Setting up an open80211s mesh

[Ashish Gupta via Devel]

Hi!

I'm trying to set up a mesh network (OPEN mesh network) using the
instructions on https://github.com/cozybit/open80211s/wiki/HOWTO

I'm running a vanilla kernel, but as far as I know the support has
been in the kernel since '11 , so that shouldn't be the issue.
Any ideas on how I could fix this? I want to set it up so that I can
build stuff on top of it.

(Both machines are running hardware with the ath_9k driver which seems
to be the most supported driver for setting up meshes)

This is what I've tried so far:

The shorter version:

***@xyz:/home/yz# service network-manager stop

network-manager stop/waiting

***@xyz:/home/yz# iw --debug dev wlan0 interface add mp0 type mp
mesh_id abcdefgh
***@xyz:/home/yz# iw --debug dev mp0 set channel 2
***@xyz:/home/yz# ifconfig mp0 hw ether 94:a0:c0:b1:11:42
***@xyz:/home/yz# ifconfig mp0 192.168.3.82

***@xyz:/home/yz# iw --debug dev wlan0 interface add mp1 type mp
***@xyz:/home/yz# iw --debug dev mp1 set channel 2
***@xyz:/home/yz# ifconfig mp1 hw ether 94:a0:c0:b1:11:45
***@xyz:/home/yz# ifconfig mp1 192.168.3.84

***@xyz:/home/yz# iw --debug dev mp1 mesh join abcdefgh
***@xyz:/home/yz# iw dev mp0 station dump

***@xyz:/home/yz# iw --debug dev mp1 mesh join abcdefgh
command failed: Operation already in progress (-114)

***@xyz:/home/yz#
-- End of shorter version

At this time, I see "Not connected" If i try to query the interface's
status using link in the iw utility.

I've tried creating these scenarios :

Interface mp0 and mp1 on the SAME machine.
Interface mp0 and mp1 on Different machines.

But in both these situations, I'm not able to ping the IP addresses
from each other.

I have gone through the linux wireless page on iw a few times but that
doesn't seem to offer much help.

Any ideas why the node is not able to connect to the mesh ?
Thanks a lot!

PS - In case someone's interested, this is the longer version of the
same with debug enabled :
(Putting this at the end of the mail so that its not mandatory to scroll down)

***@xyz:/home/yz# iw --debug dev wlan0 interface add mp0 type mp
mesh_id abcdefgh
-- Debug: Sent Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 56
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410774963
.nlmsg_pid = 25362
[PAYLOAD] 40 octets
07 00 00 00 08 00 03 00 03 00 00 00 08 00 04 00 6d 70 ................mp
30 00 08 00 05 00 07 00 00 00 0c 00 18 00 61 62 63 64 0.............abcd
65 66 67 68 efgh
--------------------------- END NETLINK MESSAGE ---------------------------
-- Debug: Received Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 36
.nlmsg_type = 2 <ERROR>
.nlmsg_flags = 0 <>
.nlmsg_seq = 1410774963
.nlmsg_pid = 25362
[ERRORMSG] 20 octets
.error = 0 "Success"
[ORIGINAL MESSAGE] 16 octets
.nlmsg_len = 16
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410774963
.nlmsg_pid = 25362
--------------------------- END NETLINK MESSAGE ---------------------------
***@xyz:/home/yz# iw --debug dev mp0 set channel 2
-- Debug: Sent Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 44
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775000
.nlmsg_pid = 25660
[PAYLOAD] 28 octets
02 00 00 00 08 00 03 00 0e 00 00 00 08 00 26 00 71 09 ..............&.q.
00 00 08 00 27 00 00 00 00 00 ....'.....
--------------------------- END NETLINK MESSAGE ---------------------------
-- Debug: Received Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 36
.nlmsg_type = 2 <ERROR>
.nlmsg_flags = 0 <>
.nlmsg_seq = 1410775000
.nlmsg_pid = 25660
[ERRORMSG] 20 octets
.error = 0 "Success"
[ORIGINAL MESSAGE] 16 octets
.nlmsg_len = 16
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775000
.nlmsg_pid = 25660
--------------------------- END NETLINK MESSAGE ---------------------------
***@xyz:/home/yz# ifconfig mp0 hw ether 94:a0:c0:b1:11:42
***@xyz:/home/yz# ifconfig mp0 192.168.3.82
***@xyz:/home/yz# ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:8969 errors:0 dropped:0 overruns:0 frame:0
TX packets:8969 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:977314 (977.3 KB) TX bytes:977314 (977.3 KB)

mp0 Link encap:Ethernet HWaddr 94:a0:c0:b1:11:42
inet addr:192.168.3.82 Bcast:192.168.3.255 Mask:255.255.255.0
inet6 addr: fe80::96a0:c0ff:feb1:1142/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:40 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:10108 (10.1 KB)

