. It is suited for use with dynamic routing protocols such as the NetWare Link Services Protocol™ (NLSP™) or RIP (Routing Information Protocol).

NetWare MultiProtocol Router 3.0 also provides the ability to configure a WAN link for on-demand connections. This means that the link is active only when traffic is directed to the link. On- demand calls specify that the connection should be established only when needed. These types of connections are terminated whenever the link is idle for a specified period of time. Maintenance data, such as routing updates, are suppressed.

The inclusion of asynchronous routing support in the NetWare MultiProtocol Router makes the product suitable for connecting locations that generate very low levels of network traffic, for which network managers previously could not justify permanent connectivity. With current 28.8 Kbps modems, asynchronous connectivity is suitable for E- mail between sites, network management, and even light file transfer. Under ideal conditions, this type of connection can carry more than 10 MB of data per hour in each direction.

Figure 1: In this scenario, Router C is connected to LAN A with a permanent link and to LAN B with an on-demand link.

Configuration Concepts

Configuring the router involves some planning and decision making. You must know the details of the network in which you are placing the router, the type of connectivity you want, and the configuration details of the peers to which you are connecting the router.

This section discusses the basic concepts you must know to make the right decisions when configuring the network protocols you want to route using the NetWare MultiProtocol Router 3.0. It also states assumptions made to simplify configuration.

Routing Protocols. NetWare IPX™ and TCP/IP configurations offer several dynamic routing protocols. Two general types of routing protocols are available: distance vector and link state.

The following table shows the distance vector and link state protocols that are supported by NetWare MultiProtocol Router 3.0.


NetworkProtocol
DistanceVector Routing Protocol
LinkState Routing Protocol

IPX

RIP

NLSPwith RIP/SAPCompatibility (Default)

TCP/IP

RIP (Default)

OSPF

Apple Talk

RTMP

-------

Your choice of routing protocols is determined largely by which routing protocols are currently used in your network. For example, an older network (such as a NetWare 2 network) might have several routers that can support only distance vector routing. For permanent connections, the default protocols are used: NLSP for IPX and RIP for IP.

If your network contains routers that support both link state and distance vector routing, your router will need to support both types. In networks that have nothing but newer routers, it is best to configure the routers to use only link state routing protocols. Although this is not a very likely scenario, it might be a possible goal to achieve over time by gradually updating your routers and migrating to the exclusive use of link state routing protocols.

Caller Authentication. Using public switched data or telephone networks provides a high level of communication flexibility that is not possible with dedicated circuit data networks. You can quickly reconfigure WAN connections to support changes in network topology requirements, without incurring the delays often experienced when working with external service providers. However, along with this flexibility comes the potential for unauthorized access. Just as anyone can call your telephone number, anyone can attempt to establish a PPP connection to your NetWare MultiProtocol Router software and gain access to your LAN.

To provide protection against unauthorized router access over public switched data or telephone networks, the PPP specification defines two optional authentication protocols that authenticate inbound call attempts:

  • The Password Authentication Protocol (PAP)

  • The Challenge Handshake Authentication Protocol (CHAP)

The main difference between the two protocols is that PAP sends the password string across the WAN in clear text, whereas CHAP uses the password to encrypt a challenge string. These protocols ensure that the local system can accept calls only from authorized remote systems. Authentication is based on a remote system identified by a user ID and a password.

With the NetWare Link/PPP software, you can configure either PAP or CHAP as the inbound call authentication protocol type for each interface. The system maintains one or more user- configured authentication databases. The database contains a list of IDs and passwords that represent each remote system authorized to place inbound calls to the PPP interface.

Selecting a WAN Interface

When selecting a asynchronous WAN interface port, you must decide the type of COM port to use. Two types are available to choose from: your PC system COM port or a third party intelligent asynchronous interface(see Figure 2).

Figure 2: You can choose from two COM port configurations for your asynchronous WAN interface port.

PC COM Port Interfaces. Asynchronous PC COM port interfaces are generally adequate for allowing a single user to use the WAN link for exchanges such as file transfers and E- mail. As shown in Figure 2, using the PC system's COM ports along with modems and the NetWare MultiProtocol Router software allows you to convert an existing server or PC into a router with no additional hardware required. However, PC COM port interfaces are a poor choice if you need to interconnect multi-user LANs.

Simple asynchronous interfaces use the PC's CPU for all processing and typically provide low- speed connectivity. The performance of this type of interface depends on the type of UART (serial communications controller) chip used in you system:

  • The 8250/16450 UART has a single-character receive buffer and generates one PC system interrupt for each send/receive character. Because of this, simple COM ports that use the 8250/16450UART are not recommended for use with NetWare MultiProtocol Router 3.0.

  • The 16550 UART has a 16-byte transmit/receive buffer, which provides better performance.

Installing multiple interfaces (COM1 through COM4) is not recommended because this might overload the PC's CPU and decrease the overall system performance.

Intelligent Asynchronous Interfaces. Intelligent asynchronous interfaces are generally sufficient for low- end, multiple- user on- demand connectivity. They typically provide low- to medium- speed connectivity (1200 to 38,400 bps). Examples of intelligent boards are the Digiboard PC/8e and Hayes* ESPCA. When configuring multiple asynchronous interfaces, this type of interface is a better choice than non-intelligent boards because much of the communications processing is done by the intelligent board rather than by the PC's CPU. They also provide the flexibility for faster WAN connections.

Intelligent asynchronous interfaces are a poor choice for permanent interconnections of large topology LANs. Maintenance traffic over permanent connections can require significantly more bandwidth than is available from asynchronous interface drivers. Furthermore, there is additional host processing for the character mode AIO interface than for the frame mode WAN HSM interface (see Figure 3).

