Mobile Computer Zebra - Disconnection - Mobility Express 18.5.131

[Welcome2008]

Hi,

I recently bought a new android terminal (Zebra MC2700) which unfortunately has disconnection problems causing the connection to be lost with an As400 client (Mocha app), my network is made up of several devices.

AIR-AP1852E-E-K9 (4ap) AIR-CAP1602I-E-K9 (2ap) AIR-CAP1602E-E-K9 (2ap)

After sending the logs to Zebra Support for analysis, I am prompted to have the APs checked and firmware updated.

I wonder if by purchasing a SmartNet support I can solve the disconnection problem or if I will only be able to get the firmware update from Cisco and not solve the actual problem!

[Rich R]

Ordinarily - yes - but you could also find a recent security advisory that affects 8.5 code and find the section which says "Customers without Contracts" then email TAC (don't phone) quoting the URL of the advisory, the paragraph just mentioned and the version and URL for the software you want to download and serial number of your AP/WLC.  Then TAC should publish it to you directly.

This one should be suitable: Cisco Access Point Software Arbitrary Code Execution Vulnerability because https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvw45507 lists 8.5.182.0 as a fixed release so spot on.

"Customers Without Service Contracts

Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html

Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade."

[Welcome2008]

Hi,

I have update the ME to 18.5.171, but the issue is already present.

I see this disconnection in the zebra device logs, why ? What happen ?

<6>[ 6317.866375] [schedu][0x25aed34690][11:36:59.989141] wlan: [2017:I:WMA] [11:36:58.072000] [ROAM_TRIGGER]: VDEV[0] Reason: "PERIODIC SCAN" Sub-Reason: LOW RSSI PERIODIC SCANCur_rssi_threshold: 0
<6>[ 6317.866444] [schedu][0x25aed34c40][11:36:59.989217] wlan: [2017:I:WMA] [11:36:58.072000] [ROAM_SCAN]: VDEV[0] Scan_type: FULL next_rssi_threshold: 0 dBm 
<6>[ 6317.866478] [schedu][0x25aed34eed][11:36:59.989252] wlan: [2017:I:WMA]      AP BSSID           TSTAMP       CH   TY  ETP  RSSI/SCR CU%/SCR TOT_SCR
<6>[ 6317.866517] [schedu][0x25aed351dd][11:36:59.989291] wlan: [2017:I:WMA] 00:3c:10:6b:d5:80 [11:36:58.072000] 2437 P_AP    0  81/0     0/0      750
<6>[ 6317.866632] [schedu][0x25aed353dd][11:36:59.989318] wlan: [2017:I:WMA] 00:3c:10:6b:d3:e0 [11:36:58.098000] 2412 C_AP   58  74/0    10/0     1490
<6>[ 6317.866662] [schedu][0x25aed35c9d][11:36:59.989435] wlan: [2017:I:WMA] 34:a8:4e:bb:ba:d0 [11:36:58.078000] 2412 C_AP   33  87/0    12/0      750
<6>[ 6317.866689] [schedu][0x25aed35ebe][11:36:59.989463] wlan: [2017:I:WMA] 00:3c:10:6b:3e:e0 [11:36:58.100000] 2412 C_AP   10  93/0    16/0      750
<6>[ 6317.866716] [schedu][0x25aed360c4][11:36:59.989490] wlan: [2017:I:WMA] e0:d1:73:1b:92:50 [11:36:58.158000] 2437 C_AP   41  82/0    30/0      750
<6>[ 6317.866744] [schedu][0x25aed362c5][11:36:59.989517] wlan: [2017:I:WMA] e0:89:9d:5a:14:f0 [11:36:58.244000] 2462 C_AP   19  90/0    26/0      750
<6>[ 6317.866770] [schedu][0x25aed364d6][11:36:59.989544] wlan: [2017:I:WMA] 00:3c:10:6b:d3:c0 [11:36:58.259000] 2462 C_AP   51  82/0    13/0      750
<6>[ 6317.866798] [schedu][0x25aed366e5][11:36:59.989572] wlan: [2017:I:WMA] [11:36:59.981000] [ROAM_RESULT]: VDEV[0] FAILED Reason: No ACK for Re-assoc req
<6>[ 6317.866837] [schedu][0x25aed369c8][11:36:59.989610] wlan: [2017:I:WMA] [11:36:58.169000] [ROAM_TRIGGER]: VDEV[0] Reason: "HIGH RSSI" Sub-Reason: FULL SCAN
<6>[ 6317.866863] [schedu][0x25aed36bc0][11:36:59.989636] wlan: [2017:I:WMA] [11:36:58.169000] [ROAM_SCAN]: VDEV[0] Scan_type: PARTIAL  {}
<6>[ 6317.866895] [schedu][0x25aed36e2d][11:36:59.989669] wlan: [2017:I:WMA]      AP BSSID           TSTAMP       CH   TY  ETP  RSSI/SCR CU%/SCR TOT_SCR
<6>[ 6317.866933] [schedu][0x25aed3710f][11:36:59.989707] wlan: [2017:I:WMA] 00:3c:10:6b:d5:80 [11:36:58.170000] 2437 P_AP    0  78/0     0/0     1130
<6>[ 6317.866960] [schedu][0x25aed37304][11:36:59.989733] wlan: [2017:I:WMA] [11:36:58.170000] [ROAM_RESULT]: VDEV[0] FAILED Reason: SCAN NOT STARTED
....
<6>[ 6317.908192] [schedu][0x25aedf87aa][11:37:00.030969] wlan: [2017:I:SME] disassoc from peer 00:3c:10:6b:d5:80reason: 2 status: 539 vid: 0
....
<6>[ 6317.925963] [schedu][0x25aee4bc79][11:37:00.048739] wlan: [2017:I:HDD] Disconnect reason: 2 WLAN_REASON_PREV_AUTH_NOT_VALID vendor: 0 LG: 0

