Even Simple Data Models Are a Huge Win
Dan Augustine sent me a wonderful example illustrating how even a very simple data model together with some automation templates can simplify a large-scale deployment.
We have a 100 router installation coming up for our schools and both of our installation vendors do not use open source templating tools and they are not willing to share.
Having taken the Data Models in Network Automation part of your Network Automation Concepts webinar, I decided to install GitLab, make an Ansible project and invite our installation partners to the project.
Where Would You Need DNS Anycast?
One of the publicly observable artifacts of the October 2021 Facebook outage was an intricate interaction between BGP routing and their DNS servers needed to support optimal anycast configuration. Not surprisingly, it was all networking engineers' fault according to some opinions1
There’s no need for anycast2/BGP advertisement for DNS servers. DNS is already highly available by design. Only network people never understand that, which leads to overengineering.
It’s not that hard to find a counter-argument3: while it looks like there are only 13 root name servers4, each one of them is a large set of instances advertising the same IP prefix5 to the Internet.
Where Would You Need DNS Anycast?
One of the publicly observable artifacts of the October 2021 Facebook outage was an intricate interaction between BGP routing and their DNS servers needed to support optimal anycast configuration. Not surprisingly, it was all networking engineers’ fault according to some opinions1
There’s no need for anycast2/BGP advertisement for DNS servers. DNS is already highly available by design. Only network people never understand that, which leads to overengineering.
It’s not that hard to find a counter-argument3: while it looks like there are only 13 root name servers4, each one of them is a large set of instances advertising the same IP prefix5 to the Internet.
netsim-tools Release 1.0
It looks like netsim-tools reached a somewhat stable state, so it was time to do a cleanup and publish release 1.0 (also available on PyPi, use pip3 install –upgrade netsim-tools to fetch it).
During the cleanup, I removed all references to the obsolete scripts, leaving only the netlab command. I also found an old bash script that enabled LLDP passthrough on Linux bridges and made it part of netlab up process; your libvirt-based labs will have LLDP enabled by default.
Interested? Install the tools and follow the tutorials to get started.
netsim-tools Release 1.0
It looks like netsim-tools reached a somewhat stable state, so it was time to do a cleanup and publish release 1.0 (also available on PyPi, use pip3 install –upgrade netsim-tools to fetch it).
During the cleanup, I removed all references to the obsolete scripts, leaving only the netlab command. I also found an old bash script that enabled LLDP passthrough on Linux bridges and made it part of netlab up process; your libvirt-based labs will have LLDP enabled by default.
Interested? Install the tools and follow the tutorials to get started.
Worth Reading: Operators and the IETF
Long long time ago (seven years to be precise), ISOC naively tried to bridge the gap between network operators and Internet Vendor Engineering Task Force1. They started with a widespread survey asking operators why they’re hesitant to participate in IETF mailing lists and meetings.
The result: Operators and the IETF draft that never moved beyond -00 version. A quick glimpse into the Potential Challenges will tell you why IETF preferred to kill the messenger (and why I published this blog post on Halloween).
Worth Reading: Operators and the IETF
Long long time ago (seven years to be precise), ISOC naively tried to bridge the gap between network operators and Internet Vendor Engineering Task Force1. They started with a widespread survey asking operators why they’re hesitant to participate in IETF mailing lists and meetings.
The result: Operators and the IETF draft that never moved beyond -00 version. A quick glimpse into the Potential Challenges will tell you why IETF preferred to kill the messenger (and why I published this blog post on Halloween).
Worth Reading: Programming Sucks
Just FYI: if you’re wondering about the wisdom of every networking engineer should become a programmer religion, you might benefit from the Programming Sucks reality check. I had just enough exposure to programming to realize how spot-on it is (and couldn’t decide whether to laugh or cry).
Worth Reading: Programming Sucks
Just FYI: if you’re wondering about the wisdom of every networking engineer should become a programmer religion, you might benefit from the Programming Sucks reality check. I had just enough exposure to programming to realize how spot-on it is (and couldn’t decide whether to laugh or cry).
Nonlinear Effects of Optimization-Induced Complexity
We have school holidays this week, so I’m reposting wonderful comments that would otherwise be lost somewhere in the page margins. Today: Minh Ha on recent Facebook failure and overly complex systems (slightly edited).
