Software Defined Networks

The InternetAT&T announced last week that they are going to implement software defined networking (SDN) in their network and that over a few years they will replace other kind of telecom gear. They say that over time this is going to save them billions on hardware costs. This announcement probably is a watershed moment for the telecom industry and is going to have huge implications for the way we build our networks and the vendors we use for routers and switches.

For those who are not familiar with the term, SDN is an idea that got started at UC Berkeley in 2008 and is now starting to hit the market. Its core concept is to use generic low cost routers, switches and other network hardware and to control them with specialized and centralized software. Today the routers that operate our networks come as packages of combined hardware and software, of which software is the more expensive component. Each vendor has their own way of doing things and you will find networks that are Cisco centric or Juniper centric, and network technicians become proficient with a specific brand of equipment.

But SDN is going to change all of that. With SDN a company like AT&T will be able to buy one set of centralized software and control their devices all over the network. The equipment becomes secondary in this configuration and AT&T could mix and match different brands of equipment. The biggest obvious savings will come in that they are not having to buy the software again each time they buy a router.

But there are even bigger savings promised with SDN over time. The promise of the technology is that companies can tailor their networks on the fly by making a software change rather than swapping or upgrading hardware systems. For a company that is as decentralized and huge as AT&T this could be transformational. I am sure many of you have waited before for AT&T to make facilities available because they were in the middle of a network upgrade. AT&T says that it is not unusual today for them to take 18 months to effectuate complex network changes. With SDN they could do it on the fly, and even after taking time with testing and double checks, they will be able to effectuate major changes in weeks instead of many months. And if circumstances dictate it, such as in an emergency, they could make changes on the fly.

SDN will give a whole new set of tools to network engineers. Today traffic is forwarded using industry standards such as MPLS, BGP or OSPF. With SDN a network engineer will be able to get extremely granular with traffic. For example, they might shuttle all traffic that is experiencing jitter to a specific place in the network. Since an SDN network is programmable it is going to give them flexibility they never have had.

This announcement has to be putting fear into the large telecom vendors like Cisco, Juniper and Alcatel. These companies supply the majority of the gear to the large network providers and the companies who are pioneering SDN are much smaller start-ups. Cisco and others are already climbing onto the SDN bandwagon and developing products, but there is no doubt that SDN will hurt these vendors. The billions of dollars of savings envisioned by AT&T has to come from somewhere. Carriers will be buy cheap generic switches and routers, will be able to keep them longer and are not likely to be as loyal to specific vendors as they were in the past.

This announcement should not send you out quite yet to change your own network to SDN. The industry is still in its infancy and the cost of the master SDN software is really steep today. But like every change of this magnitude the product will eventually get cheaper and work its way down into the rest of the industry. Let’s let AT&T figure out the bugs and at some point this will become the industry norm.

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