The Gathering Technical blog Tech:Net

We are online!

02 Apr 2017, by Martin Karlsen from Tech:Net

The beacons are lit!

We are happy to report that the internet connection for TG17 is up and running.

Tech:Net decided to take the "pre-TG" preparations one step further this year by building our backbone network and installing our DHCP/DNS servers a week before schedule! This gives us the opportunity to tweak and polish all the nuts and bolts of our most critical infrastructure without being on site.

What does this mean for us? It means that we're able to deploy and provision our edge switches from day 1 without waiting for internet access or the DHCP/DNS-servers to be installed on the first day.

Pretty sweet!

core firewall

Stay tuned - we will post details about our network design later on..

Labels: Tech TG17

Invitation: Tech meetup at The Gathering 2017!

21 Mar 2017, by Kristian Lyngstøl from Tech:Net

Do you do Tech-stuff at a computer party? Any computer party? Then this is for you.

We are looking to put together an informal "Tech-meetup" during The Gathering 2017. The exact program is yet to be decided, the only thing we know is who we want there: Anyone who are part of a tech crew at a computer part or similar event.

This is the result of seeing just how many great people there are out there. And to be more open about what we do at The Gathering, or any other computer party.

The idea is simple: We meet up during the event. Most likely some time during Friday (daytime), but that's subject to change. We perhaps do a small presentation of TG tech crew with a twist of some sort, Q&A, and then open the floor to discussion about whatever. There's no super-hard agenda. We can talk about TCP checksum mechanics, DHCP lease times, cable termination, how to best store switches, what candy makes for the best NOC-candy, pros and cons of renting equipment versus buying it. Or just exchange "war stories".

Does this sound interesting? Then drop me a mail at and let me know. This isn't an application, just a "I want in! I've been setting up the network at this local party with 40 participants for the last few years and this would be fun!" thing.

I'm sure we should've put together a better sign-up process, but we're lazy.

Well, I'm lazy anyway. If my mail-box explodes due to this, we might have to rethink this.

From "our" side you can expect me and whoever I manage to kidnap. I know several people in the NOC have expressed an interest. We'll also obviously provide some sort of room.

Labels: Meetup, Tech TG17

TG15 wireless design - with Meru networks :)

28 Mar 2015, by Marius Hole from Tech:Net

Simplifying and making WiFi less complex and ready to adopt the user needs.

The image below is an example of how channel layers can be deployed to support high client density areas such as a open space like TG. For this we will use different ESSIDs, some deployed on multiple channels some may only be needed on one or two channels. The ESSID used for video broadcasting may be at just one channel. This channel is then "in the air" reserved for this purpose only. Do we need capacity it's all about adding in AP's and maybe using more channels for this ESSID.

This can in general actually for TG be handled by just one wireless controller, but for density and RF reasons we can spilt the channels and ESSID we need across multiple controllers also. We have also placed in a redundant controller ready if one of the master controllers should fail.

In addition we use the unique Airtime Fairness technology Meru provides by default.
Meru's Airtime Fairness governs Wi-Fi access so that every client gets the same amount of time, ensuring consistent performance for the users. With Meru Airtime Fairness(r), the speed of the network is not determined by the slowest traffic. By allocating time equally among clients, Airtime Fairness allows every transmission to move at its highest potential. At TG this is very useful since we will serve many wifi clients in same RF space ☺. So we will most likely use all the possible RF bandwidth, but dived equal to the clients based on air time.

Network Management:
For getting the option to monitor and follow the wireless network at TG we use Meru Network Manager
We can then track down clients, usage per AP/radio, controller and so on. This will give a good insight where to fine-tune and optimize the entire installation at TG.

Here is the latest revision of the wireless design, the different colors indicates different layers:

(we will make the final version in high quality format available after TG).

Here are some relevant links to Meru resources, if you are interested in wireless networking:

Network design TG15 and FAP

26 Mar 2015, by Marius Hole from Tech:Net

Most of the Tech:Net-crew is traveling up to Vikingskipet already tomorrow to establish the internet-connection and some of the most critical components of the infrastructure. From Saturday morning we'll be working on getting the core equipment up and running so that we are absolutely sure that we can provide the best and the most stable networking services for our users when they arrive on Wednesday.

Here is the last revision of the network design:
(we will make the final version in high quality format available after TG).

For some years now, The Gathering has utilized different methods for automatic provisioning of the edge switches that the participants connect to. The first iteration of this system was used to configure ZyXel switches, and was called 'zyxel-ng'. Then, in 2010, The Gathering bought new D-Link edge switches with gigabit ports. New wendor, new configuration methods. 'dlink-ng'[1] was born. It had lots of ugly hacks and exception handling. This was due to several reasons, but mainly because the D-Link's wouldn't take configuration automatically from TFTP/FTP/similar.

