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If you were me - design question

Okay - we have a bandwidth issue and I just wanted to see what you think some good options are.

Quick run down of the setup:

We have 200 employees at our main office. This is growing at a rate of 40 per year for the last few years. I was employee #65 3 years ago.

We have a T1 Internet connection.

We also have 15 VPN sites. Each of these sites have DSL lines with bandwdith in the 128-512K range. They have Cisco 3002 boxes connecting to a 3005 box here. We do expect to have more sites to add, but the number is leveling off.

So, there is not doubt we've reached a point where we need more bandwidth. The question is what solution do with we go with?

A) Fractional T3

B) Secondary T1

And if we go with a secondary T1, do we use an alternate provider? Do we set up BGP? Do we run both lines off one or two routers? Do we just send all VPN traffic through one T1 and everything else out the other?

Your comments and thoughts are appreciated!




Re: If you were me - design question

Depending on the criticality (from a redundancy standpoint), if both options are available to you, I'd lean toward the Frac DS3. It will absolutely have a higher up-front cost and set-up cost / effort, but future increases in bandwidth are only a phone call away .... The physical media will be in place and tested, all they have to do is light up the new channels (and, of course, you'll need to reconfigure the router (and/or mux).

If you've decided that some site absolutely must be connected, then go for the second T1 from a different provider (or a "diverse" routing from the same people) - either way make sure the sales person understands that diversity is as important as the bandwidth (separate paths, separate entrances to the building, separate equipment, etc).

In a perfect world, you'd be able to get redundant DS3s / frac DS3s ;->



Community Member

Re: If you were me - design question

There is not enough information here to give a response that is any better than saying flip a coin, or just pick the least expensive option. So I'll point out some of the decision points and ask you to fill in the blanks. The answer should start becoming clear as you do so.

Redundancy Value:

How important is the data or applications being run over the connection to your business?

Will an outage bring the business to a halt and start costing you money or is it just a nuisance?

How important are the VPN connections to the end users?

Can the VPN users complete their jobs using only their internet connections and wait for the VPN connection to become available?

Are you running any web servers onsite?

Are there extranet connections to other partners?

Is true diversity even available from the local provider or is it only available beyond the POP?

Financial Value:

What is breakeven point of the FT3 service vs. x number of T1s?

What is the cost of upgrading the site to FT3 service vs. adding another T1?

Is there an option to get free installation of the FT3 service for a contractual commitment of time?

What will true diversity cost at the various points (diverse entrance faculties, diversity from wire centers, and diversity from POP)?

Growth Value:

What applications are foreseen at this business and what are the bandwidth requirements per user (from a WAN perspective)?

How many users can this site ultimately house and what are the worst case bandwidth requirements at 100% occupancy?

Once the business needs are documented the technical details of design are fairly easy. Most of the time is spent in risk assessment to the business and end users.

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