The AP sends a heartbeat - which is actually a WiFi frame over the GRE tunnel to the controller (which as this is a RAP is inside the IPSec tunnel - so tunnel in a tunnel).
When the controller gets this frame it checks to see if the tunnel is valid - if not it send back an ICMP unreachable message. The AP will then immediately rebootstrap or connect to the defined backup LMS.
If the tunnel is valid it replies straight back to the AP.
So how do you get the messages below;
Depending on the AP type the default packet loss is significantly different, for a RAP it is 30 consecutive heartbeat losses, and for campus AP this is 8 heartbeat losses (30 seconds and 8 seconds respectively).
This can be over ridden by;
(Aruba650) (config) #ap system-profile test
(Aruba650) (AP system profile "test") #boot?
bootstrap-threshold The number of missed heartbeats that will cause the
AP to rebootstrap. Range: 1-65535. Default: 8.
2013-01-26 05:31:25 Missed heartbeats: Last Sequence Generated=28371 Last Rcvd=28340
we can see here you have lost 30 heartbeats.
In 'newer' releases we do make it slightly easier to debug what's going on.
On the controller you can issue the following command;
(Aruba) #show datapath tunnel heartbeat
Datapath Tunnel Table Entries
-----------------------------
Flags: E - Ether encap, I - Wi-Fi encap, R - Wired tunnel, F - IP fragment OK
W - WEP, K - TKIP, A - AESCCM, G - AESGCM, M - no mcast src filtering
S - Single encrypt, U - Untagged, X - Tunneled node, 1(cert-id) - 802.1X Term-PEAP
2(cert-id) - 802.1X Term-TLS, T - Trusted, L - No looping, d - Drop Bcast/Mcast,
D - Decrypt tunnel, a - Reduce ARP packets in the air, e - EAPOL only
C - Prohibit new calls, P - Permanent, m - Convert multicast
n - Convert RAs to unicast(VLAN Pooling enabled), s - Split tunnel
V - enforce user vlan(open clients only)
# Source Destination Prt MTU Acls BSSID Decaps Encaps Heartbeats Seqnum Missed Outoforder Cpu QSz Flags
------ -------------- -------------- --- ---- ------------------- ----------------- ---------- ---------- ---------- ------ ------ ---------- --- --- -----
41 192.168.254.9 192.168.254.247 47 1500 0 0 0 0 D8:C7:C8:C0:CC:48 12785 0 12783 12898 107 0 6 0 TES
21 192.168.254.9 192.168.254.252 47 1500 0 0 0 0 D8:C7:C8:C0:CC:50 328758 0 328756 3848 2764 0 5 0 TES
56 192.168.254.9 192.168.254.249 47 1500 0 0 0 0 D8:C7:C8:C0:CC:42 12775 0 12773 12889 107 0 7 0 TES
13 192.168.254.9 192.168.254.251 47 1500 0 0 0 0 D8:C7:C8:C0:CC:2E 1009988 0 1009986 35441 8487 0 5 0 TES
47 192.168.254.9 192.168.254.236 47 1500 0 0 0 0 D8:C7:C8:C0:CC:36 1009263 0 1009261 34711 8482 0 6 0 TES
23 192.168.254.9 192.168.254.41 47 1500 0 0 0 0 00:24:6C:CE:99:32 28280 0 27816 27824 0 0 7 0 TES
(Aruba650) #
To debug the AP;
(Aruba650) #show ap debug gre-tun-stats ap-name office
GRE HBT Tunnel Stats
--------------------
AP IP Controller IP Sent Count HBT Tx Seqnum Idle (secs) Rcvd Count HBT Rx Seqnum Idle (secs)
----- ------------- ---------- ------------- ----------- ---------- ------------- -----------
192.168.254.252 192.168.254.9 331558 3884 0 328794 3884 0
GRE Tunnel Packet Stats
-----------------------
MAC BSSID Tun Input In IP Frags To WLAN Idle (secs) Rate pps From WLAN Tun Output Out IP Frags Idle (secs) Rate pps
--- ----- --------- ----------- ------- ----------- -------- --------- ---------- ------------ ----------- --------
00:26:B0:C0:AF:4B 8C:C5:00 5208 0 5208 60 0 4796 4796 0 60 0
00:27:10:2C:2A:A4 8C:C5:00 539461 2 539461 0 6 409290 409290 2 0 6
01:80:C2:00:00:00 8C:C5:00 157497 0 157879 0 0 0 0 0 0 0
FF:FF:FF:FF:FF:FF 8C:C5:00 174278 0 174278 0 0 0 0 0 0 0
01:00:5E:7F:FF:FA 8C:C5:00 256402 0 256402 0 3 0 0 0 0 0
01:00:5E:00:00:FB 8C:C5:00 5636 0 5636 120 0 0 0 0 0 0
(Aruba650) #
To check speed /duplex of the ethernet port of the AP you can issue the following command;
(ArubaTelford) #show ap debug port status ap-name gscott-rap5
Tue Feb 12 10:12:11 2013
AP "gscott-rap5" Port Status
----------------------------
Port MAC Type Forward Mode Admin Oper Speed Duplex 802.3az PoE TX-Packets TX-Bytes RX-Packets RX-Bytes
---- --- ---- ------------ ----- ---- ----- ------ ------- --- ---------- -------- ---------- --------
0 00:0b:86:66:0d:a3 GE N/A enabled up 1 Gb/s full N/A N/A 12453993 6146002748 23991004 9685567011
1 00:0b:86:66:0d:a4 FE tunnel enabled down N/A N/A N/A N/A 0 0 0 0
2 00:0b:86:66:0d:a5 FE N/A disabled down N/A N/A N/A N/A 0 0 0 0
3 00:0b:86:66:0d:a6 FE N/A disabled down N/A N/A N/A N/A 0 0 0 0
4 00:0b:86:66:0d:a7 FE tunnel enabled down N/A N/A N/A N/A 0 0 0 0
(ArubaTelford) #