What is MPLS? A Simple Explanation

What is MPLS?

MPLS stands for ‘multiprotocol label switching’; it’s a technique that can be used to ensure you’re making the most of your available bandwidth, and not ‘wasting’ bandwidth on unnecessary tasks. There’s a lot of technical and in-depth information around detailing what it is and how it works, but right now let’s strip everything back to basics and take a look at the simplest MPLS explanation.

You drive up to the car park of a large shopping centre you’ve never visited before. There are not only multiple entrances, but there’s also many different ways to get from where you are now to the shop that you want to go to. At each fork in the path that you come to, you need to check the signs and make a decision about which way to go in order to get to your destination in the quickest way.

Data does the same on an IP network. Data has a known final destination but it has no known route. Instead, it does what we would do in an unknown shopping centre; it reads the signs at every fork it comes to.

This slows the data down, meaning that you’re not getting the most from your available bandwidth. This is where MPLS can help; it essentially acts as a built-in map for data, reading the types of traffic, and directing using label switched paths lsps.

Why is MPLS used?

Multiprotocol Label Switching is a protocol routing technique used to transfer packets of data. MPLS Networks add labels to data when it passes through, the labels can also be changed or taken away completely. The labels are there to make sure the data goes where it needs to.

This technique makes sure that digital packets reach their destination as quickly and efficiently as possible. MPLS labeled Data was created in the ’90s to allow for more efficient data transfer & traffic flows compared to the traditional IP routing.

We use MPLS for various reason such as:

• Reduced Congestion– When data’s transferred the MPLS network will figure out the best and less congested path to take. It has an intricate Traffic Engineering Option that allows traffic to pass through non-standard paths. This reduces latency which allows for faster more effective data transfer. This is one of the key benefits of Mpls.
• Bandwidth Prioritisation– Higher priority data can borrow capacity from lower priority data. This allows the most important data to get to its destination quickly with ease.
• Better Uptime– Data’s sent extremely quickly over the best and most suitable paths using various protocols which can include frame relay, layer 2.5 & OSI model.
• User Experience– You can prioritise high priority data such as VoIP. MPLS lets you configure your settings to set which type of traffic needs to be prioritised.
• Scalability– With multiprotocol label switching(mpls) you can do the automatic configuration of your network to set up more tunnels or label-switching paths to allow more traffic. You can use it with virtual private networks too which can aid security on your network.

How does it work?

MPLS changes a routed network to something like a switched network. It’s a lot faster compared to the traditional Internet Protocol (IP) routing, hence the popularity. Instead of forwarding data packets on a hop-by-hop basis the data paths are founded for source-destination pairs. The paths that are created in MPLS are called label-switched paths (LSP).

It works by having an Ingress route at the beginning of a label-switched path, each LSP can only have one ingress router. IP packets are masked with an MPLS Network Layer 2 frame by the Ingress router (label switch router), that IP packet is then sent to the next router in the path using a mode ATM.

Next the IP packet enters the transit router, this router passed the IP packet to the last stage in the path. Each LSP can have anything from zero to 253 transit router in an LSP.

Finally, the IP packet is sent to the Egress router. The Egress router removes the MPLS Layer 2 mask to turn it back to a standard IP packet.

This packet is then forward to its destination IP address using details in the IP forwarding routing table. Once the packet reaches its destination the relevant parties can see it. There is one Egress router in an LSP, the Ingress router is a popular choice.

What is the difference between WAN & MPLS?

WAN and MPLS are two completely different things, MPLS is a protocol you use on a network. WAN stands for Wide area network, it’s just a way of letting your sites communicate.

There’re many ways of connecting your sites, one of the main ways in via a Point to Point Leased Line. MPLS is a protocol that controls the routing of data to allow for the quickest and efficient data transfers.

An MPLS can be used in conjunction with a WAN. An MPLS WAN (Network Protocols) is used to connect multiple offices all around the world. When WAN and MPLS are utilised together it allows efficient data transmission to all your sites. Scalability is also another factor, you can deploy MPLS WAN to over 1000 sites if needed, brilliant for global businesses.

MPLS WAN allows businesses to give control of routing to the service provider they are with. This subsequently means less WAN engineers needED within your business, saving money. It also allows you to effortlessly transfer any type of data. This WAN connectivity is considered one of the best compare to Ethernet WAN etc.

Will SD WAN replace MPLS?

It is undecided if SD WAN will replace MPLS. SD-WAN is an overlay service whereas MPLS is an underlay service. So, to compare them is slightly unfair as they are completely different services.

Having said that, both technologies have their own set of pros and cons, after listing them you can decide which service is best for you.

SD WAN Pros:

• Price– SD WAN is cheaper compare to MPLS. Again, this is due to them being different technologies.
• Geographic Boundaries– There are no boundaries with SD WAN. It can be deployed anywhere in the world.
• Scalability– It is easily scalable as it a virtual network.
• No Bandwidth Penalties– You can easily upgrade/add links with no charge.
• Cost-Effectiveness– Because you can mix and match different network links, such as 4G and broadband etc.

SD WAN Cons:

• DIY– SD WAN is managed and deployed by your IT team, meaning you may have to employ WAN specialists which could increase your outgoings.
• Security– SD WAN provides an advantage when accessing cloud-based applications, I.e. encrypted data, but they don’t provide any on-site security functionality.

MPLS Pros:

• QoS (Quality of Service)– It has no packet loss, with fixed latency and little to no jitters.
• Reliable– It has served for years making directed routes from one router to another, successfully transferring data.
• Priority Changing– Higher priority traffic is given more bandwidth, which makes important traffic get to if destination more efficiently. Some data is put to the bottom of the stack in terms of priority. This also is handy for real-time applications such as VoIP.

MPLS Cons:

• Price– MPLS can be quite pricy.
• Bandwidth Penalties– You do not have unlimited bandwidth, the cost per megabit can be high. So, if you’re send data-heavy content then that might increase the price.
• Security– MPLS does not come with build in security. If the security isn’t rightly implemented this could lead to network vulnerabilities.

Reference: Leased Line Comparision and Wikipedia