Computer hardware information

There are hundreds of internet based timing sources that allow computers running NTP to synchronise to a UTC time - however, there are several drawbacks in relying on the Internet for a timing reference:

Security is paramount for most computer networks and NTP, one of the Internet’s oldest protocols, is equipped with its own security measures in the form of authentication. Authentication verifies that each timestamp has come from the intended time reference by analysing a set of agreed encryption keys that are sent along with the timing information.

Unfortunately, internet time sources can not be authenticated and Microsoft, Novell and others “strongly recommend” that internet sources are not used for a timing reference as it could leave a network vulnerable and open to malicious hackers, viruses or even a DDoS attack (Distributed Denial of Service - where a server is inundated with traffic rendering it useless).

Also a survey by MIT (Massachusetts Institute of Technology) of over 900 internet time references, discovered nearly half were offset by over ten seconds (one by a staggering six years - but there were fortunately not many peers) and less that a third where described as being at all “useful”.

The report also discovered that many internet time reference hosts were too far away from their peers to allow any accurate time synchronisation to take place.
Fortunately a dedicated NTP network time server can receive other sources of UTC time which do offer complete security, authentication and are far more accurate and reliable.

The first is the national time and frequency broadcasts transmitted by several countries. In the US the signal is referred to as WWVB and is broadcast by NIST (National Institute for Standards and Technology) in Colorado. In the UK the National Physical Laboratory (NPL) broadcasts the MSF signal from Cumbria and similar systems are broadcast in Germany (DCF-77), Japan (JJY) and France (TDF).

Another, equally accurate and secure method is to use the timing signals broadcast by the American GPS (Global Positioning System).

The GPS is currently the world’s only Global Navigation Satellite System, although Europe’s Galileo and the Russian GLONASS system are expected to be up and running over the next five years.

It is a consequence of needing accurate timing information to be able to pin-point positioning that GPS satellites all contain an atomic clocks and the signal that is broadcast can be received and used by a network time server.

KVM (Keyboard, Video, Mouse) is a piece of hardware that allows users to control multiple computers from one keyboard, video monitor and mouse. The signal is controlled by a switch on the hardware that allows you to go back and forth between the computers you want to control. KVM devices come in two forms. One is a local remote device which allows you to control your computer equipment up to 1000 feet away. The other is KVM over IP. This is the type of remote KVM that is used in colocation facilities.

Remote KVM over IP uses a dedicated microcontroller and video capture to get keyboard, video and mouse signals. The signals are then compressed into packets and sent over the Ethernet to the remote location where they are then decompressed and converted back into a graphic image or keyboard or mouse command.

There are many practical ways which you can use remote KVM when your servers are at a colocation facility. First of all, KVM over IP gives you a convenient way to access your servers without having to come down the facility. You can perform the tasks that normally would require you to come down from the comfort of your own home or office. Many colocation providers who have remote KVM support Internet Explorer, Mozilla Firefox and Netscape browsers on Windows, Linux, Unix and OS X platforms.

Some of the major benefits of using KVM or IP are that you can perform remote installation of new or upgraded operating systems just as if you were right there in the room, standing in front of your server. You can also troubleshoot on the server that has lost its network connection. Additionally, should you need more assistance, you can collaborate with the onsite technicians to help solve the problem.

Remote KVM is a cost-effective solution for solving problems with your server and also for performing routine upgrades and installations. Instead of having to drive all the way down to your colocation provider (which isn’t always possible if your colocation facility is located across the country or in a different country entirely), you have the ability to configure your server without having to physically attach a mouse, keyboard and monitor to the machine. And you don’t have to pay a technician at the site to do it for you either.

KVM over IP puts the control of your server back in your hands. Not only do you not have to rely on someone else to do the work for you, but it also allows you to save time and money by working directly from your home or office.

Today’s networks usually employ UTP (unshielded twisted pair) cable. It resembles, but should never be confused with, telephone cable. The tight twist of each pair is tightly spec’d and is what gives it noise immunity. For most data networks, Category 5e or 6 rated UTP cable is used. My recommendation is that in new construction, all communication cable, whether intended for data or voice, should be at least Category 5e UTP. The cable that’s permanently installed in walls, ceilings, and floors should be solid (not stranded) conductor.

In special cases, STP (shielded twisted pair) may be needed. In high electrical noise environments, or for vertical runs in tall buildings, or between buildings, fiberoptic cable makes sense. Today, short runs of fiberoptic cable consist of low-cost plastic (not glass) fibers with low cost light sources, in multi-mode. (The light beam is allowed to bounce around within the fiber; it’s lossy, but who cares, over distances less than a thousand feet?) Using fiber, rather than copper, between buildings eliminates electrical hazards caused by lightning strikes and earth differential voltages between buildings.

Plenum rated cable

Regardless of whether you run UTP, STP, or fiberoptic cable in your building, the new cable must conform to local building and fire codes. This often means that if the cable runs within the space above false ceilings, its jacket must be plenum rated. In many — but not all — buildings, the space above the false ceilings is used to carry return air back to an air handler. In these cases, plenum rated cable must be used. If your building has separate air return ducts, you may not need to use plenum rated cable; check with your local building code enforcement authority before buying cable.

Structured Cabling

The correct way to cable a building is to install outlet boxes with quad RJ-45 wallplates in each office. Pull all the cables from all offices on each floor back to a central wire closet. (These are called “home runs”.) Number all cables consecutively with several number tags on each cable — especially their ends.

The closet should contain a 19 inch wide open relay rack with Category 5 or better RJ-45 connector panels. While connectorizing the cables, label each connector with its cable number.

Within the rack we’ll mount switches and / or routers as needed. The telephone PBX should be mounted in the closet or co-located with the file servers. We’ll use short stranded wire Category 5 or better patch cables between the connector panels and switches and telephone PBX as needed.

At each quad category 5 RJ45 wallplate, label each RJ45 connector with its cable number.

The result is that in each office, any of the four RJ-45 connectors can carry anything from the wire closet: inside phone, outside phone, Internet, local area network, data terminal traffic, etcetera. At any time, any of the RJ-45 connectors can be reconfigured just by moving patch cables inside the wire closet.

Within each office, just use a short flexible Category 5e patch cable to connect the computer, telephone, etcetera to the appropriate RJ-45 connector in the wallplate.

In practice, many offices will need two or even more quad wallplates, to allow easy movement of furniture in the future. It’s a pleasure to work within a building with structured cabling, because people, computers, phones, and furniture may be moved where needed.

If your budget is tight, dual or triple (instead of quad) RJ-45 wallplates may be substituted, if some loss of flexibility is acceptable.

Cable plant certification

Serious cable contractors will certify cable plant to Category 5 or higher standards. They use specialized test sets to perform the certification, which often can produce printed output or talk to a PC. I recommend having your cable plant certified, for two reasons:

Conclusion

Pay careful attention to your cable plant: it’s the foundation of your information system. Its cables carry your enterprise’s lifeblood.