What is MPLS

MPLS stands for "Multiprotocol Label Switching". In an MPLS network, incoming packets are assigned a "label" by a "label edge router (LER)". Packets are forwarded along a "label switch path (LSP)" where each "label switch router (LSR)" makes forwarding decisions based solely on the contents of the label. At each hop, the LSR strips off the existing label and applies a new label which tells the next hop how to forward the packet.

What problems does MPLS solve?
The initial goal of label based switching was to bring the speed of Layer 2 switching to Layer 3. Label based switching methods allow routers to make forwarding decisions based on the contents of a simple label, rather than by performing a complex route lookup based on destination IP address. This initial justification for technologies such as MPLS is no longer perceived as the main benefit, since Layer 3 switches (ASIC-based routers) are able to perform route lookups at sufficient speeds to support most interface types.

Advantages of MPLS.
Traffic Engineering - the ability to set the path traffic will take through the network, and the ability to set performance characteristics for a class of traffic.
VPNs - using MPLS, service providers can create IP tunnels throughout their network, without the need for encryption or end-user applications.
Layer 2 Transport - New standards being defined by the IETF's PWE3 and PPVPN working groups allow service providers to carry Layer 2 services including Ethernet, Frame Relay and ATM over an IP/MPLS core.
Elimination of Multiple Layers - Typically most carrier networks employ an overlay model where SONET/SDH is deployed at Layer 1, ATM is used at Layer 2 and IP is used at Layer 3. Using MPLS, carriers can migrate many of the functions of the SONET/SDH and ATM control plane to Layer 3, thereby simplifying network management and network complexity. Eventually, carrier networks may be able to migrate away from SONET/SDH and ATM all-together, which means elimination of ATM's inherent "cell-tax" in carrying IP traffic.

Difference between Cat 5e and Cat 6

This is one of the most common questions we're asked. There are two major differences:
•Signal to noise ratio
•Bandwidth used to test the cable
The first difference is the most important. Cat 6 Cat 6 is twelve times less "noisy", than Cat 5e. When your computer sends data across your network some data packets are lost or corrupted along the way. These packets have to be resent by the system. The better the signal to noise ratio is on your network, the less often this happens.
As computer networks become faster, the signal to noise ratio becomes more important. If the network is racking up packets that must be resent faster than it can resend them, the network may eventually fail or slow to a crawl with the backlog. Using cable and components that have better signal to noise ratios, such as those rated to Cat 6, can help to prevent this potential problem.
As for the testing bandwidth, the official Cat 5e standard calls for testing across a bandwidth of 100 MHz. The Cat 6 standard calls for testing across a bandwidth of 250 MHz. The reality is that most computers and networking equipment only transmit across a frequency range of 100 MHz. (In the future, of course, actual utilization of greater bandwidth may become more common.)
When it comes down to it, however, this particular stat isn't all that important. Many cable companies tout the high bandwidth of their cable. Some even test up to as high as 700 MHz. It sounds great for marketing, but the truth is that the MHz rating is not the same as speed. All cable rated Cat 5e or Cat 6 is capable of Gigabit Ethernet. The MHz rating is just the frequency range used for testing the cable.

Best coax cable type for television

First figure out what you're installing it for. If you're putting it in to run regular cable television (CATV) or master antenna television (MATV), you don't need coax with special sweep-testing. The signals from these types of inputs are very strong. If you're planning on using satellite television (SATV), however, you'll want to make sure that you use coax that has been sweep-tested to 3GHz as recommended by most satellite service providers.
In any of these cases, you want to use RG-6.
Then it comes down to the shielding. Coaxial cable has two types of shielding: a foil and a braid. A 40% braid is a loose braid and is the most economical. It is generally used in places like motels where getting perfect reception isn't terribly important because people will only be there for a night or two. A 60% braid is the standard braid for RG-6. Most professional installers use RG-6 with a 60% braid. Quadshield coaxial cable has two foils and two braids. RG-6 Quadshield is the premium choice for RG-6 and is used by most people who have the chance to choose the cable for their own systems.

The type of conductor in your coaxial cable will also be important. The two conductors you will find in coax are copper clad steel (CCS) or solid copper core (SCC). Copper clad steel will be suitable for most installations, but if you want the best signal possible, then you should look to purchase a cable that has a solid copper conductor. The stronger signal produced by a solid copper conductor is ideal when you are using a satellite signal or you are looking for the best signal for your HDTV. The copper clad steel conductor will work for both satellite and HDTV, but to make sure your signal is as strong as it could be, then use the solid copper conductor.

Another thing to look for is UL listing or ETL verification. This independent testing ensures that cable actually is what the seller or manufacturer claims that it is. There is a lot of bargain coax out there without any sort of independent testing mark, so you'll want to specifically ask about this before making a purchase.

VSAT

VSAT (Very Small Aperture Terminal) is a satellite communications system that serves home and business users. A VSAT end user needs a box that interfaces between the user's computer and an outside antenna with a transceiver. The tranceiver receives or sends a signal to a satellite transponder in the sky. The satellite sends and receives signals from an earth station computer that acts as a hub for the system. Each end user is interconnected with the hub station via the satellite in a star topology. For one end user to communicate with another, each transmission has to first go to the hub station which retransmits it via the satellite to the other end user's VSAT. VSAT handles data, voice, and video signals.
VSAT is used both by home users who sign up with a large service such as DirecPC and by private companies that operate or lease their own VSAT systems. VSAT offers a number of advantages over terrestrial alternatives. For private applications, companies can have total control of their own communication system without dependence on other companies. Business and home users also get higher speed reception than if using ordinary telephone service or ISDN.