Author: Tom Barbette

I wanted to explore a bit about the power consumptions of CPEs in Belgian ISPs. This blogpost is not to be considered research-grade, it’s more a hobbyist’s peak into the power consumption of the equipment.

My main questions were: is there a significative power consumption difference between ISPs (inside consumer’s homes). And more importantly: is there a “hidden” cost behind some ISP. And finally, does the network usage impact the power consumption.

I switched ISPs 3 times in a row, and I give here a graph (taken from Home Assistant which is recording the measures from a TP-Link P110 plug) and a CSV file for the same period.

Voo

Before switching to Orange, I captured the consumption of Voo(Cable/Docsis) for a week. The amplifier and modem ensemble consumes around 20.2 watts (note the Y axis, this graph is actually a straight line).

Orange

I stayed at Orange (Cable/DOCSIS) for about 6 months. The consumption includes the mandatory amplifier and the modem in bridge mode. Note that the amplifier is the same as Voo. The Wi-Fi is deactivated. It seems some update from Orange impacted the consumption, which is now around 16.8 Watts. It is a 3 Watts improvement over Voo, which, for a year represents 26kWh, so roughly 10€ in electricity.

I have no explanation for the increase in power at the end of October (another update?). Similarly there are a few spikes in September, it could be false positives I would not make conclusions based on that. This is not related to the traffic pattern, because day-to-day it’s the same power consumption. I tried to launch a speedtest and observe the instantaneous consumption and I couldn’t spot any difference.

Proximus Fiber

I then switched to Fiber with Proximus, as soon as I could. The connection is much faster: 500Mbps symmetrical.

The equipment is divided in two part : the ONT which “converts” the fiber to Ethernet, and then the modem that includes a switch, WiFi and telephony.

You observe 3 steps here. At the beginning I had the Modem in router mode, with Wifi activated at 8.5Watts. That’s what most people would have.

Then, the second step at 7Watts is with the Modem in Bridge mode, without WiFi. In bridge mode the modem directly give a public IP address to a single equipment connected to it. Typical for people with their own routers.

But one can go further. What I have used since February is directly the ONT at a spectacular 2,75Watts. I don’t need the modem because I don’t have fixed telephony, and don’t use WiFi in my garage. I have my own access points and want my home router anyway to handle my own ICT (I have some websites handle at home, home automation, etc).

Conclusion

First, the network usage does not impact the device’s power consumption. It is not surprising. All those modems are gigabit-capable or even more. The Orange allowance of my subscription is 150 Mbps, Voo was around the same. Hence, the modem is residing in its idle zone. With Proximus the ONT “rises” to 3 Watts during a speedtest instead of 2,75. It’s marginal.

The second question was the hidden cost. Proximus Fiber equipment drives as low as 8,5 Watts. That’s a 8,3 Watt reduction from Orange. That’s 73 kWh/year, at the Belgian average of 0,35€/kWh it’s roughly 25€ per year It’s not nothing, but it’s not high compared to the price of the subscription itself. If you have no use for the modem, then you gain 14Watts or 123kWh/year. That’s a more consequent 43€ saved.

73kWh is also 2% of the power consumption of the average Belgian household. Again, not nothing, but probably not the most urgent thing to do for the planet. It’s already much more than stupid “advices” like unplugging transformers of charging a smartphone on solar panels.

CONTEXT

This project is part of the novel CyberGalaxia project, part of CyberExcellence, and funded by the FEDER European fund.

This one to two-year contract (to be discussed) will take place at Galaxia, location of many companies active in cybersecurity and space, such as Rhea, Telespazio and, of course near the ESA and the Euro Space Center. The researcher will have the opportunity to train on two demonstrators, including a cyber range.

While this contract is limited and, therefore, too short to conduct a PhD, it is possible to look for further funding to conduct a PhD (typically four years in Belgium) with the ENSG. Applying as a post-doc is also possible. The salary will be matched with UCLouvain’s salary scale.