Figure 3: NetWare WAN architecture.

Some high- performance synchronous boards, such as the Microdyne Synchronous/+ and the Eagle Technology NW2000, also support asynchronous mode. This is useful if you need to use both types of connections. These boards can offer higher performance due to the frame mode operation of the WAN HSM.

Using AIO Drivers with NetWare MultiProtocol Router

The WAN Hardware Support Module- AIO adaptation layer (WHSMAIO) module supports asynchronous interfaces provided by AIO- compliant drivers and associated hardware. The primary features of WHSMAIO are as follows:

  • Provides a software- only interface that converts between an AIO- type driver and the WAN HSM™(Hardware Specific Module™) driver interface expected by NetWare Link/PPP --two common AIO- type drivers are AIOCOMX.NLM and AIODGXI.NLM

  • Supports up to 16 AIO ports per PC system

  • Requires no hardware parameters (these are supplied to the AIO drivers)

Router Management

The NetWare MultiProtocol Router 3.0 software offers multiple utilities to manage the router and its operation on the internetwork. Managing the router after it is configured consists of the following major tasks:

  • Verifying the configuration to make sure everything is up and running and has the characteristics you intended

  • Monitoring the router to find out whether it is performing efficiently, and to detect possible problems

  • Configuring and managing connectivity equipment

  • Optimizing the router to make routing more efficient

  • Testing connectivity and troubleshooting

The utilities available to help you configure and manage your router include the following:


You can find more detailed information on these utilities by referring to the NetWare MultiProtocolRouter 3.0 Advanced Configuration and Management Guide. A brief explanation also appears in the Quick Reference Guide.

  • Management utilities, such as INETCFG, FILTCFG, and CPECFG, to configure and optimize the router or attached modems, CSU/DSUs, and so on

  • Testing utilities such as PING and IPXPING to test connectivity

  • Monitoring utilities, such as PPPCON, IPXCON, ATCON and TCPCON, to help you check how each protocol is functioning and to help you identify potential problems

  • Command- line utilities, such as TPING and CONLOG, and commands such as REINITIALIZE SYSTEM to help you monitor, test, and implement configuration changes to your router

Monitoring your router during and after initial configuration can help you detect potential problems and identify its optimization needs. You can also use the management utilities in conjunction with each other to isolate problems.

Configuring NetWare Multi-Protocol Router 3.0

This section explains how to configure the NetWare MultiProtocol Router 3.0 software for permanent asynchronous connections. It presents a checklist of tasks to be completed before you configure the router, and then introduces the INETCFG utility.

Pre-Configuration Checklist

Prior to configuring NetWare MultiProtocol Router, you must have completed the following tasks:

  1. Install NetWare 3.12 or 4.10.

  2. Install NetWare MultiProtocol Router 3.0.

  3. Install a WAN adapter in the system (follow the guidelines included with your WAN adapter).

  4. Ensure that your system has adequate memory (refer to the NetWare MultiProtocol Router Rules of Thumb guide).

  5. Gather the following information about each remote server:

    a. Server namesb. Network addressc. Common password that will be used

The INETCFG Utility

The Internetworking Configuration (INETCFG) utility is a menu- driven utility used to configure the NetWare MultiProtocol Router 3.0 software. It is installed during the installation of NetWare MultiProtocol Router 3.0.

The menus in INETCFG are structured in a logical manner. You can perform a basic configuration of an asynchronous connection by following the menus and completing the following steps:

  • Configure LAN and WAN hardware

  • Configure Data Link Layer protocols on the WAN ports

  • Configure WAN call records

  • Configure Network Layer protocols

  • Bind Network Layer protocols to the hardware

These steps match the order in which the menu items are presented in INETCFG (see Figure 4).

Once you complete the configuration steps in INETCFG, you must exit the utility and reinitialize the router. You can do this either by issuing the REINITIALIZE SYSTEM command at the system console or by restarting the router.

Figure 4: INETCFG main screen.

Configuring a Permanent Dial-Up WAN Connection

The following sections take you through the steps necessary to add asynchronous IPX and IP routing to a server having an existing LAN interface with IP and IPX configured.


Check the NetWire®electronic bulletinboard frequently for the latest versionsofthe AIO.NLM and AIOCOMX.NLM files.

AIO.NLM and AIOCOMX.NLM are usedby many Novell products.If you install another product thatuses AIOdrivers on the server running NetWare MultiProtocolRouter3.0, check the versions of these filesbefore and after the installationof the newproduct. If problems occur with the WHSMAIOports afterthe installation of a new productthat uses the AIO.NLM or AIO-COMX.NLMfiles,try using the previously installed versionsof these files.

Configuring a WHSMAIO WAN Board Driver. NetWare MultiProtocol Router 3.0 supports any asynchronous hardware that has a driver written to the AIO specifications. This hardware includes COM ports on the PC, as well as cards from Digi International, Hayes, and other manufacturers. The support for these drivers is indirect because the AIO driver is first loaded and configured outside of INETCFG. Then WHSMAIO is configured in INETCFG to interface to the AIO driver.

To configure the WHSMAIO WAN board driver, complete the steps outlined below.

Load the AIO Driver. The configuration tool for WHSMAIO requires the AIO driver to be loaded prior to configuring WHSMAIO. To load an AIO driver, complete the following steps:

  1. At the system prompt, type the load command for the AIO driver you want to use for WAN communications with the router. For example, to load the COM port driver to use the built-in system COM ports, type:

    LOAD AIOCOMX <Enter<

  2. Note the port speed.

    The AIOCOMX driver lists the speed for which the UART is rated. Use this speed as the Interface Speed in the Network Interfaces configuration for this WHSMAIO port.

