Monday, May 18, 2009

How Do You Determine The Right Wide Area Network (WAN) Architecture For A Voice/Data Network?

The first and foremost thing in deciding about the WAN architecture of any organization is ....

- How many locations you would like to connect?

- Architecture - hub and spoke or mesh architecture?

- What applications would be run on this network .... Voice, Video, Data?

- Precisely which applications will be run in case of Data?

- What will be the % each QoS will take, the total of all three should be 100%?

- Voice is the premium level QoS and hence the most expensive as it is a real time communication, followed by video and then data.

- How many users precisely will be using the network at a given point of time at each location?

- What will be the concurrency factor? Are you are looking for 100% concurrency or you can manage with lesser concurrency?

- What is the scope of scalability at each location and hub location?

- Will the access to internet also be given to users?

- Internet at a central location can help you in implementing and enforcing various security policies of your organization.

- Do you want to give access to the network resources to a mobile user?

The answer to all these questions will help in arriving at the MPLS bandwidth required at each hub and spoke location.

Honestly speaking no organization should ideally try to do this calculation themselves. Instead they can hire a consultant or a telecom service provider to do this activity as they are experts in designing this solution. With their help you can easily decide upon the bandwidth for each location, select suitable router, make redundancy plans, routing the traffic on atlantic or pacific routes, blah blah.

For help walking through the analysis .... and determining the best solution .... take advantage of the free help at WAN Solution

Ideally I also recommend to give the freedom of providing and managing the routers at each location to the Telecom service provider. Then it becomes a managed solution and the service provider can easily monitor your network in the event of an outage. They then can remotely login into the routers and manage your complete network giving you higher uptimes and SLAs.

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Blogger yasir said...

good article

12:07 PM  
Anonymous Scott Coleman said...

Pretty good read, I do have 2 comments however.

First all MPLS networks are not created equal. We started with one type of MPLS network and had horrible performance with our Cisco IPT solution. The network was migrated to another type of MPLS network and things got a whole lot better.

Second I don’t know that I agree with the premise to go with a managed solution. I think it depends on the size of the network and the internal resources available to monitor the network. We have a relatively large WAN; around 50 nodes. We use Orion and a couple of other tools to monitor the network so when things start happening the Service Desk and Network Staff are notified. We don’t need to pay the extra cost to have the Telecom provider manage the network.

7:58 AM  
Anonymous Adam Brenner said...

Given the fact that connectivity options are available in all types and sizes, you can connect all of them through one provider. From large offices requiring DS-3s or optical circuits, down to remote offices and home-based users that can log in remotely via vpn clients through their own internet connections, some MPLS providers offer methods to connect all of them.

It is rare that all sites require connectivity to all sites. A hub and spoke architecture can be of use in some cases, but even a full mess solution will not generally consume additional bandwidth as users will pull data from locations where required, so a full mesh solution, as simple as it is to configure and troubleshoot, will prevent users from accessing the head-end when data transmission is required between two alternate locations.

Your applications and number of users at peak hours will be the two greatest factors in determining bandwidth requirements. Researching bandwidth usage for an application and multiplying that by the maximum number of users at peak hours is a good place to start. A good server administrator will be able to see the largest number of concurrent connections per application, giving you an tighter estimation of your bandwidth requirements.

Where QOS is concerned, both Voip and Video should be classified as premium, as that will prevent packetloss and delay variation (jitter). Not all data is the same. Servers such as Citrix and SNA based devices react poorly to packetloss but can survive jitter. Be sure your provider offers a middle of the road class of service that prevents packetloss but is less costly than a premium level.

Scalability depends on your business model. You may see little or no growth in a particular region, or you may have ambitious forecasts. If you have to go through the process of moving to a larger office building in order to accommodate a substantial increase in staff, then you have to move your circuit regardless and can at that time increase the size of your circuit(s).

Managed services: The choice is yours. Are you an IT firm or an insurance company? There is no need to hire someone in-house to manage your router when you have only two main offices. At the same time, if you have 5,000 employees spread over 10 locations and there is a constant need for desktop, laptop and voice support, you may do better to hire an individual or a team at each location for day to day support. Don't manage your own firewall at the internet edge unless you really know what you're doing as this can be a recipe for disaster. Find a truly knowledgeable security professional, outsource your firewall management, or use a service provider that offers "firewall in the cloud", the latter being the most cost efficient.

7:40 PM  

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