Architecture

SD-Access is an intent-based network design for enterprises. It is built on the Cisco Digital Network Architecture (DNA) and is combination of the campus fabric design and Digital Network Architecture Centre. SD-Access adds a fabric capability to a enterprise network through automation and can provide automated end to end segmentation to separate a user, device…

The simplified campus design relies on switch clustering such as the virtual switching system (VSS) and stacking technologies such as StackWise, where multiple switches are treated as a single logical switch. These technologies can be applied to any of the layers in the network design to simplify them. Simplifying the network through the use of…

Routed access is a configuration where Layer 3 is extended all the to access layer switches; one layer further than the distribution layer. The access layer switches act as Layer 3 gateways for the hosts that they are connected too, as well as providing Layer 2 switching. Access to distribution Layer 2 trunks are replaced…

A traditional local area network design uses a Layer 2 access layer with a Layer 3 distribution layer. The distribution Layer 3 provides the network gateway for the Layer 2 access layer hosts. Where possible, it is recommended to restrict a VLAN to a single access layer switch to eliminate topology loops which are a…

A three tier design separates the core and distribution layers and are recommended when there are more than two pairs of distribution switches required. This creates a core, distribution, and access layer in the network. Multiple pairs of distribution switches are usually required for a few reasons. One can be that there is a network…

Smaller networks may have their departments spread across multiple floors within a building. These environments may not require a separate core network, so collapsing the core function into the distribution layer may help on costs in designing a suitable network. The combined distribution and core layer will provide connectivity to the WAN (remote data centres,…

When the network grows above three distribution layers in a single location, a core layer should be considered to optimise the network design. The core layer is the backbone of the network and aggregation point for multiple networks and distribution layers. It is to provide scalability, high availability and convergence to the network. The core…

The main function of the distribution layer is to aggregate access layer switches within a building. The distribution layer provides a boundary between the Layer 2 domain and the Layer 3 domain into the core network. The boundary provides two key functions. The Layer 2 side creates a boundary for Spanning Tree Protocol, limiting propagation…

The network access layer, or network edge, is where users or endpoints connect to the network. Users connect to the network through a Gigabit ethernet port or 802.11 wireless. Whilst in most cases the users will not require the full bandwidth made available to them through the network port, there is the headroom available for…

The hierarchical network design model splits the network into several modular layers There modular layer in the design model has its own area to implement their own specific functions The hierarchical network design model provides an easy to way to scale the network and keeps a consistent deployment method. Having several modular layers keeps the…