As mobile networks have evolved over time to an all-IP architecture, Carrier Ethernet has become an important standard for data transport and interfaces.
The technology is widely used in telecom networks. TW Telecom isthe third-largest U.S. provider of Carrier Ethernet services.
Mike Rouleau, senior vice president of strategy and business development for TW Telecom, said that getting Carrier Ethernet architecture right means looking at how the service is designed and delivered, and how the solution incorporates different capacities of the electronics and the switching infrastructure.
“As we look at it, we’re looking at how does it scale? How many ports can we support? How available is the infrastructure, meaning the redundancy of certain electronics and protection for switching. How do you then make sure the service is staying up for those five-9’s (99.999%) of reliability that we always talk about in the industry?” Rouleau said.
Rouleau talked about the “highly survivable” ring topology in Carrier Ethernet architecture.
“We have redundancy built into the infrastructure, to continue to deliver services even in the event that we have an issue somewhere in the network,” he said. Another element of physical Carrier Ethernet network architecture, he said, was making sure that back-up power sources are readily available.
CARRIER ETHERNET ARCHITECTURE VS MPLS
“We feel very strongly that we’ll see more and more MPLS in the backhaul environment,” said Nir Halachmi, product line manager for TelCo Systems, which supports both Carrier Ethernet and MPLS services. “We think that today in the market, more and more operators are starting to see the value and utility of MPLS to the demarcation site.”
Halachmi said that MPLS has several advantages over Carrier Ethernet, including:
– Traffic engineering capabilities. “The service can guarantee an SLA without errors; this is a very, very important attribute in the mobile backhaul environment,” he said. “Everybody wants to optimize the network. If you have traffic management, you can get more balance and more performance out of your network.”
– Scalability, particularly in regards to being able to handle large small-cell deployments. “Everyone wants small cells. It’s a more efficient, smarter way of utilizing the air interface, but the mobile backhaul side of the small cell is a challenge.
“What we foresee is that mobile operators will start to face a lot of challenges with the exponential growth of the scale of the network,” Halachmi said.
“Customers are going both ways,” said Irit Gillath, TelCo Systems’ director of global marketing. “Some of them, Ethernet worked for them for quite some time. As you’re offering more and more services and more devices, scalability becomes a bigger issue and Ethernet doesn’t necessarily have the answer.
“It’s a good technology, but it has its limitations.”
Carrier Ethernet is limited to a “service space” of just over 4,000 because of limitations on its 12-bit headers – although, she noted, there are creative ways around that which get more complicated and difficult as the numbers increase. MPLS, however, has labels with 20 bits and those labels can be re-used because they are only locally relevant and can easily scale up to a service space of 1 million or more.
– Interoperability. “What we think is that we’ll start to see more operators moving away from the turnkey solutions or service solutions, and not be tied to using one supplier – to start opening their own negotiations on each part of the network,” Halachmi said. “In that case, they’ll look for third-party interoperability.”
He said that TelCo is well-positioned in the market because of its demonstrated interoperability to integrate its smart-edge focus with third-party network cores – the network piece that carriers are likely to be the most reluctant to replace because of the significant investment already made.
“At the end of the day in mobile backhaul, the operator’s only interest is the service,” said Halachmi. “It doesn’t care about how many boxes are there, or how many layers it has – only the point-and-click operation to configure the service, manage the service, and troubleshoot the service.”
“What we are seeing is that the mobile backhaul market will drive a lot of the wholesale opportunities,” Halachmi said. “A lot of the Tier 1 and 2 operators have figured out that it’s easier and simpler and more efficient to go into leased services based on fiber from a wholesale provider” rather than dabble with other backhaul technologies such as microwave, he said.
CONVERGING NETWORKS
“We’re coming up on LTE releases that are going to support the ability for base stations to communicate,” said Glen Hunt, principal analyst for network routing and infrastructure for Current Analysis.
Hunt said that he also expects to see more IP MPLS moving into backhaul – because network operators aren’t just building mobile networks, they’re building converged advanced networks. And MPLS offers a protocol-agnostic environment to carry multiple types of traffic with varying quality of service characteristics.
“They are not building next-generation mobile backhaul networks, or next-generation business networks, or residential networks,” Hunt said. “They’re building one network. They might not always put all the traffic on the same equipment or the same network links, but one of the things they’re looking at is going to a common set of gear that can support all kinds of services, all types of traffic.
“You don’t want to build three different networks. You want to use the same network for mobile backhaul, for business services and for residential services.”
Companies such as Juniper Networks are already recognizing this trend toward convergence. Ananth Nagarajan, senior director of product management for Juniper noted that they have named certain routers more simply as “access points” and “universal edge” products, emphasizing their ability to advance network connectivity rather than specifically recommending them for a particular type of traffic.
However, one of the great strengths of Carrier Ethernet is that it is widely utilized and widely understood, and companies are more likely to be able to rely on their own IT departments to manage their networks.
“One reason why people like Carrier Ethernet is, it’s a familiar technology,” said TW Telecom’s Rouleau. “It gives them great rates, great capacity and high availability, and rapid restoration.”
