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Networking Guide for Cisco Unity Release 5.x (With Microsoft Exchange)
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Chapter 5 AMIS Networking
AMIS Concepts and Definitions
In compliance with the AMIS protocol, Cisco Unity batches outgoing messages by node, with a
maximum of nine messages per batch. If there are more than nine messages for a particular node,
Cisco Unity ends the AMIS session after sending the ninth message, hangs up for a brief period of time,
and then redials the node to send the next batch of messages.
The AMIS protocol specifies that a message be a maximum of eight minutes long. During an AMIS
transmission, before playing a message, the originating node sends to the destination node the length of
the message. If the message is too long, the destination node may refuse the message and skip to the next
message. However, some voice messaging systems will accept longer messages. If the voice messaging
system refuses the message, a non-delivery receipt (NDR) is returned to the sender. If a subscriber sends
a message that is longer than eight minutes, Cisco Unity will attempt to transmit it. In addition,
Cisco Unity may accept messages longer than eight minutes. For each incoming message, Cisco Unity
checks the space available in the subscriber mailbox and the Maximum Message Length setting on the
Subscriber > Messages page to determine whether to accept the message.
Incoming AMIS messages to Cisco Unity are delivered to subscriber mailboxes only, and cannot be
delivered to public distribution lists. Additionally, incoming messages must be addressed to the primary
extension of the subscriber; messages addressed to an alternate extension will not be delivered. See the
“Inbound Messages Are Delivered Only to Primary Extensions” section on page 5-42 for additional
information.
Note that for incoming AMIS calls, the initial “handshake” between the originating system and
Cisco Unity must take place in a call handler, such as the Opening Greeting call handler. For AMIS
Networking to be properly configured, you need to ensure that all incoming AMIS calls are routed to a
call handler. When Cisco Unity is initially installed, the default setting is for the call routing table to
route calls to the Opening Greeting call handler; thus it is properly configured for AMIS Networking. If
the call routing table has been modified after installation, you need to make sure that a rule is in place
in your call routing table to route any incoming AMIS calls to a call handler.
Port Usage and Schedules
In the Cisco Unity Telephony Integration Manager (UTIM) and in the Cisco Unity Administrator on the
System > Ports page, you can designate which ports on your system are used for outgoing AMIS calls.
All ports are used for incoming AMIS calls.
AMIS transmissions can be lengthy and thus tie up ports on your Cisco Unity server. For example, 10
hours of AMIS messages take at least 10 hours of port time to transmit. A 2-minute message that is sent
to a public distribution list that contains 200 AMIS recipients results in 200 messages in the outbound
queue, and would require at least 6.5 hours of port time to transmit.
When multiple ports have been designated for outgoing AMIS messages, Cisco Unity uses all designated
ports as message traffic warrants. The total number of ports used is limited by the availability of ports
that have been designated for outgoing AMIS calls. For example, if there are 10 ports available for
outgoing AMIS messages, and 10 hours of messages to deliver, all 10 ports are used for message
delivery, and the time to transmit all of the messages will be about one hour plus the time it takes to place
the calls and establish the AMIS sessions.
Outbound messages are sorted according to their destination, and then batched into groups of 9. If there
are multiple destinations, multiple ports are used to transmit the messages. If there are numerous
messages to one destination, each batch of messages (with a maximum of nine per batch) is transmitted
on a different port, if one is available. In other words, if you have multiple ports designated for AMIS
message delivery, multiple ports will be used to handle the messages to a single node, as needed. As the
number of messages for a particular node increases, an additional port is added when the number of