Hi, so I’ve been trying to understand the pricing structure of the Relay service and as far as I can tell:
3GiB per CCU per month is roughly 3GiB / 30days / 24hours / 60minutes / 60seconds = 1.21 KiB/second
So ideally, to hit the 3GiB per CCU per month and 50 CCU per month at the same time we would want to use 1.21 KiB/second per player?
Firstly, I am just looking for some clarification on this as I’m assuming if we have a 4 player Relay session the data sent between them is exponentially larger? So, per request, we actually want to be sending the square root of 1.21 by 4? Is that correct? As we have 4 players each sending data to eachother, or is it only doubled because the relay server takes all 4 player’s data and sends it back, thus 2 calls back and forth?
Secondly, is overhead data counted towards the pricing bandwidth? I’ve been testing with a relay session of 2 players, without sending any game data at all. However, in the Unity Relay dashboard overview, the bandwidth usage is showing that I’m using 11.5 KiB per minute when the player and host are connected. Considering I am not sending any game data, I assume this is all overhead from the NetworkConnection class keeping the connection alive?
11.5KiB / 60 (60 seconds in a minute) leaves us with .19 KiB/s of overhead.
So my question is would that .19KiB/s of overhead take away from my allowance of 1.21KiB/s and leave me with roughly 1.02KiB/s??
Lastly, if this overhead doesn’t take away from my allowance, is there a way to filter this in the bandwidth usage overview so I can see exactly what does eat into my bandwidth allowance?
Hey StatisHero, that is correct. If you use less than ~1.21 KiB/second per player on average, and the month ends with 50 or less CCUs, there will be no fees.
The cost of data is not doubled: only egress is billed, not ingress. For example, in this scenario: Alice -1-> Relay -2-> Bob, only the arrow #2 is billed.
In a game of four players, the peers will usually only send their updates to the host, not to each other. Thus it isn’t some kind of factorial function over the number of peers.
All data that goes through the Relay connection applies against this ~1.21 KiB, including what you refer to as overhead. Note that the Unity Transport will produce less overhead if you are sending game data (it will not send PINGs unless it has to in order to keep the connection alive).
There is no way to filter out the non-payload from the payload bytes on the dashboard.
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Thanks, this is great info.
One last thing. After some testing I have been sending 22 bytes, 15 times per second per CCU, so 330 bytes which equates to 19.3KiB per minute per CCU. When testing with two players, in the dashboard it shows this as roughly 109-110 KiB per minute.
If I’m understanding this right, then from Host → Relay → Player is two calls, and Player → Relay → Host is another two calls meaning that 19.3KiB for each call would be quadrupled to about 77.2 KiB overall but we can actually find the egress by doing something like (bandwidth/minute / (no. of players * no. of players)) because both arrows are being calculated in total bandwidth?
This would leave me with 110 / (2*2) = 27.5 KiB/m and down to 450 b/s. If we factor that into the 1.2KiB/s allowance it’s the 330 bytes I’m sending and an extra 120 of ‘overhead’.
This is a satisfying amount of data for me, but I really don’t feel like I got that right. I’m just trying to understand where the extra unaccounted data is coming from as I’m going to be working with syncing many more objects and need to know my limits and what is feasible.
When you relay 22 bytes, the packet size is actually 60 bytes due to the RELAY packet header (see Relay message protocol).
If you send more data per packet, the overhead will be smaller.
In this example: Player -1-> Relay -2-> Host -3-> Relay -4-> Player, the arrows 2 and 4 are billed, not 1 and 3.
So we end up with
2 * (22 + 38) * 15 * 60 = ~105.5 KiB