Decoding MPLS VPN and its Advantages

Ordinarily, it seems that the public Internet, when coupled with IPsec encryption, can be effectively used for corporate WAN. Although a public Internet connection can be used to access WAN from some sites, it does not meet the capacity, uptime and performance demands of the converged applications used today. This is because such a consumer-grade connection treats all kinds of traffic in the same way irrespective of its significance and latency needs

How is MPLS Different? – Multiprotocol Label Switching (MPLS), on the other hand, is an enterprise-grade solution that sets up prioritised and highly efficient routes for business traffic.

When an organisation has an MPLS-based network, any packet entering its zone gets assigned to a particular forwarding equivalence class (FEC) that is specified by tagging on a short bit sequence to the packet. To understand the functioning of an MPLS system, you also need to know what is MPLS router.

What Is MPLS Router?

Each router in the network has a table that assists in the handling of packets with specific FECs. Whenever a packet enters the network, an MPLS router does not need to perform header analysis. The successive routers keep using the label as an index into the table that grants them a new FEC for that packet.

With this process, the MPLS-based network can consistently manage packets with particular characteristics. The packets that facilitate the flow of real-time traffic including video and voice can be easily mapped to low latency routes in an MPLS network, which is not the case with traditional routing.

Components of MPLS VPN

MPL VPNs are primarily of three types, including Layer 2 circuits, Layer 2 VPNs, and Layer 3 VPNs. Some of the components of MPLS VPNs are as follows:

• Provider edge routers or PE routers are present in the network of providers. The PE routers help in connecting the customer edge routers. The CE routers or custom edge routers are found on the customer sites. PE routers have the ability to support the functionalities of MPLS and VPN.
• Every VPN has a virtual tunnel, usually in the form of an LSP or label-switched path. A pair of PE routers is connected to this virtual tunnel so that they can connect to the customer routers.
• Provider routers are present within the core of the network of your provider. But the provider routers are not connected to any routers on the customer site. Instead, the provider routers are part of the tunnel present between two PE routers. Provider routers can support LSP functionality due to the tunnel support. However, the provider routers do not support the functionalities of the VPN.
• Customer routers are present in the form of switches at the customer’s site. CE routers are connected to the network of providers. Typically, CE routers serve as IP routers. However, the CU routers can also be Ethernet switches, Frame Relay, or Asynchronous Transfer Mode (ATM).

The PE routers perform every VPN function. The CE routers or provider routers are not responsible for performing any of the VPN functionalities.

Routing of MPLS VPN

VPNs tunnel traffic moves from one customer site to another. It uses a public network for the transition. However, some requirements need to be met for a smooth transition. The requirements are as follows:

• Standard IP forwarding deals with forwarding traffic from customer end routers to the provider end routers.
• An LSP gets established through the provider network with the help of PE routers.
• A router lookup is performed after the PE routers receive inbound traffic. The lookup provides the next hop of an LSP. As a result, traffic gets followed along the LSP.
• The inbound traffic ultimately reaches the PE routers. The outbound PE routers help in popping the MPLS label. As a result, traffic can be forwarded as a result of conventional IP routing.

MPLS Advantages and Disadvantages

The various MPLS advantages and disadvantages are discussed below:

The Key Advantages of MPLS

• Quality of Service:

  Businesses that use MPLS VPN are assured of a high QoS for their Internet connectivity, and as a result, the apps and software that are in the cloud or run on the Internet perform seamlessly. An organisation subscribing to MPLS can sign up for a certain level of QoS as per its requirements. This means that the minimum thresholds for jitter, latency and packet loss can be specified while taking the connection. This applies to different kinds of traffic – voice, video, e-mail services, transmitting of bulky files and other software applications.

• Any-to-any connectivity:

  By using an MPLS network, an organisation also benefits from any-to-any connectivity. This feature is particularly helpful for the functioning of video and voice applications with any-to-any patterns – MPLS makes it easier to connect sites, which helps in the management of such traffic patterns. MPLS connectivity enables the addition of new remote connections. No additional hardware system is required at the primary system for adding new connections. Since it’s based on cloud technology, point to point connectivity is not required.

• Outsourced routing:

  This is another reason to use the MPLS network. The service provider manages the routing of WAN for the subscriber, and the business need not put its internal team on this job. When it comes to handling the day-to-day operations and ensuring the proper working of all devices, MPLS is a better alternative than conventionally routed and managed networks.