ORGANISATION/COMPANY

Université catholique de Louvain

Institute of Information and Communication Technologies, Electronics and Applied Mathematics (ICTEAM)

RESEARCH FIELD

Networking, Systems, NFV, CyberSecurity

MINIMUM REQUIRED QUALIFICATIONS

The candidate must have obtained a Master’s degree in computer science before the start date (April 2024, can be adapted). If applying as a post-doc, the same rule applies to the doctoral dissertation.

APPLICATION DEADLINE

ASAP, applications will be reviewed every two weeks until a candidate is found.

LOCATION

The applicant will share his or her time between Galaxia in Transinnes which is where the contact will be established, and a second office in Louvain-La-Neuve. The split of her/his time is to be discussed. Given that access to Galaxia is limited with public transport, the applicant should have their own car.

TYPE OF CONTRACT

Research Engineer, 1 to 2 year position, full-time

Funded as part of the CyberGalaxia FEDER project.

JOB STATUS

Full-time

HOURS PER WEEK

38

OFFER DESCRIPTION

The applicant will join the ENSG, but work partly at Galaxia in Transinnes with other members of CyberGalaxia.

The candidate will build a network audit system to allow auditors to run analyses on network traffic without violating user privacy or regulations such as the GDPR. To this end, the candidate will build a verifier that ensures that the private data of users analyzed by the audit system are aggregated in a sufficient manner before being exported to the listener. For instance, the program can scan each connection to check the recipient’s secure server name (TLS SNI) but can only output a proportion of users heading to the servers of this or that service provider. The system will be based on Retina, a system previously built in a consortium including the ENSG and Stanford ESRG.

SKILLS/QUALIFICATION

• Successful student
• Good in the Operating System, computer systems/architecture and networking courses
• Knowledge of programming in Rust is a plus, else comfortable with low level languages like C
• Autonomy, research-minded

SUBMISSION

Please send to tom.barbette@uclouvain.be:

(a) Curriculum vitae;

(b) Motivation letter;

(c) Transcript of grades for freshly graduated/graduating students

We will get back to you, the selection process includes in general a first informal meeting via Teams, and then an in-person interview.

REQUIRED LANGUAGES

ENGLISH: at least B1

French is not required but is a plus

Other positions

See the range of possibilities at the Efficiency of Networked Systems Group

Removing the Internet Box

If you have your own router, there’s no reason to use Proximus’s CPE (the Internet Box, which was called BBox in the past). Indeed, the fiber comes with two devices: the ONT, which has a fiber “in” and an ethernet port “out” (trying to speak to a large audience here), and the router itself. The router takes care of WiFi and VoIP (fix phone).

A lot of people had their modem in “bridge” mode already in the past, so they’d use their own router and WiFi access point. With fiber, using the bridge mode if you don’t have telephony doesn’t make any sense, you can just get rid of the Internet Box.

It will be the subject of another post, but the gains are substantial in term of electricity consumption. The ONT only consumes around 2.5 Watts. The Internet Box consumes an additional 6.5 Watts that can be removed. So that’s 56kWh, or around 20euros of electricity per year. It also slows the down the latency by something around 1.5ms, which, knowing the latency with fiber is around 6.7ms without the box is quite consequent.

WAN Connectivity

The following explains how to get connectivity when directly connecting your router to the ONT. This tutorial assumes Ubuntu 22.04. I use ifupdown, like old people instead of the novel netplan, on 22.04 it must be installed:

sudo apt update
sudo apt install ifupdown net-tools

The traffic towards the internet must be tagged on the VLAN 20. IP address is given via DHCP. There is no more PPPoE.

