Message Networking network configurations

Supported network configurations

Message Networking supports the following network configurations. See Sample network topologies for illustrations of the network topologies discussed in this topic.

Hub-and-spoke topology: In this configuration, each system is only networked to the Message Networking system, which provides the conversion between the various protocols. Every system in the network can be networked to every other system using any of the protocols supported by Message Networking.

The Number of Bridged Machines option on the Customer Options page must be set to 500 (the maximum).

Bridge topology: Message Networking supports a bridge network topology, in which Message Networking provides the network protocol conversion that allows a single remote machine or multiple remote machines to communicate with the rest of the systems in the network. In this scenario, Message Networking is normally not processing messages between the other systems in the network, but is dedicated to providing communication from the new systems to the existing network systems. A bridge topology is useful in a situation where new systems purchased support protocols not supported by the other systems in the network. A bridge topology can take the following forms:

A Message Networking system is used for each new system that is being bridged. While this topology is more costly because it requires a dedicated Message Networking system for each system as a bridge to the other networked systems, it provides greater network reliability as there is no single point of failure.
One Message Networking system is shared among multiple bridged machines.

To use a bridge topology, the Number of Bridged Machines option on the Customer Options page is set to the number of remote machines each Message Networking system is bridging, and each new system must be administered as a bridged system on the appropriate Message Networking system. For example, if you want to add three new systems to your existing network, and you purchase a Message Networking system to act as a bridge between the new systems and your existing network, then the Number of Bridged Machines must be set to 3 on the Message Networking system and you must administer each new system as a bridged system on the Message Networking system.

Sample bridge network configurations are provided on the Avaya support web site. Go to http://www.avaya.com/support and then navigate to the Message Networking page.

Hybrid topology: Message Networking supports a hybrid network topology, in which a combination of point-to-point, hub-and-spoke, or bridging exists within the same network. A hybrid network topology usually involves multiple Message Networking systems and Interchange systems.

General network configuration considerations

The following general network configuration considerations apply to Message Networking:

Analog fallback: Octel 250/350 and Octel 200/300 systems that are networked digitally in a point-to-point configuration have the ability to fall back to Octel Analog if the system is unable to send the message over the TCP/IP data network. Message Networking does not support this fallback either in an inbound (that is, messages from an Octel 250/350 or Octel 200/300) or an outbound direction. Although analog fallback does not occur on the Message Networking system when the TCP/IP network is unavailable, messages are rescheduled for delivery (based upon predefined delivery schedules), and no messages are lost. As more redundancies continue to be built into TCP/IP networks at the data level and these networks become more reliable, the need for analog fallback to be built at the application level becomes less of a requirement. This is true much in the same way that many other data applications, such as email, PC client access to message mailboxes, do not depend on analog fallback at the application level.

Uniform Network Address length: Message Networking supports a uniform Network Address length from 3 to 10 digits. In some configurations, a prefix can be used when defining a dial plan. A prefix is a number that is dialed by the sender of a message before entering the digits of the Network Address (for example, dialing a 1 before a 10-digit Network Address). The prefix 1 is not actually transmitted to the Message Networking system along with the Network Address. In some networks, prefix use can give the appearance to the sender that the address lengths are variable but, in reality, the same number of digits is always transmitted to the Message Networking system for the Network Address. Message Networking does support variable-length addressing for Modular Messaging systems. For additional information on variable-length addressing, see Administering numeric address mapping.

Multiple-length mailbox IDs: Message Networking does not support multiple length mailbox IDs within the same message server. Each message server can have a different length mailbox ID, but the length of mailbox IDs cannot vary within a given message server.

Multiple Message Networking and Interchange 5.4 systems in a network: In a network that includes multiple Message Networking or Interchange 5.4 systems, a message cannot traverse more than two Message Networking or Interchange systems during a delivery. Each Message Networking and Interchange system must be administered on every other Message Networking or Interchange system in the same network.

