Friday, July 03, 2009

Ethernet Over Copper .... Pros And Cons

The only PROs for Ethernet Over Copper (EOC) is definite immediate cost savings and maybe rapid implementation with the CONs being upgrade limitations, susceptibility to external influences (aging copper line plant and distance from the CO) and the interference.

For core/backbone links I think fiber is a must in most cases as it gives you the ability to easily scale up for increased bandwidths and different technologies, (MPLS, CWDM etc) over the same fiber. The distance limitations are at least 100 times that of EOC in most cases (dependent on interconnecting technology) The only CON here is the cost of implementation but the ROI over the years to come would be so worth it.

EOC does have its place as last mile to the users, from the wiring closet to the servers, workstations etc where distance is far less of an issue and in most cases interference sources can be limited by proper cabling SOPs.

I have had the chance to see it from the Service Provider perspective and there is hardly ever an issue with a fibre connection apart from hardware failure on the interconnecting devices and even that is rare.

So the maintenance cost with the fiber is normally small to non-existent whereas for EOC expect routine maintenance to ensure QoS or even basic service in some situations.

No doubt copper technology is cost effective as compared to Fibre Optics in short distance. But considering the long distance, Fibre Optics is the best solution in terms of maintenance and several losses occurring in the electrical medium.

Copper wires are very susceptible to several interferences. One that is the worst case is the EMP effects on electrical medium such as copper wires. With a burst of electromagnetic radiation from an explosion or a suddenly fluctuating magnetic field .... the resulting electric and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges. This results in likely damages to electronics equipment and electrical infrastructure.

So, especially the most critical applications or any mission critical departments should consider these effects. Care should be taken while designing the network of an organization. This must include your electical wires also which comes outside to your organization. To eliminate the EMP effects in electrical wires, one should use EMP filters depending upon the capacity to isolate your standby equipment.

Let me throw out some of the more esoteric differences.

* Copper interfaces and modules are more prevalent and possibly cheaper.

* Copper interfaces usually come at the cost of higher oversubscription rates for the ASICs compared to fiber primarily due to port densities on the modules or cards.

* Physical separation between the copper plant and fiber plant is often desired to differentiate between client/server and network infrastructure traffic. Often separate raceways are (or should be) employed.

* Higher bandwidth technologies come available over fiber before copper catches up.

In addition to being dramatically cheaper (multimode fiber can double the cost of a workstation), copper is the only realistic means to implement power over ethernet, which can also realize savings in a number of ways.

Fiber is great for backbones if it is cost effective. Ultimately if the business need for fiber exceeds the cost then go with fiber. The same applies to freespace, though the costs with freespace are more administrative than equipment.

I would default to 10/100/1000 copper and answer questions about bandwidth, EM interference, and user motility with fiber and RF as the cases arise. A good example of needing fiber is in applications where cables pass by machinery, like in a CAD/CAM/JIT shop. Jobs come in and are passed into the hopper which is on a machine next to a big lathe. Also in energy production you are going to want fiber passing withing a certain distance of turbines.

A solid foundational understanding of engineering principles won't steer you wrong. And to the question of distance with copper you can always install low power ARM microservers configured as routers and repeaters that are powered by the ethernet cables themselves.

Basically, it all depends on the size of the budget. Particularly in the sense of local area networking .... where the choices are wireless or wired.

Fiber is the ideal choice if your budget can support it due to the low cost to expand bandwidth in the future. With glass, you pay up front for future expansion.

Now, let's focus on WiFi/WiMax v. EOC.

1. Do you have a competant staff who can support access points, intrusion detection and mitigation, and wireless security in general?

2. Do you have an existing EOC infrastructure? How old, how capable?

3. Multi-building campus? Hybrid technologies are best here. A combination of glass, copper and wireless.

In summary, the answer is "It depends."

If I had an existing plant, with patch panels and switches, I'd keep them running as long as possible. Not every PC needs Gigabit Ethernet access.

I would, however, run redundant fiber rings connecting every closet and the data centers.

For assistance navigating all the decisions to reach the best solution for your network .... I suggest the free help available via Bandwidth Solution

Labels: , , ,

1 Comments:

Anonymous Anonymous said...

Good information. Lucky me I found your blog by chance (stumble
upon). I've bookmarked it for later!

my weblog ... Ethernet over Copper ()

5:26 AM  

Post a Comment

Links to this post:

Create a Link

<< Home