The Cisco Three Layer Hierarchy Model

The Cisco Three Layer Hierarchy Model

Cisco systems have invented a three layered Hierarchical Model for simplifying the task of networking and for enhancing the efficiency to a greater extent. These three layers break down the networking system making it more intelligible and workable for both smaller and larger networking setups. However, the Layered model assists and facilitates the larger networks even more and can be seen as a great development in the field of networking.

With the advent of Cisco Three Layer Hierarchy Model the comprehension of the network layout and functioning has become quite easier. Since each layer possesses its own functioning thus troubleshooting has also become considerably easier. Despite all these enhanced features Cisco Three Layer Hierarchical Model remains to be cost-effective.

The Cisco Three Layer Hierarchical Model entails the following layers:

Core Layer

Core Layer acts as a fulcrum point for the entire network setup. Its layout consists of high speed cables such as fiber cables and high-end switches. It basically works in transferring a large amount of data with high speed, owing to the implanted devices such as high-end switches and routers in this particular layer.

It has the capability to alter traffic data at the fastest rate. It is a very critical yet simply designed layer. It is devised to manage and balance the load and often uses mesh topology. The latency period is lower in Core Layer, and hence its performance in data transmission is enhanced. Fault tolerance is also one of the specific features of core layer. It encapsulates a backup system which is termed as ‘redundancy’ which saves the network operation in case of any failure.

Distribution Layer:

This layer act as a bridge or a junction between, core and Access Layer. It ensures proper routing between sub-nets and VLANs of packets. The primary function of this layer is to provide accessibility between the two layers and between the packets and core by ensuring the performance of functions such as routing, WAN access and filtering.

Distribution layer performs multiple functions and is not function specified such as the other two layers. All the access layer switches, including OSI Layer 3 switches and routers which are LAN-based, stem from distribution layer, and is an active participant in core routing design. Furthermore, key functions of distribution layer include: Static routing and security filtering, including hiding network numbers (internal), combining LAN wiring and connections of WAN.

Access Layer:

Lowermost layer of the Cisco model, Access Layer or ‘Desktop layer’ provides the widest variety of features. It basically links inter network resources with local work group. It enables access to different work groups, being a junction of the provision of many networking services, and ensures that most of the resources be made available locally for the users.

This also involves the execution and implementation of many configuration-related tasks. It has Layer 2 and Layer 3 services, plus a number of authentication servers including: Radius and TACACS+. Access layer also segments by creating separating domains of collision.

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