Using a higher speed causes line errors and lost data. It is possible to purchase an intelligent asynchronous interface board that supports higher speeds.


Note: Some AIO drivers, such as AIOCOMX, allow you to configure theinterface to a speed above the default limit. If WHSMAIO failsto load because the default speed limit has been exceeded, youmight be able to increase the AIO driver speed limit. The procedurefor increasing this speed limit differs from driver to driver,but is typically set by adding a load-time parameter to the driverLOAD command. For example, for the AIOCOMX driver, use the MAXRATE=maximum_interface_speed parameter, where maximum_interface_speed is an integer representing the bits-per-second speed of the interface.

Add the Load Line for the AIO Driver to the AUTOEXEC.NCF File. To have the AIO driver automatically load every time the router is started, add the load line to the AUTOEXEC.NCF file. You can do this from within INETCFG.

  1. Start the Internetworking Configuration utility by typing the following at the system console:

    LOAD INETCFG <Enter<

  2. From INETCFG's main menu, select "Manage Configuration".

  3. Select the "Edit AUTOEXEC.NCF" option.

  4. Insert the load line for the AIO driver before the SYS:ETC\INITSYS.NCFline.

    Here is an example of an AUTOEXEC.NCF file with the AIO driver load line added:

    :load aiocomxsys:etc\initsys.ncfunload conlog:

  5. Press <Esc< and save your changes.

Configure the AIO Board to Use WHSMAIO. Once the AIO driver is loaded and configured, you can proceed to configure WHSMAIO.

  1. If you have not already done so, load INETCFG.

  2. Choose the "Boards" option from the main menu.

  3. Press <Ins< to add a new board.

  4. Choose the WHSMAIO driver.

    If you are using a multiport AIO driver or have morethan one AIO driver loaded, you must select a port. After the board is configured, you can configure the WHSMAIO port for asynchronous PPP communications in the Network Interfaces option of INETCFG.

Assigning a Data-Link Protocol to an Asynchronous Port. Each WAN port must be configured to use a data-link protocol, and any parameters specific to that port, such as port speed and modem type, need to be configured.

To configure an asynchronous dial-up line interface, complete the following steps:

  1. From the Internetworking Configuration main menu, select "Network Interfaces".

    The Network Interfaces window displays a list of network interfaces associated with each configured board.

  2. Select an unconfigured network interface and press <Enter<.

  3. Select PPP in the Available Media window and press<Enter< to select the data-link protocol for this particular board.

  4. The Modem/DCE Type field is already highlighted; press <Enter<. A list of the PPP modem/DCE device types is displayed.

  5. Select the appropriate modem attached to the WAN port being configured, then press <Enter<.

    The default modem type of None should be used only with leased lines, null modems, and other directly connected communications links requiring no device management. None should also be used for all DTR- controlled devices.

    If your modem type is not listed but uses Hayes AT commands, select Hayes Compatible.

    If your modem type is not listed but supports DTR dialing, select NO MODEM INSTALLED.

    To enable DTR dialing, go to Modem/DCE Options and change the Dialing Mode to DTR Controlled. Your modem must also be configured for DTR dialing. Refer to the manufacturer's instructions and to the NetWare MultiProtocol Router 3.0 NetWareLink/PPP Reference for more information.

  6. Press <Enter< to return to the PPP Network Interface Configuration screen.

  7. Select the Interface Speed field and press <Enter<.

  8. Select the Interface Speed matching the highest DTE speed supported by the modem type selected and not exceeding the speed of your AIO driver, then press <Enter<.

    All other parameters can be left at their configured default values.

  9. Press <Esc<, select Yes to save changes to the configuration, then press <Enter<.

    The Configured Interfaces screen is displayed with the interface you just configured. The interface status is Enabled. You can use the <Tab< key to toggle between Enabled and Disabled.

    This creates a PPP interface with the following attributes:

    • Character asynchronous HDLC framing

    • RS-232 interface

    • Internally clocked linespeed (user- specified)

    • 1500- byte MRU(payload data) size

    • Inbound Caller Authenticationrequired (PAP or CHAP)

    • No PPP data compression

    PPPRFC- defined defaults for all other optionvalues

    You can selectively change the values of these parameters, if necessary. Refer to the NetWare MultiProtocol Router 3.0 Advanced Configuration and Management Guide for detailed information.

  10. Press <Esc<gt; to return to the Internetworking Configuration main menu.

After you have configured the appropriate PPP interfaces, you need to configure one or more WAN Call Destinations, as described next.

Setting Up a WAN Call Destination. The WAN Call Directory is a list of WAN call configurations. You must create one WAN call configuration for each destination with which your router will communicate. (For more information about setting up WAN Call Destinations, refer to the NetWare MultiProtocol Router 3.0 Installation and Basic Configuration Guide.)

To configure a WAN Call Destination for a PPP network interface, complete the following steps:

  1. From the Internetworking Configuration main menu, select "WAN Call Directory."

    The Configured WAN Call Destinations window is displayed. This window has no entries if no WAN Call Destinations are configured.

  2. Press <Ins< to configure a new WAN Call Destination.

    The prompt New Call Destination Name: allows you to enter a name of up to 47 alphanumeric characters for the new WAN Call Destination.

    The WAN Call Destination name entered here is used in several other menu options when a WAN Call Destination name needs to be identified. You should use a descriptive name, such as the name of the remote destination, or a branch or store number.

  3. Enter a name for the new WAN Call Destination, then press <Enter<.

    A list of supported wide area media is displayed. These media are available on previously configured interfaces.

