On Routing Protocol Metrics
This LinkedIn snippet just came in from the someone is not exactly right on the Internet department:
Unlike IGP protocols, BGP is not dependent on a single type of metric to choose the best path.
EIGRP is an immediate counterexample that brought the above quote to my attention, but it’s worth exploring the topic in more detail.
On Routing Protocol Metrics
This LinkedIn snippet just came in from the someone is not exactly right on the Internet department:
Unlike IGP protocols, BGP is not dependent on a single type of metric to choose the best path.
EIGRP is an immediate counterexample that brought the above quote to my attention, but it’s worth exploring the topic in more detail.
Public Videos: Routing Protocols
One of the delightful side effects of leaving the paid content business is that I no longer have to try to persuade anyone that my content is any good. That includes the “this video is now public” announcements – instead of elaborate introductions, I’ll just publish a short blog post with the links.
As of today, these videos (along with dozens of previously-released videos) from the Routing Protocols section of the How Networks Really Work webinar are no longer behind a login wall:
Upcoming BGP Labs, 2024 Edition
It’s that time of the year when we create unreachable goals and make empty promises to ourselves (or others) that we subconsciously know we’ll fail.
I tried to make that process a bit more structured and create external storage for my lab ideas – I started publishing more details on future BGP lab scenarios. The lab descriptions contain a high-level overview of the challenge and the lab topology; the details will be filled in later.
Want to know what’s coming in 2024? Check out the Upcoming Labs page of the BGP Labs project.
Upcoming BGP Labs, 2024 Edition
It’s that time of the year when we create unreachable goals and make empty promises to ourselves (or others) that we subconsciously know we’ll fail.
I tried to make that process a bit more structured and create external storage for my lab ideas – I started publishing more details on future BGP lab scenarios. The lab descriptions contain a high-level overview of the challenge and the lab topology; the details will be filled in later.
Want to know what’s coming in 2024? Check out the Upcoming Labs page of the BGP Labs project.
Public Cloud Networking Hands-On Exercises
I got this request from someone who just missed the opportunity to buy the ipSpace.net subscription (or so he claims) earlier today
I am inspired to learn AWS advanced networking concepts and came across your website and webinar resources. But I cannot access it.
That is not exactly true. I wrote more than 4000 blog posts in the past, and some of them dealt with public cloud networking. There are also the free videos, some of them addressing public cloud networking.
Public Cloud Networking Hands-On Exercises
I got this request from someone who just missed the opportunity to buy the ipSpace.net subscription (or so he claims) earlier today
I am inspired to learn AWS advanced networking concepts and came across your website and webinar resources. But I cannot access it.
That is not exactly true. I wrote more than 4000 blog posts in the past, and some of them dealt with public cloud networking. There are also the free videos, some of them addressing public cloud networking.
Goodbye, ipSpace.net Subscription
I ran the first webinar as an independent author almost exactly fourteen years ago1, with the first ticket sold just before New Year’s Eve. I kept focusing on individual webinars until someone asked me, “Would it be possible to buy access to everything you did?” His question effectively created the ipSpace.net subscription, with the first one sold in late 2010 (I still have the email that triggered the whole process).
Goodbye, ipSpace.net Subscription
I ran the first webinar as an independent author almost exactly fourteen years ago1, with the first ticket sold just before New Year’s Eve. I kept focusing on individual webinars until someone asked me, “Would it be possible to buy access to everything you did?” His question effectively created the ipSpace.net subscription, with the first one sold in late 2010 (I still have the email that triggered the whole process).
Happy Holidays and All the Best in 2024!
My video editor sent me the perfect let’s-wrap-up-this-year video:
I wish you a few quiet days disconnected from the technology and all the best in 2024!
End-of-Year Cleanup: OSPF Blog Posts
After procrastinating for months, I finally spent a few days cleaning up and organizing OSPF blog posts (it turns out I wrote almost 100 blog posts on the topic in the 18 years of blogging).
