Insanely high Network Buffer (uplink) making online gaming a no-can-do.
You might want to consider setting up a ThinkBroadband "Broadband Quality Monitor", to get a continuous graph of how latency is affecting your connection.
You do need your router set to reply to external PING requests.
If your router is capable of selective PING replies, then the ThinkBroadband IP addresses to respond to are 80.249.99.164/28 and 2a02:68:1::164
@Kritya wrote:
I've ran this test multiple times. Times when I've been the only one in my house with only a single firefox tab open. The results are always around this mark, varying from 580-640ms.
... and your point is what ?
When you run a buffer-bloat test, your connection is deliberately saturated, then PING times are measured WHILE the connection is overloaded. This gives the latency of your connection when the router is running flat out.
To reduce the latency, you need to apply uplink QoS/Traffic shaping to REDUCE the uplink bandwidth (to about 85..90%) to give enough headroom for higher priority packets (such as gaming and PING, etc) to take precedence over normal browsing, streaming, and downloading. In addition, by applying router QoS/Limiting, you are moving the point where your upstream is losing packets, and control of TCP ACKs, from the point of lowest uplink bandwidth (i.e. your phone line) to the outgoing buffer in your router. This means your network has much better buffering and stream control, as the local buffer properly handshakes, rather than relying on packet resends otherwise required to recover the lost packets on your WAN port.
@Kritya wrote:
Network Buffers can only be controlled by your ISP, so you have to contact them and hopefully they will adjust them or remove them."
For the problem you are describing, the above statement is irrelevant.
ISPs, on the BT network, do have limited buffering on the downlink side. but that is to ensure that the rate at which data is sent from their servers to the BT exchange, matches the BT profile.
Uplink isn't really buffered once it leaves you router, as the slowest point in the network is your connection to the telephone exchange. Therefore if you want to improve latency, then YOU need to control the uplink buffer from your network.
The only buffer related issue that Plusnet are likely to help you with, is if the Plusnet "Current Line Speed" profile is incorrectly set higher than the BT "Line profile", which can result in packet loss and latency - because that means Plusnet could be sending more traffic to your exchange than your line can handle. This seems unlikely from the figures you've quoted.
@Kritya wrote:
If this is not the case, then I will be glad to adjust settings in the hub provided by PlusNet, but if the hub itself is causing these issues with default settings then it raises the question of why it's being provided to customers in that state.
The equipment provide by Plusnet is the cheapest that they can get away with, that suits the vast majority of customers. It is NOT suitable for demanding users, who require extensive network controls, or low latency.
If I were you, my advise would be to research which router would fit your requirements, and then buy a 'used' router on eBay, as people are always upgrading broadband equipment, and second hand prices are often next to nothing.
If you want a better understanding about eliminating latency then watch this YouTube video -
This is the video I used to eliminate latency (I run a pfSense router).
To get the explanation on traffic shaping, skip to 15:35, as up until that point is just an overview of pfSense router software.
The principles of what this video explains, can be applied to other routers with QoS / shaping.
Good luck !
By all means give that a try, but I'm slightly doubtful whether any 'switch' can manage internet gateway flow control,
as (most) switches tend to have little (if any) buffering, whereas flow-control / QoS / traffic-shaping, requires decent sized buffers AND managed queues for the different levels of traffic priorities (i.e. gaming / VoIP / ICMP / http / torrent / etc).
Good luck with your efforts, and let us know how you get on. 