  4. Select PPP as the wide area medium, then press <Enter<.

    The PPP Call Destination Configuration window is displayed. The Call Type selection is highlighted. This selection specifies the type of connection to be made: permanent(continuously active) or on-demand (activated by the presence of data traffic to the remote peer).

    To set up a WAN Call Destination for permanent calling through a specific interface, leave this parameter set to Permanent(the default value).

  5. Select Interface Name, then press <Enter<. Select an interface name from the pop- up list displayed.

    This field allows you to select the name of the configured WAN interface through which this WAN Call Destination can be accessed.

  6. If you are using a modem that supports AT Command dialing, select Telephone Number, enter up to 32 alphanumeric characters, and then press <Enter<.

    This phone number applies only when AT Commands is specified as the Dialing Mode for the interface selected. When the Dialing Mode is specified as DTR Controlled, the modem must be configured with the number offline, as specified by the modem manufacturer.

  7. Select Password, enter up to 47 alphanumeric characters, then press <Enter<.

    The value specified in this field must be the PAP password (or the CHAP secret value) expected from the remote peer during the PPP inbound authentication. If the Outbound Authentication is set to anything other than None, a password must be specified; it cannot be left blank.

    For this WAN Call Destination to succeed, this password and the local system ID must also be configured in the Inbound Authentication database of the called router.

  8. Select Local System ID, enter up to 47 alphanumeric characters, then press <Enter<.

    This field allows you to specify the name sent to the remote peer during authentication of an outbound call to identify this system when using this WAN Call Destination. The default value is the local system server name.

  9. Select Remote System ID, then press <Enter<. Select from the pop- up list displayed, or press <Ins< to create a new remote system ID.

    This field allows you to specify the name of the remote peer associated with this WAN Call Destination, typically the remote system server name. By default, the Remote System ID is blank; however, an entry is required.

    Leave all other parameters in the PPP Call Destination Configuration window at their default values. For a complete discussion of the other parameters in this window, see the NetWare MultiProtocolRouter 3.0 Advanced Configuration and Management Guide.

  10. The WAN Call Destination you just configured appears in the list of configured WAN Call Destinations. Press<Esc<; if prompted, select Yes to save the changes to the WAN Call Destination, then press <Enter<.

  11. If prompted, select Yes to synchronize the inbound authentication database, then press <Enter<.

    The inbound authentication database is made to agree with the outbound call authentication parameters in this WAN Call Destination configuration. This is useful if you expect to receive calls from systems you make calls to.

  12. Press <Esc< to return to the Internetworking Configuration main menu.

Configuring IPX Protocol Parameters. For the most basic NetWare IPX Router configuration, you need only enable the Packet Forwarding option as described here. You can (and should) accept the defaults on all the other parameters.

To configure the IPX protocol parameters, complete the following steps:

  1. From the Internetworking Configuration main menu, select "Protocols".

    The Protocol Configuration menu is displayed.

  2. From the Protocol Configuration menu, select IPX, then press <Enter<.

    The IPX Configuration window is displayed.

  3. If this machine is to function as a router, the Packet Forwarding option must be enabled. If it is disabled, select Packet Forwarding, press <Enter<, select Enable, then press<Enter<.

    It is not necessary to change the values of any of the other parameters in this window. Leave all other parameters at their default values. For a complete discussion of other parameters displayed in this window, see the NetWare MultiProtocol Router 3.0 Advanced Configuration and Management Guide.

  4. Press <Esc<; if prompted, select Yes to save changes to the configuration, then press <Enter<.

  5. Press <Esc< to return to the Internetworking Configuration main menu.

Binding IPX to a WAN Interface. After configuring the IPX protocol parameters, complete the following steps to bind IPX to a WAN interface and select a permanent WAN Call Destination:

  1. From the Internetworking Configuration Main menu, select "Bindings".

    A new window displays a list of the configured protocol-to-interface bindings.

  2. Press <Ins<.

    A new window displays a list of the configured protocols.

  3. Select IPX, then press <Enter<.

    A new window displays a list of the configured network interfaces.

  4. Select a WAN interface from the list, then press <Enter<.

    A new window displays the parameters for binding IPX to the selected WAN interface.

  5. The Permanent WAN Call Destinations option is highlighted; press <Enter<.

    A new window displays the configured WAN Call Destination for this bind, if any. Only one permanent WAN Call Destination is allowed when IPX is bound to a PPP interface.

    5a. If no WAN Call Destination is displayed, press <Ins<.

    The WAN Call Destination Entry window appears.

    5b. The WAN Call Name option is highlighted. To select a defined WAN Call Destination, press <Enter<.

    A new window displays a list of the available permanent WAN Call Destinations, if any have been configured for this interface.

    5c. Highlight the desired WAN Call Destination, then press <Enter<.

    The selected WAN Call Destination appears in the WAN Call Destination Entry window.

    5d. Press <Esc< to display the list of configured WAN Call Destinations.

    The selected WAN Call Destination appears on the list of configured WAN Call Destinations.

    Remember, only one WAN Call Destination is allowed when IPX is bound to a PPP interface, even though this list appears to have room for several more.

    5e. Press <Esc< again to return to the Binding IPX to a WAN Interface window.

    It is not necessary to change the values of any other parameters in this window. Leave all other parameters in this window at their default values. For a complete discussion of the Expert Bind options, see the NetWare MultiProtocol Router 3.0 Advanced Configuration and Management Guide or the NetWare MultiProtocol Router 3.0 IPX Reference.


    Note: IPXWAN II does not require you to configure a network number for WAN links; MultiProtocol Router 3.0 does not allow you to do so.

