ISR4331 router speed and duplex hardcore

[AndrewHow]

Hi,

i'm facing issues for the ISR4331 which the speed and duplex needed to hardcore to 100mbps and duplex full. It is running isr4300-universalk9.03.16.04b.S.155-3.S4b-ext.SPA.bin version. It is connected to switches WS-C3850 version cat3k_caa-universalk9 03.07.04E.

Are the model WS-C3750G also need manual configure speed and duplex with ISR4331? I find this amusing ot it is software bug for ISR4331 router.

[Georg Pauwen]

Hello,

what happens if you leave the 4331 interface on 'auto negotiate' ? Does it negotiate half duplex ?

[AndrewHow]

Hi George,

Yes it is half duplex. What it is happening? Do you need to shut and unshut the port? so far I have hardcode it to duplex full and change the speed.

[Georg Pauwen]

Try and set the media type on the interface, and check if that changes the behavior:

media-type rj45

or

media-type sfp

depending on which interface you are connecting the 3850 to.

[AndrewHow]

Both end are GigaEthernet port, how come isr4331 does not choose rj45?

[Georg Pauwen]

Hello,

check if you are hitting the bug below. Either way, does it work when you manually set the media type ?

EHWIC-1GE-SFP auto media type is not working properly
CSCuy43787
Description
Symptom:
A EHWIC-1GE-SFP containing a 1000baseT SFP may result in the link staying down/down and the configured speed/duplex being automatically changed.

Conditions:
The EHWIC-1GE-SFP must not have a media type manually configured and the card must have a 1000baseT SFP installed along with a working ethernet connection on the builtin RJ45 port. The interface must be manually configured for 100/Full duplex. When the problem occurs (normally after a reboot) the running configuration will automatically change to 1000/Full and the link will stay down/down.

Workaround:
Manually set the preferred media type using the command "media-type sfp" or "media-type RJ45".

[Leo Laohoo]

Keep an eye out with the SFP module and the IOS.  There are several GLC-T and SFP-GE-T bugs affecting 16.X.X and it's just identifying which one to avoid.  

A good example is CSCvd90801. 

When in doubt, raise a TAC Case and get TAC to officially confirm which version to use/avoid.