After a failed network-wide update on the night of December 27th to 28th, several buildings experienced unspecific internet outages. We are in the process of resetting all devices and hope this will fix the disturbance. When resetting, the devices will restart, and you will be completely offline for up to 15 minutes. This was, of course, not planned. Please always report outages directly to us and not in any messenger groups. As soon as we receive feedback, we can take appropriate action.
The internet at Welfenstrasse 80 is not working right now.
We first heard about this issue on November 11, 2023, after 10 PM, but the information was not very clear at first.
After checking the wireless bridge from a distance and ruling out other possible causes, we hope it’s just a loose mount on the bridge.
But, we are worried that we might need to replace it.
Just to be safe, we are sending a request today for a replacement to StuWe.
All checking and fixing work depends on the weather, because we need to go on the roof to do it.
So, we are hoping for better weather tomorrow to check the hardware in person.
As always, please report right away if something isn’t working. Describe the problem and what kind of tech you are using. We already know how important the internet is, so you don’t need to mention that. Just tick the box if you feel like saying that.
Update Tuesday 14.11.2023 6:30 pm:
In the morning, it became clear that there would be a long break in the rain, which might allow us to work on the roof in Hohenheim. That’s why we decided to have a meeting during lunch break. One of us, who was professionally near Hohenheim, was able to be on the roof in Egilolfstraße during the conversation and check the antenna there and its alignment.
Originally, we thought that the antennas had reached the end of their life and needed to be completely replaced. Getting new ones would probably have been possible by the end of the week, but in the meantime, the poor internet connection would remain. Therefore, we came up with the idea to dismantle a part of a radio bridge, which was used as a test setup, from another roof and replace it in Hohenheim today. Right after the meeting, we implemented this and around 16:50, we were able to replace the antenna on Welfenstraße, which was responsible for the disturbance. After some driving and a bit of traffic, I am now here dictating this text, which I will have ChatGPT format before I leave for the evening.
We hope that the system is now working again and plan to create redundancy soon. This way, if this pair of antennas fails, it can automatically switch to a better system.
Of course, we would prefer to have a fiber optic connection to you, as we usually do, but that seems difficult.
Update 15.11.2023, 7:30 pm:
A new day, a new attempt! Unfortunately, the exchange in Welfenstraße yesterday was not successful. Therefore, we have now placed the antenna that we had removed there on Egilolfstraße and thus swapped everything once.
Currently, there are no new outages to report, and we hope to gain some time to decide on 2 more antenna pairs. These should then be able to function in continuous operation as redundancy for several years.
Once you are in Hohenheim, such an exchange is quickly completed. The travel time alone today was approximately 3 hours.
Update 16.11.2023, 8:15 am:
Now sign of a problem since the exchange, but also no feedback from anyone who lives there.
We currently think that the radio bridge might have a problem. To check this, we need to go to Hohenheim and climb onto the roof of Egilolfstrasse.
Today at 2:50 PM, we restarted the hardware and are now monitoring the transmission values. We hope the issue is due to the current weather, as the weather and our availability don’t match the necessary work.
Please let us know in the next few days about your experiences with the internet connection so far.
According to yesterday’s diagnosis, it seems that a lightning strike damaged some chips on the switches in the basement.
We are currently setting up the configuration on the new switches.
Afterwards, we will install the switches in Provenceweg. This will cause a brief network outage, as we will have the cables in hand.
We won’t be able to respond to emails in the basement. If you have any questions about the duration, come visit us in the basement at number 9 (towards the center of the building).
Update 12:30 PM: Everything has been swapped out and upgraded from 100 Mbit/s to Gigabit. Feel free to run our speed test and let us know if something still isn’t working.
Please fix the fucking network. There are so many problems with it. Impossible…
Unknown author, Hohenheim 13.05.23 –
We have been receiving emails like this in the past few days. It’s understandable, considering the outages we’ve had in the past week, turning Hohenheim into an internet wasteland. Believe us, we want nothing more than to have the finest internet flowing through the fiber optics. However, let’s take a look at why it’s sometimes not that simple.
