Goosemaster, in the enterprise, expect to see an order of magnitude jump in Ethernets. 100Mb/s links -> gigabit, gigabit links -> ten gig. A fairly straightforward upgrade ratchet. What's also extremely interesting is the 10 gigE WAN PHY, which is still not widely available, but will allow 10gigE links to be built on top of SONET OC192c links. Why is that interesting? See Garion's post about WDM, and see my next paragraph. SONET metro/carrier transmission gear is wicked expensive, and getting much of the same performance out of cheaper 10gigE switching equipment will help make high speed MANs more cost effective.
Metro area networks are a boom waiting to happen. Today's access network is terrible. We have 100Mb/s, gigabit, now 10gig LANs, but most of the business world lives on T1s, DS3s, and maybe if they're lucky OC3s. Want to interconnect a few offices? Unless you have a big budget, this is a frame net or an IPsec VPN over those same slowish uplink lines. There are realities of peering and cost structures today that make it still cost prohibitive to build very very high speed full net access, but a fast (100Mb/s, gigE) closed metro network that you can attach a few offices to and also get some traffic shaped full net access out of is still a major improvement from where we are now. Unfortunately, (a) the telcos are NOT helping cheap MAN deployment as it cuts directly into where they think they make money (if telcos had cheap MAN offerrings, they'd sell more of them, though, and have happier customers... *sigh*), and (b) the CLECs who have been in this business all were in the early part of their ramp-up when the bubble burst - most of them didn't survive and those that did had to retrench and worry about staying alive rather than growing. And unfortunately, in the access/meto market, footprint rules.
Goosemaster, to more narrowly address your question, Juniper has an OC-192c POS PIC. I don't know what Juniper and Cisco have as beta products and I don't know what random start-ups are trialing, but normally looking at Juniper's top end PIC will give you a pretty good idea of what the top end WAN line speeds in use are. Note that this is slightly deceptive because carriers often are using DWDM to mux many of those on a fiber, and optical switching or just plain patching in order to create cut-through circuits to different locations. So for example, a fiber from Washington, DC to Philadelphia, PA might well carry an OC-192c link between those two points, and also carry the first hop of a Washington, DC to New York, NY OC-192c link. The router thinks they're two separate fibers because that's what will come into the router, but the backhoe will demonstrate otherwise 😉
spidey07, in practice fiber and termination quality remains a limiting factor on much of this stuff.
