maxrebo Posted August 3, 2016 Posted August 3, 2016 Can someone shed some light on where I`m going wrong here. We have 4 Core fibre to a building off the main block, one pair is set up and working in to a 3com switch (on admin net) another pair is terminated in the fibre patch panel awaiting patching (for me to have the curriculum network in this building) I have a HP 2530-24G switch and purchased a "HP x121 1G SFP LC SX Transceiver" to attach in a SFP port. (Which i have done 1st problem - when i plug the Transceiver in i get an initial link (Green arrow lights up) but then goes off - Is this right or should it be constant green? The Patch lead im using is a 2Mtr LC(Dx) ST Dx 50/125 2.8mm Lead On the other switch (admin net) the Transceiver is permanently lit green so im wondering if i have the wrong Transceiver?! I`m thinking some of the kit is wrong somewhere!
localzuk Posted August 3, 2016 Posted August 3, 2016 A few things to check - that both transceivers are using all the same methods of transmission, and also that the patch leads are of the same type as the main fibre. (the 50/125 bit). 1
Blue_Cookeh Posted August 3, 2016 Posted August 3, 2016 (edited) FYI we use those transceivers in those switches. IIRC there should be a light that stays on permanently to indicate there is a transceiver present in the slot, this can also be checked with the "show tech transceivers" command. Example from our switch: SW-OFF-TOP# show tech transceivers transceivers Transceiver Technical Information: Port # | Type | Prod # | Serial # | Part # -------+-----------+------------+------------------+---------- 25 | 1000SX | J4858C | MYXXXXXXXX | 1990-4395 27 | 1000SX | J4858C | MYXXXXXXXX | 1990-4395 28 | 1000SX | J4858C | MYXXXXXXXX | 1990-4395 Edited August 3, 2016 by Blue_Cookeh 1
maxrebo Posted August 3, 2016 Author Posted August 3, 2016 FYI we use those transceivers in those switches. IIRC there should be a light that stays on permanently to indicate there is a transceiver present in the slot, this can also be checked with the "show tech transceivers" command. Example from our switch: SW-OFF-TOP# show tech transceivers transceivers Transceiver Technical Information: Port # | Type | Prod # | Serial # | Part # -------+-----------+------------+------------------+---------- 25 | 1000SX | J4858C | MYXXXXXXXX | 1990-4395 27 | 1000SX | J4858C | MYXXXXXXXX | 1990-4395 28 | 1000SX | J4858C | MYXXXXXXXX | 1990-4395 Thanks for this info, yes i thought it was strange that the light came on then went off, i tried it in 2 different slots and it did the same in both. I think this is my first problem, do you have to configure anything on these switches when installing a transceiver?
pantscat Posted August 3, 2016 Posted August 3, 2016 No need to configure anything special unless you're going to be creating a trunk or VLAN-tagging. It's not a spanning tree issue is it? If you've already got an uplink in place, spanning tree could be disabling the port. 1
maxrebo Posted August 3, 2016 Author Posted August 3, 2016 No need to configure anything special unless you're going to be creating a trunk or VLAN-tagging. It's not a spanning tree issue is it? If you've already got an uplink in place, spanning tree could be disabling the port. Its a brand new switch out of the box, nothing configured as of yet, so i dont think so? Could be wrong though!?
pantscat Posted August 3, 2016 Posted August 3, 2016 I'd be surprised if it's configured to have STP on out-of-the-box. Any other uplinks? What device is on the other end of the fibre? how old is the fibre link? 1
maxrebo Posted August 3, 2016 Author Posted August 3, 2016 I'd be surprised if it's configured to have STP on out-of-the-box. Any other uplinks? What device is on the other end of the fibre? how old is the fibre link? No other uplinks The fibreis probably about 6 years old, i think my main issue is determining if the transceiver is faulty, if as suggested above I should be receiving a Transceiver present light on the SFP ports (and I`m not) then I`m presuming that its a faulty transceiver? The switch on the other end is a 3 com. I haven't actually checked connection yet as i thought if there isn't a light on the Transceiver port then that¬s an issue to start. Unfortunately i dont have another to test! Probably will have to order another
localzuk Posted August 3, 2016 Posted August 3, 2016 (edited) Ok. I have just tested one of our spare GBICs here. The solid green light goes off if there is not connection. The GBIC itself is fine though. So, your issue more than likely lies in the fibre itself, a mismatched patch lead or the transceiver at the other end. What transceiver is at the other end? And what type of fibre is in between? Is it 50/125 (OM2+) or is it 62.5/125 (OM1)? If you need another to test with, I have a load of spares here now so could pop one in the post if you need it? Edited August 3, 2016 by localzuk 1
maxrebo Posted August 3, 2016 Author Posted August 3, 2016 Ok. I have just tested one of our spare GBICs here. The solid green light goes off if there is not connection. The GBIC itself is fine though. So, your issue more than likely lies in the fibre itself, a mismatched patch lead or the transceiver at the other end. What transceiver is at the other end? And what type of fibre is in between? Is it 50/125 (OM2+) or is it 62.5/125 (OM1)? Thats a great help thank you, Its a 3Com switch at the other end, (a 3com Baseline 5500) these are the core switches (and all the other fibre links around the school are 3com to 3com come to think of it!) Im going to have to buy another HP and Transceiver at the other end and patch it into that i suppose?!
maxrebo Posted August 3, 2016 Author Posted August 3, 2016 Ok. I have just tested one of our spare GBICs here. The solid green light goes off if there is not connection. The GBIC itself is fine though. So, your issue more than likely lies in the fibre itself, a mismatched patch lead or the transceiver at the other end. What transceiver is at the other end? And what type of fibre is in between? Is it 50/125 (OM2+) or is it 62.5/125 (OM1)? If you need another to test with, I have a load of spares here now so could pop one in the post if you need it? Im guessing its 50/125 (OM2+) and the transceiver is working fine, i think i will make sure i havent mismatched the patching on the fibre Is it always red on the left? how do you tell which way round it is? Not done much fibre patching before tbh!!
