Moore's Law is not going to solve the problem of increasing bandwidth consumption, according to Jim Theodoras, ADVA (News - Alert) Optical director of technical marketing. Simply put, most of the cost of increased network throughput is not caused by the prices of underlying silicon.

 

Another way of putting matters is that shaving 10 percent off the cost of a box no longer will save enough money on the whole end-to-end network. As bandwidth demand continues to climb and revenue-per-bit continues to fall, network operators will need to look elsewhere for efficiencies.

 

The cost drivers lie in bigger problems such as network architecture, routing, backhaul, routing protocols and personnel costs, he says. As one example, Theodoras said that there often is redundant equipment in the network.

 

Core IP routers used to run at 10-percent utilization, plus a redundant hot standby, so overall utilization of those resources was five percent, he said. Now, with better optimization processes, networks do not require a one-for-one ratio of active to hot standby routers. 

 

Network architectures also are being examined and changed. Verizon (News - Alert) is looking at ways to bypass routers in its networks except when local traffic has to be dropped. The problem is that, as traffic volume grows, and changes, the "protocols can't keep up, even if you have unlimited numbers of routers," Theodoras said.

 

The original network architectures worked fine for lower traffic volumes, but as they scale, that breaks down. "So router bypass is needed," Theodoras said. "Verizon has been talking about a different architecture, where ATM and SDH traffic is segregated," for example, he says.

 

Every core router should not have to process all traffic. Instead, traffic should bypass routers whenever possible. "There are too many packet aggregation layers today," Theodoras said. "You want to get to core routers as fast as possible from the network edges.”

 

"Just backhaul and make decisions later" is the principle, he said.

 

That approach also works better these days than it did years ago, when network traffic patterns were different. In "the old days" most traffic was to and from enterprise data centers. Then traffic shifted a bit as more end user to end user traffic was added.

 

These days, video and content tend to dominate, so traffic is now "server to person." Networks with a high degree of flatness, using lots of long backhaul links, work better than they might have in the past.

 

The big impact on networks is that less aggregation is needed close to the network edges. Operations improvements also help.

 

“One of the trends with carriers is the desire to do more in the network operations center and less with truck rolls, Theodoras  said. “Another trend is to need and use lower cost labor with lower training requirements for network installation, setup, and maintenance.”

 

Both trends will allow carriers to squeeze more profit out of their services. What a network organization wants is the ability to use lesser-trained people to manage a network from a NOC (News - Alert), even when those people have no specific optical communication training or skills. The management software tool should automatically discover the whole network, create a map of the network and then use simple wizards to walk NOC personnel through the process of setting up a desired service.

 

“What level of expertise do you need, and when?” Theodoras asked.

 

Even routing protocols, and methods for assigning quality of service tags, are changing as traffic changes. Routers were not initially designed to handle video, and “video broke them,” Theodoras said. QOS marking was added, as well as various session protocols, and the problem was solved, at least for a while.

 

But video traffic is morphing again. It is no longer scheduled or on-demand content. Now networks have to handle high-definition video streaming from multiple sources to diverse destinations. That is a different sort of problem.

 

ADVA says hierarchical QOS scheduling and low-latency gear, are the solutions for those different video demands.  ADVA incorporates HQOS in all its products, and has the lowest latency transport gear, Theodoras said. Round-robin scheduling used to work for video, but will not work so well in the future.

 

With hierarchical routing, bandwidth demand goes down by a factor of 10, even when the number and capacity of the core routers remains the same, he said.

 

Bandwidth demand continues to climb, and revenue per bit continues to drop, considerations such as these increasingly will determine whether network providers can keep revenue and cost in some workable relationship.