Capacity Planning in the good old days, was an issue that impacted neighborhoods with web hogs in the them. Peak usage hours were dreaded, teenagers downloading music were seen as a scourge, and web surfers were just plan old annoying. What did these people think the internet was for?
How things have changed. Today people not only download music and surf the web but also watch movie content, make video conference calls, teach classes, and do just about anything else they can think of. What they haven't thought of yet is just around the corner. Smartphones, pc's, tablets and refrigerators all use the internet. Almost everyone uses the internet daily. Every kid (big and small) who has ever watched a sci-fi movie wants to make that "cool thing" happen that they saw on the big screen. Ideally your network will make it happen for them.
Capacity Planning is a topic that gets a lot of discussion and I will outline some solutions that big and small cable operators can use. I will stress (as in previous articles) that capacity planning goes hand in hand with Broadband Internet Security. Theft of Service will fill your well planned network just as fast as legitimate users. Only the thieves aren't paying for it and they are opening you up to libel.
Capacity planning for cable networks in its simplest form is planning for future demand by subscribers. Typically the most difficult element to plan for is data, which is typically provided over the DOCSIS network, though this could also be offered over other methods such as Ethernet over Passive Optical Networks (EPON). Many times the driver for expanding the data pipe are seeing utilization statistics from a back-office dashboard that are rapidly approaching the limits of the existing network to provide. If no capacity planning has been done, this quite often results in just one more day at the office where everyone is struggling to put out another fire. The goal of capacity planning is to project out at least five years in the future to see where data bottle necks will occur and expand the network before it happens. This could mean node splits, CMTS upgrades, or other network changes. But a big factor is that the CAPEX is planned for and the expansion can occur in a timeframe that is driven by the cable operator rather than data growth controlled by the subscriber.
Capacity planning is something that every cable operator big and small can do with the right experience and complex Excel spreadsheet (I use MATLAB due to its superior capabilities). Though many times tactical business operations and other critical activities tend to push this type of planning to the back burner. Implementing some simple metrics can make capacity planning possible. To get started, do the minimum by creating a folder on your computer and why not call it "Capacity Planning". Next here is a list of things to start populating the folder with:[list type="list2"]
Now if you are serious about this and you start collecting the above data, your folder will start to fill up fast. But you'll figure out the structure you need for a database, the commands you need to query the information from the CMTS, etc. You'll want to retain all information for a five-year period, though you can begin capacity planning even with estimates based on the last year - some planning is better than no planning.
The modeling itself can be done in Excel. You will need to account for future CMTS growth, DOCSIS overhead, analysts anticipated data growth over the next five years integrated with your own system's actual growth etc. I have found Excel to be too limiting for so many variables and recommend MATLAB that can hand multi-dimensional arrays. MATLAB also has a very nice add-on, which makes it much more accurate for five-year projections.
I strongly recommend that if you are not currently implementing any capacity planning in your network that you consider it in the near future. It will help you predict what your future capital expenditures will be, when and where you will make outside plant changes, and will likely improve your short-term buying decisions. Also, making a thorough analysis of your network and then continuously monitoring trends of the analysis is useful in identifying anomalies such as a sudden change in traffic utilization. When there are large shifts in traffic utilization in a network further investigation is warranted as perfect cloned modems and/or hidden modems may be present utilizing large amounts of bandwidth in a theft-of-service situation.