AP negotiating 100Mb instead of 1Gbps

[umeshunited]

Hi All,

Cisco AIR-AP3802I-B-K9 is connected to cisco WS-C4506-E on module WS-X4648-RJ45V+E . WLC is having version as 8.2.166.0 Now the problem is some AP are negotiating 100 Mb even though they are connected to Gig interface of the switch. 

I tried cable testing " test cable-diagnostics tdr interface gigabitEthernet " but it says "%C4K_IOSDIAGMAN-4-TESTNOTSUPPORTEDONMODULE: Online cable diag tdr test is not supported on module"

I also tried configuring speed and duplex on switch manually.

As soon as I try to manually set it , switch port will go down and AP won't come up.

[Leo Laohoo]

---

@umeshunited wrote:

I also tried configuring speed and duplex on switch manually.

As soon as I try to manually set it , switch port will go down and AP won't come up. 

---

It does sound like one of the cable pairs, pair "D", is faulty.  

Because TDR isn't supported on the line card, switch the cable to the port found in the supervisor card temporarily and then the TDR test once again.

[umeshunited]

Sure. But as of now do not have any local support who can help me plug the cable to SUP. It may take 3 to 4 days to get someone there. But I will try my best.

[balaji.bandi]

From Cat 4506 

can you post the running config of that port and capabilities.

show ver

show run interface gi x/x/x

show interface gi x/x/x capabilities

what is the distance of AP and Switch

[umeshunited]

Please find output :

Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-IPBASEK9-M), Version 12.2(53)SG2, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 16-Mar-10 03:16 by prod_rel_team
Image text-base: 0x10000000, data-base: 0x1259256C

ROM: 12.2(44r)SG5
Darkside Revision 4, Jawa Revision 9, Tatooine Revision 140, Forerunner Revision 1.21

Switch uptime is 5 years, 44 weeks, 1 day, 16 hours, 56 minutes
System returned to ROM by reload
System restarted at 01:02:50 EST Sat Jan 19 2013
System image file is "bootflash:cat4500e-ipbasek9-mz.122-53.SG2.bin"
Last reload reason: Unknown reason

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
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If you require further assistance please contact us by sending email to
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cisco WS-C4506-E (MPC8548) processor (revision 8) with 524288K bytes of memory.
Processor board ID FOX1430GQAD
MPC8548 CPU at 1GHz, Supervisor 6L-E
Last reset from Reload
4 Virtual Ethernet interfaces
148 Gigabit Ethernet interfaces
2 Ten Gigabit Ethernet interfaces
511K bytes of non-volatile configuration memory.

Configuration register is 0x2101

Switch#sho run inter gi 2/47
Building configuration...

Current configuration : 352 bytes
!
interface GigabitEthernet2/47
description Wireless AP
switchport access vlan 443
switchport mode access
switchport port-security maximum 3
switchport port-security
switchport port-security aging time 2
switchport port-security aging type inactivity
spanning-tree portfast
spanning-tree bpduguard enable
ip dhcp snooping limit rate 900
end

Switch#sho int gi 2/47 cap
Switch#sho int gi 2/47 capabilities
GigabitEthernet2/47
Model: WS-X4648-RJ45V+E-RJ-45
Type: 10/100/1000-TX
Speed: 10,100,1000,auto
Duplex: half,full,auto
Auto-MDIX: yes
Trunk encap. type: 802.1Q
Trunk mode: on,off,desirable,nonegotiate
Channel: yes
Broadcast suppression: percentage(0-100), hw
Multicast suppression: percentage(0-100), hw
Flowcontrol: rx-(off,on,desired),tx-(off,on,desired)
VLAN Membership: static, dynamic
Fast Start: yes
CoS rewrite: yes
ToS rewrite: yes
Inline power: yes (Cisco Voice Protocol/IEEE Protocol 802.3af)
SPAN: source/destination
UDLD: yes
Link Debounce: no
Link Debounce Time: no
Port Security: yes
Dot1x: yes
Maximum MTU: 9198 bytes (Jumbo Frames)
Multiple Media Types: no
Diagnostic Monitoring: N/A
Queuing: rx-(N/A), tx-(1p7q1t)
Switch#

Sorry , I am at the remote location , no idea about distance btw AP and switch.

