Category: Current State

Why a Router?

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Router: With a router, you can create your own small computer network in your dorm room, where your devices usually go online via Wi-Fi through your router. Your router is connected to a device called a switch, which is typically located in the basement of your dorm. This switch is usually directly connected to us at Fichtenweg 5 in Tübingen via fiber optic cable. From there, the connection goes to the Data Center of the University of Tübingen, and from there to BelWü and beyond. The term Internet is based on the interconnectivity between networks.

To communicate between devices on the Internet, they need to find each other. For this, there are IP addresses, which we can compare to phone numbers for this explanation. We have a limited number of these addresses and can provide each of you with one. Since nowadays you have more than one device that wants to go online at the same time, it would cause problems without a router.

Access Point: An access point is not a router and does not create its own network. An access point is an entry point for a network. The access point needs an IP address to function. We give you exactly one IP address. If you connect an access point in your room, it gets an IP address from us. A smartphone connected to the access point does not go online at first, and you can’t access the access point because they don’t know each other’s addresses. The access point usually does not ask for a new IP address and forgets the assigned one after a while. A device in the Wi-Fi of the access point, such as a smartphone, continuously asks for an IP address and gets one from us after a maximum of two minutes if the access point has no more IP addresses. Then the smartphone can go online. Your laptop, however, will not go online through the access point. Therefore, you need a router.

Range Extender: Range extenders increase the range of a Wi-Fi network and do nothing else. So, you can’t do much with a range extender; at best, it might work like an access point.

Important Note: If you unplug your router and connect a laptop directly to the network socket, please wait 2 minutes before assuming there is an error or doing further diagnostics. The limitation to one IP address per room has a timer of 60 seconds. After 2 minutes, you will definitely have a new IP address from us if your devices are configured correctly.

We will no longer support FritzBox routers

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Starting from April 1, 2024, we will no longer support FritzBox routers in our network.

For a short while now, we’ve had all the permissions needed to tackle the ongoing issue with FritzBox routers.

We’ve been advising against using FritzBox routers for a while due to their cost and features that are unnecessary for a student dormitory setting. We’ve also linked to this advice in our guide since 2022.

Besides the wasted money, we’ve received complaints from various dorm areas saying, “when I’m away for a while and come back, I have to unplug and replug my router to get online.”

We were able to reproduce this issue widely when we upgraded a slightly neglected dormitory to Gigabit at the beginning of the year. During the upgrade, the dormitory also received Alcatel switches, which we’ve been exclusively using since 2012. With these switches, those with compatible routers could now enjoy Gigabit, but for those using FritzBox, the situation got worse.

Currently, it seems that FritzBox routers are the only ones unable to obtain an IP from our DHCP server a second time, eventually going offline.

We are conducting a small test setup to try and replicate this phenomenon observed in the wild, but it’s taking time.

We should invest in the next generation of switches, but that takes too long considering the short time residents stay in the dormitory, making it unreasonable to ask anyone to daily reset their FritzBox.

Therefore, we’ve decided to phase out FritzBox routers from our network by April 1, 2024, the start of the summer semester.

Those with older devices can receive a special configuration for their connection from us. Old devices are defined as: FritzBox routers that were in use in either of the two dormitories before their upgrade (Konrad-A-Str. and Viktor-R-Str.), i.e., the winter semester of 2023-2024.

In all other dorm areas, FritzBox routers haven’t worked for almost a decade, so we see no legitimate reason for complaints.

Anyone buying a FritzBox, despite our advice since 2022, will have to live with potentially needing to reconnect it daily. We will not invest our volunteer time into a special connection configuration just because someone chose to spend more money on a product we advise against.

When and how we will deploy our next generation of switches, which manufacturer they will be from, and whether FritzBox routers will work with them is not yet decided, and we ask that you refrain from inquiries about this.

Those interested in network technology are, of course, welcome to discuss and research this issue with us, but “I paid a lot of money and want my device to work” is not an argument here!

In short: from the summer semester of 2024, we will no longer support FritzBox routers in our network.

Four out of nearly 6000 connections blocked

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In rare cases, we must temporarily block certain connections to protect our network. This is done because of what are called abuse reports, which indicate that abusive activities might be happening from a connection. We receive this report from the BelWü-CSIRT (Computer Security Incident Response Team), and our task is to stop the abuse with appropriate actions, which we do by turning off the connection of the room.

What is an abuse report?

In short, an abuse report is triggered when suspicious or unusual activities are observed coming from an internet connection. This could be, for example, sending spam emails or unauthorized attempts to access other computers. Often, you may not be aware of this behavior because it is usually caused by viruses or other malicious software that has secretly installed itself on one of the devices in the network.

No blame on you

We want to emphasize that such a blocking is in no way meant as a blame towards the affected users. In most cases, you are victims of malicious software acting without your knowledge. Our priority is to quickly identify and solve the problem to prevent further damage.

Why we block the connection

The fastest and most effective way to inform you about a possible security issue is by temporarily turning off the connection. This measure immediately attracts attention and prompts most users to contact us right away. This way, we can address the problem together as quickly as possible.

