What is NBN CVC?
What is NBN CVC?
The NBN Co has released a statement saying that they will be reducing the amount of CVC (Capacity Virtual Circuit) on their network. As this relates to retail service providers (RSPs) it would appear to relate more to end-users, however, this article is meant as a technical explanation of what a capacity virtual circuit is and how it affects end user speeds during peak hours.
For those who don’t know what CVC stands for – Capacity Virtual Circuit – basically it’s the amount of capacity per user that an internet provider buys from the NBN. The maximum amount that an RSP can purchase is 100Mbps, so if you buy 50Mbps services then your ISP must have purchased at least 50Mbps * 3 = 150Mbps of CVC capacity from the NBN.
The actual amount that your ISP purchases is something that you CAN NOT see unless you are on a naked (unlocked) connection and measure throughput yourself.
One of the biggest complaints by end-users to their RSP has been slow speeds during peak usage times – usually around 7 pm local time in Australia. This would lead people to ask why their service is so slow when they can only be using 25-50Mbps of their purchased 100Mbps connection? Unfortunately, there isn’t much we can do about this because it’s largely out of our hands. The reason being is that providers have to pay for more bandwidth than they sell if they want quality internet services, as most RSPs don’t add enough capacity to their network. There is a lot of work involved in purchasing, installing and configuring this equipment so it makes sense why they wouldn’t want to pay for much more than needed.
The main issue here is that the CVC costs are passed on to end-users through their internet bills. At least the NBN Co has reduced them by around 30%, but if you’re an RSP then it would make business sense to push more traffic towards your network rather than someone else’s. Therefore if you have a smaller amount of CVC bandwidth required by your ISP then expect slower speeds during peak hours unless you upgrade your service (which may not be possible or very expensive). If you want to know how much your provider is paying – we recommend contacting them and asking.
If you’re an end-user then there’s not much else to do than to encourage your internet provider to purchase more CVC bandwidth, however, they have no real incentive to do so – as mentioned above it is expensive and likely not a great business decision for RSPs. The only thing you can really do is contact your Liberal Senator or Member of Parliament (assuming you live in Australia) about this issue and ask them what the government will be doing about this. If enough people complain/raise awareness then there might be some movement from the government on this issue in order to try to TTN and HFC was that ISPs have to be competitive and therefore prices will come down. Unfortunately, this has not been the case for internet users, where the CVC changes are the latest example of this issue.
If you’re interested in changing ISP then we recommend looking at Aussie Broadband – they have a “speed test” tab that allows you to get an idea of what your current maximum speeds are over NBN (note: it won’t show speeds during peak times). If you’re close (or equal) to 100Mbps then it would make sense to contact your provider with a complaint or raise a support ticket about slow speeds without any more CVC bandwidth being added to their network. Otherwiseforce NBN Co to reduce prices.
While something that was started by Turnbull back when he lead the push for FTTN in Australia, it doesn’t seem like he cares much about the actual speeds of end-users on NBN (probably because he uses a VPN), however, there are other people who do care and we would love to see some changes taking place.