Strange Cat 3650 port behaviour

chrisayres · ‎06-30-2015

Hi we are replacing 3750's with 3650's and the ports on the new switches are behaving a bit strange.

End devices that worked fine on 3750's are having connectivity issues on the 3650's

See below output from a 3650

How can the port be running at half duplex when it is configured at full, also if the port is config'd to 100Mb/s the end device won't connect at all although it is configured as 100FD

This is just 2 examples of a range of strange behaviours, has anyone seen anything similar

interface GigabitEthernet2/0/4
switchport access vlan 4
switchport mode access
switchport voice vlan 501
duplex full
no snmp trap link-status
no mdix auto
storm-control broadcast level 5.00
storm-control multicast level 30.00
spanning-tree portfast

sho int g2/0/4

Half-duplex, 100Mb/s, media type is 10/100/1000BaseTX

Charles Hill · ‎06-30-2015

Hello chrisayers,

half duplex is normally a speed/ duplex mismatch or bad cabling.

I would set switchport and pc to auto/auto.

If that doesn't resolve the issue, test the cable with tdr.

see link below on how to use tdr.

https://supportforums.cisco.com/document/74231/how-use-time-domain-reflectometer-tdr

Hope this helps,

Please rate helpful posts

Thanks

Leo Laohoo · ‎06-30-2015

If that doesn't resolve the issue, test the cable with tdr.

see link below on how to use tdr.

https://supportforums.cisco.com/document/74231/how-use-time-domain-reflectometer-tdr

Charles,

For the record, TDR and 3650/3850 ... they DON'T go well. Not even with IOS-XE version 3.6.X.

Charles Hill · ‎06-30-2015

Thank you for the info.

We currently don't have either in our network, but when and if we get some more money, we want to migrate to 3850s.

Thanks again.

Leo Laohoo · ‎06-30-2015

we want to migrate to 3850s.

I'd recommend you hold off.

This is the main probable reason why the 3560X/3750X are still around. IOS-XE is not what everyone (in Cisco) hopes it to be. For the Marketing team, it's super. For the people who support it, it's a friggin nightmare!

Might be stable for some but we've got one in our new building and we just don't seem to run out of jokes about how "stable" the IOS-XE vs IOS.

In this particular case, TDR: Perfected since 15.0(2)SE and ... you CANNOT use it even with 3.6.X. The "accuracy" level is like running 12.2(25)SEE! If I was to troubleshoot a potential Layer 1 issue on a 3650/3850, I'd rather just pull the cables off and stick a more-reliable 2960S or a 3750X. TDR and 3650/3850 ... You've gotta be joking, mate!

Charles Hill · ‎06-30-2015

Thank you for that info!!!!

I'll pass that on to my manager.

(+5) to Leo

Leo Laohoo · ‎06-30-2015

ROFL!

I presume you work with Phil Carter, right?

The reason is because he's created a thread too. It's HERE.