Mobile providers are embracing Ethernet backhaul as a way to economically meet future wireless bandwidth requirements...
despite some lingering concerns that clocking issues could degrade voice quality.
"If you [had talked] about Ethernet to service providers a few years ago, they would have kicked you out and you would have feet marks on your backside," said Ray Mota, chief strategist, Synergy Research Group. But no longer: Ethernet's potential for greatly reduced capital and operational expenditures means that carriers want to make it work.
"You're starting to get a lot of financial guys going to technical guys who despise Ethernet ... because it lacks clocking and saying, 'Figure it out!' " Mota said.
Mota recently surveyed 41 operators on their backhaul plans. Respondents told him that their primary concerns with Ethernet backhaul were that clocking and synchronization standards have not been completely standardized.
Operators unfamiliar with Ethernet are understandably concerned about changing technologies, especially if specific features haven't been completely by standards groups – in this case, the Metro Ethernet Forum, among others. Independent wireless operators have worked primarily with traditional TDM networks. But service providers with Ethernet experience have fewer carrier Ethernet concerns.
This lack of standardization for synchronization and clocking leads to less cost-effective workarounds to achieve frequency and phase synchronization across the backhaul.
"If you do some of that, it works from an architectural perspective," Mota said. "But from a cost perspective, it doesn't save you as much."
Even as those issues are being resolved, carriers are beginning to feel real pressure to provide the bandwidth that Ethernet affords them, particularly as emerging 4G technologies like WiMax and LTE loom on the horizon, threatening to demand even more throughput from backhaul networks.
"I think [Ethernet] might be the only alternative to get the bandwidth that's needed," said Glen Hunt, principal analyst with Current Analysis. "There is continued build-out of T1s, particularly with bonding, but I think Ethernet is the best [long-term] option here."
Carriers looking for packet solutions
Aside from pure cost-per-bit considerations, Hunt said, carriers are eager to move to a completely consolidated, packetized network, which would simplify their infrastructure and cut management costs while easing implementation of new services.
In the meantime, he said, there will be a staggered transition between legacy and Ethernet backhaul.
"It's an evolutionary thing, as with most telecom stuff," Hunt said. "The TDM isn't going to go away overnight, but it is going away." In many cases, Hunt and Mota agreed, carriers are pushing phone data networks -- which aren't as sensitive to clocking issues -- onto Ethernet while maintaining voice over legacy equipment.
Vendors have responded by trying to tailor their options to allow a mix of both TDM and Ethernet backhaul.
Seshadri Sathyanarayan, senior product marketing manager with Juniper, wrote in an email: "The primary issue here is in the complexity and scale of deployed mobile networks and the fact that operators are having to deploy new technologies (such as 3G and HSPA) at the same time as optimizing the cost of their existing networks."