Overlay Networks Are the Answer to Slow-Moving Service Provider WANs
October 24, 2012 Leave a comment
- Network operators are competing with enterprise technology for value-added services.
- Enterprises, being more nimble, can bring up new services faster regardless of their service provider.
One day in 1994, I called my local telephone company about getting a foreign exchange line to a nearby city so that I could stop paying local long distance. I was told the install would cost $1,500 and the monthly charge was $500. I asked why it was so expensive, and the representative said that the prices covered the cost to run the line 30 miles and a monthly right-of-way rental. My next question – “Can I see the crew run the line and do I get to keep it when I am done?” – was met with silence and then a “no.” That was my first run-in with the rigid IT and archaic processes at a large telco, and it illustrates a problem IT faces today.
Talk to any WAN administrator and you will find that little has changed in the intervening years. WAN service additions and changes can take weeks or months to come online, even those that do not require physical facilities to be run. Granted, service providers support thousands of customers, and the providers have to ensure reliable service for each of them, which results in slow and careful planning for even the smallest of changes.
Luckily, there are alternatives such as standards-based and proprietary tunneling protocols that can end-run around limitations in carrier services and let enterprise administrators treat the WAN like dumb pipes. For example, network administrators can use GRE and IPSec to encapsulate Layer 2/3 protocols in a tunnel and route traffic between sites according to internal routing rules. The Location/Identification Separation Protocol (LISP), which is an IETF experimental protocol promoted by Cisco, can detach a host’s IP address from its location on the Internet by tunneling the IP traffic between two LISP-enabled routers. There are also start-ups such as ConteXtream providing overlay network products that can span data centers over the WAN or deliver content efficiently to end stations.
Network overlays solve a number of configuration and management issues, because administrators can support IT requirements without having to get a service provider involved. With enterprises pushing into public/private/hybrid cloud computing and BYOD/mobility support, the demands on WAN and LAN networking are getting more complex and service providers are challenged to keep up with the changes. IT can take control of its destiny.
Of course, there is a price. The additional overlay can make application troubleshooting difficult, because the physical and virtual networks are independent of each other. There are also technical problems such as increased packet overhead squeezing the available payload size smaller and smaller, but IT can accommodate those issues and still gain a lot of value using an overlay. If your network is not meeting your needs, examine overlays and new network protocols.