February 1998

BY JAMES SHEN

Internet telephony is still in its infancy. While there are already some practical applications, such as the ability to make a voice call from one multimedia enabled computer to another over the Internet, or the use of Internet telephony gateways to enable phone to phone Internet calling, a great deal of further improvement in technology, engineering, and implementation should be expected in the Internet telephony arena. One of the most promising areas of development is Internet Telephony Network Management (ITNM) technology.

CURRENT STATUS OF THE INTERNET
Internet telephony technology is based on the Internet infrastructure. During the past decade, growth of the Internet infrastructure has been explosive, and the expansion shows no signs of slowing down. While Internet access is available in most major cities worldwide, the accessibility and reliability of the network varies significantly. On one hand, constant upgrades on the Internet backbone in more industrialized countries are generally able to accommodate the increasing demand of Internet access from end users. On the other hand, in many developing countries, the shortage of Internet bandwidth often causes network traffic jams. For example, many Internet Service Providers (ISPs) in countries such as Brazil and China operate their services on 64 Kbps Internet links. Because data lines are very expensive in those countries, ISPs are often unable to set up a redundant Internet access.

However, the demand for Internet telephony services is significant within those countries with high telecom tariffs. Those same countries also lag behind in their Internet development. Internet telephony services in those areas are therefore facing the following challenges:

• Unguaranteed bandwidth of the Internet.
• Unpredictable performance of the Internet.
• Unbalanced development of the Internet.
• Disparate telephony signaling systems (for Internet faxing and voice messaging).

Overall, the Internet provides an unprecedented infrastructure for implementation of Internet telephony applications because of its worldwide coverage and ubiquitous nature. However, the quality of service (QoS) of today’s Internet cannot meet the requirements of telephony applications. Many companies are planning to establish global Internet telephony networks. The lack of reliability and manageability on the Internet mandates special network management capabilities to support the implementation of these plans. Internet Telephony Network Management should include, but not be limited to, the following functionality:

NETWORK AND NODE MONITORING
ITNM agents residing at each node will collect information about ports, servers, and routers. ITNM agents will send the information to a Management Information Base (MIB), which is normally located at both the local node and the network control center. Internet telephony applications can use this information to report network status and other information to network administrators.

In order to monitor the telephony ports of a gateway, a dedicated modem port is normally needed to periodically call in to the telephony ports and test the connectivity. This type of monitoring or testing is necessary to ensure that inbound telephony traffic will have access to the gateway. Of course, ITNM agents should also monitor the port status for outbound telephony traffic. This task is performed by the ITNM agent located in the host server. Whether or not traffic can be sent from gateway A to B, the connection needs to be monitored for Internet fax and voice messaging applications. Further, the available bandwidth needs to be measured constantly for realtime Internet phone applications.

ALERTING AND REPORTING
Based on the information that the monitoring element obtains, alerting is the next natural step. Alerting can be categorized by three types such as critical, major, and minor. Alerting should also be directed to three different administrators as follows:

• Node Operator (for node and port failure and difficulties).
• Internet Uplink Network Administrator (for Internet connection failure and difficulties).
• ITNM Control Center (for all kinds of failure and difficulties).

NETWORK TRAFFIC MANAGEMENT (NTM)
Traffic Volume Control: The bandwidth of the Internet from point A to B cannot be guaranteed today. Based on the available bandwidth at any given time on the path, call traffic control can be implemented to maintain the QoS. For example, with current IP phone technology, 16 Kbps bandwidth is required for establishing a realtime voice communication channel. 32 Kbps bandwidth can only accommodate 2 voice channels. If the bandwidth increases to 64 Kbps at a later time, 4 simultaneous Internet phone calls can take place and so on. Node Backup: If there is a node failure happening in the network, a node backup plan needs to be implemented immediately. For example, if a node in Singapore fails temporarily, the nodes in Malaysia can take the responsibility to terminate traffic for the Singapore area.

Dynamic Routing: If the Internet is too busy to take additional calls, overflow should be directed to either an alternative node or even the PSTN. By doing so, the transmission is guaranteed by both the Internet network and PSTN. The usage of node and network can also be maximized, when several nodes in the same area can be used to terminate traffic if the designated gateway is busy.

