Distribution

With the rising demands of the converged network, the recent developments in network design are the Cisco Borderless Network. The Cisco Borderless Network is a network design that allows organizations to support a borderless network that can connect any person, everywhere on any device very securely and consistently. This design address IT and business challenges.

The Cisco Borderless Network structure merge wired and wireless access, as well as access control, policy and performance management of different device types. The hierarchical infrastructure of hardware is also scalable and flexible, the Figure below illustrates the Cisco Borderless Network which provides two primary sets of services: network services and endpoint services; network services and endpoint services; all services managed by an integrated management solution. This design enables different network elements to work mutually and also allow to access resources from any place at any time; as providing optimization, scalability as well as security.

Hierarchy in the Cisco Borderless Network

The Cisco borderless switched network primary need is availability, flexibility, security, and manageability. The borderless switched network should also deliver current and future need. The basic principles of the Borderless switched network are the following:

• hierarchical network Design
• Modularity
• Resiliency
• Flexibility

Understanding the principle to fits in a different situation is very important. The hierarchical borderless switched network is providing a base for the network designer to cover security, mobility, and unified communication features. Cisco designs three-tier and two-tier hierarchical network for a campus. The figure below illustrates the Cisco hierarchical network design. The three-tier of this design are the access, distribution, and core layers.  Every layer of this design can be seen as a clear structured module with particular roles and functions in the campus network.

The campus hierarchical network design which containing modularity also provide critical network services with resilient and flexible.  The modularity also provide assistance for increase and change that occurs over time

Access, Distribution, and Core Layers

Access Layer

The access layer is the place where traffic enters or exits the campus network. It is also the edge of the campus network. Usually, the main function of an access layer is to give network connectivity and access to end-users.  The switches of the access layer connect to switches of the distribution layer. The switches in the distribution layer apply network foundation technologies such as routing, QoS, and security.

To meet user need and network application, the next-generation switching platforms now present extra converged integrated; and quick services to different types of endpoints at the edge of the network. Creating intelligence into the switches of an access layer allows applications to act on the network more capable and securely.

 Distribution Layer

The distribution layer provides connectivity between the access layer and core layer including, many important functions. This layer provides intelligent switching and routing. The distribution layer provides network access policy functions to access the network as long as differentiated services to different classes of service applications at the edge of the network. This layer also providing high ease of use throughout the redundant distribution layer switches to the end-user and equal-cost paths to the core layer. The distribution layer also aggregate large-scale wiring closet networks and aggregates Layer 2 broadcast domains and Layer 3 routing boundaries

Core Layer

This layer is the backbone of the Cisco borderless network. The core layer connects several layers of the campus network and work as the aggregator for all the other campus blocks and interconnects the campus with each other inside the network. The core layer main function is to give speedy fault isolation and high-speed backbone connectivity.

Collapsed Core Network

Three-tier campus network usually planed for organizations where the access, distribution, and core, each are required as separate layers. This is required because of a basic, cost-effective, scalable, and efficient physical layout design for the large-scale network where many campuses exist. The best practice is to make an extended-star physical topology from the main campus to all other campuses.

The campus where fewer users accessing the network or single building campus usually not required a separate core and distribution layers. Network structure required in this situation is called a collapsed network. It is also called two-tier campus network.  In a collapsed network the role of the core switches moves to the distribution switches, merging the core-and distribution layer. The figure below illustrates the collapsed campus network example.