STEP 3: Establish directory
replication between the sites.
After you have installed both of the
X.400 connectors, you need to establish directory replication by configuring a
directory replication connector. To begin, select File, New Other, and Directory
Replication Connector from the Main Admin Program screen. Next, select the
remote site name from the list, and type in the server name of the target server
at the remote site. Select No, the Remote Site Is Not Available on this
Network, and click OK.
At this point, you will see the Directory Replication Connector Properties
dialog box shown in Screen 2. Change the Display name and the Directory
name from the default names to names that are meaningful within your
organization; for example, X400Directory and X400Directory, respectively. (If
possible, make the display and directory names the same to avoid confusion.)
Next, in the Site Name box, list the remote site that you are connecting to
(i.e., the site you want to replicate directories with). For the local and
remote bridgehead servers, you can change the target servers if you have
multiple servers at each site. It is important to understand that, at this
point, you are configuring one server at each site that will act as the focal
point for directory updates between the local servers at the main site and the
target server at the remote site. Instead of having all servers in each site
freely replicating with each other, you are assigning certain servers this
responsibility in an effort to efficiently use the link between sites.
After you enter the correct properties, click the Schedule tab. For testing
purposes, choose Always, which triggers update requests to the remote server
every 15 minutes. Once the X.400 connection is working, you can choose a button
that best reflects your desired schedule for directory updates. However, do not
select Never because this selection will disable replication for this connector.
If you want to configure a directory replication hub, click the Sites tab.
Specify which inbound sites you want updates from and which outbound sites you
want to send updates to. Click OK; you now have a Directory Replication
connector established between the main site and the remote site.
If you click on the main site and then Expand Configuration in the Main
Admin Program screen, the connector you just established will appear under the
Directory Replication icon. The Main Admin Program screen will also show the
remote site once the connector runs the first time, even if it is unsuccessful
at establishing contact with remote site. The local copy of the directory will
also contain the Site and Configuration objects. Depending on network bandwidth
and availability, the time to complete replication will vary. Because this link
is remote, do not expect instant gratification.
Installing and Configuring Connectors Between an Internal and External
Site
Suppose you want to link your Exchange organization site in Colorado with an
X.400 messaging system in Texas. You decide to install an X.400 connector using
the TP0 and X.25 transport and network protocols. After you install and
configure the underlying software and hardware, you can install and configure
the X.400 connector in three steps.
STEP 1: Install the EiconCard and
software.
Eicon Technology (http://www.eicon.com) supplies the software,
WAN Services for NT, and the interface
card you need to connect your system directly to X.25 interconnect services. The
procedure to install the Eicon software and card depends on which version of the
software you have. With version 2.x and greater, you simply insert the card into
the appropriate slot in the PC and load the CD-ROM, letting NT find the hardware
and prompt you to install the software. With the 1.x version, you might need to
add the Eicon software and card to your NT server in the traditional manner of
using the Network Settings portion of the Control Panel.
STEP 2: Configure the EiconCard and
software.
The Eicon configuration program is a graphical program that is
easy to navigate and use. Even better, you need to configure only WAN services,
making the configuration process relatively painless.
To begin, go to the WAN Services - Configuration dialog box shown in Screen 3. Under WAN Services, you will find configuration settings for High-Level Protocols, X.25, HDLC, and Direct for each installed card. These settings must match the parameters set by the network service provider. Thus, you will need the following information before you configure WAN Services:
* Node type: Most nodes are data terminal equipment (DTE). Most modems are
data circuit-terminating equipment (DCE). The node type determines, among other
things, what types of control signals pass on the wire and which of the devices
is responsible for providing those control signals. If you configure both the
node type and modem to be DTE or DCE, confusion will result at the hardware
level and the end systems will not communicate. People often make this error,
especially when they read the RS232 definition of DTE and DCE.
* DTE address: This address is analogous to your network phone number. Your
network service provider can provide your DTE address.
* Type and number of virtual circuits: With X.25, you can have multiple
virtual circuits on one physical connection, usually in multiples of four. (The
charge for service increases accordingly.) Most standard configurations contain
four virtual circuits.
* Packet sizes (minimum and maximum allowable): These parameters must match
the network service provider's specifications. If the parameters don't match,
excessive negotiation and timeouts can lead to failed connections and circuit
delays.
* Window sizes (minimum and maximum allowable): The window size specifies
how many outstanding packets that require acknowledgement can be sent before the
sending system requests acknowledgement. These parameters must match the network
service provider's specifications. Improper settings can cause significant
transmission delays.
In addition to needing this information to configure WAN Services, you will
need it for another reason. X.25 network services providers often require you to
submit a detailed, preinstallation configuration document that contains these
parameters and addresses.
STEP 3: Install a new MTA Transport Stack.
Assuming that you already
have installed the TCP/IP MTA Transport Stack and Eicon's WAN Services for NT,
you need to add a new transport stack: the Eicon X.25 MTA Transport Stack. From
the Main Admin Program screen, select File, New Other, MTA Transport Stack, and
Eicon X.25 MTA Transport Stack. Select the local server, and then click OK. The
Eicon X.25 General Properties page will appear. You can either accept the
default name or change it. Fill in the X.121 Address field with the number your service provider supplies you. (Your service provider might refer to this number as the DTE or data network identification code--DNIC--address.) Often, you can leave the Call User Data, Facilities Data, and OSI Address boxes blank. (Your service provider will have this information, if you need it.)
The T, S and P selectors on the General Properties page distinguish among multiple software stacks running on a host system and are required when you're connecting to many computer systems for the purposes of transferring X.400 messages. A nice feature of the General Properties configuration page is the Hex and Text buttons. If you select Hex, Eicon X.25 will display T, S, and P selector values in hex. If you select Text, Eicon X.25 will display the selector values in US ASCII text.
On the General Properties page, select the I/O port associated with the Eicon card installed (usually port 1.) Select the Leased Line button for direct
connection via a leased circuit. Select OK. You will see that your choices now
include a TCP/IP X.400 connector and an Eicon X.25 X.400 Connector.
Congratulations, you now have installed multiple transport stacks with NT Server
and linked them to Exchange.
The Dynamic Duo Awaits
Now that you have the necessary hardware, software, and protocols in place,
the dynamic duo of Exchange and the X.400 connector are ready to battle the evil forces of high traffic and slow connections. By establishing reliable, fast, and cost-effective communications, this dynamic duo can help save your day.
OSI and X.400 Help files discussed on page 144 are available for downloading from Windows NT Magazine's Web site at http://www.winntmag.com.