Today’s networks typically include voice, video, network management, mission-critical, and routing traffic in addition to bulk user traffic. Each type of traffic has different performance (bandwidth, delay, and jitter) and security requirements.
Network design models provide a framework for integrating many different types of traffic into the network.
Over the years, several models have been used to help describe how a complex network functions. These models are useful for designing a network and for under-standing traffic flow within a more complex network.
There are three models: the traditional Hierarchical Model, the Enterprise Composite Model and the Cisco Enterprise Model.
The Enterprise Network Model is divided into three large sections:
Enterprise Campus: Switches that make up a LAN
Enterprise Edge: The portion of the enterprise network connected to the larger world
Service Provider Edge: The different public networks that are attached
The Enterprise Edge details the connections from the campus to the WAN and includes:
- Internet connectivity
- Remote access
Planning for Complex Networks
The Service Provider Edge is just a list of the public networks that facilitate wide-area connectivity and includes:
- Internet service provider (ISP)
- Public switched telephone network (PSTN)
- Frame Relay, ATM and PPP
The Campus Architecture component is basically the same as in the Composite model. It includes routing and switching integrated with technologies such as IP telephony and is designed for high availability with redundant links and devices. It integrates security features and provides QoS to ensure application performance. It is flexible enough to add advanced technologies such as VPNs, tunnels and authentication management.
The Data Center component provides a centralized, scalable architecture that enables virtualization, server and application access, load balancing and user services. Redundant data centers might be used to provide backup and business continuity.
The Branch Architecture extends enterprise services to remote offices. Network monitoring and management is centralized. Branch networks include access to enterprise-level services such as converged voice and video, security, and application. Resiliency is obtained through backup local call processing, VPNs, redundant WAN links, and application content caching.
The WAN component provides data, voice and video content to enterprise users any time and any place. QoS, SLA, and encryption ensure a high-quality secure delivery of resources. It uses IPsec or MPLS VPNs over Layer 2 or Layer 3 WANs, with either a hub-and-spoke or mesh topology.
NETWORKING SOLUTIONS TOPOLOGY