***@xyz:/home/yz# iw --debug dev wlan0 interface add mp1 type mp
-- Debug: Sent Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 44
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775080
.nlmsg_pid = 26229
[PAYLOAD] 28 octets
07 00 00 00 08 00 03 00 03 00 00 00 08 00 04 00 6d 70 ................mp
31 00 08 00 05 00 07 00 00 00 1.........
--------------------------- END NETLINK MESSAGE ---------------------------
-- Debug: Received Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 36
.nlmsg_type = 2 <ERROR>
.nlmsg_flags = 0 <>
.nlmsg_seq = 1410775080
.nlmsg_pid = 26229
[ERRORMSG] 20 octets
.error = 0 "Success"
[ORIGINAL MESSAGE] 16 octets
.nlmsg_len = 16
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775080
.nlmsg_pid = 26229
--------------------------- END NETLINK MESSAGE ---------------------------
***@xyz:/home/yz# iw --debug dev mp1 set channel 2
-- Debug: Sent Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 44
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775098
.nlmsg_pid = 26387
[PAYLOAD] 28 octets
02 00 00 00 08 00 03 00 0f 00 00 00 08 00 26 00 71 09 ..............&.q.
00 00 08 00 27 00 00 00 00 00 ....'.....
--------------------------- END NETLINK MESSAGE ---------------------------
-- Debug: Received Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 36
.nlmsg_type = 2 <ERROR>
.nlmsg_flags = 0 <>
.nlmsg_seq = 1410775098
.nlmsg_pid = 26387
[ERRORMSG] 20 octets
.error = 0 "Success"
[ORIGINAL MESSAGE] 16 octets
.nlmsg_len = 16
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775098
.nlmsg_pid = 26387
--------------------------- END NETLINK MESSAGE ---------------------------
***@xyz:/home/yz# ifconfig mp1 hw ether 94:a0:c0:b1:11:45
***@xyz:/home/yz# ifconfig mp1 192.168.3.84
***@xyz:/home/yz# ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:9049 errors:0 dropped:0 overruns:0 frame:0
TX packets:9049 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:983682 (983.6 KB) TX bytes:983682 (983.6 KB)

mp0 Link encap:Ethernet HWaddr 94:a0:c0:b1:11:42
inet addr:192.168.3.82 Bcast:192.168.3.255 Mask:255.255.255.0
inet6 addr: fe80::96a0:c0ff:feb1:1142/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:48 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:11628 (11.6 KB)

mp1 Link encap:Ethernet HWaddr 94:a0:c0:b1:11:45
inet addr:192.168.3.84 Bcast:192.168.3.255 Mask:255.255.255.0
inet6 addr: fe80::96a0:c0ff:feb1:1145/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