  6. Press <Esc< again; if prompted, select Yes to save the IPX bind parameters, then press <Enter<.

    A new window displays the configured protocol-to-interface bindings. The IPX binding you just configured is highlighted in the list.

Configuring IP Protocol Parameters. For the most basic TCP/IP router configuration, you need only enable the Packet Forwarding option as described here. You can (and should) accept the defaults on all the other parameters.

To configure the TCP/IP protocol parameters, complete the following steps:

  1. From the Internetworking Configuration main menu, select "Protocols".

    The Protocol Configuration menu is displayed.

  2. From the Protocol Configuration menu, select TCP/IP, then press <Enter<.

    The TCP/IP Configuration window is displayed.

  3. If this machine is to function as a router, the Packet Forwarding option must be enabled. If it is disabled, select Packet Forwarding, press <Enter<, select Enable, then press <Enter<.

    It is not necessary to change the values of any of the other parameters in this window. Leave all other parameters at their default values. For a complete discussion of other parameters displayed in this window, see the NetWare MultiProtocol Router 3.0 Advanced Configuration and Management Guide.

  4. Press <Esc<; if prompted, select Yes to save changes to the configuration, then press <Enter<.

  5. Press <Esc< to return to the Internetworking Configuration main menu.

Binding TCP/IP to a WAN Interface. After configuring the IPX protocol parameters, complete the following steps to bind IPX to a WAN interface and select a permanent WAN Call Destination:

  1. From the Internetworking Configuration Main menu, select "Bindings".

    A new window displays a list of the configured protocol-to-interface bindings.

  2. Press <Ins<.

    A new window displays a list of the configured protocols.

  3. Select TCP/IP, then press <Enter<.

    A new window displays a list of the configured network interfaces.

  4. Select a WAN interface from the list, then press <Enter<.

    A new window displays the parameters for binding TCP/IP to the selected WAN interface.

  5. The WAN Network Mode option is highlighted. Press <Enter<, select Unnumbered Point-to-Point from the list displayed, then press <Enter< again.


    Note: Each network interface typically requires an address assignment. For WAN interfaces, MultiProtocol Router 3.0 also supports unnumbered interfaces. To simplify configuration, unnumbered interfaces are used in the examples.

  6. Select the Permanent WAN Call Destination option. Then press <Enter<.

    A new window displays the configured WAN Call Destination for this bind, if any. Only one permanent WAN Call Destination is allowed when TCP/IP is bound to a PPP interface.

    6a. Press <Ins<. The WAN Call Destination Entry window appears.

    6b. Highlight the desired WAN Call Destination, then press <Enter<.

    The selected WAN Call Destination appears in the WAN Call Destination Entry window.

    6c. Press <Esc< to display the list of configured WAN Call Destinations.

    The selected WAN Call Destination appears on the list of configured WAN Call Destinations.

    Remember, only one WAN Call Destination is allowed when TCP/IP is bound to a PPP interface, even though this list appears to have room for several more.

    6d. Press <Esc< again to return to the Binding TCP/IP to a WAN Interface window.

    It is not necessary to change the values of any other parameters in this window. Leave all other parameters in this window at their default values. For a complete discussion of the Expert Bind options, see the NetWare MultiProtocol Router 3.0 Advanced Configuration and Management Guide or the NetWare MultiProtocol Router 3.0 TCP/IP Reference.

  7. Press <Esc< again; if prompted, select Yes to save the TCP/IP bind parameters, then press <Enter<.

    A new window displays the configured protocol-to-interface bindings. The TCP/IP binding you just configured is highlighted in the list.

  8. Press <Esc< to return to the Internetworking Configuration Main menu.

Implementing the Configuration. To implement the configuration changes you have made, you must issue the REINITIALIZE SYSTEMcommand at the system console or restart the router.

Understanding On-Demand WAN Connectivity

With NetWare Link/PPP, on- demand WAN connections are established at the request of network protocols, based on the presence of user data that must be routed to a destination across the connection. If no data is flowing across an on- demand WAN connection for a preset, configurable period of time, the connection is terminated.

On-demand WAN connections are similar to the way a telephone is used. An outbound call to a remote party is placed by dialing the phone number, and a connection is made when the remote party picks up the phone. A conversation takes place and terminates when one of the parties hangs up the receiver. When a telephone is not in use, it is available to place other outbound calls or accept inbound calls from remote parties. The costs for using the telephone are based on the duration and distance of each call.

The analogy between NetWare Link/PPP on- demand connections and telephone calls is not superficial. Voice- grade telephone lines can be used to establish low bandwidth (typically 2400 bps to 28,800 bps) on- demand connections. Depending on bandwidth requirements, placing on- demand connections over PSTNs (Public Switched Telephone Networks) can be a simple and quick way to establish temporary connectivity between remote LANs.

On-demand connections have the following advantages:

  • Cost - On-demand connections terminate when there is no data to route across the connection. This means that you pay only for the time the connection is in use, not for idle time as in the case of a permanent WAN connection.

  • Flexibility - You might initially use a single interface to establish an on-demand call to a remote LAN. After the connection terminates, you can use the same interface to establish another on-demand connection to a different remote LAN. Unlike permanent WAN connections, no service provider involvement is necessary to connect to a different destination.

On-Demand WAN Connection Concepts

NetWare Link/PPP takes advantage of switched- circuit networks to provide a cost- effective alternative to dedicated data networks that permanently connect remote LANs. This section covers configuration concepts and procedures for NetWare Link/PPP on-demand WAN connections.

Caller Authentication. For on-demand connections, you must configure outbound calls to specify an authentication protocol type, a Local System ID, and a password. To accept inbound on- demand connections, you must configure the PPP interface to validate the authentication information supplied by the calling system. Using PAP or CHAP authentication is recommended for all permanent switched circuit connections, required for on- demand connections, and recommended for permanent dial-up connections.