We are almost always available

Please note that we are also available on weekends and outside regular working hours. If your internet connection unexpectedly stops working, do not hesitate to contact us. We are ready to analyze the problem and offer you steps to solve it. Together, we can ensure that your connection is quickly safe and fully functional again.

Conclusion

The security and reliability of our network are very important to us. Through proactive measures like these, we want not only to ward off potential threats but also to raise awareness of the importance of network security. We thank you for your understanding and cooperation in keeping our shared digital environment safe.

If you have any questions or concerns, we are always here for you.

Quo vadis Gigabit?

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In Geislingen, Sigmaringen, and Albstadt, we have installed Gigabit switches for quite some time. It was more of a coincidence that these places were equipped with Gigabit internet before Tübingen and Hohenheim.

We have just checked how many residents of the dormitories actually use the offered Gigabit internet.

The results are somewhat sobering: In Albstadt, 53% of the residents use the Gigabit internet, in Sigmaringen it’s 33%, and in Geislingen only 25%.

This raises the question of whether we have not informed well enough that Gigabit can be used with the right router, or whether the residents simply do not need such high internet speed.

Hohenheim 16th of May

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We were able to accomplish almost everything we had planned yesterday.

We dismantled and disconnected the three generations of network technology that were stacked on top of each other.

We managed to clean the room to some extent with a broom we found. Once we speak to the janitor, we will find a place for all the electronic waste (see picture).

One of the switches currently in use didn’t look promising during the removal, so we will replace it this Tuesday evening (starting from 6 PM, depending on traffic).

This means that we will need to unplug the cables of the residents of Egilolfstraße 51 to 59 again, and they won’t have internet during this time. Some rooms will be offline for about an hour, while others will experience shorter outages.

Afterward, the room should be prepared for the installation of the main network connection for the entire Hohenheim area.

The relocation and upgrade of this connection still depend on the IT department of the student services.

We hope that with this cleanup operation, we have eliminated any obstacles that could potentially further delay the final resolution of the network issues in Hohenheim.

Hohenheim 15th May 2023

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In preparation for a solution to the persistent problem, we are cleaning up Egilolfstraße 57 and bringing it up to the standard required by the working group. Unfortunately, the room looks like in the pictures, so we expect it to take 2 to 4 hours. During this time, there may be intermittent network outages for certain parts of our network in Hohenheim.

We are working quickly, but you are welcome to visit us.

Hohenheim 25th of April 2023

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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.

Hohenheim: Fruwithstraße and Egilofstraße from 53 onwards

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As part of the cleanup work that the Network Working Group in Hohenheim is finally able to tackle, I plan to publish some events on our blog.

Here’s a short text explaining why we’re worried about the cabling in the mentioned dormitories, since only a few have looked at the cables in their rooms.

I’ll compare the cables from the dormitories in the Hibuka building in the French Quarter in Tuebingen, where I lived extensively. There, we had cables for the doorbell at the front door (2 wires), cable for the telephone connection TAE (6 wires), cable connection (2 wires TV, 2 wires radio), and a double network socket (two cables with 8 wires each).

Why two network cables for one room? If one cable is damaged, the other can be used as a replacement, and you don’t have to lay a new cable from the room to the basement.

The TERA cabling is much more economical. Over a single cable with 8 wires, two wires are used for TV, two for the combination of doorbell and telephone. This leaves 4 wires to establish a 100 Mbit network connection.

If one wire is damaged, the internet network access is gone.

If one wire of the network cable is damaged in the French Quarter, there will only be 100 Mbit instead of 1000 Mbit or we switch to the spare cable.

Given the fact that TERA cables are only manufactured on demand and this type of cabling seems to be very rare, I assume that the savings in installation costs compared to the risks in operation have not prevailed.

From a purely network perspective, we have only half a network cable, without any reserves in the mentioned dormitories.

Nothing will change without construction activity. But building is not within the scope of our volunteer working group.

If there is a cable, we will make the best internet access possible for you.

Even though we can’t do much at the moment, please inform us about any possibly defective network connections and other problems. If only your apartment knows about a problem, nothing will improve.

Thanks for your interest,
Heinrich from the Netz-AK (short for Netzwerk Arbeitskreis = Network Work-group)

https://en.wikipedia.org/wiki/TERA

Upgrade Schwerzstrasse 1

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We need to make some unplanned changes to our hardware in your basement.

We can start working from 6 PM in Hohenheim.

Your internet will be down while we work, but we’ll finish by 10 PM. After that, all rooms will be back online, and the speed will be increased to 1 GBit from the previous 100 MBit. You can check the speed by running our speedtest.

 

Speed test

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We have set up an internal test for you some time ago. At netz-ak.de/speedtest, you can see how much your connection in your dorm room can handle.
We hope that all devices connected to our network via cable have a ping of less than 5 and an insignificant jitter.

A high jitter of over 5 indicates that the device from which you are measuring is connected via Wi-Fi and may be affected by what we call the 2.4 GHz problem.

Both download and upload should be just below the respective maximum of your building, i.e. 100 MBit/s or 1 GBit/s (1000 MBit/s). You can find out how fast the connections in your dormitory are under the expandable map on the  facts and figures page.

Currently, none of the dormitories are reaching the limit of their connection.