First, let’s provide an overview of the locations in Hohenheim:
23 buildings
50 Layer-2 switches
1660 connections in the user network
2x 1 Gbps uplink towards the student union
As you can see, currently, all the connections converge at Schwerzstrasse 1 and then split into two lines towards the student union.
Line 1: Egilolfstrasse 49, 51, 53, 57, 59; Fruhwirthstrasse 3-13; Welfenstrasse 80; and Chausseefeld 1-9.
Line 2: Egilolfstrasse 41, 43, 45; and Schwerzstrasse 1-3.
Both lines are equally loaded.
That’s the infrastructure setup.
Timeline:
In early April, we were requested to provide internet to Schwerzstrasse 3, which had been renovated and is now available as a dormitory.
During the initial inspection, we were informed that Schwerzstrasse 2 would undergo major renovation and the power would be shut off there.
At that time, Schwerzstrasse 2 still housed the uplink for the entire Hohenheim, and that required power. So, it was planned to move that hardware to Schwerzstrasse 3 on the same day. Fiber optics between the buildings are available and can be used.
April 19, 2023
We drive towards Schwerzstrasse 2 to check if there are enough lines to move the uplink towards Schwerzstrasse 3. We find a chaos of fiber optics and start taking notes.
According to the notes, everything should be fine, except for the shortage of cables. Ancient plug connections were used for the fiber optics.
April 24, 2023
We took time off to tackle the cabling in the new dormitory.
We arrived at 2 p.m. and immediately started equipping the new cabinet.
However, we encountered the first problem during the reconstruction of the uplink. The individual ports towards Stuwe remained offline. A measurement revealed that the attenuation was too high. You can imagine it as stuffing cotton in your ears. You hear much less and don’t understand everything.
The same applies to light; the further away or worse the material, the less you can see. That’s why many front doors have frosted glass. Light enters, but you can only see a little from the other side.
We suspect that the fiber optic between Schwerz.3 and Schwerz.1 might be defective or contaminated, acting like frosted glass.
As a result, we installed the uplink in Schwerz.1 to mitigate this attenuation. However, only one of the two lines came online there as well. We started trying different lines between Schwerz.1 and Schwerz.2 and eventually found at least 2 out of 24 fibers where the switch received enough information to provide a bit of internet.
That should be sufficient for one night, and we returned to Tübingen. Departure at 7 p.m.
Schwerzstrasse 3
April 25, 2023
Since we couldn’t find any documentation regarding Hohenheim in our records (at least the previous responsible person didn’t leave any), we went to Hohenheim with pen and paper in hand.
We diligently conducted measurements and discovered that the damaged line must be between Schwerz.2 and the university’s data center.
The staff at the data center were very helpful and showed us the relevant fibers and a switch, which belonged to Stuwe. We included it in our documentation. However, we don’t have access to it, so we couldn’t perform much diagnosis.
As a precaution, we replaced the fiber optic cable in the data center. We also noticed on a map in the machine room that there must be another building between the university and Schwerzstrasse. We headed there but unfortunately didn’t find anyone available.
Disappointed, we replaced a few more fiber cables in the patch panel of Schwerzstrasse 2 with higher-quality ones, hoping to improve the poor connection. Departure at 6 p.m.
Uplink Hohenheim
April 26, 2023
We drove back, this time to the mysterious Building 1.21. In the basement, we found a cabinet with our fibers. We replaced the connecting cable between the panels in the cabinet and headed towards the university. However, the attenuation was still the same. Cleaning the fiber optics didn’t yield any results, so we switched to another fiber to rule out any faults. Unfortunately, it didn’t work at all.
We dismantled everything and drove back to Tübingen since the shared car reservation was only for 5 hours, and we had already spent 4.5 hours there.
We returned in the evening to continue the troubleshooting. Since the lines worked fine in Schwerzstrasse 2, we installed a homemade amplifier solution until we could reach the data center again. Departure at 9 p.m.
If it works, it aint stupid
April 27, 2023
Early in the morning, we headed straight to the data center. By now, we had become adept at pleading for entry, and we replaced the fiber optics with another pair. Then we proceeded towards Emil-Wolf-Strasse (Building 1.21) and made the necessary connections. Lo and behold, the attenuation value improved from -23 dBm to a fantastic -7 dBm (significantly better).