My interface connected to the ONT is enx00e04c680a48

/etc/network/interfaces

auto enx00e04c680a48
iface enx00e04c680a48 inet manual
	post-up /etc/network/enable_vlan.sh
iface enx00e04c680a48 inet6 manual

allow-hotplug internet0
iface internet0 inet dhcp
iface internet0 inet6 auto
        dhcp 1
        request_prefix 1
  	accept_ra 2

/etc/network/enable_vlan.sh

#/bin/bash
ip link add link enx00e04c680a48 name internet0 type vlan id 20
exit 0

The exit 0 part is an awful trick to avoid failing if the vlan is already created (for instance if you do sudo service networking restart).

That’s it. If you restart the networking service, you’ll get both an IPv4 address and an IPv6 /64 range. Interestingly, you get the /64 prefix through RA, but for your local network, you may use DHCPv6 to get a /56 range. It’s quite practical because you don’t have to subdivide the /56 range yourself.

internet0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 91.178.XX.XX netmask 255.255.240.0  broadcast 91.178.207.255
        inet6 2a02:a03f:XXXX:XXXX:cd9e:7208:f4b:2751  prefixlen 64  scopeid 0x0<global>
        inet6 2a02:a03f:XXXX:XXXX:2e0:4cff:fe68:a48  prefixlen 64  scopeid 0x0<global>
        inet6 2a02:a03f:XXXX:XXXX:ff8d:359a:c3c6:86d3  prefixlen 64  scopeid 0x0<global>
        inet6 2a02:a03f:XXXX:XXXX:f308:aacb:a438:6322  prefixlen 64  scopeid 0x0<global>
        inet6 2a02:a03f:XXXX:XXXX:d800:106e:5a53:6d86  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::2e0:4cff:fe68:a48  prefixlen 64  scopeid 0x20<link>
        inet6 2a02:a03f:XXXX:XXXX:8c4e:b44b:2fa8:ec27  prefixlen 64  scopeid 0x0<global>
        inet6 2a02:a03f:XXXX:XXXX:fc26:be7c:b9fd:dc0  prefixlen 64  scopeid 0x0<global>
        inet6 2a02:a03f:XXXX:XXXX:45b3:1bcb:7aef:5adf  prefixlen 64  scopeid 0x0<global>
        ether 00:e0:4c:XX:XX:XX  txqueuelen 1000  (Ethernet)
        RX packets 27423813  bytes 32859906931 (32.8 GB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 21693717  bytes 7316444742 (7.3 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

LAN Connectivity

For IPv4, it’s just standard NAT. For IPv6 you must enable IPv6 prefix delegation.

First, enable IP forwarding. If you have a firewall, remember to allow the FORWARDING traffic.

/etc/sysctl.conf

#Uncomment the following lines
net.ipv4.ip_forward=1
net.ipv6.conf.all.forwarding=1

To enable the NAT, either you directly add an IPTables rules somewhere:

sudo iptables -A POSTROUTING -s 192.168.1.0/24 -o internet0 -j MASQUERADE

Or, you add the following line for the UFW firewall, in /etc/ufw/before.rules:

-A POSTROUTING -s 192.168.1.0/24 -o internet0 -j MASQUERADE

In both cases, change your local network range according to your setup.

IPv6 Prefix Delegation

You have to add the following script found at https://wiki.debian.org/IPv6PrefixDelegation in /etc/dhcp/dhclient-exit-hooks.d/prefix_delegation:

# This script assigns a delegated IPv6 prefix obtained via DHCPv6 to another interface
#
# Usage: This scrips is designed to be called from dhclient-script (isc-dhcp-client).
#
# LOCATION: /etc/dhcp/dhclient-exit-hooks.d/prefix_delegation
# RECOMMENDED PACKAGES: ipv6calc

# CONFIGURATION OPTIONS

# Define the interface to which a delegated prefix will be assigned
# This must not be the same interface on which the prefix is learned!
IA_PD_IFACE="br0"

# Provide a space separated list of services that need to be restarted or reloaded after a prefix change
# Services must be controllable via systemd's systemctl, the default action is restart
# Service names may be followed by a colon and action name, to override the default action
# Supported actions are: restart and reload
# Example: IA_PD_SERVICES="shorewall6:reload dnsmasq"
IA_PD_SERVICES=""

