How does metro Ethernets differ from traditional carrier data services?
The alternatives are private line, which is a synchronous optical network (SONET) based architecture that is basically circuit switched, and frame relay, which is a packet technology. But frame relay is a non-broadcast technology which means that if we have just connectivity we have to fully mesh the various nodes on the network in order for all of them to speak to each other. Then we have Ethernet, which is packet based, but is broadcast capable. What obstacles does metro Ethernet need to overcome?
The work that we have to do at the moment is to make a bus-type LAN technology fit into a ring based metro architecture. Ethernet does not allow loops. That's a no-no. We have the spanning tree protocol, which keeps the packet from being caught in a loop, so when you put that in a ring it's a real problem. We also have some distance issues. There's usually a time-to-live packet that tells Ethernet whether or not it reached its destination. As we extend the reach we're going to have to figure out ways to stay within that time-to-live packet or we extend it. We also need to improve the security aspects. We also need to improve the performance monitoring and management capabilities. Where did metro Ethernet get its start?
It began from the success that Ethernet had in the local area network (LAN) environment. It is a very simple technology when compared to some of the other alternatives. It's well understood. How many cities have metro Ethernets?
It's extremely popular. It's not extremely available. That is due to fiber availability for the most part. The second part is, service providers are still working out some of the issues that we have with metro Ethernet. They're waiting for some of the standards to be in place like resilient packet ring (RPR). I think that the second wave (of metro Ethernet service providers) has learned from the first early adopters. They learned that it was a viable technology, that the end-user was interested in it. So they are cautiously rolling out the services. What does it take to set up a metro Ethernet? Are there any ongoing projects?
In the most basic level you would need pretty much the same as you would need for any service. You would need the fiber availability. You would need a customer premise device. The preference there would be a switch -- but today it's probably a router with a switch behind it. At the local serving office you would need an aggregation device like a next generation SONET box. What is the "last mile" problem?
No fiber, or substandard fiber, and trenching is very expensive. Depending on location it could be as low as $40 a foot or as high as $100 a foot. That makes the business case a little more difficult for the carrier. In a lot of places -- I've heard Baltimore is one of them, D.C is another and places in New York where there is a moratorium -- you can't lay new fiber. That's where the utilities and municipalities have an edge; they're taking the lead because they already own those rights of way. One of the cheapest, cleanest ways to deliver metro Ethernet is from some of the new emerging coarse wave division multiplexing (CWDM) platforms. Coarse wave relieves that fiber exhaust, relieves the security issues. It's payload and protocol agnostic so you can also offer whatever other services that system will support. If I were a network manager what could metro Ethernet do for me?
It would bring you technology that you're used to. It's a simple hand off. It would also eliminate some of the nasty encapsulation schemes that we have like packet over SONET. It provides some thing that is comfortable, familiar and at a much lower price. What are the emerging trends in metro Ethernet?
What we're finding is that overseas service providers are adopting this technology much quicker, for many reasons, but primarily because a lot of their activities are subsidized by the government, or because of recent de-privatization deregulation. I think that cable operators are also in a perfect position to take advantage of this technology. They have a lot of fiber already out there in their hybrid fiber coax deployments. They have a tendency to be moving towards pure fiber. As they go forward they will be laying just fiber. I also think that the standards development will bring down the cost of components and subsystems, which will bring down the cost of the service and that will lead to a widespread adoption.
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The verticals that are taking advantage of it now are pretty clear: the financial community, very large enterprises, large insurance companies and companies with large campuses. Medical to some extent, but it's not doctor's offices it's more bio technical research, and universities. The municipalities themselves, a lot of cities are banding together with their research organizations, with their K-12, with their universities, and they jointly lay the fiber, jointly own the fiber and each entity gets a strand or two out conduit for instance. That's a real win-win situation if they can wade through the politics.