Remote System Identification. Using PAP or CHAP authentication also provides a method of remote system authentication. When the local system accepts an inbound on- demand connection, the remote system must be identifiable so the local system can reestablish the connection if it is terminated before the data transfer is complete. This is similar to asking telephone callers for their phone numbers, in case you need to call them back.

On-demand connections work reliably only if the called system can establish a return connection. This requires proper configuration of static routes and services, WAN Call Destinations, and network interface authentication at both ends of the connection. Therefore, if a called NetWare MultiProtocol Router system does not have the required configuration information necessary to reestablish a connection to the calling system, it does not accept the initial connection attempt.

Because the ID strings used by PAP and CHAP authentication provide a peer system identification mechanism that solves this problem, PAP or CHAP authentication is required for on- demand connections. The local and remote system ID strings associated with PAP and CHAP authentication typically represent the NetWare server names of the local and remote NetWare Link/PPP connection peers.

Static Route and Service Databases. As described earlier, NetWare Link/PPP on- demand connections are initiated at the request of network protocols when data is present that must be routed to a remote LAN. They are terminated when the NetWare Link/PPP WAN connection is determined to be idle.

Standard network protocols generally expect each WAN circuit to provide permanent connections to all remote systems. This is because the network protocols rely on periodic communication with remote systems to dynamically exchange routing updates and, in the case of the IPX protocol, service advertising updates.

Periodic maintenance exchanges can result in a constant stream of data across the NetWare Link/PPP connection, which prevents on- demand connections from terminating due to idle link detection.

To limit maintenance traffic, on-demand connections do not exchange routing or service information. Rather, both ends of the link must have enough information to be able to call each other. Because no routing traffic crosses an on-demand link, you must preconfigure remote routes and services manually on the local router with static routes and services. This way, the connection can remain inactive until data needs to cross it. When NetWare MultiProtocol Router receives a request for a static route or service, it makes a WAN call to the configured node.

With static tables, entries are only required for the services and routes used across the on-demand link. This acts like route and service filtering, because routes and services that are not accessed are not included in the static tables.

Two techniques are used to limit table size. One is using services gatekeepers (see the September 1994 AppNote entitled "Effectively Managing RIP and SAP Traffic with Filtering"). The other is setting default routes.


Note: Support for default routes was added to IPX with the version ofthe IPXRTR.NLM released on Novell's electronic support mechanisms in February 1995.

Static routes and services for on-demand connections are configured at the network protocol level by using the INETCFG utility. They let the protocol know which WAN Call Destination to use to reach that route, as well as information about the remote router (IP address, number of hops, and so on). In the case of IPX, the Static Routing Configuration (STATICON) utility provides a simplified method to configure static routes and services by accessing information from an immediate neighbor (see Figure 6).

To use STATICON, you must configure an initial IPX static route or service to a neighbor using INETCFG.

Figure 6: Example of a static service table for on-demand connectivity through the STATICON utility.

Converting to On-Demand Dial Up WAN Connection

In this example, the previously configured permanent connections will be changed into part-time connections. As before, this is done by following the menus in the INETCFG utility.

Setting Up an On-Demand WAN Call Destination

To set up an on-demand WAN call destination, complete the following steps:

  1. At the server prompt, type

    LOAD INETCFG <Enter<

    The Internetworking Configuration main menu is displayed.

  2. From the Internetworking Configuration main menu, select 'WAN Call Directory".

    The Configured WAN Call Destinations window is displayed.

  3. Highlight the previously configured WAN Call Destination and press <Enter<.

  4. The PPP Call Destination Configuration window is displayed. The Call Type selection is highlighted. This selection specifies the type of connection to be made: permanent(continuously active) or on-demand (activated by the data).

    Select On- Demand (activated by data).

  5. Press <Esc< to return to the Internetworking Configuration main menu. Answer 'Yes" to save changes.

Configuring IPX Protocol Parameters

Static routes and services are required to run IPX over an on-demand WAN connection.

To configure the IPX protocol parameters, complete the following steps:

  1. From the Internetworking Configuration main menu, select "Protocols".

    The Protocol Configuration menu is displayed.

  2. From the Protocol Configuration menu, select IPX, then press <Enter<.

    The IPX Configuration window is displayed.

  3. Select On-Demand Calls, then select Enabled.

  4. Select Static Services for On-Demand Calls.

    From the Static Services for On-Demand Calls menu, press <Ins< and configure the following parameters:

    WAN Call Destination - Name of the WAN Call Destination. User data packets are routedover the on-demand call to this destination.

    Service Name - Name of the service to be accessed through the on-demand call. This name, which is typically the server name, is added to thelocal service and routing tables.

    Service Type - SAP service type for this service, expressed as a hexadecimal number. This is typically the file server type (0004). Press <Insert< to display a list of possible service types.

    Service Address Network- Network number of the service. If you are specifying a file service or a service on a server or router, enter the internal network number of that server or router.

    Service Address Node - Node address where the service resides. If you are specifying a file service or a service on a server or router, enter 1. If you are specifying a NetWare 2 file server, specify the NIC address of LAN board A.

    Service Address Socket- Socket number on which this service listens for service requests. If you are specifying a file service, enter 0x0451.


    Note: It is recommended that you use STATICON to configureuncommon services that are not a file service.

    Hops to Service- Number of routes crossed to reach the service.

    Ticks to Service - Number of ticks needed for a packet to reach the destination network. Add one tick to this value for each LAN hop.

