Archive

Category Archives for "ipSpace.net"

New Project: BGP Hands-On Labs

Approximately 30 years ago I managed to persuade the powers-that-be within Cisco’s European training organization that they needed a deep-dive BGP course, resulting in a 3 (later 5) day Advanced BGP Configuration and Troubleshooting (ABCT) course1. I was delivering that course for close to a decade, and gradually built a decent story explaining the reasoning and use cases behind most of (then available) BGP features, from simple EBGP sessions to BGP route reflectors and communities2.

Now imagine having more than a dozen hands-on labs that go with the “BGP from rookie to hero” story available for any platform of your choice3. I plan to make that work (eventually) as an open-source project that you’ll be able to download and run free-of-charge.

Worth Reading: MP-TCP in Hybrid Access Networks

Wouldn’t it be nice if your home router (CPE) could use DSL (or slow-speed fibre) and LTE connection at the same time? Even better: run a single TCP session over both links? The answer to both questions is YES, of course it could do that, if only your service provider would be interested in giving you that option.

We solved similar problems with multilink PPP in the networking antiquity, today you could use a CPE with an MP-TCP proxy combined with a Hybrid Access Gateway in the service provider network. For more details, read the excellent Increasing broadband reach with Hybrid Access Networks article by prof. Olivier Bonaventure and his team.

Worth Reading: MP-TCP in Hybrid Access Networks

Wouldn’t it be nice if your home router (CPE) could use DSL (or slow-speed fibre) and LTE connection at the same time? Even better: run a single TCP session over both links? The answer to both questions is YES, of course it could do that, if only your service provider would be interested in giving you that option.

We solved similar problems with multilink PPP in the networking antiquity, today you could use a CPE with an MP-TCP proxy combined with a Hybrid Access Gateway in the service provider network. For more details, read the excellent Increasing broadband reach with Hybrid Access Networks article by prof. Olivier Bonaventure and his team.

Worth Reading: Eyes Like Saucers

Gerben Wierda published a nice description of common reactions to new unicorn-dust-based technologies:

  • Eyes that glaze over
  • Eyes like saucers
  • Eyes that narrow

He uses generative AI as an example to explain why it might be a bad idea that people in the first two categories make strategic decisions, but of course nothing ever stops people desperately believing in vendor fairy tales, including long-distance vMotion, SDN or intent-based networking.

Worth Reading: Eyes Like Saucers

Gerben Wierda published a nice description of common reactions to new unicorn-dust-based technologies:

  • Eyes that glaze over
  • Eyes like saucers
  • Eyes that narrow

He uses generative AI as an example to explain why it might be a bad idea that people in the first two categories make strategic decisions, but of course nothing ever stops people desperately believing in vendor fairy tales, including long-distance vMotion, SDN or intent-based networking.

Multipath TCP (MPTCP) Resources

Brian Carpenter published a list of Multipath TCP resources to one of the IETF mailing lists1:

You might also want to listen to the Multipath TCP podcast we recorded with Apple engineers in 2019.


  1. … along with a nice reminder that “it might be wise to look at actual implementations of MPTCP before jumping to conclusions”. Yeah, that’s never a bad advice, but rarely followed. ↩︎

Multipath TCP (MPTCP) Resources

Brian Carpenter published a list of Multipath TCP resources to one of the IETF mailing lists1:

You might also want to listen to the Multipath TCP podcast we recorded with Apple engineers in 2019.


  1. … along with a nice reminder that “it might be wise to look at actual implementations of MPTCP before jumping to conclusions”. Yeah, that’s never a bad advice, but rarely followed. ↩︎

Configuring Linux Traffic Control in a Sane Way

Smart engineers were forever using Linux (in particular, its traffic control/queue discipline functionality) to simulate WAN link impairment. Unfortunately, there’s a tiny hurdle you have to jump across: the tc CLI is even worse than iptables.

A long while ago someone published a tc wrapper that simulates shitty network connections and (for whatever reason) decided to call it Comcast. It probably does the job, but I would prefer to have something in Python. Daniel Dib found just that – tcconfig – and used it to simulate WAN link behavior on VMware vSphere.

Configuring Linux Traffic Control in a Sane Way

Smart engineers were forever using Linux (in particular, its traffic control/queue discipline functionality) to simulate WAN link impairment. Unfortunately, there’s a tiny hurdle you have to jump across: the tc CLI is even worse than iptables.

A long while ago someone published a tc wrapper that simulates shitty network connections and (for whatever reason) decided to call it Comcast. It probably does the job, but I would prefer to have something in Python. Daniel Dib found just that – tcconfig – and used it to simulate WAN link behavior on VMware vSphere.

Worth Reading: Another BGP Session Reset Bug

Emile Aben is describing an interesting behavior observed in the Wild West of the global Internet: someone started announcing BGP paths with an unknown attribute, which (regardless of RFC 7606) triggered some BGP session resets.

One would have hoped we learned something from the August 2010 incident (supposedly caused by a friend of mine 😜), but it looks like some things never change. For more details, watch the Network Security Fallacies and Internet Routing Security webinar.

Worth Reading: Another BGP Session Reset Bug

Emile Aben is describing an interesting behavior observed in the Wild West of the global Internet: someone started announcing BGP paths with an unknown attribute, which (regardless of RFC 7606) triggered some BGP session resets.

One would have hoped we learned something from the August 2010 incident (supposedly caused by a friend of mine 😜), but it looks like some things never change. For more details, watch the Network Security Fallacies and Internet Routing Security webinar.

1 31 32 33 34 35 183