
Author Archives: Ivan Pepelnjak
Author Archives: Ivan Pepelnjak
One of the viewers of Rachel Traylor’s excellent Graph Algorithms in Networks webinar sent me this feedback:
I think it is too advanced for my needs. Interesting but difficult to apply. I love math and I find it interesting maybe for bigger companies, but for a small company it is not possible to apply it.
While a small company’s network might not warrant a graph-focused approach (I might disagree, but let’s not go there), keep in mind that almost everything we do in IT rides on top of some sort of graph:
I’ve been saying the same thing for years, but never as succinctly as Alastair Cooke did in his Understand Your Single Points of Failure (SPOF) blog post:
The problem is that each time we eliminated a SPOF, we at least doubled our cost and complexity. The additional cost and complexity are precisely why we may choose to leave a SPOF; eliminating the SPOF may be more expensive than an outage cost due to the SPOF.
Obviously that assumes that you’re able to follow business objectives and not some artificial measure like uptime. Speaking of artificial measures, you might like the discussion about taxonomy of indecision.
I’ve been saying the same thing for years, but never as succinctly as Alastair Cooke did in his Understand Your Single Points of Failure (SPOF) blog post:
The problem is that each time we eliminated a SPOF, we at least doubled our cost and complexity. The additional cost and complexity are precisely why we may choose to leave a SPOF; eliminating the SPOF may be more expensive than an outage cost due to the SPOF.
Obviously that assumes that you’re able to follow business objectives and not some artificial measure like uptime. Speaking of artificial measures, you might like the discussion about taxonomy of indecision.
Scott Berkun wrote another great article that’s equally applicable to the traditional notion of design (his specialty) and the network design. Read it, replace design with network design, and use its lessons. Here’s just a sample:
Scott Berkun wrote another great article that’s equally applicable to the traditional notion of design (his specialty) and the network design. Read it, replace design with network design, and use its lessons. Here’s just a sample:
In the last part of my chat with David Bombal we discussed interesting technologies networking engineers could focus on if they want to grow beyond pure packet switching (and voice calls, if you happen to believe VoIP is not just an application). We mentioned public clouds, automation, Linux networking, tools like Git, and for whatever reason concluded with some of my biggest blunders.
In the last part of my chat with David Bombal we discussed interesting technologies networking engineers could focus on if they want to grow beyond pure packet switching (and voice calls, if you happen to believe VoIP is not just an application). We mentioned public clouds, automation, Linux networking, tools like Git, and for whatever reason concluded with some of my biggest blunders.
Recently I joked there’s significant difference between AWS and Azure launching features:
Those with long enough memories shouldn’t be surprised. It’s not the first time Microsoft is using the same tactics.
Recently I joked there’s significant difference between AWS and Azure launching features:
Those with long enough memories shouldn’t be surprised. It’s not the first time Microsoft is using the same tactics.
Minh Ha left another extensive comment on my Is Switching Latency Relevant blog post. As is usual the case, it’s well worth reading, so I’m making sure it doesn’t stay in the small print (this time interspersed with a few comments of mine in gray boxes)
I found Cisco apparently manages to scale port-to-port latency down to 250ns for L3 switching, which is astonishing, and way less (sub 100ns) for L1 and L2.
I don’t know where FPGA fits into this ultra low-latency picture, because FPGA, compared to ASIC, is bigger, and a few times slower, due to the use of Lookup Table in place of gate arrays, and programmable interconnects.
Minh Ha left another extensive comment on my Is Switching Latency Relevant blog post. As is usual the case, it’s well worth reading, so I’m making sure it doesn’t stay in the small print (this time interspersed with a few comments of mine in gray boxes)
I found Cisco apparently manages to scale port-to-port latency down to 250ns for L3 switching, which is astonishing, and way less (sub 100ns) for L1 and L2.
I don’t know where FPGA fits into this ultra low-latency picture, because FPGA, compared to ASIC, is bigger, and a few times slower, due to the use of Lookup Table in place of gate arrays, and programmable interconnects.
Scott submitted an interesting the comment to my Does Unequal-Cost Multipath (UCMP) Make Sense blog post:
How about even Large CLOS networks with the same interface capacity, but accounting for things to fail; fabric cards, links or nodes in disaggregated units. You can either UCMP or drain large parts of your network to get the most out of ECMP.
Before I managed to write a reply (sometimes it takes months while an idea is simmering somewhere in my subconscious) Jeff Tantsura pointed me to an excellent article by Erico Vanini that describes the types of asymmetries you might encounter in a leaf-and-spine fabric: an ideal starting point for this discussion.
Scott submitted an interesting the comment to my Does Unequal-Cost Multipath (UCMP) Make Sense blog post:
How about even Large CLOS networks with the same interface capacity, but accounting for things to fail; fabric cards, links or nodes in disaggregated units. You can either UCMP or drain large parts of your network to get the most out of ECMP.
Before I managed to write a reply (sometimes it takes months while an idea is simmering somewhere in my subconscious) Jeff Tantsura pointed me to an excellent article by Erico Vanini that describes the types of asymmetries you might encounter in a leaf-and-spine fabric: an ideal starting point for this discussion.
The reader asking about infrastructure-as-code in public cloud deployments also wondered whether he has any chance at mastering on-premises network automation due to lack of programming skills.
I am starting to get concerned about not knowing automation, IaC, or any programming language. I didn’t go to college, like a lot of my peers did, and they have some background in programming.
First of all, thanks a million to everyone needs to become a programmer hipsters for thoroughly confusing people. Now for a tiny bit of reality.
The reader asking about infrastructure-as-code in public cloud deployments also wondered whether he has any chance at mastering on-premises network automation due to lack of programming skills.
I am starting to get concerned about not knowing automation, IaC, or any programming language. I didn’t go to college, like a lot of my peers did, and they have some background in programming.
First of all, thanks a million to everyone needs to become a programmer hipsters for thoroughly confusing people. Now for a tiny bit of reality.
Who would have thought that you could get better at what you do by figuring out how things you use really work. I probably made that argument (about networking fundamentals) too many times; Julia Evans claims the same approach applies to programming.
Who would have thought that you could get better at what you do by figuring out how things you use really work. I probably made that argument (about networking fundamentals) too many times; Julia Evans claims the same approach applies to programming.
I thought I was snarky and somewhat rude (and toned down some of my blog posts on second thought), but I’m a total amateur compared to Corey Quinn. His last masterpiece – Machine Learning is a Marvelously Executed Scam – is another MUST READ.
I thought I was snarky and somewhat rude (and toned down some of my blog posts on second thought), but I’m a total amateur compared to Corey Quinn. His last masterpiece – Machine Learning is a Marvelously Executed Scam – is another MUST READ.
Years ago I wrote a series of blog posts comparing transparent bridging and IP routing, and creating How Networks Really Work materials seemed like a perfect opportunity to make that information more structured, starting with Transparent Bridging Fundamentals.