10GBASE-T is now in the premium position, used primarily in data centers and on servers. It, too will eventually become mainstream, built into most new equipment, but it will need to maintain backward compatibility for many years.
40 and 100 Gbps Ethernet currently have a niche in the market, and market forces will determine which, and which standard of each, becomes the most prevalent. As they become more common, prices for 10GBASE-T will drop.
The R&D has already been done for the slower speeds, and ethernet is basically built on a chip now, so it really doesn't cost any more to offer the slower speeds since there are still legacy devices around which need the slower speeds.
The Cisco document in the link above was written a long time ago, but the first question is basically the same thing you are asking.
Review Questions
Q - Shouldn't all 10Base-T networks just be upgraded to 100 Mbps? Why
or why not?
A - Not necessarily-if the current 10Base-T network is repeater-based,
replacing the repeaters with 10/100 nonsaturating switches would
result in an automatic n times increase in the average available
bandwidth for each end station.
Q - Which 100Base version(s) are recommended? Why?
A - 100Base-TX is recommended if the horizontal wiring is Category5 or
better UTP. If the horizontal cabling is Category 3, 100BaseT4 can be
used, but it may be difficult to acquire (some reports indicate that
because 100Base-TX was available more than a year before T4, it
captured as much as 95 percent of the market). 100Base-T2 is not
available.
Q - Which 1000Base version(s) are recommended? Where would they be
used?
A - 1000Base-T, is recommended if the horizontal cabling is Category 5
or better UTP. 1000Base-SX can be used if the horizontal cabling is
multimode optical fiber, as well as for some multimode backbones.
1000Base-LX can be used for either single-mode or multimode optical
fiber (see Table 7-5). 1000Base-CX can be used for short-haul
equipment-room jumpers up to 25 meters.
Q - What cable types should be used for new networks? For upgrading
existing networks? Why?
A - New or replacement UTP links may be Category 5E or better to allow
for data rate growth to 1000 Mbps. Multimode fiber may be used as
indicated in Table 7-5 for 1000Base-SX, or as noted in the paragraph
following Table 7-5 for 1000Base-LX. (These fibers will also provide
future support for shorter distances [between 100 and 300 meters,
depending on the wavelength] at 10,000 Mbps.) To be truly future-proof
and to ensure that you will be able to operate longer-distance
backbones, choose single-mode fiber.
Q - How do you know when a network needs to be upgraded? Where do you
start?
A - There are several ways:
- Your users will tell you (but often only after they have crossed the frustration threshold).
- Your network management system should be capable of indicating the load characteristics for each DCE port.
- Your organization is considering adding new applications (such as multimedia) that will require more communication bandwidth.
- Your organization is growing, and there are not sufficient DCE ports in the right locations to accommodate the additional users.
After you have determined the need, you can consider the options.
Remember that the network elements with the longest useful life (the
link media, followed by the network servers and network switches) can
also be the most expensive to replace. Choose with an eye to future
growth, and consider reusing these elements wherever possible.
