[riot-users] Multihop Network

Cenk Gündogan cenk.guendogan at fu-berlin.de
Mon Sep 21 15:30:58 CEST 2015

Hey Santiago,
> I am quite new in this brave new world of IOT. Sorry if the question 
> then is maybe trivial.
All questions regarding IoT and RIOT are welcome on this mailing list (:

You are right, `desvirt` is suitable for creating virtualized networks 
and is a great tool to test your
application in a controlled environment.
If you want to deploy your app on real hardware though, `desvirt` will 
not help you here.

If you want to communicate over multiple hops, then you need to 
configure routes so that your nodes
know in which direction incoming traffic must flow.
These routes can be configured either statically by using the `fibroute` 
command from within the RIOT shell, or by using a routing protocol that 
configures the routes dynamically.

Let's try both ways:

You can start an experiment from the IoT-Lab website or directly from 
the command line via a Makefile that we provide in 
 From within the `gnrc_networking` example folder in RIOT you can call:

IOTLAB_EXP_NAME=multihop_test IOTLAB_DURATION=30 BOARD=iotlab-m3 make 
iotlab-exp -I ../../dist/testbed-support`

user_name must be replaced by your login account for the IoT-Lab Testbed.
With IOTLAB_PHY_NODES you can specify the nodes you want to use for your 
experiment. You can also choose single nodes that are further apart like 
this: IOTLAB_PHY_NODES=1-3+7-10+15
IOTLAB_DURATION=30 <-- this is the duration of the experiment in minutes

Assuming the experiment started successfully, you can then communicate 
with the nodes directly from the command line like this:
`IOTLAB_USER=user_name BOARD=iotlab-m3 make iotlab-term -I 

This command may prompt you for a password if your SSH key that you 
uploaded to the IoT-Lab testbed for SSH usage is password protected.

Once you are connected, the serial aggregator of the iot-lab testbed 
will be started and you have a console
from where you can control every node.

For the following I assume you have an experiment with nodes 1 + 5 + 10 
and the `gnrc_networking` example flashed on every node.

Static routing:
1) configure a global IPv6 address for every node like this:
     m3-1;ifconfig 7 add dead:beef::1 (or any other ipv6 address you desire)
     m3-5;ifconfig 7 add dead:beef::5
     m3-10;ifconfig 7 add dead:beef::10
2) configure static routes:
     m3-1;fibroute add dead:beef::5 via fe80::x_5
     m3-1;fibroute add dead:beef::10 via fe80::x_5
     m3-5;fibroute add :: via fe80::x_1
     m3-5;fibroute add dead:beef::10 via fe80::x_10
     m3-10;fibroute add :: via fe80::x_5

you have to look up the link local addresses (fe80::x_1,5,10) via the 
`m3-x;ifconfig` command.
Now you can start e.g. a udp server on all nodes with this single 
command `udp start server 8888`.

To communicate e.g. from node m1 over node m5 to node m10 you can then do:
`m3-1;udp send dead:beef::10 8888 hello`. Et voilà, multi hop 
communication with static routes.

To save most of the preconfiguration needed for multi-hop communication, 
you can use a routing protocol.
Currently, you can only use RPL, but we also have an AODVV2 
implementation, which is mostly done porting to the new network stack 
(AFAIK, correct me if I'm wrong).

Starting from a running experiment with the same preconditions as above 
(just execute `reboot` to bring the nodes back to the initial state):
1) configure a global IPv6 address for the root node of RPL
     m3-1;ifconfig 7 add dead:beef::1
2) initialize RPL on interface 7 for all nodes
     rpl init 7
3) start a RPL DODAG with m3-1 as root node and an instance id of 1
     m3-1;rpl root 1 dead:beef::1

Within a couple of seconds, all nodes should have correctly configured 
routes and you should be able to ping or send udp packets from one node 
to any other node that participates in the RPL dodag.
You can check the RPL state of a node by issueing the `rpl` command, 
e.g. `m3-1;rpl`.

Let me know if you have further questions (:


On 21.09.2015 12:20, Santiago Bragagnolo wrote:
> Hi all!
> I am quite new in this brave new world of IOT. Sorry if the question 
> then is maybe trivial.
> I am looking for a solution for sending a packet from a node to an 
> other through an other node using a wireless radio connection. For 
> this I'am using iot-lab platform (iot-lab.info), working strictly with 
> M3 cortex based nodes.
> These nodes of course will not be in direct range, and that is why i 
> need a multihop network.
> Then my question is how to build up a network in between different IOT 
> nodes and finally being able to send packets.
> I already tried searching in google and in the documentation, and the 
> best link I arrived is the following :
> https://github.com/RIOT-OS/RIOT/wiki/Virtual-riot-network
> from the following conversation:
> https://lists.riot-os.org/pipermail/users/2015-July/000389.html
> I understand that desvirt creates a virtual network for me, but i 
> cannot arrive to understand how to deploy that into a real set of 
> nodes, since it looks more as a simulation than to a real deployment.
> If any one can give me a better clue about how to solve this problem 
> it would be great.
> Thank you very much!
> Santiago.
> _______________________________________________
> users mailing list
> users at riot-os.org
> http://lists.riot-os.org/mailman/listinfo/users

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