Cisco Enterprise Architecture
The Cisco Enterprise Architecture model divides the network into building
blocks and gives best practices for the architecture of each one. The traditional
three-layer model (Core, Distribution, and Access) is still around and can be
integrated into the design of components of the Enterprise Architecture model.
Enterprise Architecture building blocks include the following:
■ Campus—The enterprise core, or headquarters. The campus building
block contains routing, switching, security, Voice over IP (VoIP), wireless,
and so on.
■ Data center—Server and application resources. Redundant data
centers provide business continuity and allow load balancing.
■ Branch office—Remote locations that contain services similar to the
campus but are administered centrally rather than at each location.
■ Teleworker—Either a small office, home office, or a mobile user.
Extends data (and possibly voice) services to these users over a virtual
private network (VPN) using broadband WAN access.
■ WAN—Connects all the different blocks together. Converges voice,
video, and data over an IP WAN that provides security, quality of
service (QoS), and ubiquitous access.
WAN options between the campus and branch offices include traditional
Layer 2 connections such as Frame Relay, ATM, and leased lines. Multiprotocol
Label Switching (MPLS) can provide any-to-any connectivity between the
sites and is highly scalable. IPsec VPNs across the Internet can also be used.
This short cut is concerned mainly with how the campus, branch, and small
office, home office (SOHO)/teleworker portions of the network use the WAN
to communicate with each other to provide network services to their users.