End-of-Year Cleanup: OSPF Blog Posts
After procrastinating for months, I finally spent a few days cleaning up and organizing OSPF blog posts (it turns out I wrote almost 100 blog posts on the topic in the 18 years of blogging).
Setting Source IP Address on Traffic Started by a Multihomed Host
In the Path Failure Detection on Multi-Homed Servers blog post, I mentioned running BGP on servers as one of the best ways to detect server-to-network failures. As always, things aren’t as simple as they look, as Cathal Mooney quickly pointed out:
One annoyance is what IP address gets used by default by the system for outbound traffic. It would be nice to have a generic OS-level way to say, “This IP on lo0 should be default for outbound IP traffic unless to the connected link subnet itself.”
That’s definitely a tough nut to crack, and Cathal described a few solutions he used in the past:
Setting Source IP Address on Traffic Started by a Multihomed Host
In the Path Failure Detection on Multi-Homed Servers blog post, I mentioned running BGP on servers as one of the best ways to detect server-to-network failures. As always, things aren’t as simple as they look, as Cathal Mooney quickly pointed out:
One annoyance is what IP address gets used by default by the system for outbound traffic. It would be nice to have a generic OS-level way to say, “This IP on lo0 should be default for outbound IP traffic unless to the connected link subnet itself.”
That’s definitely a tough nut to crack, and Cathal described a few solutions he used in the past:
BGP Challenge: Merge Autonomous Systems
Here’s a challenge in case you get bored during the Christmas break: merge two networks running BGP (two autonomous systems) without changing anything but the configurations of the routers connecting them (the red BGP session in the diagram). I won’t give you any hints; you can discuss it in the comments or a GitHub discussion.
Hopefully, you won’t have to deal with something similar in real life, but then we know that crazy requirements trump good designs any day of the week.
BGP Challenge: Merge Autonomous Systems
Here’s a challenge in case you get bored during the Christmas break: merge two networks running BGP (two autonomous systems) without changing anything but the configurations of the routers connecting them (the red BGP session in the diagram). I won’t give you any hints; you can discuss it in the comments or a GitHub discussion.
Hopefully, you won’t have to deal with something similar in real life, but then we know that crazy requirements trump good designs any day of the week.
Review: Unnumbered Interfaces in netlab
A while ago, Chris Parker published a nice blog post explaining how to configure unnumbered interfaces with IS-IS in Junos. It’s well worth reading, but like my Unnumbered Ethernet Interfaces blog post, it only covers one network operating system. What if you want to do something similar on another platform?
How about using the collective efforts of the team developing device configuration templates for netlab? As of December 2023 netlab supports:
Review: Unnumbered Interfaces in netlab
A while ago, Chris Parker published a nice blog post explaining how to configure unnumbered interfaces with IS-IS in Junos. It’s well worth reading, but like my Unnumbered Ethernet Interfaces blog post, it only covers one network operating system. What if you want to do something similar on another platform?
How about using the collective efforts of the team developing device configuration templates for netlab? As of December 2023 netlab supports:
Worth Reading: The AI Supply Paradox
Eric Hoel published a spot-on analysis of AI disruptiveness, including this gem:
The easier it is to train an AI to do something, the less economically valuable that thing is. After all, the huge supply of the thing is how the AI got so good in the first place.
TL&DR: AI can easily disrupt things that are easy to generate and thus have little value. Seeing investors trying to recoup the billions pouring into the latest fad will be fun.
Worth Reading: The AI Supply Paradox
Eric Hoel published a spot-on analysis of AI disruptiveness, including this gem:
The easier it is to train an AI to do something, the less economically valuable that thing is. After all, the huge supply of the thing is how the AI got so good in the first place.
TL&DR: AI can easily disrupt things that are easy to generate and thus have little value. Seeing investors trying to recoup the billions pouring into the latest fad will be fun.