    The WAN Call Destination will be the one configured in the previous step. The information for all other parameters is accessible from the service table in IPXCON, provided the permanent connection is currently operational. You only need to configure a static service for the router on the other side of the on-demandlink. This will create the corresponding static route. All other IPX static routing can then be configured with STATICON.

    IPX configuration for on-demand operation is explained in detail in the NetWare MultiProtocol Router 3.0 Advanced Configuration and Management Guide, starting on page 65.

  5. Press <Esc<; if prompted, select Yes to save changes to the configuration, then press <Enter<.

Configuring IP Protocol Parameters

Static routes and services are required to run TCP/IP over an on-demand WAN connection.

To configure the TCP/IP protocol parameters, complete the following steps:

  1. From the Protocol Configuration menu, select TCP/IP, then press <Enter<.

    The TCP/IP Configuration window is displayed.

  2. Select Static Routing, press <Enter<, select Enable, then press <Enter<.

  3. Select Static Routing Table, then press <Enter<.

    From the Static Routing Table menu, press <Ins< and configure the following parameters:

    Route to Network or Host - Destination at the other end of the static route, which can be a single IP host or an IP network (that is, a group of hosts).

    Default Route - Another option you can select. If the router must forward a packet for which it can find no destination in its routing table, it uses the default route. If the router has no other place to send the packet, it sends it to the next hop router for the default route instead of discarding it. This type of "blind forwarding" keeps a packet on the network until a router can forward it to its final destination (see Figure 7).

    Figure 7: The default route is sent whenever a router must forward a packet for which there is no destination in its routing table. must forward a packet for which there is no destination in its routing table."

    IP Address of Network/Host - Address of the destination network or host. To select froma list of symbolic network names and addresses, press <Insert<.

    Subnetwork Mask - If the destination is an IP network, this is the subnetwork mask of that network.

    Next Hop Type - Indicates whether the next hop on the static route is an IP address or a WAN Call Destination.

    Select WAN Destination for an on-demand call.

    Press <Enter<, then select one of the configured WAN Call Destinations.

    Metric for this route - Number of hops to the destination. This metric is directly proportional to the cost of the route. Given two routes to the same destination, the router chooses the lower-cost route.

    If you want to use the static route as a backup route to a dynamic route, select a value that is higher than the cost associated with the dynamic route. This will ensure that the dynamic route remains the preferred route under typical conditions.


    Note: Do not set this metric value to 16 or more, unless you want to disable the route.

    Type of route - Specifies whether the static route is active or passive.

    If the static route is active and the router discovers a lower- cost dynamic route to the same destination, it uses the lower-cost route instead of the active static route. If the lower-cost route becomes unavailable, the router returns to using the active static route.

    A passive static route is always used, regardless of whether the router discovers a lower-cost route to the same destination.

    Select Active for an on-demand route.

    The WAN Call Destination will be the one configured in the previous step. The information for all other unspecified parameters is accessible from the routing table in TCPCON, provided the permanent connection is currently operational.

    TCP/IP configuration for on-demand operation is explained in detail in the NetWare MultiProtocol Router 3.0 Advanced Configuration and Management Guide, starting on page 132.

  4. Press <Esc<; if prompted, select Yes to save changes to the configuration, then press <Enter<.

  5. Press <Esc< to return to the Internetworking Configuration main menu.

Binding IPX to a WAN Interface

After configuring the IPX protocol parameters, complete the following steps to deselect a permanent WAN Call Destination for on-demand applications:

  1. From the Internetworking Configuration main menu, select "Bindings".

  2. Highlight the previously configured IPX WAN binding, then press <Enter<.

  3. Select the Permanent WAN Call Destination option, then press <Enter<.

    A new window displays the configured WAN Call Destination for this bind.

    3a. Press <Del<. The previously configured permanent WAN Call Destination entry will be removed.

    3b. Press <Esc< again to return to the Binding IPX to a WAN Interface window.

  4. Press <Esc< again; if prompted, select Yes to save the IPX bind parameters, then press <Enter<.

    A new window displays the configured protocol- to- interface bindings. The IPX binding you just configured is highlighted in the list.

  5. Press <Esc< to return to the Internetworking Configuration main menu.

Binding TCP/IP to a WAN Interface

After configuring the IPX protocol parameters, complete the following steps to deselect a permanent WAN Call Destination for on-demand applications:

  1. From the Internetworking Configuration main menu, select "Bindings".

  2. Highlight the previously configured TCP/IP WAN binding, then press <Enter<.

  3. Select the Permanent WAN Call Destination option, then press <Enter<.

    A new window displays the configured WAN Call Destination for this bind, if any. Only one permanent WAN Call Destination is allowed when TCP/IP is bound to a PPP interface.

    3a. Press <Del<. The previously configured permanent WAN Call Destination entry will be removed.

    3b. Press <Esc< again to return to the Binding TCP/IP to a WAN Interface window.

  4. Select RIP Bind Options, then press <Enter<.

    4a. Select Status, then press <Enter<.

    4b. Select Disabled, then press <Enter<.

    4c. Press <Esc< again to return to the Binding TCP/IP to a WAN Interface window.

  5. Press <Esc< again; if prompted, select Yes to save the TCP/IP bind parameters, then press <Enter<.

    A new window displays the configured protocol-to-interface bindings. The TCP/IP binding you just configured is highlighted in the list.

  6. Press <Esc< to return to the Internetworking Configuration menu.

Implementing the Configuration

To implement the configuration changes you have made, you must issue the REINITIALIZE SYSTEMcommand at the system console or reboot the router.

