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Introduction

MAP-T (RFC 7599) is a stateless IPv4/IPv6 transition mechanism that enables IPv4 services over an IPv6-only network using algorithmic translation.

Translation happens at:

   MAP Customer Edge (CE): A device functioning as a Customer Edge
                           router in a MAP deployment.  A typical MAP CE
                           adopting MAP Rules will serve a residential
                           site with one WAN-side IPv6-addressed
                           interface and one or more LAN-side interfaces
                           addressed using private IPv4 addressing.

   MAP Border Relay (BR):  A MAP-enabled router managed by the service
                           provider at the edge of a MAP domain.  A BR
                           has at least an IPv6-enabled interface and an
                           IPv4 interface connected to the native IPv4
                           network.  A MAP BR may also be referred to as
                           simply a "BR" within the context of MAP.

MAP-T High-Level Architecture

MAPT Configuration

Customer Edge: Enable/Disable MAPT feature with below distro's from build

DISTRO_FEATURES_append = " feature_mapt"
DISTRO_FEATURES_append = " nat46"

Border Relay: Setup done in ubuntu machine ( linux kernel 5.15 )

Installation

sudo apt-get install isc-dhcp-server

Open file /etc/dhcp/dhcpd.conf and update as below

ddns-update-style none;
default-lease-time 3600;
max-lease-time 7200;
authoritative;
option custom-upstream-rate code 242 = unsigned integer 32;
option custom-downstream-rate code 243 = unsigned integer 32;

option domain-name "hsd.pa.crnrstn.comcast.net" ;

subnet 10.42.0.0 netmask 255.255.255.0 {
option routers 10.42.0.10;
option broadcast-address 10.42.0.255;
option domain-name-servers 1.1.1.1, 8.8.8.8;
range 10.42.0.3 10.42.0.254;

}

Open file /etc/radvd.conf
interface eth1 {
AdvSendAdvert on;
AdvManagedFlag on;
AdvOtherConfigFlag on;
prefix 2001:558:6013:100::/64 {
AdvOnLink on;
AdvAutonomous on;
};
};

Open file /etc/dhcp/dhcpd6.conf and update as below

ddns-update-style none;
default-lease-time 3600;
max-lease-time 7200;
option dhcp-renewal-time 1800;
option dhcp-rebinding-time 2880;
option client-class-information code 97 = string;
authoritative;
option dhcp6.map-option code 95 = string;
subnet6 2001:558:6013:0100::/64 {
range6 2001:558:6013:0100::1000 2001:558:6013:0100::1fff;
prefix6 2001:558:6013:0100:: 2001:558:6013:fe00:: /56;
option dhcp6.map-option 00:59:00:16:00:08:18:c0:a8:14:00:30:20:01:05:58:60:13:00:5d:00:04:08:08:00:00:00:5b:00:09:40:00:64:ff:9b:00:00:00:00;
option dhcp6.name-servers
2001:4860:4860::8888,
2001:4860:4860::8844;
}

Once all changes are done, restart the dhcpd and radvd service.

sudo systemctl restart isc-dhcp-server
sudo systemctl restart isc-dhcp-server6
sudo systemctl restart radvd

● isc-dhcp-server.service - ISC DHCP IPv4 server
     Loaded: loaded (/lib/systemd/system/isc-dhcp-server.service; disabled; vendor preset: enabled)
     Active: active (running) since Mon 2026-04-06 15:22:33 IST; 135ms ago
       Docs: man:dhcpd(8)
   Main PID: 45322 (dhcpd)
      Tasks: 4 (limit: 18942)
     Memory: 4.6M
        CPU: 24ms
     CGroup: /system.slice/isc-dhcp-server.service
             └─45322 dhcpd -user dhcpd -group dhcpd -f -4 -pf /run/dhcp-server/dhcpd.pid -cf /etc/dhcp/dhcpd.conf eth1

Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: PID file: /run/dhcp-server/dhcpd.pid
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Wrote 3 leases to leases file.
Apr 06 15:22:33 CHTSL00399 sh[45322]: Wrote 3 leases to leases file.
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Listening on LPF/eth1/70:88:6b:81:04:e6/10.42.0.0/24
Apr 06 15:22:33 CHTSL00399 sh[45322]: Listening on LPF/eth1/70:88:6b:81:04:e6/10.42.0.0/24
Apr 06 15:22:33 CHTSL00399 sh[45322]: Sending on   LPF/eth1/70:88:6b:81:04:e6/10.42.0.0/24
Apr 06 15:22:33 CHTSL00399 sh[45322]: Sending on   Socket/fallback/fallback-net
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Sending on   LPF/eth1/70:88:6b:81:04:e6/10.42.0.0/24
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Sending on   Socket/fallback/fallback-net
Apr 06 15:22:33 CHTSL00399 dhcpd[45322]: Server starting service.
● isc-dhcp-server6.service - ISC DHCP IPv6 server
     Loaded: loaded (/lib/systemd/system/isc-dhcp-server6.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2026-04-06 15:22:33 IST; 122ms ago
       Docs: man:dhcpd(8)
   Main PID: 45333 (dhcpd)
      Tasks: 4 (limit: 18942)
     Memory: 3.3M
        CPU: 18ms
     CGroup: /system.slice/isc-dhcp-server6.service
             └─45333 dhcpd -user dhcpd -group dhcpd -f -6 -pf /run/dhcp-server/dhcpd6.pid -cf /etc/dhcp/dhcpd6.conf eth1

Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: PID file: /run/dhcp-server/dhcpd6.pid
Apr 06 15:22:33 CHTSL00399 sh[45333]: Wrote 0 NA, 0 TA, 0 PD leases to lease file.
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Wrote 0 NA, 0 TA, 0 PD leases to lease file.
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Bound to *:547
Apr 06 15:22:33 CHTSL00399 sh[45333]: Bound to *:547
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Listening on Socket/7/eth1/2001:558:6013:100::/64
Apr 06 15:22:33 CHTSL00399 sh[45333]: Listening on Socket/7/eth1/2001:558:6013:100::/64
Apr 06 15:22:33 CHTSL00399 sh[45333]: Sending on   Socket/7/eth1/2001:558:6013:100::/64
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Sending on   Socket/7/eth1/2001:558:6013:100::/64
Apr 06 15:22:33 CHTSL00399 dhcpd[45333]: Server starting service.
● radvd.service - Router advertisement daemon for IPv6
     Loaded: loaded (/lib/systemd/system/radvd.service; disabled; vendor preset: enabled)
     Active: active (running) since Mon 2026-04-06 15:22:33 IST; 37ms ago
       Docs: man:radvd(8)
    Process: 45348 ExecStartPre=/usr/sbin/radvd --logmethod stderr_clean --configtest (code=exited, status=0/SUCCESS)
    Process: 45349 ExecStart=/usr/sbin/radvd --logmethod stderr_clean (code=exited, status=0/SUCCESS)
   Main PID: 45350 (radvd)
      Tasks: 2 (limit: 18942)
     Memory: 516.0K
        CPU: 64ms
     CGroup: /system.slice/radvd.service
             ├─45350 /usr/sbin/radvd --logmethod stderr_clean
             └─45351 /usr/sbin/radvd --logmethod stderr_clean

Apr 06 15:22:33 CHTSL00399 systemd[1]: Starting Router advertisement daemon for IPv6...
Apr 06 15:22:33 CHTSL00399 radvd[45348]: config file, /etc/radvd.conf, syntax ok
Apr 06 15:22:33 CHTSL00399 radvd[45349]: version 2.18 started
Apr 06 15:22:33 CHTSL00399 systemd[1]: Started Router advertisement daemon for IPv6.

