Overview

This document describes two variations of the CTI FastSync Hub for Windows Post Office central server system configuration. These variations, the “Multi-Server (Cluster) Configuration” and the “Multi-Leg Configuration,” provide maximum flexibility for a wide variety of needs.

The “Multi-Server” installation uses one or more NT Servers to act as an auxiliary firewall server(s) in addition to the NT Server designated as the Post Office server. This scenario will be seen most often in large hub installations where the communications burden is too great to be borne efficiently by a single PC.

The “Multi-Leg” installation allows users from separate networks to communicate over a common network backbone. This scenario accommodates the situation where Post Office clients are pre-installed on separate networks with separate access to the Post Office. For example, an Engineering Department server using TCP/IP and another Accounting Department server using Novell’s IPX. Both scenarios are discussed in detail below.

Multi-Server Cluster Installations

In smaller installations, a single NT Server can be used as the Post Office administrator and as a communications server for dial-up firewall connections. As network volume increases however, this server could become bogged down, until at some point it may become beneficial to shift to a multi-server installation.

In a multi-server cluster installation, one or more additional computers (PCs) are configured as communication servers only. These communication servers provide dial-up firewall connections only while the “master” NT Server continues to provide the Post Office maintenance functionality. The master NT Server can continue to act as a communications server as well, or it can be dedicated solely to maintenance functions, off-loading all communications functions to the other auxiliary server(s). The diagram below shows a typical multi-server cluster installation.

Installation of the auxiliary servers is a simple matter of installing another computer on the same network backbone as the master server, then installing the Post Office Administrator software on the auxiliary server(s) using the “Communications Server Only” option. The auxiliary server must be given full network access to the master server s “Master Shared Directory”. Next, a unique name is assigned to the auxiliary server. This name is then programmed into the master server, while both the name and the full path of the master shared directory are programmed into the auxiliary server. Any network operating system (TCP/IP, Novell Netware, Microsoft, et cetera) can be used for the network backbone.

The Multi-Server installation also can be used for other purposes than just load sharing. For example, a multi- server installation can be used to create priority classes for users. Consider a Post Office with 100 users, 10 of which are to be granted high-priority status. A high priority server could be established and configured with 5 modems. The phone number for these modems would then be given only to the high priority users, yielding a 2:1 user-to-modem ratio. A low priority server could also be established and configured with 10 modems. The phone number for these modems would be given to all users, yielding a 10:1 user-to-modem ratio. Thus, the high-priority server will provide greater access to the high priority users, due in part to its lower user-to-modem ratio, and in part to the lower number of installed modems, which in turn reduces processor overhead.

Multi-Leg Installations

The Multi-Leg installation accommodates the situation where the Post Office users, for whatever reason, are installed on separate networks. For example, consider an organization with an Engineering department that is on its own TCP/IP network, and an Accounting department that is on its own Novell (IPX) network. These two networks are not interconnected for security reasons. The multi-leg configuration could be used if a FastSync Post Office is to be installed with access to all Engineering and Accounting personnel. The Engineering department would be configured as one leg, while the Accounting department would be configured as another leg.

To do this, a computer would be installed as the Post Office NT server and a network backbone would be installed between the Post Office server, the Engineering server and the Accounting server as shown in the diagram below. This network backbone would be a third network, independent of the Engineering and Accounting networks. Any network topology (TCP/IP, Netware, Microsoft, et cetera) could be used for this backbone network. The Post Office server would be granted full access to one directory on the Engineering server and one directory on the Accounting server. The full path names of these shared directories are then programmed into the Post Office Administrator. At this point the Post Office server acts as a gateway between the two separate networks, allowing file transfers through the FastSync Hub Mailbox system. The Engineering and Accounting networks would remain isolated from each other for all other purposes. Although this is a less efficient configuration (the Post Office server must now perform the functions of a gateway in addition to its usual functions), it is useful for situations such as this, where users are on separate networks that need to be kept separate for all purposes other than FastSync file transfers.

A Question from the Field...

We want to put several Post Office Servers on different LANS in either different locations or countries.  Can this be done and can the FastSync Hub Servers be linked together so it's transparent to the Clients on the WAN?  How is file transfer timing affected?  Didier Durand, IntraConnect S.A., Athens, Greece.

Answer:  Yes, the CTI FastSync Hub can be configured to connect several local networks together. In such a configuration, each end user will experience the response times of their local network, not the response time of the remote connection. For example, if a user in New York were to send a large file to a user in Athens, the New York user would send the file over his local network at local network speeds. The FastSync Hub would then forward the file to Athens where it can be picked up by the Athens user on his local network at local network speeds. Of course there may be a delay in sending the file between Athens and New York, but the end users will not experience this delay.

To implement this, you would install one central Post Office at one central location. This Post Office (which consists of the central Post Office Administrator and a single Post Office Daemon) would track all users on all networks and would be responsible for directing files between the appropriate networks. The Post Office should be installed on a network backbone that is also connected to the other local networks. If this network backbone is a TCP/IP network, you may use the Multiple Server Installation described on page 14 and illustrated in Figure 8 of the Planning, Installation and Maintenance Guide. If the network backbone is not a TCP/IP network, you must use the Multiple Network Installation described on page 15 and illustrated in Figure 9. The TCP/IP configuration is preferred where possible because it makes much more efficient use of the network backbone. In the TCP/IP configuration you would install a separate Mailbox Server on each local network and configure the Mailbox Servers to share data with the central Post Office Daemon via their shared directories.  Click here to download The Hub Planning and Installation Guide (a small 94Kb zip file).

Click here for information on the Mailbox System

Click here for Clustering Information