Blue_Cookeh Posted August 3, 2016 Posted August 3, 2016 The fibre patch is reversed on one end so it's like: Switch A ______ Switch B Receiver <--- Transmitter Transmitter ---> Receiver Also look in the switch's logs around the time you plugged the GBIC in, you can use `show logging` on the switch to view it. 1
localzuk Posted August 3, 2016 Posted August 3, 2016 Thats a great help thank you, Its a 3Com switch at the other end, (a 3com Baseline 5500) these are the core switches (and all the other fibre links around the school are 3com to 3com come to think of it!) Im going to have to buy another HP and Transceiver at the other end and patch it into that i suppose?! Does the 3com not have its own SFP module you're connecting to? Simplest way I've found to make sure you connect up the right fibres? Plug it in one end, and look at the light coming through the fibre the other end. Don't look directly at it, but on a slight angle. Then you'll be able to match them up - lit to the dead one and vice versa. 1
maxrebo Posted August 3, 2016 Author Posted August 3, 2016 Yeah, the 3com has its own SFP module patched through, I`m slightly guessing as it was patched through at the other end before my time (and there little documentation) but i think i know which fibre it is at the other end It goes into!
localzuk Posted August 3, 2016 Posted August 3, 2016 Yeah, the 3com has its own SFP module patched through, I`m slightly guessing as it was patched through at the other end before my time (and there little documentation) but i think i know which fibre it is at the other end It goes into! Can you track it down and find out the model number of that SFP module? 1
maxrebo Posted August 3, 2016 Author Posted August 3, 2016 Can you track it down and find out the model number of that SFP module? Yeah I would have to take it out to check. or log in to the switch I think i will try the mis matched patch leads in the morning and then get info on the module on the 3com switch and see if its compatible with the HP
mukz Posted August 3, 2016 Posted August 3, 2016 Also worth checking the fibres are plugged in the right way around on the patch on Both ends - happened to me three or four times before. 1
maxrebo Posted August 5, 2016 Author Posted August 5, 2016 Quick question - are St to ST (both pairs black) different to St to ST red and black both ends?
pantscat Posted August 5, 2016 Posted August 5, 2016 No - as long as it's the correct type of fibre (e.g. 50/125 or 62.5/125), you'll be fine. 1
kennysarmy Posted August 5, 2016 Posted August 5, 2016 Can someone shed some light on where I`m going wrong here. We have 4 Core fibre to a building off the main block, one pair is set up and working in to a 3com switch (on admin net) another pair is terminated in the fibre patch panel awaiting patching (for me to have the curriculum network in this building) I have a HP 2530-24G switch and purchased a "HP x121 1G SFP LC SX Transceiver" to attach in a SFP port. (Which i have done 1st problem - when i plug the Transceiver in i get an initial link (Green arrow lights up) but then goes off - Is this right or should it be constant green? The Patch lead im using is a 2Mtr LC(Dx) ST Dx 50/125 2.8mm Lead On the other switch (admin net) the Transceiver is permanently lit green so im wondering if i have the wrong Transceiver?! I`m thinking some of the kit is wrong somewhere! Can't you test the 2nd fibre pair is working by patching it in to the known working 3com switch (admin net) ?
xenonive Posted August 5, 2016 Posted August 5, 2016 (edited) Are you using the copper ports to the left of the fibre module ? Most likely they are dual personality ports and you can only use one or the other , the copper takes priority over fibre module . Else will be patch cable needs swapping over . To see which is the transmission cable hold piece of paper over the end of the cable and one I'll have slight red glow , don't look straight in to the cable because it is a laser Edited August 5, 2016 by xenonive
Mistert89 Posted August 6, 2016 Posted August 6, 2016 We just had a new building handed over. Contractor connected the fibre as Tx-Tx and not Tx-Rx because it was 'default'. Appears our existing building was installed as Tx-Rx (I'd crossover), so simply had this changed. As we were using LC-LC fibres, we couldn't check this for ourselves. I had assumed GBICs operated auto-sense like "everything" does these days........ They don't!
OPTCORE Posted May 23, 2017 Posted May 23, 2017 I guess it is wrong, the transceiver need connect as TX-RX, RX-TX. We just had a new building handed over. Contractor connected the fibre as Tx-Tx and not Tx-Rx because it was 'default'. Appears our existing building was installed as Tx-Rx (I'd crossover), so simply had this changed. As we were using LC-LC fibres, we couldn't check this for ourselves. I had assumed GBICs operated auto-sense like "everything" does these days........ They don't!
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