I incidentally commented on your NSF post some 3 weeks before […the Facebook outage…] happened, on the unpredictable nature of nonlinear effects resulting from optimization-induced complexity. Their outage just drives home the point that optimization is a dumb process and leads to combinations of circular dependency that no one can account for and test.
Nonlinear Effects of Optimization-Induced Complexity
We have school holidays this week, so I’m reposting wonderful comments that would otherwise be lost somewhere in the page margins. Today: Minh Ha on recent Facebook failure and overly complex systems (slightly edited).
I incidentally commented on your NSF post some 3 weeks before […the Facebook outage…] happened, on the unpredictable nature of nonlinear effects resulting from optimization-induced complexity. Their outage just drives home the point that optimization is a dumb process and leads to combinations of circular dependency that no one can account for and test.
Big Picture: BFD, Non-Stop Forwarding, and Graceful Restart
We have school holidays this week, so I’m reposting wonderful comments that would otherwise be lost somewhere in the page margins. Today: Erik Auerswald’s excellent summary of BFD, NSF, and GR.
I’d suggest to step back a bit and consider the bigger picture: What is BFD good for? What is GR/NSF/NSR/SSO good for?
BFD and GR/NSF/NSR/SSO have different goals: one enables quick fail over, the other prevents fail over. Combining both promises to be interesting.
Big Picture: BFD, Non-Stop Forwarding, and Graceful Restart
We have school holidays this week, so I’m reposting wonderful comments that would otherwise be lost somewhere in the page margins. Today: Erik Auerswald’s excellent summary of BFD, NSF, and GR.
I’d suggest to step back a bit and consider the bigger picture: What is BFD good for? What is GR/NSF/NSR/SSO good for?
BFD and GR/NSF/NSR/SSO have different goals: one enables quick fail over, the other prevents fail over. Combining both promises to be interesting.
EVPN/VXLAN Complexity
We have school holidays this week, so I’m reposting wonderful comments that would otherwise be lost somewhere in the page margins. Today: Minh Ha on complexity of emulating layer-2 networks with VXLAN and EVPN.
Dmytro Shypovalov is a master networker who has a sophisticated grasp of some of the most advanced topics in networking. He doesn’t write often, but when he does, he writes exceptional content, both deep and broad. Have to say I agree with him 300% on “If an L2 network doesn’t scale, design a proper L3 network. But if people want to step on rakes, why discourage them.”
EVPN/VXLAN Complexity
We have school holidays this week, so I’m reposting wonderful comments that would otherwise be lost somewhere in the page margins. Today: Minh Ha on complexity of emulating layer-2 networks with VXLAN and EVPN.
Dmytro Shypovalov is a master networker who has a sophisticated grasp of some of the most advanced topics in networking. He doesn’t write often, but when he does, he writes exceptional content, both deep and broad. Have to say I agree with him 300% on “If an L2 network doesn’t scale, design a proper L3 network. But if people want to step on rakes, why discourage them.”
Interactions Between BFD and Graceful Restart
We have school holidays this week, so I’m reposting wonderful comments that would otherwise be lost somewhere in the page margins. Today: Dmitry Perets on the interactions between BFD and GR.
Well, assuming that the C-bit is set honestly (will be funny if not) and assuming that the Helper is using this bit correctly (and I think it’s pretty well defined what “correctly” means - see section 4.3 in RFC 5882), the answer is pretty clear.
Interactions Between BFD and Graceful Restart
We have school holidays this week, so I’m reposting wonderful comments that would otherwise be lost somewhere in the page margins. Today: Dmitry Perets on the interactions between BFD and GR.
Well, assuming that the C-bit is set honestly (will be funny if not) and assuming that the Helper is using this bit correctly (and I think it’s pretty well defined what “correctly” means - see section 4.3 in RFC 5882), the answer is pretty clear.
Feedback: How Networks Really Work
A few weeks ago I asked my subscribers which webinar they’d like to see in November (thanks a million to everyone who replied!). Not surprisingly, network automation got the top spot, but I was a bit sad to see my long-term pet project at the bottom of the list:
Feedback: How Networks Really Work
A few weeks ago I asked my subscribers which webinar they’d like to see in November (thanks a million to everyone who replied!). Not surprisingly, network automation got the top spot, but I was a bit sad to see my long-term pet project at the bottom of the list:
Worth Reading: Making a Case for Automation Architecture
In case you’re ever asked to justify an investment in network automation, read How to Make the Case for Automation Architecture first. Not surprisingly, it includes the evergreen what problem are you trying to solve?