Tuesday, April 15, 2008

WAN Transparency Via Ethernet

The ideal network is one that users aren't aware of. They don't sit and ponder what type of LAN it is or how fast the backbone is running. It's like electricity. You plug in and then forget about it. It's just there as a service with all the capability you can use. That's transparency.

Many local area networks have started to meet this definition. With nearly every NIC able to support at least Fast Ethernet at 100 Mbps and many supporting Gigabit Ethernet, company LANs are able to support business applications transparently. The real network speed bump is hit when you exit the LAN on your way to the Internet or another company facility. Wide Area Networks or WANs tend to be anything but transparent.

There are two things that make WANs a pain to deal with. First is the disconnect between LAN and WAN protocols. Everything on the LAN runs over Ethernet, most applications using TCP/IP. Your wiring, switches, and protocols are all standardized. After some amount of effort, you've got it all playing together smoothly. Adding new users is no big deal. Even new applications such as IP security cameras join the network without much ado.

Now look at the WAN. Your access is likely by TDM carrier, such as T1, DS3, or SONET fiber optic carrier. These can be configured as telephone trunks, point to point data connections, or dedicated Internet access. There are also Frame relay networks that might be accessed using low speed connection such as ISDN BRI. The one thing all of these transport technologies have in common is that they need special interface equipment. TDM carriers require a CSU/DSU or Channel Service Unit / Data Service Unit to keep the line synchronized and perform the protocol conversion. ISDN BRI uses an ISDN Terminal Adapter and Frame Relay requires a FRAD or Frame Relay Access Device.

In itself, the signal interfacing and protocol conversion isn't such a big deal. The proper CPE or Customer Premises Equipment is often provided by the carrier or is contained on a plug-in circuit card for your PBX phone system or network edge router. But it does introduce another layer of complexity, and often an efficiency penalty that comes from stuffing packets into TDM timeslots and back again. It's nothing like the limitations you encounter when trying to send data through an analog phone line, but there is a price to pay. That price is usually extracted in dollars and service availability.

T1 line services have plunged in price over the last few years. But a newcomer, Ethernet WAN, has done even better. T1 service is almost universally available and can be configured for PBX telephone, dedicated Internet access, VoIP SIP trunking, or point to point data service. Each line is good for 1.5 Mbps, although you can bind them together to increase WAN speed.

The WAN bandwidth limitation is the second frustration, and the big one suffered by companies that have grown to dozens or hundreds of employees, or need high speed file transfers. Everything moves swiftly on the LAN, but try to send a video or high resolution image across town or across the country and you wait. The WAN to LAN connection is something like connecting a garden hose a fire hose. Sometimes it seems like connecting a drinking straw to a fire hose. Nothing moves fast through that constricted connection.

T1 bonding might get you to 10 Mbps standard Ethernet speed, but that's about it. You can sometimes elect to bring in DS3 service at 45 Mbps, but you might need to be lit for fiber optic service to do it. Fiber optic bandwidths are virtually unlimited, as long as your budget is too. This is where Ethernet WAN service shines. With fiber optic drops from a competitive carrier POP (Point of Presence) or Ethernet over Copper connections where fiber optic construction is too expensive, the cost per Mbps is anywhere from half to a tenth of what you'll pay for equivalent TDM services.

Ethernet WAN connections are usually available in speeds that mirror Ethernet LAN bandwidths. These are 10 Mbps, 100 Mbps and 1,000 Mbps. Once you've matched your WAN speed to your LAN, at least for traffic leaving the premises, your entire network will once again become transparent to the users.

Want to see how much you can improve your WAN connections for a lot less cost than you'd expect? Use our handy Ethernet Services Search Engine to see Ethernet WAN connections available in your area.

Click to check pricing and features or get support from a Telarus product specialist.

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