In order to ensure that your service is stable and able to appropriately distribute different streams of data within your OverTheBox network, you must enable QoS (Quality of Service)

For example you might need to allocate a dedicated channel to telephony streams over a download to ensure optimised communication.

With this in mind OverTheBox offers Upload QoS which you can customise according to your needs.

This guide is designed for expert users.

How it works (packet marking)

OverTheBox runs a Queueing QoS. This means that it is able to prioritise certain types of data streams over others.
This is only possible for Upload traffic, In fact QoS for Download traffic only works directly via the OVH infrastructure, it is currently being developed for the next versions of OverTheBox
The OverTheBox system has many restraints when it comes to implementing QoS compared to a traditional connection:

  • The maximum speeds for WAN (if1, if2 etc.) interfaces are not automatically known by OverTheBox. However without this value it is not possible to correctly balance the load between these interfaces. This is why you will be prompted for your connections' IP speeds when QoS is enabled, we will go back to this in the Activation section.

  • On the WAN (if1, if2 etc.) interfaces, outgoing data is already encapsulated in the tunnel that enables aggregation, it is therefore not possible to distinguish the types of data streams at this level.

To solve the latter problem, OverTheBox rewrites the layer 3 (IP)'s DSCP field (which enables packet marking) onto the VPN tunnel header.
This marking can then be seen by the WAN interfaces (if1, if2 etc.). These interfaces are then able to differentiate the types of data flow and placed in different priority queues
.

How is this marking done?

When data (possibly from a local network) is transmitted by OverTheBox, the data is analysed for packet marking purposes. This is the information that is analysed:
  • The protocol (UDP, TCP etc.)
  • The source IP
  • The source port
  • The destination IP
  • The destination port
The packet in question can then be encapsulated in the tunnel (vtun/glorytun) and it can be identified because of this marking.
The following type of traffic is marked by default (If QoS is enabled):
  • CS6: nothing by default (high priority)
  • CS5: SSH, Telnet
  • CS4: Steam
  • CS3: WEB
  • CS2: the rest (normal traffic)
  • CS1: Mail, FTP (low priority)
.

What happens to the marked packets?

On the WAN interfaces (if1, if2 etc.), the marked packets are placed into priority queues:

  • Queue 1 (Network control) CS6 packets
(high priority)
  • Queue 2 (Realtime): CS5 packets + OVH VoIP
  • Queue 3 (Signaling): CS4 + CS3 packets
  • File 5 (Scavenger): CS1 packets ([blow priority)

The idea is simple, at a given moment, there are two possibilities:
  • The bandwidth is not saturated: no priority or limitiation is imposed, the packets are transmitted in a transparent way.
  • If your bandwidth is saturated:
The maximum bandwidth is then shared between the different queues. Each queue is limited to a certain percentage and maximum bandwidth. In the end, all the bandwidth is used but it is appropriately distributed across the queues.
Example: Your bandwidth is saturated and only packets marked CS6 and CS5 pass as they exit OverTheBox
There are therefore two queues concerned (Queue 1 and Queue 2), this pie chart explains how bandwidth is shared:
Another example: With five different marked data streams leaving OverTheBox when the bandwidth is saturated
This system means, among other things, that optimum telephony quality is maintained to the detriment of a data trasmission, when there are periodic bottlenecks.

Enabling QoS

In order to activate QoS by default, please follow this guide: Error, link to guide #2246 not found.

Customising QoS

As indicated before. You can mark certain packets (in CSx) to include them in a specific priority. This means you can guarantee an optimal quality of service for a chosen application.
The default configuration is already optimised for generic use (Upload, VoIP OVH etc.), customisation is only recommended if you want to prioritise a particular application.
Example: Whateve happens, you want to guarantee that your online video game is stable. The game server has the following public IP address: XXX.XXX.100.100 on the 5555 port.
To do this:
  • Click "Add"
A new line will appear
  • Fill in details as in the following image
  • Place this line at the top of the list using the arrows, as in the adjacent illustration, so that the marking is taken into account.
  • Click on "Save & Apply"
This will mark the chosen packets as CS6, and they will be included in the priority queue (see packet marking how it works)
This configuration might not be processed straight away. Please restart OverTheBox if this is the case.
This is just an example. You can adapt it to any type of network application.