Five years had passed. We'd outgrown the number of switches that was bought in 2010, and we needed more. After thorough research and several rounds with RFQ's, we decided to buy new switches for TG15. We ended up buying Juniper EX2200's as edge switches. This meant, once again, a new configuration tool. We had this in mind when writing the RFQ, so we already knew what to expect. After some testing, trial and error, we landed on a proof-of-concept. It involves DHCP Option 82, custom-made DHCP-server and some scripts to serve software- and configuration files over HTTP. The name? Fast and Agile Provisioning (FAP)[2].


With this tool, we can connect all the edge switches on-the-fly, and they'll get the configuration designed for that specific switch (based on what port on the distro they connect to). If the switch doesn't have the specific software we want it to have, it'll automatically download this software and install it.

It's completely automated once set up, and can be kept running during the entire party (so f.ex. if an edge switch fails during the party, we can just replace it with a blank one, at it'll get the same configuration as the old one).


The network at The Gathering 2015

08 Feb 2015, by Marius Hole from Tech:Net

As The Gathering 2015 draws closer we thought it was about time for an update regarding the network.

We have been in a comprehensive round of evaluation of and purchasing new edge/access switches to replace the D-Link's that have been the access-switches for the last 5 events. After a lot of planning, meetings, e-mails, more meetings, shortlisting and more meetings - we ended up with choosing nLogic as our main collaborator , and we are happy to announce that TG will be using equipment from Juniper Networks for TG15 and the years to come. nLogic have been very forthcoming and fantastic to work with and we look forward to work with them. nLogic is a consultancy company in Oslo, which happens to be a Juniper Elite Portfolio Partner in Norway.

Most of the equipment have been purchased as part of the deal with nLogic, with very good prices (of course, or we could never have afforded purchasing these cool switches). Thus, the equipment will end up being owned by KANDU/TG, free for us to do what we want with them after the contract ends and we, of course, have paid the bank all its money...

As core-switches this year we will be using two Juniper QFX5100-48S switches. These high-performance, low-latency switches are based on the Trident 2 chipset and offers 48 x 10G and 6 x 40G interfaces making them ideal to run as core-switches in a network such as ours.

This year we will be running the Juniper EX3300-48P switches in stacks (Virtual-Chassis) of four with 20Gbps uplink to the core-switches (upgradable to 80Gbps if needed). The EX3300-48 comes with 48 x 1G copper and 4 x 10G SFP+ interfaces. Running these switches in a stack will grant us both full redundancy as well as the scalability and speed we need. This switch model will also be used for the backend network in the arena (CamGW, LogGW, etc).

For The Gathering 2015 will will be utilizing the EX2200-48T-4G as the edge switches. The EX2200-48 comes with 48 x 1G copper and 4 SFP interfaces and offers a rich feature set ideal for us. Of functionality worth mentioning are; IGMP- and MLD snooping, first-hop security for both IPv4 and IPv6 (IP-source-guard, IPv6-source-guard, DHCP-snooping, DHCPv6-snooping, IPv6 ND-inspection, dynamic ARP-inspection), sFlow, DHCPv4 option 82, DHCPv6 option 17/37, etc.

Other switches:
NocGW and TeleGW this year will consist of stacks of EX4300-24T and QFX5100-48S. This gives us the ideal port-combination of 1G, 10G and 40G and also providing us with a fully redundant 80G (2*40GbE) ring between TeleGW, NocGW and Core.
With the above setup in mind we have designed a network where we can suffer an outage of any single network element without experiencing outage on any critical services.

This weekend we have fulfilled one of the Juniper workshops at nLogic, lead by senior network consultant Harald Karlsen, which is in the trail for us in Tech:Net (and some from Tech:Server and Tech:Support) to be prepared for working with Juniper Junos after 10, very good and pleasant, years with Cisco IOS.

**Here are some pictures from the weekend at nLogic (*) :


IMG_5023Organizer without his morning coffee is as useless as a switch with no power (?) ;)

The wireless experts wants to learn more about R&S! :)

MacGyver making himself ready for making a bomb out of some cables,
a switch and some Junos configuration...

"We do not agree with the teacher! NO! NOT AT ALL!"

"Fresh air. So strong. Must inhale slowly."

Teacher-Karlsen shows the students the equipment that they will work on...

j- :)

Ida :)

"This is not at all anything near, in the vicinity or close proximity of Cisco IOS, WHAT?"

They said 10 minutes, chocolates and coffee... and the room emptied in 10 seconds flat...

nLogic heroes! :)

The concentration is deep...

IMG_5062And the arguments high...

And low...

And yes, that is the button you press to turn the computer on!

That throat have great need of some beverage...

:Server demonstrates to :Net how to take the network down...

And the concentration is like... BSDeep

So deep that the Organizer had to leave the room...

Which lasted like... 10 minutes?

That good old OSPF!

"I'm not sure if you were supposed to actually delete all the interfaces?"

"Not to worry, I'll make a restore device out of some paperclips,
a CAT5 cable and an old hard-drive"

(*) All pictures are taken, owned and copyright by Marius Hole - ask before you download them and use them somewhere!



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