***@xyz:/home/yz# iw --debug dev mp1 mesh join abcdefgh
-- Debug: Sent Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 40
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775169
.nlmsg_pid = 26812
[PAYLOAD] 24 octets
44 00 00 00 08 00 03 00 0f 00 00 00 0c 00 18 00 61 62 D...............ab
63 64 65 66 67 68 cdefgh
--------------------------- END NETLINK MESSAGE ---------------------------
-- Debug: Received Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 36
.nlmsg_type = 2 <ERROR>
.nlmsg_flags = 0 <>
.nlmsg_seq = 1410775169
.nlmsg_pid = 26812
[ERRORMSG] 20 octets
.error = 0 "Success"
[ORIGINAL MESSAGE] 16 octets
.nlmsg_len = 16
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775169
.nlmsg_pid = 26812
--------------------------- END NETLINK MESSAGE ---------------------------
***@xyz:/home/yz# iw dev mp0 link
Not connected.
***@xyz:/home/yz# iw dev mp0 info
Interface mp0
ifindex 14
type mesh point
wiphy 7
***@xyz:/home/yz# iw dev mp1 info
Interface mp1
ifindex 15
type mesh point
wiphy 7
***@xyz:/home/yz# iw dev mp0 station dump
***@xyz:/home/yz# iw --debug dev mp1 mesh join abcdefgh
-- Debug: Sent Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 40
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775258
.nlmsg_pid = 27519
[PAYLOAD] 24 octets
44 00 00 00 08 00 03 00 0f 00 00 00 0c 00 18 00 61 62 D...............ab
63 64 65 66 67 68 cdefgh
--------------------------- END NETLINK MESSAGE ---------------------------
-- Debug: Received Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[HEADER] 16 octets
.nlmsg_len = 60
.nlmsg_type = 2 <ERROR>
.nlmsg_flags = 0 <>
.nlmsg_seq = 1410775258
.nlmsg_pid = 27519
[ERRORMSG] 20 octets
.error = -114 "Operation already in progress"
[ORIGINAL MESSAGE] 16 octets
.nlmsg_len = 16
.nlmsg_type = 24 <0x18>
.nlmsg_flags = 5 <REQUEST,ACK>
.nlmsg_seq = 1410775258
.nlmsg_pid = 27519
--------------------------- END NETLINK MESSAGE ---------------------------
command failed: Operation already in progress (-114)

Regards,
Ashish Gupta

[Bob Copeland via Devel]

^^^ should be mp0 (or is that a copy paste error)??

Post by Ashish Gupta via Devel
command failed: Operation already in progress (-114)

^^^ because you already joined on mp1 (instead of mp0)?

Post by Ashish Gupta via Devel
Interface mp0 and mp1 on the SAME machine.
Interface mp0 and mp1 on Different machines.

Generally you will want them on different machines, because by
default frames won't get routed over the air if both interfaces
are local (though you can play games to make this happen anyway).

[Yeoh Chun-Yeow via Devel]

Suggest to bring up a monitor interface and try to capture on the same
channel. Check whether the beacon frame is available and etc.

----
Chun-Yeow


On Mon, Sep 15, 2014 at 11:46 PM, Bob Copeland via Devel

Post by Bob Copeland via Devel
^^^ should be mp0 (or is that a copy paste error)??

Post by Ashish Gupta via Devel
command failed: Operation already in progress (-114)

^^^ because you already joined on mp1 (instead of mp0)?

Post by Ashish Gupta via Devel
Interface mp0 and mp1 on the SAME machine.
Interface mp0 and mp1 on Different machines.

Generally you will want them on different machines, because by
default frames won't get routed over the air if both interfaces
are local (though you can play games to make this happen anyway).
--
Bob Copeland %% www.bobcopeland.com
_______________________________________________
Devel mailing list
http://lists.open80211s.org/cgi-bin/mailman/listinfo/devel

[Ashish Gupta via Devel]

Thanks for the prompt responses Bob Copeland and Yeoh Chun Yeow.

I took your advice and set up a monitor interface.which in fact senses
all the beacon frames that one station is transmitting. I was able to
verify the beacon frames on Station 2 as well as Station3. The problem
is, I cannot "connect" to the station 1 when its running the mesh.

This is what I try to do :

On station 1 :
set up an interface mp0 over wlan0
Set meshid on mp0 to "meshnet"
Assign unique mac address to mp0
Assign IP address to mp0
ifconfig up the interface mp0

On station 2:
set up an interface mp1 over wlan0
Do not set meshid to anything
Assign unique mac
Assign IP address to mp1
ifconfig up the interface mp1
Try to join mesh with mesh join command ("meshnet")

On station 3 :
Set up as a monitor. Capturing packets/frames using wireshark.

Once I do this, I can observe that the station 1 keeps broadcasting
beacon frames (can see this on station 3). Station 2 does not
broadcast any frames till the time the join command is executed.

After executing mesh join on station 2 , something seems to happen
although there's no sign of a connection being established. Station 2
now starts broadcasting beacon frames broadcasting "meshnet". But
there is no connection between Station 1 and Station 2. Station 2
seems to connect to itself somehow and assume that its the only mesh
node in it's mesh and therefore starts broadcasting itself. Station 1
is still broadcasting it's beacon frames like it was.

