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Popular discussions about programming, compatibility and testing of optical transceivers.

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2votes
1 answer
100views

Cisco module signature: bytes 96-127 must match the serial number or a recoded SFP is rejected

Discussion of why re-coded modules fail Cisco validation: Cisco SFPs carry a unique signature tied to each serial number in bytes 96-127, and editing vendor name or serial makes the signature no longer match, so the switch rejects the module unless the signature is regenerated. Hardware involved…

2votes
1 answer
107views

sfp-eeprom-tool: CH341A-based SFP EEPROM reader and I2C sniffing to expose silent write failures

A small toolset that reads and writes SFP EEPROM over I2C with a CH341A programmer plus an I2C sniffer. The author found that sigrok/PulseView did not work with the analyser, that a v1.0.5 SFP coder firmware reported success while silently not writing the module (proven by I2C traces), and that the…

7votes
7comments
390views

Scripting DDM polling over I2C: which A2h bytes hold the live values and which the thresholds

I am writing a small poller that pulls temperature, voltage, bias and optical power straight off the modules on our whitebox boxes, so we get a trend line instead of someone eyeballing a link after it has already started erroring. The NOS prints pretty values, but I want the raw numbers with the…

6votes
1 answer
218views

Intel X520 in an R630 rejects a 10GBASE-T copper SFP+ with comp_codes_10g=0x00 despite allow_unsupported_sfp=1

We are consolidating a pair of R630s onto 10G and the cabling to the top of the rack is copper, so instead of pulling fibre I put 10GBASE-T SFP+ modules into the X520 cards. The switch end takes them without a word. The servers refuse to. Dell PowerEdge R630, Intel X520 (82599), dual port FS…

2votes
1 answer
104views

OPNsense 22.7: interface is disabled due to unsupported sfp on a 10G port, and the Linux ixgbe tunable does not apply

After upgrading OPNsense from the 21.x series to 22.7 a 10G SFP+ port stopped working with interface is disabled due to unsupported sfp; the newer Intel driver actively disables unrecognised modules. The poster tried to set ixgbe.allowunsupportedsfp=1 as a system tunable, which was not accepted…

4votes
2comments
152views

Zyxel XGS4600 SFP+ modules randomly stop transmitting after firmware 4.50; DDM shows TX power -inf and 0 mA bias

On Zyxel XGS4600 switches, 10G and 1G SFP+ transceivers (including an FS.com DWDM-SFP10G-80) intermittently stopped transmitting; only removing and reinserting the module restored the link. Transceiver statistics at that moment showed TX power -inf dBm, voltage at the 3.00 V low alarm and TX bias…

France fiberwolf FR asked
5votes
1 answer
165views

Dell DD9900 in an HA pair doesn't see the SFP on ethMa: State UP, link status NO, Cannot get module EEPROM information

I run a backup storage system in a data center. A pair of DD9900 in HA, network ports on the NDC QLogic. After a reboot or reseating the module, port ethMa stops seeing the transceiver, and it's not a one-off - it's a stable, repeating pattern. Dell DD9900, DD OS 7.2.0.95, HA configuration NDC…

Russia portrunner91 RU asked
7votes
5comments
304views

Lenovo RackSwitch G8124E refuses a generic 10G SR SFP+ with UNAPPROVED - SR SFP+ is DISABLED

We pulled a pair of G8124E out of a decommissioned rack and I am rebuilding them as the aggregation layer for an internal test environment. Budget for branded optics is zero, so everything goes in with generic 10G SR modules of the type we already run elsewhere. Lenovo RackSwitch G8124E, ex-IBM…

6votes
6comments
141views

Turris Omnia pins a Luleey LL-XS2510 XPON stick to 1000baseX and ethtool never offers 2.5G

My fibre WAN runs into a Turris Omnia and I moved from the ISP box to an XPON stick to drop one hop. The stick is a 2.5G part, the Omnia cage does 2.5G, and everything still lands at 1G. Turris Omnia, Turris OS 7.0.2 HBS, kernel 5.15.148 Luleey LL-XS2510 XPON SFP, RTL960x based, DFP-34X-2C2 family…

2votes
1 answer
65views

OPNsense on a budget C3758R appliance: four ix interfaces, SFP+ ports show down with an RJ45 module

On an inexpensive firewall appliance (Intel Atom C3758R, six 1GbE igc ports and two SFP+ cages wired to the CPU) OPNsense showed four ix interfaces instead of two and the SFP+ ports stayed red/down with a copper SFP+ RJ45 module, although the link LEDs lit. ifconfig -v identified ix0/ix1 as the…

5votes
1 answer
211views

Brocade 200e between Proxmox and FreeNAS: Buffer I/O error and isp0: Receive Error while all ports show online

Running a small virtualization setup: two Proxmox 6 nodes and a target on FreeNAS 11.2. While the HBAs were connected to the target directly, everything ran for months without a single error. Put a used Brocade 200e between them to avoid crossing cables, and that's when it started. two Proxmox 6…

6votes
6comments
209views

Third-party DWDM SFP+ stays down on an Arista 7050T with EOS 4.10.6 - anything short of patching the image?

We run a small regional network and pulled a spare 7050T out of stock to use as a DWDM aggregation box. Arista-coded DWDM optics for it quote close to the price of the switch, so we bought third-party DWDM SFP+ instead, and now the switch will not talk to them. Arista 7050T, EOS 4.10.6 generic…