[balaji.bandi]

 when some one available for you to assistance on this, check the distance how far.

if possible bring the AP near the switch and connect and see what the results, this could be a  Cable or Patching issue (one of the problem as part of the diagnosis).

[Oliver.Gao36]

Hey Buddy, have u resolved the problem? here i have a Cisco 9115AXI  AP, which has the same symptom like yours, i let it connect with a Cisco 2960X-48-FDP switch, no matter what i did(shut, not shut the switch interface, or reset the AP from WLC or mode button), it always sticks at speed-100.....

[Leo Laohoo]

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@Oliver.Gao36 wrote:

Hey Buddy, have u resolved the problem? here i have a Cisco 9115AXI  AP, which has the same symptom like yours, i let it connect with a Cisco 2960X-48-FDP switch, no matter what i did(shut, not shut the switch interface, or reset the AP from WLC or mode button), it always sticks at speed-100.....

---

Depending if the 2960X is running on a firmware that will support the function, run a TDR to determine whether or not there is a cable fault.  

[umeshunited]

Hi @Oliver.Gao36 ,

Leo Laohoo , is correct , I used TDR function in switch and found that one pair of the cable was faulty. One thing to keep in mind that running this test will bounce the interface so wireless clients will lose network connectivity.

To run the test use "test cable-diagnostics tdr interface XXXX " after 5-10 seconds you can see results using "show cable-diagnostics tdr int XXXX" you should see pair status as "Normal". For more info on TDR please use link that Leo Laohoo shared.

HTH.

[Oliver.Gao36]

Hi,@umeshunited

I tried your suggestions

i even asked our weak electricity supplier to check our cable, but their Fluke cable probe showed and proofed that the cable is good, i let all the APs connect with the switch, the others are all normal, only this one is running under a-100

[Scott Fella]

Have you tried to swap the patch cable and also switch to a different port? My suggestion is to take the ap and see if it negotiates at 1gb in any other switch.

[Leo Laohoo]

Oh I know what this is.
This is a "bug". I see this a lot of times on "classic" IOS APs, like 3700, and in a lot of cases running a TDR will "jar" the AP to re-negotiate to 1 Gbps.
In those cases where a TDR (Cisco or Fluke) comes up as all good, I had to send 2 x 3700 to TAC to run field analysis because no matter what we did, the AP simply will not negotiate to 1 Gbps. Engineering analysis claims the APs simply had a broken hardware.

So from that time on, whenever we have APs that refuses to negotiate to 1 Gbps, I just get it RMA-ed.  

[RL5901]

I've been told by TAC and seen this in documents as well, that TDR diagnostic is not supported on WAPs. We are experiencing much consternation within our team over this very issue. Cable testers show no open pairs but the TDR results for the switch port attached to the WAP show open pairs. It went back and forth for quite some time with a lot of finger-pointing. The junior network engineer tasked with trying to find out why some of our WAPs are running at 100 Mbps instead of 1 Gbps is blaming the team member who replaces our cables. The team member replacing our cables is showing that 2 testers show the Cat6 cable is good (end to end), but replaced the cable anyway for good measure. Replacing the cable changed nothing. I can confirm that the switch and AP are auto-negotiating at 100 Mbps. 

Cisco AIR-AP3802I-B-K9

AP Version : Cisco AP Software, ap3g3-k9w8 Version: 8.10.183.0

Switch Ports Model: WS-C3850-12X48U

SW Version: 03.07.04E

[Leo Laohoo]

IT is a software bug with the AP.  We regularly see this issue occurring on 2700/3700, 2800/3800/4800.  I rarely see this issue on Catalyst 91XX.  

Reboot the AP, by turning PoE off and on, would fix the issue.  

[RL5901]

We are also seeing this with APs connected to 9300 series switches (e.g., C9300-48U), also. The switch and AP are auto-negotiating at 1 Mbps. The junior network engineer runs a TDR diagnostic from the switch with the Wireless AP connected at the end, sees open pairs in the test results on a new Cat6 cable, and blames the technician for the lower speed (and this just goes back and forth wasting everyone's time and efforts). This is why I opened the TAC case, to confirm documentation I found that TDR diagnostic testing should not be performed with a Wireless AP connected.

The bug information is helpful. If you have the Bug ID for the lowered auto-negotiated speeds that would be even more useful (but if you don't have it that's fine).