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wan technology. ethernet/ circuit?

if you were trying to figure out what sort of wan technology you were going to use what would you most probably end up picking?

i have the option of doing a switched ethernet solution over fiber. or picking your traditional T lines. If i picked ethernet that would mean i couldn't do frame relay and all that stuff. lets pretend i had a frame relay cloud for other remote sites and i make this one an switched ethernet link. how would they connect? would it have to be through a VPN or something? what are the pros/cons of picking your circuit switched vs ethernet solution?


Re: wan technology. ethernet/ circuit?

Perhaps you can describe the ethernet solution in a little more detail?

In some ethernet based WAN solutions the provider will create 802.1Q VLANS for sending traffic from each remote site to a central site with each site having its own VLAN number. Essentially, each VLAN represents a virtual circuit much like a Frame Relay PVC, where at your central site you would bring each VLAN into a switch or router just as you would with Frame Relay DLCIs.

Selecting a WAN topology is never a cut and dry decision. Business needs, application requirements, costs, geography, etc. can all play roles in what it best for your organization.

You should not base your decision on opinions expressed in this forum.

Best to discuss this with your Cisco SE or engage a network consultant.

New Member

Re: wan technology. ethernet/ circuit?

hey thanks for the reply. To be honest i don't have much experience with ethernet based wan solutions. since it comes down to my final decision as to what get installed at this remote site i was trying to look at all the options. i could as i said, go the traditional TDM route or pick the ethernet solution. i was curious as to what sort of issues i would run into, routing, etc. what i mean is, can i still run the same routing protocols that i would normally use in a circuit environment? because essentially isn't the ethernet solution just a L2 switched solution? how does that compare to MPLS which is also switched?

pretending cost and geography isn't an issue. and also assuming that of your three sites A, B, and C. A & B are T3 lines on the same Tier 1 provider and now you have to option from the same provider to put a wan solution into site C. A&B are for this example part of a framerelay cloud. can you integrate the ethernet solution into this cloud?

i'm just curious and looking for opininos why a 802.1q vlan solution compares or is better then frame relay or atm or the more traditional wan solutions.

just trying to wrap my head around this new stuff. thanks for the response.


Re: wan technology. ethernet/ circuit?


One of the potential advantages you get with a 802.1q solution is the ability to do a multi-point network, since you could have multiple sites using the same VLAN. With FR and ATM, you are confined to p2p solutions (there are p2mp solutions possible for these but not many providers offer that).

Ethernet solutions are probably easier to upgrade than your traditional FR or ATM circuit too.

You can run pretty much any routing protocol over either of these types of technologies... You do not lose out in functionality by choosing one over the other.

If by MPLS you mean MPLS-based VPNs, then routing between your sites will be handled by your SP so you may not have as much control...

There is also aboslutely no issue having both ethernet and FR/ATM links between sites - they inter-operate quite well. However, in your example, if you are only going to have ethernet access at site C, then that will not work. You do need to have another site with ethernet access for you to have end-to-end connectivity. You cannot have a layer-2 circuit with ethernet at one end and FR/ATM at the other (unless you are using L2 VPNs).

Hope that helps - pls rate the post if it does.



New Member

Re: wan technology. ethernet/ circuit?

could you perhaps have an ethernet solution for your network but on different carriers and located geographically apart across the US?

site A with 802.1q on AT&T and site B with 802.1q on level 3. is that possible?


Re: wan technology. ethernet/ circuit?

Generally, the answer to that would be no. The only way that would be possible was if AT&T and Level3 had an ethernet interconnect where they handed off ethernet traffic for customers with links to both carriers...

In fact, the same applies to FR and ATM circuits...

Hope that helps...


New Member

Re: wan technology. ethernet/ circuit?

For what its worth, I have implemented many traditional TDM networks over the years, and recently built up a network for a customer that is made up of both TDM and ethernet. We provide a core router in one of our offices. It is the termination point for all the T1s and 1 ethernet connection. The ethernet connection goes into a provider's cloud with 5 other sites in it. All the traffic from the T1 sites must go down to one of the ethernet sites which is their main office (with server farm and operations people). In the end, each seems to work day in and day out and my customer has had no more or less problems out of either.

However, I found initial install to be more of a pain on the ethernet sites. TDM gives you remote loopback testing to isolate troubles, but with the ethernet, it seems to be it either works or it doesnt, and good luck tracking down the problem when it doesnt.

Additionally, this network made up of point to point T1s and ethernet circuits replaced a large frame network.

The choice is really going to be yours to make based on your specifics. Who has the best price, the better reputation and do you feel can provide the best service?

Like I said, this is just my experience from one turnup with one ethernet carrier.

Good luck!

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