Should You Use Ethernet For Your Voice & Data Network?

It seems that whenever you talk about an upgrade or new installation of a company's voice/data network these days you hear the buzz word "ethernet" sometime in the conversation. With all the buzz... should you seriously consider ethernet in the mix for your network solution?

Now think about that for a moment. Are you just "jumping on the bandwagon"... or is there some truth to all this hullabaloo?

To answer that let's get serious for a moment... no gushing idol worship. Just facts.

First .... it's very clear that today Ethernet has gone from a nice to have option to the preferred choice for WAN (Wide Area Networks) access links. Many companies also use it in their backbone for IP connectivity. So the question often is "why not Ethernet" ..... rather than "should you use it."

For example it is increasing commonplace that in a campus network just about all high bandwidth communications is Ethernet based. Also many things that used to be separate such as voice, CCTV, security/card locks can be migrated. Although you might need something to drive the migration. Can someone say cost savings??? Don't forget scalability with future technologies and increased performance efficiency too. All three will go over very well with your Big Boss .... and your shareholders.

If you need a few bullet points to drive home this message to that audience .... try using these:

- You really don't need a router. It is simply an Ethernet Handoff to your network.

- As you increase in bandwidth .... the per meg price goes down much quicker than with DS3 or OC3 bandwidth.

- For off-net/on-net sites Ethernet can be much cheaper than standard DS3 or OC3 bandwidth .... because you do not have to deal with loop costs.

However, I don't think Ethernet is really the common denominator, but IP (which tends to use Ethernet in most places). Since that means you don't need Ethernet everywhere and you can integrate useful technologies you might need - MPLS, VSAT, ADSL, and DS3 for example.

Be aware though that some parts of networks are likely to not be Ethernet compatible for a long time. The issue with "everything must be xx" is not whether you can get xx (sic Ethernet) in most places, but how to cope with the last few "hold outs".

A definite pro is that ethernet remains a layer 2 service. Which if you buy from a carrier means that you are in control of the routing. Whereas if you take an IP VPN service this will impact your internal routing configuration. Layer 2, Ethernet based connectivity between sites gives a lot of flexibility and often improved latency/jitter performance.

So if you're using IP today on SDH services then a migration to Ethernet should be a lot simpler. But again this depends on the scenario. Most carriers now use Ethernet as the last mile and also for backbone connectivity. This has provided higher speeds without the capital outlay .... and has the requisite reliability you should expect.

I also wouldn't use Spanning Tree and so would rely on the Network Layer to take the path decisions .... as this is a lot more deterministic and saves having multiple different protocols performing on the fly updates. Any IP application including voice and video should run just the same as over SDH .... but Ethernet would give you the options of putting Voice into it's own VLAN. Controlling bandwidth in this manner .... incorporating Ethernet .... should be so much cheaper. You could over engineer the backbone and keep things simple network managed service provider .

There are no real drawbacks using Ethernet in my mind .... and I personally believe that this would give you more flexibility than either a traditional SDH structure or an IP VPN based network.

The only Cons I can think of relate to the maintenance and troubleshooting of the network. Depending on your architecture and design, it may be a nightmare to maintain the network. For example, point-to-point is simple, but rings and mesh is challenging and will require clever and flawless design.

You really need to design and test the network carefully. You need to be aware of the type of services you will be running. Such as constant traffic, bursty traffic, low-latency traffic etc... as all of that will impact on your network and will require careful configurations. You need to have your QoS (Quality of Service) planned accurately if working with VLAN's or different types/classes of traffic.

Designed correctly, Ethernet models work well, but poorly implemented ones often have challenges. Its important for you to understand that Ethernet based WAN is not simply "plug-n-play". It requires additional planning and setup.
Overall I think there are many more pros than cons for choosing ethernet for your voice/data network . We are seeing lots of improvements to Ethernet these days via various industry working groups ..... as well as evolving packet transport technologies such as MPLS-TP and PBB-TE. So the future of etherent looks even brighter.