SFP-10G-LR recognized but no link between two Catalyst 1200 switches
Two Cisco Catalyst C1200-48T-4X switches were connected back-to-back with Cisco SFP-10G-LR modules in the ge49/te1 SFP+ slots. Both switches recognize the transceivers, the interfaces are administratively up, both ends transmit light and the DOM optical values are good, yet no link is established. The same optics and fiber link up immediately when one end is replaced by a different vendor's switch (a MikroTik). The Cisco compatibility matrix lists no 10G optics for the C1200, but the datasheet does, and Cisco TAC confirmed the datasheet. Over a year later another user reported the same behaviour with two C1200-24P-4X on firmware 4.1.7.24: 1G SFPs link fine between the two units, 10G SFP+ modules never do, although each switch links at 10G to other equipment with the same optics. No fix was found in the thread.
- Hardware: Cisco Catalyst C1200-48T-4X, Cisco Catalyst C1200-24P-4X, MikroTik switch (unspecified)
- Transceivers: SFP-10G-LR
- Form factor: SFP+
Symptoms / messages:
no link with SFP-10G-LR between two C1200 switches
transceiver recognized and optical power good
1G SFP links but 10G SFP+ does not
same optics work against a non-Cisco switch
Comments 4
Check whether the optic is listed for the switch at tmgmatrix.cisco.com; the C1200 shows no 10G optics there, though TAC later confirmed the datasheet's SFP-10G-LR support.
Upgrade both switches to the latest available firmware release and retest.
Since the datasheet and TAC agree the optic is supported, keep working the case with Cisco TAC.
A second user confirmed the same C1200-to-C1200 10G failure on firmware 4.1.7.24 while 1G SFPs work, pointing to a platform or firmware issue rather than a bad optic.