Integration with Internet Telephony Messaging Systems: When Internet Telephony Service Providers (ITSPs) start service trials, the block rates can be high because of a lack of capacity. No matter how inexpensive Internet telephony services are, customers can hardly tolerate repeated denial of services, so alternative routing must be in place. Ideally, customers should be given an overflow option for a voice message (store and forward and oneway transmission) solution. For example, if access is not available due to limited access or bandwidth, the gateway can prompt the caller “…you can leave a message. The message will reach the destination within 3 minutes.”

NETWORK MANAGEMENT FOR INTERNET FAXING
Many people believe Internet fax is easier to handle than Internet phone. To establish a global Internet faxing network, there are some challenges which are inherently different from an Internet phone network.

To begin with, we have not seen many real-time fax applications over the Internet. One of the difficulties is that two fax machines cannot have successful handshaking when the compression distorts the handshaking tone. Of course, the Internet cannot guarantee the bandwidth for uncompressed fax messages, therefore, most Internet faxing solutions are based on store and forward technology.

The store and forward systems bear the entire burden that users normally take care of by themselves using realtime faxing. Those burdens include:

• Wrong fax number.
• No fax tone at the receiving fax machine.
• Receiving fax machine is busy.
• Line error at the receiving fax machine.
• Human interference at the receiving fax machine (manually operated fax machine).
• No port available at the receiving node.
• Internet connection at the receiving node is down.

All the elements of ITNM should take the above issues into consideration. Because two machines, instead of two human beings, are communicating for Internet faxing applications, the network management needs extra intelligence. Most importantly, NTM should direct the traffic and re-direct the undelivered messages intelligently.

NETWORK MANAGEMENT FOR ROAMING ACCOUNTS
A global Internet telephony network makes worldwide roaming possible, if ITNM supports the roaming accounts. Roaming is an important feature for those customers who travel, so that the Internet telephony services they can benefit from are not limited to one area. When a roaming account accesses any gateway in the network, the account information will be passed to the Control Center for authentication. When the account has been authenticated, the traffic-sending node will allow this customer to make phone calls or send faxes. After the transmission, the call details will be sent to the Control Center for settlement. The settlement will involve three parties: the host node where the account is registered, the traffic-sending node, and the trafficreceiving node.

IMPLEMENTING ITNM
ITNM Agent Embedded in Each Node: ITNM Agent has the responsibility to collect information and monitor the ports, nodes, and network devices connected to the host within the boundary. Each agent also needs to send the information to both the local MIB and central MIB. ITNM Alerting Module: Alerting modules should reside at both local nodes and the Control Center. In case the local node has total failure, the Control Center will alert the node operator and other nodes.

MIB: Should be available in the local node, providing information for alerting and network traffic management. Network Traffic Management: Should be functioning at both the local node level and the Control Center. Before calls are sent to their destination, NTM will make an intelligent decision as to how to route the call at that very moment.

ITNM Centralized Control Center: The Control Center will synchronize ITNM agents and MIB around the network, and further coordinate the action of local alerting modules and NTMs. The Control Center will also feed least cost routing upgrade information to each node.

WHO SHOULD USE ITNM?
Any corporation with more than three nodes running Internet telephony needs to implement ITNM in order to optimize the performance of the network. Any network organizers who are planning to or have already set up a global Internet telephony network must have ITNM to manage the network.

CONCLUSION
With the help of ITNM, Internet telephony applications can be more reliable and manageable. The overall quality of service can meet the most demanding customer’s expectations. In addition, ITNM allows network organizers to provide Internet telephony settlement services and clearance house functions to facilitate the implementation of the technology.

James Shen is founder and CEO of NeTrue Communications, Inc. NeTrue Communications is a leading provider of Internet telephony solutions. Their product line includes IP Phone Gateway, Internet Fax/Voice Messaging Gateway, PC-to-Fax, and PC-toPhone software. NeTrue has been successfully managing a global Internet telephony network with more than 50 nodes in 28 countries. The network management technology is NeTrueView, a proprietary Internet Telephony Network Management (ITNM) technology. For more information, visit the company’s Web site at www.netrue.com , or call 714-870-0861.