Advanced Topics

Advanced Topics

This section explores some advanced topics relating to on-demand links with NetWare MultiProtocol Router 3.0. These topics include:

  • Setting up on-demand links with NetWare 4.10

  • Reducing traffic related to time synchronization and NetWare Directory Services (NDSJ)

  • Configuring a preferred server or preferred NDS tree

  • Using interface groups

Setting Up On- Demand Links with NetWare 4.10

If you are using NetWare 4.10 software on both sides of a NetWare MultiProtocol Router 3.0 WAN link, and if the servers are synchronizing NDS information or time over that link, NetWare exchanges a steady stream of maintenance traffic across the link to maintain Directory synchronization. The result is that the on- demand WAN link is constantly in use.

The PINGFILT.NLM file supplied with NetWare MultiProtocol Router 3.0 allows NDS to be configured to set a time window in which Directory Services updates can occur. In order for PINGFILT to work, the DSFILTER update time interval must be identical on all NetWare 4.10 servers in the customer network that have the same tree name.

Time Sychronization and Directory Synchronization. In a NetWare 4 environment, the NDS Directory information is distributed across the network. When a user's objects are added to the Directory, they are added to the local copy of the database and then propagated throughout the network to other copies (replicas) of the database. If the same object is modified in two different replicas, the order of the modification must be preserved to correctly propagate the change.

NetWare ensures the correct ordering of Directory events by time stamping them. Without a common time source, each NetWare 4.10 server can have a different reference time. Time synchronization solves this problem by synchronizing the time among NetWare 4 servers on the network.

To keep the Directory synchronized, NDS checks with all servers in a replica list on a regular basis to determine whether any changes have occurred. This is in addition to generating the traffic that propagates changes in the Directory to the replicas.

In summary, NDS and time synchronization packets are both generated frequently enough to keep an on-demand link open constantly.

Reducing Sychronization Traffic. To resolve these problems, Novell has provided updates to the Directory Services NLM (DS.NLM) and the time synchronization NLM (TIMESYNC.NLM). These updated modules allow the user to configure time synchronization and NDS synchornization traffic.

You can use two strategies to reduce the frequency with which time synchronization packets are sent across an on-demand link:

  • Configure the network so that a mimimum number of servers need to synchronize time across the on-demand link.

  • Adjust the Time Sync Polling Interval to minimize the effects of time synchronization traffic. This requires the version of TIMESYNC.NLM that shipped with NetWare 4.1 (or later). If you have a NetWare 4.0x server, you can copy the TIMESYNC.NLM file from the NetWare 4.1 software (on the NetWare MultiProtocolRouter CD-ROM disc).

For more information and instructions, refer to "Time Synchronization and NDS Synchronization for On- Demand Links" on page 27 of the NetWare MultiProtocol Router 3.0 Release Notes.

Configuring a Preferred Server or Preferred NDS Tree . If the local branch office does not have a read/write NDS replica, the user login must go across the on- demand link to a NetWare 4 server that has a read/write replica. This server is selected by IPX through tick counts, as determined by the router discovery process.

In some cases where the customer is using static routes, the tick counts might be misconfigured. For example, an Ethernet segment (with NLSP) and an on- demand link might have the same tick count assigned. In this situation, you must configure a preferred server or NDS tree to which you can attach. These parameters are set in the client workstation NET.CFG file.

It is also recommended that a read/write partition be installed in the local branch office for faster user access to the server.

Using Interface Groups

Each permanent outbound call configuration identifies a specific NetWare Link/PPP interface that is used to place the call to a remote system. However, when supporting on- demand connections, you might want to have a group of interfaces that can be shared between outbound connections. If each interface in the group provides the same capabilities, any available interface can be used to establish an on- demand outbound connection to a remote system.

Furthermore, if all the interfaces are attached to switched circuits that represent the same telephone number, inbound calls placed to that telephone number can be accepted over any available interface in the interface group. This is similar to a multiple- line business telephone. To place an outbound call, you select any available line. Multiple inbound calls placed to the main office number are directed to any available line.

NetWare Link/PPP lets you assign a symbolic name to a group of interfaces that can be used interchangeably. All interfaces in a group must have similar framing characteristics. NetWare Link/PPP outbound call configuration lets you select an interface group name rather than a specific interface name for making outbound calls. Selecting an interface group name directs NetWare Link/PPP to use any available interface within the group to establish the connection.

Defining an interface group (with the Interface Group parameter) lets you make an on- demand call on any of several network interfaces without creating an individual WAN Call Destination for each interface.

There are two steps to defining an interface group:

  • First, when defining PPP network interfaces, provide the common group name to each interface.

  • Second, to use the group, specify the interface group name in place of the interface name in the WAN Call Destination.

When the call is made, the specific interface is selected from the group. Because an interface is selected automatically when the call is made, you don't need to dedicate interfaces to specific destinations. This flexibility in selecting interfaces lets you use your WAN hardware more efficiently.

Conclusion

This AppNote has covered the basic concepts behind configuring both permanent and on-demand asynchronous WAN connections with NetWare MultiProtocol Router 3.0. It has presented step-by-step examples of how to implement these configurations, and briefly explored some more advanced topics relating to on-demand connections.

For more information, refer to the following documents that come with the NetWare MultiProtocol Router 3.0 software:

  • NetWare MultiProtocol Router 3.0 Installation and Basic Configuration Guide

  • NetWare MultiProtocol Router 3.0 Advanced Configuration and Management Guide

  • NetWare MultiProtocol Router Quick Reference Guide

  • NetWare MultiProtocol Router Rules of Thumb

  • NetWare MultiProtocol Router 3.0 IPX Reference

  • NetWare MultiProtocol Router 3.0 TCP/IP Reference

* Originally published in Novell AppNotes

Disclaimer

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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