What should I be expecting to see when Station 2 connects to Station 1
? And do I need to "mesh join" on both machines even when one of them
has an already set mesh id ? When they are connected, I should be able
to ping one host from another. I can't. I'd appreciate it if you could
point me into the right direction.

Thanks!

Regards,
Ashish Gupta

Post by Yeoh Chun-Yeow via Devel
Suggest to bring up a monitor interface and try to capture on the same
channel. Check whether the beacon frame is available and etc.
----
Chun-Yeow
On Mon, Sep 15, 2014 at 11:46 PM, Bob Copeland via Devel

Post by Bob Copeland via Devel
^^^ should be mp0 (or is that a copy paste error)??

Post by Ashish Gupta via Devel
command failed: Operation already in progress (-114)

^^^ because you already joined on mp1 (instead of mp0)?

Post by Ashish Gupta via Devel
Interface mp0 and mp1 on the SAME machine.
Interface mp0 and mp1 on Different machines.

Generally you will want them on different machines, because by
default frames won't get routed over the air if both interfaces
are local (though you can play games to make this happen anyway).
--
Bob Copeland %% www.bobcopeland.com
_______________________________________________
Devel mailing list
http://lists.open80211s.org/cgi-bin/mailman/listinfo/devel

[Thomas Pedersen via Devel]

Try this:

1. add mesh interfaces without setting meshid
2. don't mess with the mac addresses
3. link up
4. mesh join
--
thomas

Post by Ashish Gupta via Devel
Thanks for the prompt responses Bob Copeland and Yeoh Chun Yeow.
I took your advice and set up a monitor interface.which in fact senses
all the beacon frames that one station is transmitting. I was able to
verify the beacon frames on Station 2 as well as Station3. The problem
is, I cannot "connect" to the station 1 when its running the mesh.
set up an interface mp0 over wlan0
Set meshid on mp0 to "meshnet"
Assign unique mac address to mp0
Assign IP address to mp0
ifconfig up the interface mp0
set up an interface mp1 over wlan0
Do not set meshid to anything
Assign unique mac
Assign IP address to mp1
ifconfig up the interface mp1
Try to join mesh with mesh join command ("meshnet")
Set up as a monitor. Capturing packets/frames using wireshark.
Once I do this, I can observe that the station 1 keeps broadcasting
beacon frames (can see this on station 3). Station 2 does not
broadcast any frames till the time the join command is executed.
After executing mesh join on station 2 , something seems to happen
although there's no sign of a connection being established. Station 2
now starts broadcasting beacon frames broadcasting "meshnet". But
there is no connection between Station 1 and Station 2. Station 2
seems to connect to itself somehow and assume that its the only mesh
node in it's mesh and therefore starts broadcasting itself. Station 1
is still broadcasting it's beacon frames like it was.
What should I be expecting to see when Station 2 connects to Station 1
? And do I need to "mesh join" on both machines even when one of them
has an already set mesh id ? When they are connected, I should be able
to ping one host from another. I can't. I'd appreciate it if you could
point me into the right direction.
Thanks!
Regards,
Ashish Gupta

Post by Yeoh Chun-Yeow via Devel
Suggest to bring up a monitor interface and try to capture on the same
channel. Check whether the beacon frame is available and etc.
----
Chun-Yeow
On Mon, Sep 15, 2014 at 11:46 PM, Bob Copeland via Devel

Post by Bob Copeland via Devel
^^^ should be mp0 (or is that a copy paste error)??

Post by Ashish Gupta via Devel
command failed: Operation already in progress (-114)

^^^ because you already joined on mp1 (instead of mp0)?

Post by Ashish Gupta via Devel
Interface mp0 and mp1 on the SAME machine.
Interface mp0 and mp1 on Different machines.

