05-31-2016 06:39 AM - edited 03-08-2019 06:00 AM
05-31-2016 07:54 AM
Need to check the reason of the port going down.
Configure the udld aggressive and check UDLD reason is it due to what parameter?
Other option to check will be to move the cable to different port and see if the port comes up else it could be problem with the sfp / cable.
05-31-2016 08:03 AM
Not sure to catch your point.
I do not want to enable aggressive, it was a temporary behaviour and the links are WAN links not inside the DC.
Here you can see the logs:
05-31-2016 10:47 AM
sh int te2/7 trans
sh int te2/5 trans
try to change FO patchcords
try to change SFP
try to measure FO links by OLTS and OTDR
06-01-2016 12:02 AM
xxx#sh int te2/5 transceiver
Transceiver monitoring is disabled for all interfaces.
ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
If device is externally calibrated, only calibrated values are printed.
++ : high alarm, + : high warning, - : low warning, -- : low alarm.
NA or N/A: not applicable, Tx: transmit, Rx: receive.
mA: milliamperes, dBm: decibels (milliwatts).
Optical Optical
Temperature Voltage Current Tx Power Rx Power
Port (Celsius) (Volts) (mA) (dBm) (dBm)
---------- ----------- ------- -------- -------- --------
Te2/5 25.5 0.00 59.2 -- 1.1 -3.1
xxx#sh int te2/7 transceiver
Transceiver monitoring is disabled for all interfaces.
ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
If device is externally calibrated, only calibrated values are printed.
++ : high alarm, + : high warning, - : low warning, -- : low alarm.
NA or N/A: not applicable, Tx: transmit, Rx: receive.
mA: milliamperes, dBm: decibels (milliwatts).
Optical Optical
Temperature Voltage Current Tx Power Rx Power
Port (Celsius) (Volts) (mA) (dBm) (dBm)
---------- ----------- ------- -------- -------- --------
Te2/7 28.4 0.00 48.9 -- -1.0 -7.0
05-31-2016 11:03 AM
Hi!
LACP provides unidirectional failure capabilities, I honetly do not understand why it is being reported as UDLD failure.
LACP will exchange LACPBPDUs and lets say host A will expect to receive certain flags from peer to start the bundling and when not received it sends an Expired flag which peer B reacts shutting down the port. According to Juniper EX documentation you can use LACP as a workaround.
http://kb.juniper.net/InfoCenter/index?page=content&id=KB13314&actp=search
As I understand, you do not have any UDLD configuration at all in the switch, right?
So in summary, it seems you are actually having an unidirectional link failure and LACP is shutting down the port, for some reason it is being reported as UDLD log.
Allow me some time to go through some tests.
Have a nice day, best regards!
JC
05-31-2016 11:14 AM
Hi carlos
Indeed i have udld configured but normal not aggressive hence i should not get interface disabled!
I am wondering if there is a resonable reason for the issue since EX do not support udld and why c6500 disable the working interface.
Cheers
James
05-31-2016 11:53 AM
Hi!
Firstly I would like to point you to this information provided by Peter Paluch about explicit and implicit unidirectional failure detection system in UDLD:
https://supportforums.cisco.com/discussion/12091831/udld-normal-question
Accordin to this, there are three conditions that when met put the interface in err-disble no matter if it is configured as Aggressive or Normal mode, which are:
Regarding your second question:
Well, I am just talking from my own experience and as stated in the above documentation, UDLD is not really broadly documented.
I have had around three TAC cases where certain devices and I am not exactly talking about 3rd party devices, do not treat UDLD packets as expected, and this does not seem to be related to a bug or something like that but because there is some nature in the protocols not really cooperating.
As per my observations, if the UDLD enable port does detect that the link is up/up and does not receive UDLD information at all from the neighbor it goes automatically to err-disable (Of course this happen really fast). So this kind of contradict the three statements mentioned above.
If UDLD detects an up/up interface and absolutely no info is detected from the neighbor then it goes to err-disable (Be aware that this information is carried along with CDP packets). I have not had the chance to actually isolate this behavior but I will try to do it by tomorrow.
Hope it helps, best regards!
JC
06-01-2016 12:35 AM
Hi JC,
indeed my udld sessions are not bidirectional and it worked well until the mentioned issue.
Cheers
James
XXX#sh udld tenGigabitEthernet 2/5
Interface Te2/5
---
Port enable administrative configuration setting: Follows device default
Port enable operational state: Enabled
Current bidirectional state: Unknown
Current operational state: Advertisement
Message interval: 7
Time out interval: 5
No neighbor cache information stored
XXX#sh udld tenGigabitEthernet 2/7
Interface Te2/7
---
Port enable administrative configuration setting: Follows device default
Port enable operational state: Enabled
Current bidirectional state: Unknown
Current operational state: Advertisement
Message interval: 7
Time out interval: 5
No neighbor cache information stored
05-31-2016 11:15 AM
Hi carlos
Indeed i have udld configured but normal not aggressive hence i should not get interface disabled!
I am wondering if there is a resonable reason for the issue since EX do not support udld and why c6500 disable the working interface.
Cheers
James
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