Further considerations

This section summarizes information about the latency measurement, sampling, volumetry, and data.

Latency measurement method

This diagram illustrate how do we calculate latency from the QoS-Agent.

Default sampling rates

Below are the default sampling rates. Refer to the Custom configurations section to learn how to modify them.

Note: Any modification to the configuration file of a running docker needs to be followed by a restart (stop, start) of the docker.

Protocol	Sampling rate
TWAMP	every 2 seconds
ICMP	every 2 seconds
HTTP	every 2 seconds
HTTPs	every 2 seconds
TCP	every 2 seconds
UDP	every 2 seconds
TraceRoute	every 15 minutes
PacketLoss	every 5 seconds
Iperf3	every 2 hours
Lifbe	every 1 hours

Volumetry

Table below presents data consumption with a heavy configuration:

Protocol	Sampling	Hourly consumption	Daily consumption	Montly consumption
TWAMP	30 / min	0.1 Mb	2.4 Mb	74.4 Mb
ICMP	30 / min	0.2 Mb	4.8 Mb	148.8 Mb
HTTP	30 / min	0.5 Mb	12 Mb	372 Mb
HTTPs	30 / min	0.6 Mb	14.4 Mb	446.4 Mb
TCP	30 / min	0.4 Mb	9.6 Mb	297.6 Mb
UDP	30 / min	0.4 Mb	9.6 Mb	297.6 Mb

Other protocols

Protocol	Sampling	Hourly consumption	Daily consumption	Montly consumption
TraceRoute	4 / hour	2.2 Kb	53 Kb	1.7 Mb
Iperf3	12 / day	83 Mb	2 Gb	62 Gb
Lifbe	24 / day	4.3 Mb	103.2 Mb	3.1 Gb
PacketLoss	12 / min	4.3 Mb	104.2 Mb	3.1 Gb

Data locations

Influx and Grafana databases can be accessed on the analyzer host

Application	Location
Grafana	`lti_analyzer/grafana/grafana/grafana.db`
Influx	`lti_analyzer/influx/data/*`

Backups

Backup can be made by simply copying the files on a desired location, or setting up a process reading the databases.

Extending dashboards

Additional dashboards can be created. Contact your Latence Technologies' vendor for more information about it.

Use a secure DNS instead of an IP address for your analyzer

If you want to add an nginx server to your analyzer to be able to go and use a DNS address, follow these steps:

Create the server

You need :
A DNS A Record pointed at your analyzer’s public IP. This will be configured with Nginx to proxy your application server. In our example it will be demo.domain.com
The address of the application server you want to proxy. In our case it will be `http://127.0.0.1:12021).

Step 1 — Installing Nginx

sudo apt update

sudo apt install nginx

systemctl status nginx

Step 2 — Configure the Server Block

It is recommended practice to create a custom configuration file for your new server block additions, instead of editing the default configuration directly. Create and open a new Nginx configuration file using nano or your preferred text editor:

sudo nano /etc/nginx/sites-available/demo.domain.com

Copy the following block and paste it in your config file, don't forget to modify the "demo.domain.com" with the DNS A Record you assigned to your analyzer.

server {
    listen 80;
    listen [::]:80;

    server_name demo.domain.com;

    location / {
        proxy_pass http://127.0.0.1:12021;
        include proxy_params;
    }
}

Next, enable this configuration file by creating a link from it to the sites-enabled directory that Nginx reads at startup:

sudo ln -s /etc/nginx/sites-available/demo.domain.com /etc/nginx/sites-enabled/

You can now test your configuration file for syntax errors:

sudo nginx -t

With no problems reported, restart Nginx to apply your changes:

sudo systemctl restart nginx

Add TLS/SSL Certificates

Step 1— Installing Certbot

sudo apt install certbot python3-certbot-nginx

Step 2 — Confirming Nginx’s Configuration

If you followed the tutorial above then you should have a server block for your domain at /etc/nginx/sites-available/example.com with the server_name directive already set appropriately, feel free to jump to Step 3.
To check, open the configuration file for your domain using nano or your favorite text editor:

sudo nano /etc/nginx/sites-available/demo.domain.com

Find the existing server_name line. It should look like this:

...
server_name demo.domain.com;
...

If it does, exit your editor and move on to the next step. If it doesn’t, update it to match. Then save the file, quit your editor, and verify the syntax of your configuration edits:

sudo nginx -t

If you get an error, reopen the server block file and check for any typos or missing characters. Once your configuration file’s syntax is correct, reload Nginx to load the new configuration:

sudo systemctl reload nginx

Certbot can now find the correct server block and update it automatically.

Next, let’s update the firewall to allow HTTPS traffic.

Step 3 — Obtaining an SSL Certificate

Certbot provides a variety of ways to obtain SSL certificates through plugins. The Nginx plugin will take care of reconfiguring Nginx and reloading the config whenever necessary. To use this plugin, type the following:

sudo certbot --nginx -d demo.domain.com

This runs certbot with the --nginx plugin, using -d to specify the domain names we’d like the certificate to be valid for.
If this is your first time running certbot, you will be prompted to enter an email address and agree to the terms of service. After doing so, certbot will communicate with the Let’s Encrypt server, then run a challenge to verify that you control the domain you’re requesting a certificate for.

Step 4 — Verifying Certbot Auto-Renewal

Let’s Encrypt’s certificates are only valid for ninety days. This is to encourage users to automate their certificate renewal process. The certbot package we installed takes care of this for us by adding a systemd timer that will run twice a day and automatically renew any certificate that’s within thirty days of expiration.
You can query the status of the timer with systemctl:

sudo systemctl status certbot.timer

To test the renewal process, you can do a dry run with certbot:

sudo certbot renew --dry-run

If you see no errors, you’re all set. When necessary, Certbot will renew your certificates and reload Nginx to pick up the changes. If the automated renewal process ever fails, Let’s Encrypt will send a message to the email you specified, warning you when your certificate is about to expire.