Eltex MES2324FB endlessly flaps the link with a Foxgate SFP toward an Alcatel 6224, module diagnostics show N/S
Installing a new MES2324FB at a site to replace old hardware. The uplink is 1G fiber to an Alcatel 6224, Foxgate modules from the same batch as at neighboring sites.
Setup:
- Eltex MES2324FB, firmware 4.0.4.7, also tried 4.0.6 - no difference
- 1G SFP Foxgate on both ends of the link
- far end - Alcatel 6224
- short fiber, inside the site, through a patch panel
The link doesn't hold at all: comes up and immediately drops, on and on, the log is filled with the same thing over and over:
%LINK-I-Up: gi1/0/21
%LINK-W-Down: gi1/0/21
%LINK-I-Up: gi1/0/21
%LINK-W-Down: gi1/0/21Meanwhile module diagnostics are empty across all parameters:
console# show fiber-ports optical-transceiver
Port Temp Voltage Current Output Power Input Power LOS
gi1/0/21 N/S N/S N/S N/S N/S N/SWhat I've already done:
- swapped in an identical module straight out of the box and moved it to another port - exactly the same picture
- switched to a known-good fiber run bypassing the patch panel
- plugged these same modules into an Alcatel and into a D-Link - there the link comes up and stays up for days
So the modules are alive, but with this switch they don't work in any port. Is this a defective switch, or am I missing something in the port configuration?
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Comments 3
That bit about the decommissioning is exactly the answer. The modules are almost certainly reflashed for that site's vendor, and Eltex reacts to that kind of encoding exactly this way: the EEPROM doesn't read as expected, diagnostics go to N/S across every field, and the port cycles
LINK-I-Up/LINK-W-Downendlessly. We had exactly this case get resolved when the modules turned out to be flashed for HP: that site used to be run by HP, hence the box.Easy to check in five minutes: grab modules with standard factory encoding from the supplier's stock and put them in the same port. If the link comes up and
show fiber-ports optical-transceivershows numbers instead of N/S - the switch is fine, question closed.No need to bother support about
no negotiation bypass: it doesn't exist on 1G ports, and on 10G it wouldn't solve anything in this situation anyway.One thing worth turning into a habit: empty or unreadable diagnostics on a port is itself a sign of module incompatibility, not a separate minor issue. Friends of mine had the same thing on the other side with Zyxel: an XGS1930-52HP kept dropping out of management, CRC errors and STP transitions piled up on the optical uplink to a GS2220-50, and DDM on that port didn't show at all. They swapped patch cords and patch-panel ports for nothing, and it turned out the uplink was built with third-party modules encoded for D-Link. Once genuine ones went in, the flapping, CRC errors, and dropouts stopped.
Before writing the hardware off as defective, post
show version- without it the conversation is going to run into the firmware version question anyway.And separately: N/S across every field in
show fiber-ports optical-transceiverisn't "a module with no diagnostics", it's the switch not reading the module's measurement page at all. So question number two: what exactly are the modules, new from the supplier or pulled from someone else's site? Is it really the same batch as at the neighboring sites, or did you assume that from the box?Also say what the far end sees: does the port on the Alcatel bounce up and down in sync too, or is it simply silent.
On the version: 4.0.4.7, then applied 4.0.6 - behavior didn't change one bit.
Support also asked for
show versionfirst thing, then suggestedno negotiation bypass. It's not supported on 1G ports at all, and on the 10G ports I applied it just as an experiment - zero effect, and my link isn't there anyway.About the modules - I misled myself here. I wrote in the question that it's the same batch as at the neighboring sites, was sure of that; after your question I went and checked against stock records - and no. New ones from the supplier really are sitting in stock, but the specific ones I used came from a box brought back from a decommissioning: the site was being torn down and all the optics got dumped into one pile. On Alcatel and D-Link they work fine, as I said, which is why I didn't suspect them. On the far end the port blinks in sync with mine, meaning the whole link drops, not just one side.