Understanding The Difference In Computer Networking Technology
Computer networks are critical infrastructure investments for all businesses, but it’s never as easy as saying: “I need a new network solution.”
It’s much more like buying a new van. How large does it need to be? How far will you need to travel? Will you need to transport people? What types of goods need to be accounted for?
And it’s very similar with your network solution.
The way you use your computers, how they interact within your local network, and how they communicate with the outside world all influence your ideal network infrastructure.
Let’s look at some basics of computer networking.
The Basics Of The OSI Model
The Open System Interconnect (OSI) model is a standardised model used around the world to categorise the different functions involved in computer and telecommunications.
Rather than define specific equipment and technology standards, the 7 OSI model layers define concepts or stages of communications data being sent.
The benefit of such categorisation is that different companies can enhance the way their technologies are able to interact.
These are the 7 OSI layers:
Layer 1: Physical Layer: Describes how data flows through physical devices like switches and routers.
Layer 2: Data Link Layer: Identifies how data transmits between connected computers.
Layer 3: Network Layer: Provides details about controlling and routing traffic on networks with many computers and connections to other networks.
Layer 4: Transport Layer: Defines how to segment and multiplex data traffic between multiple points on a network.
Layer 5: Session Layer: Concerned with continuous data exchange sessions between two points of the network.
Layer 6: Presentation Layer: Provides compression and encryption for network services and applications.
Layer 7: Application Layer: Definition of data sharing, remote access, and APIs for all points on the network.
The important thing to keep in mind is that each layer provides a service to the layer above it, which ultimately describes the way data flows through the system.
How Do Layer 2 and Layer 3 Interact?
As mentioned above, the OSI layer model indicates that layer 3 works on top of layer 2, which works on top of layer 1.
This kind of support system ensures that a data packet or frame passes along the various points of a network seamlessly.
Data packets might originate on a client computer, but they pass through cables, network switches, router hardware, and ports to get to a destination port or computer.
Each layer defines the roles in making sure that all data routing functions are in place to support seamless traffic.
Understanding Layer 2 Sublayers
It’s also important to understand that the data link layer 2 would technically be defined as 2 distinct functions.
Sub layer 1 looks at approving access for physical machines on the network based on their MAC address, commonly referred to as the machine address.
The second sublayer is the Logical Link Layer, and it looks at the specific protocols to identify errors or synchronisation issues.
However, you cannot have one without the other, as the two support each other to establish efficient communication.
Layer 3 Functions
With layer 2 focused on the MAC address, it’s important to understand that layer 3 works on the IP address level. And that’s where sub-networking comes into play.
There’s also the complexity of IP addresses being leased, which means that they can and do regularly change on each device.
All this is not possible through the simpler address resolution protocol of layer 2 and requires configuration and maintenance of IP routing tables to get the data packets to the right destination.
Which Layer Is More Efficient?
To answer this, you first have to look at what the two layers were designed to do.
In layer 2 networking, all traffic is broadcast to all devices on the network, which makes this a very fast way to communicate.
But, the more devices there are, and the more data packets they send, the more traffic there is, and that will start to slow things down.
That’s where layer 3 comes into play.
Rather than simply broadcast traffic to every device, it uses a complex process to analyse and strip data from each packet using an IP routing table to determine the subnetwork it’s destined for.
This does create a processing overhead, but it significantly reduces congestion.
Choosing Between Layer 2 Vs. Layer 3 Switches
The first thing to note is that it’s not a question of which layer is better, as they both have their advantages and disadvantages.
Choosing Ethernet switches and routing equipment for a new or upgraded telecoms system needs to factor in a few things.
What you first need to keep in mind is that the further up the layers you move, the more complex and sophisticated the equipment becomes. From that point of view, you could argue that layer 3 is better because it can handle data better on complex networks.
But what if you don’t have a complex network?
Ultimately, making the decision between a specific layer switch or more “basic” technology will need to account for your actual requirements based on the type of traffic and number of networked devices you have.
You also need to consider whether you require extensive sub networking and VLAN functionality, which would only be possible with layer 3 switching.
And finally, within each layer, there are varying degrees of complexity depending on the choice of routers and switches to solve your communication needs. So, it’s never as simple as asking what’s better or what do I need.
And then there’s the matter of cost.
Consider The Costs
Generally speaking, the further up the OSI layers you go, the more complex the technology is, and the more costly the investment, installation, and maintenance will be.
It’s entirely possible that a smaller business may gain data traffic speeds by implementing a layer 3 solution. But if those benefits come at a significantly higher business expense, then the solution may not be justifiable.
At the same time, there are businesses where avoiding data congestion is critical to success, making layer 2 solutions, possibly not an option.