• Service level agreement (SLA):

  There is quality assurance with all MPLS connections because they are protected by documented SLAs. These contain guarantees on service delivery. AN MPLS network is deployed within the timeline promised in the network, and the uptime also matches what has been stated in the SLA. This makes MPLS a more practical option than a vanilla broadband connection for businesses.

• Security:

  While MPLS is recommended for all businesses, an organisation in the financial industry and other domains where the security of customer accounts and data is essential mainly benefit from it. Such businesses need to have secure servers and encrypted websites for transactions. MPLS adds those extra security layers to a network.

MPLS is also preferred to connect the remote offices of an enterprise securely. MPLS circuits can maintain connections through private networks, and there are no interruptions in the connectivity between different offices of the same organisation. With the opening of new offices, more sites can be safely added to the existing WAN of the business. MPLS security benefits also help in providing the best end-to-end user experience.

Here are some other benefits of MPLS VPN:

• Web conferencing, VoIP and mission-critical apps used by a business run flawlessly on an MPLS-based network.
• It is an optimum way to connect to the cloud.
• It enables the connectivity for both IP-based and non-IP based physical security systems on WAN.
• Important apps can be prioritised on the network for better usage of bandwidth.
• When they are on MPLS VPN, businesses can reduce the number of hubs in their network, and this helps them to save upon costs of network maintenance.
• One of the major benefits of the MPLS network is scalability.
• Consistent performance is also one of the benefits of MPLS in the enterprise network.

Disadvantages of MPLS

• Security:

  MPLS security feature is an advantage and disadvantage simultaneously. The security of the MPLS system is completely dependent on the user. An MPLS-VPN service provider does not provide any inherent security features. Therefore, you will have to take the initiative to arrange for the security of your network.
  You can work with your service provider to find ways of improving the security of your network. You can reduce certain vulnerabilities and safeguard your network to some extent.

• Maintenance:

  The management of an MPLS system is done through carriers. It means that the workload present on the network is not too much. However, you still need to take care of the maintenance of your MPLS-VPN network. You will be required to put in a substantial amount of effort for the maintenance of your network.
  General maintenance work cannot be conducted directly. The maintenance of your system should be done through an ISP. Technical complexities and speed limitations of the ISP make it difficult to take care of maintenance.

• Lack of control:

  Another disadvantage of MPLS is that it does not provide you with full control. MPLS configuration has to be done by the service provider. The user can gain control of the network with the help of dynamic routing. However, any user has to work closely with their service provider to enable dynamic routing.

• Expensive:

  VPN is a cost-effective solution while MPLS is priced on the higher end. But when they work together, it can be quite heavy on your pockets. The cost is even higher because there’s limited competition in the market. The requirement of WAN optimisation for streamlining the delivery will include additional expenditure. These additional expenses on top of an already pricey solution which can lead to a hole in your wallet.

• Lack of cloud optimisation:

  MPLS is optimised for connectivity between any two points. But a lack of point-to-cloud optimisation is a drawback of this system of network connectivity. No SaaS application or cloud can be accessed with the help of the MPLS system. A handful of cloud services provide access to the MPLS network. You often need to pay a premium to get access to cloud services.

• Deployment:

  Deployment becomes an issue when the office locations have a huge distance between them. Especially when the locations are spread across different states or countries, deployment takes a lot of time. Around six to eight months might be required for the smooth functioning of each site.

Conclusion

The MPLS system has its own set of drawbacks. But the advantages will ensure that the MPLS system can be in the market for the long term. Therefore, you can use the MPLS system for implementing a new network or upgrading the existing one. But before using the MPLS solution, you need to analyse your basic requirements.

Despite being over a decade old, MPLS technology is not going anywhere, anytime soon. Please speak to a Tata Tele Business Services technology advisor to know more about the MPLS VPN and its value for your business.

How does MPLS VPN work?

When it comes to MPLS VPN, the data packet gets assigned a label as it enters the network. The first router does the labeling in the path. The labeling helps in determining where the package needs to go. It also has value and different fields to help identify the required service quality, position, and time. Based on the label assigned by the first router, the next router will forward the data packet in its path.

The second router will check the label and use it to identify the following path. It also removes the existing brand and adds a new label. The process keeps on getting repeated until the packet reaches its destination. The last router removes the label from the packet to end the cycle. As the path gets predetermined, the router will only be checking the label, and there is no need to check the IP address. It helps in faster and better routing.