# Define the location of the ipv6calc executable, if installed
# If this is empty or no executable file, no EUI-64 based IPv6 address will be calculated for the interface set in IA_PD_IFACE; instead, a static interface identifier (::1) will be appended to the prefix
# Example: IA_PD_IPV6CALC="/usr/bin/ipv6calc"
IA_PD_IPV6CALC=""

# Set to yes to make logging more verbose
IA_PD_DEBUG="yes"

# END OF CONFIGURATION OPTIONS

logger -t "dhcpv6-pd" -p daemon.info "DHCPv6-PD is running"

fn_calc_ip6addr() {
        [ -z "$1" ] && return
        local ia_pd_mac
        local ia_pd_addr
        [ -e "/sys/class/net/${IA_PD_IFACE}/address" ] && ia_pd_mac="$(cat /sys/class/net/${IA_PD_IFACE}/address)"
        if [ -n "$ia_pd_mac" ] && [ -n "$IA_PD_IPV6CALC" ] && [ -x "$IA_PD_IPV6CALC" ]; then
                [ "$IA_PD_DEBUG" = "yes" ] && logger -t "dhcpv6-pd" -p daemon.debug "Debug: Determined MAC address $ia_pd_mac for interface $IA_PD_IFACE."
                ia_pd_addr="$("$IA_PD_IPV6CALC" -I prefix+mac -A prefixmac2ipv6 -O ipv6addr "$1" "$ia_pd_mac")"
        fi
        if [ -z "$ia_pd_addr" ]; then
                [ "$IA_PD_DEBUG" = "yes" ] && logger -t "dhcpv6-pd" -p daemon.debug "Debug: Failed to calculate EUI-64 based IPv6 address, using static client suffix ::1 instead."
                echo "$1" | sed 's#::/#::1/#'
        else
                echo "$ia_pd_addr"
        fi
}

fn_restart_services() {
        if [ -n "$IA_PD_SERVICES" ]; then
                local pair
                local action
                local daemon
                for pair in $IA_PD_SERVICES ; do
                        action="$(echo "$pair" | cut -d':' -f2)"
                        daemon="$(echo "$pair" | cut -d':' -f1)"
                        # Check if a valid action was provided or default to 'restart'
                        case $action in
                                reload) action="reload";;
                                *)      action="restart";;
                        esac
                        # Check if daemon is active before trying to restart or reload it (avoids non-zero exit code)
                        if ! systemctl -q is-active "${daemon}.service" > /dev/null ; then
                                logger -t "dhcpv6-pd" -p daemon.info "Info: $daemon is inactive. No $action required."
                                continue
                        fi
                        if systemctl -q "$action" "${daemon}.service" > /dev/null ; then
                                logger -t "dhcpv6-pd" -p daemon.info "Info: Performed $action of $daemon due to change of IPv6 prefix."
                        else
                                logger -t "dhcpv6-pd" -p daemon.err "Error: Failed to perform $action of $daemon after change of IPv6 prefix."
                        fi
                done
        elif [ "$IA_PD_DEBUG" = "yes" ]; then
                logger -t "dhcpv6-pd" -p daemon.debug "Debug: No list of services to restart or reload defined."
        fi
}

fn_remove_prefix() {
        [ -z "$1" ] && return
        [ "$IA_PD_DEBUG" = "yes" ] && logger -t "dhcpv6-pd" -p daemon.debug "Debug: Old prefix $1 expired."
        if [ "$(ip -6 addr show dev "$IA_PD_IFACE" scope global | wc -l)" -gt 0 ]; then
                logger -t "dhcpv6-pd" -p daemon.info "Info: Flushing global IPv6 addresses from interface $IA_PD_IFACE."
                if ! ip -6 addr flush dev "$IA_PD_IFACE" scope global ; then
                        logger -t "dhcpv6-pd" -p daemon.err "Error: Failed to flush global IPv6 addresses from interface $IA_PD_IFACE."
                        return
                fi
                # Restart services in case there is no new prefix to assign
                [ -z "$new_ip6_prefix" ] && fn_restart_services
        elif [ "$IA_PD_DEBUG" = "yes" ]; then
                logger -t "dhcpv6-pd" -p daemon.debug "Debug: No global IPv6 addresses assigned to interface $IA_PD_IFACE."
        fi
}