Jool Installation

Build the jool modules using below build instructions

sudo apt update
sudo apt upgrade
sudo apt install build-essential pkg-config
sudo wget https://github.com/NICMx/Jool/releases/download/v4.2.0-rc2/jool-4.2.0.rc2.tar.gz
sudo tar -xzf jool-4.2.0.rc2.tar.gz
sudo /sbin/dkms install jool-4.2.0.rc2/
cd jool-4.2.0.rc2/
sudo ./configure
sudo make
sudo make install

Once build completed, below modules will be generated in respective paths, add those modules to kernel path

ubuntu:~/jool-4.2.0~rc2$ find . -iname jool*ko
./src/mod/mapt/jool_mapt.ko
./src/mod/common/jool_common.ko
./src/mod/nat64/jool.ko
/src/mod/siit/jool_siit.ko

Jool configure

sudo modprobe jool_common
sudo modprobe jool_mapt
sudo modprobe jool

Enable below modules as well if not enabled
netfilter/nf_defrag_ipv4.ko
netfilter/nf_defrag_ipv6.ko

Once all modules are loaded and confirmed via lsmod

ubuntu:~/ lsmod | grep jool*
jool_mapt 20480 0
jool_common 253952 1 jool_mapt
nf_defrag_ipv6 24576 3 nf_conntrack,openvswitch,jool_mapt
nf_defrag_ipv4 16384 2 nf_conntrack,jool_mapt
x_tables 53248 9 xt_conntrack,nft_compat,xt_state,xt_tcpudp,xt_addrtype,xt_nat,ip_tables,xt_MASQUERADE,jool_mapt

Create an instance BR

sudo jool_mapt instance add "BR" --netfilter --dmr 64:ff9b::/64
sudo jool_mapt -i "BR" fmrt add 2001:558:6013::/48 192.168.20.0/24 8 8
sudo jool_mapt -i "BR" global update map-t-type BR

View the created instance using:

akhil@CHTSL00399:~$ sudo jool_mapt -i BR fmrt display
+---------------------------------------------+--------------------+----------------+----+
|                                 IPv6 Prefix |        IPv4 Prefix | EA-bits Length |  a |
+---------------------------------------------+--------------------+----------------+----+
|                         2001:558:6013::/48  |    192.168.20.0/24 | 16             |  6 |
+---------------------------------------------+--------------------+----------------+----+
akhil@CHTSL00399:~$ sudo jool_mapt instance display
+--------------------+-----------------+-----------+
|          Namespace |            Name | Framework |
+--------------------+-----------------+-----------+
|           89628c00 |              BR | netfilter |
+--------------------+-----------------+-----------+
akhil@CHTSL00399:~$

Enable dubbing for jool using sudo jool_mapt -i BR global update logging-debug true
cat /var/log/syslog

asas

Datamodels

root@Filogic-GW:~# dmcli eRT getv Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.
CR component name is: eRT.com.cisco.spvtg.ccsp.CR
subsystem_prefix eRT.
Execution succeed.
Parameter    1 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapTransportMode
               type:     string,    value: MAPT 
Parameter    2 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapBRPrefix
               type:     string,    value: 64:ff9b::/64 
Parameter    3 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapRuleIPv4Prefix
               type:     string,    value: 192.168.20.0 
Parameter    4 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapRuleIPv6Prefix
               type:     string,    value: 2001:558:6013::/48 
Parameter    5 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapEALen
               type:       uint,    value: 8 
Parameter    6 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapPSIDOffset
               type:       uint,    value: 8 
Parameter    7 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapPSIDLen
               type:       uint,    value: 8 
Parameter    8 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapPSID
               type:       uint,    value: 0 
Parameter    9 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapIsFMR
               type:       bool,    value: false 
Parameter   10 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapIpv4Address
               type:     string,    value: 192.168.20.254 
Parameter   11 name: Device.DHCPv6.Client.1.X_RDKCENTRAL-COM_RcvOption.MapRatio
               type:       uint,    value: 1