Seems it is a bug of Ap Cisco, it disconnect the device with a not valid psk.

[Rich R]

1. I think you mean 8.5.171.0 not 18.5.171

2. If you were updating why not update to the latest version 8.5.182.0 or 8.10.183.0?

3. For questions about Zebra - talk to your Zebra vendor.

4. There's just as much likelihood of the bug being on the client device - especially if other clients work fine.  Sometimes it's an incompatibility with certain features - in which cases disabling those features may work around the bug.

[Welcome2008]

1. yes
2. Because the TAC said that the versione for me base on table 13 is 8.5.171.0

Thank you for all

[Rich R]

I have no idea what "table 13" is but the only official TAC recommendation (from https://www.cisco.com/c/en/us/support/docs/wireless/wireless-lan-controller-software/200046-tac-recommended-aireos.html#anc9) is:
"Mobility Express

For Mobility Express deployments, TAC recommends using the latest 8.10 release, 8.10.181.0.  Mobility Express deployments are not susceptible to the CSCwd37092 regression, and have no need for 8.10MR8 Escalation code."
Although actually even that is out of date - it should show 8.10.183.0 because of https://bst.cloudapps.cisco.com/bugsearch/bug/CSCwd80290

But as you're stuck on 8.5 because of the end of life 1602 APs you should be using the latest - 8.5.182.0 although that will still be affected by CSCwd80290 so you'll need to set the date back when downloading to the 1602 APs.  TAC confirmed that CSCwd80290 does not affect ME APs because they download from TFTP server not the controller so 8.5.182.0 is still good.

[Welcome2008]

this is the link of table 13 - compatibility matrix.
Matrix - ME 

let's wait, if they will release update 8.5.182.7.

In all this, however, I have not solved my real disconnection problem with the zebra terminal, unfortunately.
Zebra log says: Disconnect reason: 2 WLAN_REASON_PREV_AUTH_NOT_VALID

[Rich R]

Right, ok, that table is not intended to be recommended versions and clearly hasn't been updated for a while either for ME!  It's only about compatibility and you can safely assume anything in the same major release is compatible with later revisions of that release.  So anything compatible with 8.5.17x.0 will also be compatible with 8.5.182.0.  Cisco (lack of) documentation updates is an ongoing (and growing) problem!  For recommended versions the best and most up to date source is the TAC recommended releases.

[Welcome2008]

https://www.cisco.com/c/en/us/support/docs/csa/cisco-sa-ap-ethport-dos-xtjTt8pY.html
The vulnerability up is for my 1850 series.
I have write to TAC and i receive a response, I have to contact the local customer service and get assistance directly

I update you.

[Scott Fella]

@Welcome2008 keep us posted.  I think you still have to work with the vendor, because it doesn't make sense that all other devices work fine and this one doesn't. Most vendors I have worked with have a recommended configuration guide for various wireless vendors.  I would reach back out to them to provide that.  Have you posted on their community forum?  You might get some tips there also.

[Welcome2008]

I'm in contact with assistance Zebra (2 level support). 
I have disactivated the roaming 802.11k, now. I test this tomorrow.

[Scott Fella]

Hey that is progress..... you should also look at your WLAN.... when you enable so many features that can cause devices to freak out:).  Sometimes is best to create a test SSID with the basic configurations and do some testing.  It will shock you how well devices perform.

[Welcome2008]

Hi,

what happened here ? at line 241 of attached file

[Scott Fella]

Try to use this tool to help parse debugs:
https://cway.cisco.com/wireless-debug-analyzer/

[Welcome2008]

i have open a TAC code with cisco support. 
I will be contacted by an engineer for the upgrade

[Scott Fella]

That is good.  Maybe they can look at your environment and configuration to help you sort this issue out.