fn_assign_prefix() {
        [ -z "$1" ] && return
        local new_ia_pd_addr
        new_ia_pd_addr="$(fn_calc_ip6addr "$1")"
        if [ -z "$new_ia_pd_addr" ]; then
                logger -t "dhcpv6-pd" -p daemon.err "Error: Failed to calculate address for interface $IA_PD_IFACE and prefix $1"
                return
        fi
        [ "$IA_PD_DEBUG" = "yes" ] && logger -t "dhcpv6-pd" -p daemon.debug "Debug: Received new prefix $1."
        # dhclient may return an old_ip6_prefix even after a reboot, so manually check if the address is already assigned to the interface
        if [ "$(ip -6 addr show dev "$IA_PD_IFACE" | grep -c "$new_ia_pd_addr")" -lt 1 ]; then
                logger -t "dhcpv6-pd" -p daemon.info "Info: Adding new address $new_ia_pd_addr to interface $IA_PD_IFACE."
                if ! ip -6 addr add "$new_ia_pd_addr" dev "$IA_PD_IFACE" ; then
                        logger -t "dhcpv6-pd" -p daemon.err "Error: Failed to add new address $new_ia_pd_addr to interface $IA_PD_IFACE."
                        return
                fi
                fn_restart_services
        elif [ "$IA_PD_DEBUG" = "yes" ]; then
                logger -t "dhcpv6-pd" -p daemon.debug "Debug: Address $new_ia_pd_addr already assigned to interface $IA_PD_IFACE."
        fi
}

# Only execute on specific occasions
case $reason in
        BOUND6|EXPIRE6|REBIND6|REBOOT6|RENEW6)
                # Only execute if either an old or a new prefix is defined
                if [ -n "$old_ip6_prefix" ] || [ -n "$new_ip6_prefix" ]; then
                        # Check if interface is defined and exits
                        if [ -z "$IA_PD_IFACE" ] || [ ! -e "/sys/class/net/${IA_PD_IFACE}" ]; then
                                logger -t "dhcpv6-pd" -p daemon.err "Error: Interface ${IA_PD_IFACE:-<undefined>} not found. Cannot assign delegated prefix!"
                        	ls -al /sys/class/net/
			else
                                # Remove old prefix if it differs from new prefix
                                [ -n "$old_ip6_prefix" ] && [ "$old_ip6_prefix" != "$new_ip6_prefix" ] && fn_remove_prefix "$old_ip6_prefix"
                                # Assign new prefix
                                [ -n "$new_ip6_prefix" ] && fn_assign_prefix "$new_ip6_prefix"
                        fi
                fi
                ;;
esac

Don’t forget to change the few first configuration lines. My LAN network is “br0” because I use a bridge over multiple interfaces.

That script will get the DHCP-assigned range and add it to the LAN interface. We still need to enable RADVD to advertise the prefix on the lan:

sudo apt-get install radvd
sudo update-rc.d radvd enable

/etc/radvd.conf

interface br0 # LAN interface
{
  AdvManagedFlag off; # no DHCPv6 server here.
  AdvOtherConfigFlag off; # not even for options.
  AdvSendAdvert on;
  AdvDefaultPreference high;
  AdvLinkMTU 1280;
  prefix ::/64
  {
    AdvOnLink on;
    AdvAutonomous on;
  };
};

And that’s all. Note we don’t need wide-dhcp-client anymore, which anyway has a blocking bug and seems to be unmaintained. dhclient is able to do everything we need, given the script for prefix delegation.