Generally you will want them on different machines, because by
default frames won't get routed over the air if both interfaces
are local (though you can play games to make this happen anyway).
--
Bob Copeland %% www.bobcopeland.com
_______________________________________________
Devel mailing list
http://lists.open80211s.org/cgi-bin/mailman/listinfo/devel

_______________________________________________
Devel mailing list
http://lists.open80211s.org/cgi-bin/mailman/listinfo/devel

[Ashish Gupta via Devel]

On Wed, Sep 17, 2014 at 12:25 AM, Thomas Pedersen via Devel

Post by Thomas Pedersen via Devel
1. add mesh interfaces without setting meshid
2. don't mess with the mac addresses
3. link up
4. mesh join
--
thomas
_______________________________________________
Devel mailing list
http://lists.open80211s.org/cgi-bin/mailman/listinfo/devel

Thanks for this, Thomas! The mesh finally worked, and I can now ping
the connected stations from one another.
Feels nice to see it in action.

Post by Thomas Pedersen via Devel
In addition to what Thomas suggested, you may want to make sure you're
running the same kernel on both devices, just in case there's some
issue with the neighbor comparison between two kernels.

Right now the stations I am using are running these versions of the kernels :

3.16.1-1-ARCH on station 1
3.13.0-35-generic on station 2

They seem to be connected and pinging each other. Thanks for the heads
up though, I'll be more careful and consider this if I run into
problems with other machines.

I'll try setting up the mesh gates now to enable WAN on the mesh.

PS - Is there a specific reason to it not working with changed MAC
addresses and preset mesh IDs ?

Thanks a lot for all the help!

Regards,
Ashish Gupta

[Yeoh Chun-Yeow via Devel]

Post by Ashish Gupta via Devel
PS - Is there a specific reason to it not working with changed MAC
addresses and preset mesh IDs ?

It should not have any problem if you change the MAC address of your
mesh interface provided you are using two different WiFi chipset.

For preset mesh ID, you probably need to do "iw <mesh interface> set
channel ....". Otherwise, I think that it will default to channel 1.

-----
Chun-Yeow

[Ashish Gupta via Devel]

Post by Yeoh Chun-Yeow via Devel

Post by Ashish Gupta via Devel
PS - Is there a specific reason to it not working with changed MAC
addresses and preset mesh IDs ?

It should not have any problem if you change the MAC address of your
mesh interface provided you are using two different WiFi chipset.
For preset mesh ID, you probably need to do "iw <mesh interface> set
channel ....". Otherwise, I think that it will default to channel 1.

Okay , thank you. I will keep this in mind for later experiments.

I was wondering about the mesh gate and possibly using an internet
connection over the mesh. As far as I understand it, someone in the
mesh will have to perform a NAT and forward IP packets to and from the
interface connected to the internet/access point/router. Is this
already possible ? And can I achieve this without the mesh gate or is
that a recommended requirement?

Thanks.

Regards,
Ashish Gupta

[Yeoh Chun-Yeow via Devel]

Post by Ashish Gupta via Devel

Post by Yeoh Chun-Yeow via Devel

Post by Ashish Gupta via Devel
PS - Is there a specific reason to it not working with changed MAC
addresses and preset mesh IDs ?

It should not have any problem if you change the MAC address of your
mesh interface provided you are using two different WiFi chipset.
For preset mesh ID, you probably need to do "iw <mesh interface> set
channel ....". Otherwise, I think that it will default to channel 1.

Okay , thank you. I will keep this in mind for later experiments.
I was wondering about the mesh gate and possibly using an internet
connection over the mesh. As far as I understand it, someone in the
mesh will have to perform a NAT and forward IP packets to and from the
interface connected to the internet/access point/router. Is this
already possible ? And can I achieve this without the mesh gate or is
that a recommended requirement?

If you are talking about gate announcement or active path selection
protocol, it is not necessary. But it could speed up the path selection for
peer mesh STAs since path always available. You have two choices either NAT
(L3) or bridging (L2) your mesh gate to internet access.

---
Chun-Yeow

[Bob Copeland via Devel]

Post by Ashish Gupta via Devel
there is no connection between Station 1 and Station 2. Station 2
seems to connect to itself somehow and assume that its the only mesh
node in it's mesh and therefore starts broadcasting itself. Station 1
is still broadcasting it's beacon frames like it was.

In 11s mesh, unlike ibss, all stations broadcast beacon frames all the
time, so this is normal.

In addition to what Thomas suggested, you may want to make sure you're
running the same kernel on both devices, just in case there's some
issue with the neighbor comparison between two kernels.