Collab Network Test 0321D

This is a forum for discussion about the packet traces obtained in test 0321D.

Logs

Packet Traces: Chan 1, Chan 11, Chan 6

Laptop X59 logs: All, dmesg, /var/log/messages, Telepathy/Sugar

Laptop X71 logs: All, dmesg, /var/log/messages, Telepathy/Sugar

Server logs: /var/log/messages, Laptop List

It appears clear that the logging mechanism doesn't record every frame in the air at every location!

Channel 1

The School server has MAC address of 00:50:43:28:26:2d.

Laptop X59

This laptop has MAC address 00:17:c4:11:01:f0. The school server logs show no record of a successful DHCP in the test period.

The filter most useful in this search was:

wlan.sa==00:17:c4:11:01:f0 || wlan.da==00:17:c4:11:01:f0 || wlan_mgt.fixed.sa==00:17:c4:11:01:f0 || wlan_mgt.fixed.da==00:17:c4:11:01:f0

All times in packet trace time, unless otherwise noted

• At 64.215, beacons from X59 start appearing. This probably corresponds to power up, five seconds before main processor boot at roughly 5:18:20 laptop time, giving an offset from laptop kernel time to packet trace of roughly 55 sec., but I'm having trouble correlating the laptop log with what I see in the packet traces...
• From 72.930 to 79.523, the laptop issues six IPv6 nearest neighbor discovery requests
• At 78.097, it relays an RREQ from 00:17:c4:0d:08:46
• From the laptop logs, it issued a DHCP discover at time 5:19:32 (74 sec. laptop kernel time) -> 130 sec packet trace time
• We don't see the laptop issue an RREQ, even though we see it relay another laptops RREQ at 129.370
• Between 130.9986 and 131.0167 , a number of laptops repeat an RREQ from X59
• A number of RREPs are sent by the school server starting at 131.018, to 00:17:c4:11:50:c2, but we don't see it ever sending the RREP on to X59
• According to the laptop logs, additional DHCP DISCOVER packets were sent at 76 sec. kernel time (132 sec. packet trace time), 80 sec. (136 sec. packet trace time), and 88 sec. (144 sec. packet trace time).
• From 154.500 to 154.523, we see a number of laptops relaying an RREQ from X59
• From 172.474 to 172.503, we see a number of laptops relaying an RREQ from X59
• At 172.5029, we even see the school server relay the RREQ from X59, but never see it issue a RREP.
• From 175.650 to 176.416, X59 relays a number of RREQs from other laptops
• At 176.468, we see X59 send out an RREQ barrage (4 frames at varying speeds)
• At 176.489, we see X59 send out another RREQ barrage.
• From 176.495 to 176.632 we see a number of laptops relaying the RREQs from X59, including the school server at 176.546, 176.551, 176.555, 176.558, 176.566, and 176.570.
• No RREP from the school server is seen
• At 176.580 and 176.656 see X59 relaying RREQs for other laptops
• At 177.039, it relays a broadcast ARP request for the school server
• At 178.471, we see X59 send out an RREQ barrage
• From 178.476 to 178.651 we see a number of laptop relaying the RREQs from X59
• No RREP from the school server is seen
• At 183.495, we see X59 send out an RREQ barrage
• From 183.500 to 183.521 we see a number of laptop relaying the RREQs from X59
• No RREP from the school server is seen
• At 191.475, we see X59 send out an RREQ barrage
• From 191.479 to 191.515 we see a number of laptop relaying the RREQs from X59
• No RREP from the school server is seen
• ...

Appears to be a case of the school server not responding to RREQs from this laptop.

Laptop X71

The laptop has a MAC address of 00:17:c4:11:0b:17.

• The typical situation, lots of RREQs relayed at the beginning.
• At 97.767 is a message you don't see very often: a barrage of route errors, sent from X71 to the school server.
• At 105.596 we see a relayed version of an RREQ from X71
• From 105.597 to 105.608, the school server sends an RREP to X71 via another laptop, but no retransmission to X71 was captured.

Can anybody tell me why there the same RREP is transmitted eight times by the school server, each time at 1 Mb/s ?

• From 115.582 to 115.601, we again see a number of laptops relaying an RREQ from X71
• At 115.603, the school server sends an RREP to X71 via another laptop. No retransmission to X71 was captured.

This time, it was four identical packets, sent at 1 Mb/s

• From 115.607 to 115.612, we see more laptops relaying the same RREQ from X71
• At 115.612, the school server sends another burst of RREPs to X71 via another laptop. No retransmission to X71 was captured.
• From 126.623 to 126.647, we again see a number of laptops relaying an RREQ from X71
• At 126.644, the school server sends an RREP to X71 via another laptop. No retransmission to X71 was captured.
• From 170.599 to 170.642, we again see a number of laptops relaying an RREQ from X71
• At 170.6228, we see the school server relaying an RREQ it should be responding to. We see this again at 170.6273, 170.6293, and 170.6330.

As the packet has an ANYCAST address, I guess it is reasonable that the school server continues to relay it ?

• From 175.638 to 175.662, we again see a number of laptops relaying an RREQ from X71. Again, the school server is one of the relaying nodes.

• ...
• From 214.192 to 214.194, and again from 214.278 to 214.280, X71 relays another laptops's RREQ.
• At 214.337, X71 issues a barrage of RREQs for the DHCP ANYCAST address.
• From 214.342 to 214.479, a number of laptops relay the RREQ from X71, including the school server
• No RREPs are seen
• At 214.609, X71 issues a barrage of RREQs for the DHCP ANYCAST address.
• From 214.631 to 214.705, a number of laptops relay the RREQ from X71
• No RREPs are seen
• At 215.611, X71 issues a barrage of RREQs for the DHCP ANYCAST address.
• From 215.613 to 215.643, a number of laptops relay the RREQ from X71, including the school server
• No RREPs are seen
• ...

X71 can be seen relaying RREPs from the school server to other laptops. Are we missing the RREPs which are then ignored by the firmware/driver on the laptop ? Possibly.

During the period of time that these laptops seemingly failed to receive an RREP, the school server did properly respond to some other laptops.

Other Channels

The other channels were not supported by the School server. Any traffic on them is either laptops looking for a school server or bleed-over from channel 1.