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Platform: N3K-C3548P-10GX Code: 6.0(2)A8(10a) When trying to use a break-in configuration (e.g. taking 4 x 10 Gbps and combining to 40 Gbps). We are seeing failures when using a mix of different manufacturer transceivers (Cisco based: Avago/Finisar/Oplink/Accelink). This results in the interface stay down with error sfpAbsent after bundling the interfaces with "speed 40000" configuration and the log below will be generated: `show logging log` 2019 Sep 16 06:28:38 SWITCH_A %USER-2-SYSTEM_MSG: USD:neutron_usd_uc_xcvr_fcot_chk_port_state_40g:1782: port 42 SFP is of different type at "Link length support for copper" 0x28 vs 0x0 - neutron_usd _uc
When trying to use a break-in configuration (e.g. taking 4 x 10 Gbps links and combining them to logical 40 Gbps). The links will remain down (sfpAbsent). We will also see an error in the logging (see below): `show logging log` 2019 Sep 16 06:28:38 SWITCH_A %USER-2-SYSTEM_MSG: USD:neutron_usd_uc_xcvr_fcot_chk_port_state_40g:1782: port 42 SFP is of different type at "Link length support for copper" 0x28 vs 0x0 - neutron_usd _uc This is seen when using a mix of transceivers from a mix of Cisco transceivers from different manufacturers (Avago/Finisar/Oplink/Accelink) Checking the FCOT information xcvr (Transceiver) information there may be a discrepancy between the Copper distance field on some transceivers: show hardware internal neutron-usd-uc xcvr fcot-info 41 | i copper Link length support for copper 0 m Ethernet1/41 type is 10Gbase-SR name is CISCO-FINISAR show hardware internal neutron-usd-uc xcvr fcot-info 42 | i i copper Link length support for copper 40 m <===== SFP+ 10Gbase-SR reporting a copper distance Ethernet1/42 type is 10Gbase-SR name is CISCO-ACCELINK show hardware internal neutron-usd-uc xcvr fcot-info 43 | i i copper Link length support for copper 40 m <===== SFP+ 10Gbase-SR reporting a copper distance Ethernet1/43 type is 10Gbase-SR name is CISCO-OPLINK show hardware internal neutron-usd-uc xcvr fcot-info 44 | i i copper Link length support for copper 0 m Ethernet1/44 type is 10Gbase-SR name is CISCO-AVAGO This field is based on SFF-8372 Rev 12.3 data field address A0H 18 "Length (OM4 or copper cable)" and can represent either the link length in Copper (meters) or OM4 (meters x 10). It appears that for some transceivers this field is unused. The function used to combine the bundle will check and compare these value and if they differ fail to bring up the bundled 40G link.
Currently the only workaround is to use transceivers that all share the same value for "length". This can be inspect using the following command: ! Where 'x' = front panel port number ! ! Here we inspect the value of "Link length supported for copper is" and ensure all transceivers ! to be bundled share a matching value for length. ! show hardware internal neutron-usd-uc xcvr fcot-info x | i i copper OR ! Where 'x' is the module number ! Where 'y' is the port number ! e.g. ethernet1/1 ! ! Here we inspect the value of "Link length supported for copper is" and ensure all transceivers ! to be bundled share a matching value for length. ! show int ethernet x/y transceiver details