The key 5 characteristics of Scalable Internetworks are:
1. Reliable and available: An internetwork is usually up for 24 hours a day and seven days a week, throughout the year. Therefore, one of the key components is Reliability and availability.
2. Efficient: Efficiency means optimization of resources keeping in view available bandwidth. An internetwork should have less amount of overhead traffic, such as broadcasts, routing updates etc.
3. Responsive: It is necessary that the internetwork meet QoS requirements for different protocols. Cisco IOS has been developed keeping in view the QoS demands. For example, SNA may require a different QoS compared to say, IPX.
4. Adaptable: An internetwork should be able to accommodate disparate networks and protocols. The available protocols may include for example, TCP/IP, IPX, and SNA. An adaptable internet should be able to accommodate legacy as well as latest technologies.
5. Accessible and Secure: An internet should be accessible by using different technologies, such as dial-up, dedicated, switched connections. At the same time, it should provide secure environment.