Hybrid networks: Message Networking supports hybrid network configurations in which there is a mix of point-to-point and Message Networking message server connections. It is important to be careful in planning the dial plan of such a network to ensure that the desired delivery path is followed when subscribers use the network. One issue that can occur in a hybrid network is "double name-back." This is a condition in which a subscriber has two paths to send a network message to a recipient: one as a direct point-to-point connection and another through the Message Networking system. When this occurs, two remote subscriber directory entries can be stored on the local message server: one for the point-to-point path and another for the Message Networking path. In this case, senders using the dial-by-name feature can get back two responses for the same person (for example, "Press 1 for John Smith, Press 2 for John Smith"). This condition can be prevented by defining one dial plan path by which a sender can send a message to a recipient.

Upgrading from Octel Analog to Digital: Message Networking does not support the ability to change the connection type for a message server networked using Octel Analog to Aria Digital or Serenade Digital. These machines must be deleted from the Message Networking database and readministered as Aria Digital or Serenade Digital. Subscriber lists stored on the message servers can be impacted when the remote machine is deleted and then readministered.

Moving from a point-to-point configuration to Message Networking: Note the following considerations when moving from a point-to-point configuration to Message Networking:

The dial plan can change such that lists stored on local message servers can be impacted. This impact might require that a user reenter the list with the new Message Networking network address. Octel 250/350 servers support the ability to move a prefix from one remote machine to another (that is, from a remote machine connected point-to-point to a Message Networking system). When this is done, the lists that reference subscribers on the moved remote node remain unchanged.
The deletion of remote subscribers when moving from a point-to-point to a Message Networking topology also causes the inability to use the INTUITY AUDIX Personal Address Book feature (Message Manager) to identify and address any deleted remote subscribers. Other related mailbox features that are affected include the Personal Directory (Touchtone User Interface Options 5, 2) and Names Directory (Touchtone User Interface Option **6, when addressing a message). Local INTUITY AUDIX subscribers would need to replace any deleted remote subscribers in their Personal Directory. The Personal Address Book and Names Directory are re-created when messaging remote subscribers via Message Networking. The Message Networking dynamic updates feature adds these to the local messaging system one-by-one on a real-time basis as messaging occurs between the systems.
Message header information is lost permanently for old or saved messages stored in a subscriber's mailbox that were received from remote subscribers who were later deleted (as a result of moving from a point-to-point configuration to Message Networking). Saved messages in this case lose their header information and indicate a message from an unknown subscriber. In addition, end users do not have the ability to reply to messages from the deleted subscriber. The customer should be alerted to this condition prior to the conversion to the Message Networking network. Subscribers should take note of important saved messages and be prepared for this situation. In addition, unnecessary saved messages should be deleted before the Message Networking conversion.
For Octel Analog, non-LDAP-based SMTP (VPIM and MIME), and AMIS remote machines, there are several possible methods of adding remote subscribers into the Message Networking system. The following is a list of these methods in order of preference:
1. Bulk add by file
2. Self-registration
3. Sending a message through the Message Networking system
4. Subscriber Parameters page
5. Demand remote update (Octel Analog)
6. Bulk add by range

Note that the bulk add by range utility is lowest on the preference list. While this method is a viable option, it should only be used when the other methods cannot be used. If you do plan on using this utility, take note of the following considerations:
- When using bulk add by range, the administrator should limit the range administered on the Message Networking system to the actual range (or subranges) used on the remote message server. Otherwise it is possible for tens of thousands of default subscribers to be added for remote machines that actually only have a few hundred subscribers. Having thousands of unused default subscribers can impact system performance.
- Since Aria Digital and Serenade Digital systems support a demand NameSend and INTUITY AUDIX and Avaya Modular Messaging systems support Demand Remote Update to initialize the Message Networking subscriber database, a bulk add by range should never be used for these machine types (nor should any of the other add methods listed above). Additionally, the digital system types notify Message Networking when a new subscriber is added so that the Message Networking system can update its directory. In all cases, customers are encouraged to upgrade to a digital connection as the directory updates and administrative procedures for digital systems are much more robust than those for analog systems.