| When determining the amount of bandwidth a client | | | | design, identify current bandwidth usage across the |
| needs, you first have to understand why the client | | | | network, identify bottlenecks, and where T circuits are |
| needs internet/WAN connectivity. Initially you want | | | | being employed, where they are using MPLS or |
| work with the client to develop an idea of what the | | | | metro-e circuits, where they are using dark fiber, if any. |
| client wants to get from the internal network, in other | | | | Ultimately you want to understand where their current |
| words develop a list of business drivers. | | | | problems lay from layer 1 and 2 perspectives based |
| Does the company require*:o Use of VOIPo Are they | | | | on the current design and then you will need to break |
| using Voip nowo Will the use it in the futureo How | | | | the network down logically at layer 3 and 4 examining |
| many trunks do they currently support and how much | | | | what protocols are being used and how they are |
| bandwidth is currently being used at the core by those | | | | being broadcasted across broadcast domains which |
| trunkso Use of IP Telephony (voice to the desktop)o If | | | | can create sluggish communications. Is the client using |
| they are using IP telephony, are they using only SIP or | | | | VOIP and not using QOS, is the client using a lot of |
| are they using other protocols and other applications of | | | | DHCP relay, are there multicasts being broadcast that |
| the feature set on the phones and what are the | | | | are creating superfluous traffic, etc... |
| manufacturers recommended guidelines on bandwidth | | | | Once you have a clear picture of the current network |
| consumptiono If they are not using IP telephony, do | | | | configuration and you have base lined the network, |
| they know what protocols and applications of the | | | | and have identified their current issues via a gap |
| feature set on the phones they will use, and what are | | | | analysis then you can move on to identifying "how |
| the manufacturers recommended guidelines on | | | | much bandwidth they need" internally. |
| bandwidth consumptiono What internal applications do | | | | From an external perspective you need to simply |
| they use currentlyo What are the bandwidth | | | | perform a firewall analysis of inbound and outbound |
| requirements of those applications currentlyo What are | | | | traffic and match that against the CIR of your ISP |
| the manufacturer or developer's guidelines on how | | | | pipe(s). You may also want to extrapolate any new |
| much bandwidth to useo Does the client plan to add | | | | data gleaned from your research into the forecasted |
| additional applications they know are heavy on | | | | use of applications for additional bandwidth usage in |
| bandwidth usage?o Does the client use any security | | | | the future. |
| scanning that may take up resources?o When do the | | | | So to summarize you will need to use the following |
| scans occur and are those during peak timeo Do they | | | | methodology: |
| plan to add security scanning, and if so where (the | | | | 1. Identify the business requirements and drivers |
| core or edge or across aggregation points)?o Does | | | | 2. Understand the technical requirements |
| the client currently use QOS, and if so have they | | | | 3. Identify how data is being transported currently |
| manually queued traffic or are they using difserv? | | | | 4. Conduct an OSI based network analysis |
| *These are a good sample of questions, but in short, | | | | 5. Develop a Gap analysis with suggested solutions |
| you are conducting a workshop to identify the | | | | 6. Develop a high level plan and provide the customer |
| business and technical drivers of the organization | | | | with an estimated band width requirement based on |
| You will also want to examine the current network | | | | evidentiary matter obtained in steps 1 - 5. |