The patch cable for Egilolfstrasse 45 had a bend and, lacking a better replacement, we substituted it with a multimode fiber (not ideal). Will it work? We quickly documented the changes and headed home. Departure at 4 p.m.
April 28, 2023
Disappointment struck. The uplink was now running smoothly, but Egilolfstrasse 45 seemed to be causing problems. We returned and replaced the multimode patch cable with a single-mode cable. From that point on, things started working smoothly again, and we happily returned home.
May 5, 2023
All the residents from Schwerzstrasse 2 have now moved to Schwerzstrasse 3. We noticed that four rooms were not properly patched (apologies for the mix-up!). We went there and corrected the connections. From Schwerzstrasse 2, we removed the equipment from the floors before the major renovation began. It was quite eerie there, but it seemed like there had been a good party.
May 7, 2023
Initial reports of disruptions in Egilolfstrasse 53-59. Evening outages were observed. We discovered numerous errors in the log. We went there in the evening and replaced the module at the switch (those things keep breaking).
Fiber Module SFP
May 8, 2023
Under load, especially in the evenings, we noticed an increasing number of errors. As a result, the traffic briefly decreased and then recovered. You may have experienced internet outages, but we noticed them through the error counter:
Both of these values should be 0. It seems that either the fiber or the module is faulty.
Once again, we visited the location and swapped the fiber to eliminate it as a potential issue. However, we still encountered the same problem.
Two tests are pending:
Checking the port on the Stuwe switch.
Testing or replacing the fiber module at the switch.
We sent an email to the responsible person since we cannot access external hardware.
May 12, 2023
We received a response from the responsible person at Stuwe.
The examination and, if necessary, replacement will be carried out by the HEDV as part of the uplink expansion. However, the uplink expansion can only take place after the work on Schwerzstrasse 2 is completed.
According to his opinion, the uplink switch needs to be moved to another building, but which building is still uncertain. Until then, everything will remain as is.
Unfortunately, the responsible person will not be available on Friday.
That’s the summary of the events in the past few weeks.
Tomorrow, we will make another round of calls and try to find a solution with the responsible person, if they are available. We are just as frustrated as you are, and we are doing everything we can to provide you with a good internet connection. However, as you can see, sometimes it’s not just technical issues that are at play.
As soon as we have any new updates, we will notify you here.
All Hohenheimer dormitories are connected to our network through a central hub.
Until now, this hub was located at Schwerzstrasse 2.
The building is undergoing renovation and will be without power for a while.
The plan was to relocate the hub to the newly renovated Schwerzstrasse 3.
Unfortunately, the connection between the buildings was so poor that we had to move the hub to Schwerzstrasse 1, which delayed the internet interruption accordingly. We planned for 10 minutes, but it took 3 hours.
During operation, we found that the connection there works, but is also too poor for continuous use.
Therefore, we will replace the connections again at around 12 p.m. today.
To keep the interruption short, we will send two teams. We expect the interruption to last less than an hour, ideally just a few minutes.
Update 4:50pm: Thanks to qualified feedback, an unexpected new problem that occurred during the repair of the fiber optic problem was identified and fixed around 4:30 pm. I’ll quote the translated message and thank you on behalf of the Netz-AK.
Hi, we know you’re working hard to switch over to Schwerzstraße. Since we haven’t heard anything new about the switch attempt at 12:00 since this morning’s blog post, we wanted to let you know (in case it hasn’t already been done) that if everything is back to normal, our flat still has problems. Greetings
Nevertheless, we also understand messages that explain to us that the internet is important for studying.
The fiber optic problem was traced to the edge of our network and optimized soon.
Today we exchanged a damaged network switch in Hohenheim. The outage affected around 24 connections. During replacement, the connected houses in Chausseefeld and Welfenstraße were also briefly offline.
Unfortunately another device failed during restart. We can only exchange this device tomorrow on December 29th, 2022. Until then around 24 connections will be offline in Egilolfstraße.
Update 29.09.2022:
Together with the Hohenheim IT we could fix the problem, but the hardware has to be replaced soon.
We have access to the buildings again.
Update 05.10.2022:
There was a power out this night and some more ports were damaged. The hardware will be replaced soon.
on 
