For the longest time businesses, small and large, insisted that WAN service be delivered exclusively on a MPLS network. Consumer grade Internet was not perceived as reliable, secure or fast enough to support the operational demands of commercial entities. These days, however, more enterprises are having trouble saying no to business-class or even consumer-grade Internet services, which offer more bandwidth than traditional WAN services at a fraction of the cost and with faster provisioning.
Let’s have a look at some of the advantages and disadvantages of IP VPN over Internet advantages over private line MPLS circuits:
This is probably the major incentive for most IT managers (and their CFO’s) to consider an Internet based Wide Area network. ISP’s provide a simple, ubiquitous network access. The price for internet connectivity is considerably cheaper than almost any WAN MPLS service, making it extremely attractive for companies seeking to cut telecom costs.
The IT group manages the VPN tunnel created between sites. They are able to implement rapid network configuration changes to address any network problems requirement changes. With full access to the terminating equipment like routers and firewalls, corporate technical managers have visibility to the network conditions and can implement changes and fixes provided of course if the have the internal skill and resources.
For critical applications alternative network routing, on another internet circuit is possible in the event of failures or problems on the primary connection. This redundancy restoral time can be configured internally ad is not reliant on the service provider restoration times.
When configuring the VPN, engineers can also configure remote VPN access for users traveling around the country or world, a feature most companies would have to pay additional money for to receive from their service providers.
Perhaps one powerful advantage but one not always appreciated is the ability to add new features and capabilities as they are introduced by hardware vendors and not be restricted to the timelines and cost imposed by the service provider.
Given all of the above advantages, including cost, what are the negatives associated with a full migration to VPN over IP?
Here are some of the potential disadvantages of Internet IP VPNs over most WAN MPLS network architectures:
Higher Packet Loss and Latency
The basic premise of the Internet is a network of networks. By definition then the path that data may take is not guaranteed and is , in most cases going, to be longer with a resultant increase in latency (the further data travels the longer it will take to get there). Similarly the data path may have an increased likelihood of congestion points that create increased packet loss. Increased latency and packet loss will result in a reduction in the quality of experience, longer time required to transfer large files and problems in data backup and synchronization. Again there are some powerful solutions that can mitigate the problems of Packet Loss and Latency.
In IP VPN over the Internet you are delivering your data over an open network. This means that the security of your data is your responsibility. You and your organization must be aware of the inherent dangers and ensure data is encrypted to the appropriate levels and your network equipment is protected. This is not a topic to be taken lightly, as the damage can be devastating. It was always assumed that a private (MPLS) network was considered more secure and while that may be true to a degree recent examples underline that regardless of the network your data is potentially vulnerable.
Quality of Service
The goal of QoS is to provide guarantees on the ability of a network to deliver predictable results. Elements of network performance within the scope of QoS can include uptime, throughput, delay, and error rate. In order to deliver a guaranteed QoS you need control the network end to end. In the IP VPN over Internet model, QoS is only managed in the LAN. From there on, packets enter the ISP’s network. Everything in the Internet is based on a “best effort” delivery mechanism. Any QoS tagged packets are, in most cases, ignored by the ISP.
Class of Service Prioritization
Class of Service (CoS) is a way of managing traffic in a network by grouping like types of traffic (for example, e-mail, streaming video, voice, large document file transfer) together and treating each type as a class with its own level of service priority. Unfortunately in the Internet world segregation of service types and assigning priorities is not possible. There are some technologies that provide Class of Service capabilities by utilizing multiple paths.
Real Time Applications
Delivery of real-time applications like voice and live video streaming are very demanding. The delivery network needs to have low latency and packet loss in order to deliver an acceptable quality experience. Pixilation, clipped audio and frozen applications are all symptoms of latency and packet loss. Again applications that offset these network issues can improve the application delivery.
The bottom line is that IT decision makers must weigh the pros and cons and perform a true business case analysis in deciding the best path to deliver WAN connectivity. What is clear is that with today’s business class internet service and tools that address the latency and packet loss issues a strong case can be made for considering IP VPN over the Internet as a viable business choice!