What is a Network Diagram.
A network diagram (also known as a network map), is a visualization of the different elements that make up a computer network. It shows all these elements, how they are interconnected and the relationships that exist between them.
Types of Network Diagrams.
There are different ways of classifying network diagrams. Depending on how we classify them, we have different types:
- Classification based on level of detail.
- High Level Design (HLD). A high level design is usually the first document created that shows how a network looks like. It is used mainly at the early stages of a project to show what is the global idea of it, or on presentations to give an overview on how the network looks.
- Low Level Design (LLD). This is a very detailed view of the network with all the components and all the interactions between them. This diagram should include names and IPs of all network devices (routers, switches, firewalls, load balancers, ...), switching and routing protocols (STP, VRRP, OSPF, BGP, ...). These diagrams are used mainly by network engineers to have an understanding on how the network looks like in order to be able to operate and expand it.
- Classification based on "OSI layer" (even if the OSI model is not used on networks).
- Layer 2 Diagrams (physical diagrams). These diagrams show the physical devices that make up the network with the cables used to interconnect them. It can also include parts of the configuration of the devices. It should never include anything beyond what is pure layer 2 as this can lead to confusion as of how the network look like.
- Layer 3 Diagrams (logical diagrams). On these diagrams, we show how the network works from a logical point of view. On this diagram we expand the physical network into the "virtualized" view. So, here we will show existing vlans and how they are connected together, VRFs, logical interfaces, IPs and routing protocols should go into this diagram.
The topology of a network is the arrangement of the different elements that make the network. It identifies how each element is interconnected with each other and the different layers of this network.
There are different network topologies that you can use when designing your network (and drawing it with NetworkMaps).
- Ring. The network devices are connected forming a ring. This way, between any pair of switches there are two possible paths providing redundancy to the solution.
- Mesh. Each network device is connected to one or many network devices depending on the needs. This is the most flexible solution but does not provide a standard design. It is mainly used on WAN environments where the distance between network elements makes it difficult to interconnect them.
- Full Mesh. All network devices are connected to each other. This solution is the extreme point of a Mesh topology. This solution is used only on very specific parts of the network due to the complexity of the cabling needed (and the little value it adds in medium-large networks).
- Star. Network devices are connected to a central point (the core of the network). This central point can be one device or multiple devices for redundancy. This is the most used topology on datacenter networks as it can provide the required bandwidth and redundancy with the minimum number of connections between devices. It has different variations.