Hello,
I have strange problem (or maybe a feature) on two C3750X-24S-S switches (24fiber optics ports). http://www.cisco.com/c/en/us/support/switches/catalyst-3750x-24s-s-switch/model.html#~tab-documents
On both switches Cisco iOS 15.2.4E1 is installed. I`m using 100Mbit multimod SFP (wavelength 1310nm) - GLC-GE-100FX, which is according to this list compatible (and should be working) with my switches http://www.cisco.com/c/en/us/td/docs/interfaces_modules/transceiver_modules/compatibility/matrix/100MB_Tx_Matrix.html
In my case GLC-GE-100FX works only on ports 13-24 but not on the ports 1-12. On first 12 ports 1Gbit SFPs (single or multimode) are working fine, but 100Mbit don`t work at all.
If I connect 100Mbit MM GLC-GE-100FX to any of first 12 ports and connect it to lets say media converter I get link-flap error. If I disable link-flap (errdisable command) port goes up/down few times and in the end stays down.
If I connect same 100Mbit MM GLC-GE-100FX to ports 13-24 to the same media converter with same cable everything works fine.
I also tried putting half/full duplex and adjusting bandwidth on port, but still no luck. 100Mbit SFP works fine on ports 13-24 and with no adjustments needed.
If I put GLC-GE-100FX in one of the ports that it is not working on (port 6 in this case) and try a few commands I get following:
sh interfaces gi1/0/6
reliability 255/255 tx/rxload 1/255
sh interfaces gi1/0/6 capabilities
GigabitEthernet1/0/6
Model: WS-C3750X-24S
Type: 100BaseFX SFP
Speed: 100
Duplex: half,full
Trunk encap. type: 802.1Q,ISL
Trunk mode: on,off,desirable,nonegotiate
Channel: yes
Broadcast suppression: percentage(0-100)
Flowcontrol: rx-(off,on,desired),tx-(none)
Fast Start: yes
QoS scheduling: rx-(not configurable on per port basis),
tx-(4q3t) (3t: Two configurable values and one fixed.)
CoS rewrite: yes
ToS rewrite: yes
UDLD: yes
Inline power: no
SPAN: source/destination
PortSecure: yes
Dot1x: yes
I have no idea what to do. Switches are brand new and not yet configured. Is it possible that some kind of hardware error is in question, am I missing some iOS command, or is it maybe a feature on 3750X fiber series?
