Even though Gartner declared SDN obsolete before plateau in their 2021 Networking Hype Cycle, most vendor marketers never got the memo. Anything that interacts with network devices in any way1 is called an SDN controller. Let’s try to throw some minimal amount of taxonomy into that mess based on how these controllers interact with network elements (physical or virtual).
Even though Gartner declared SDN obsolete before plateau in their 2021 Networking Hype Cycle, most vendor marketers never got the memo. Anything that interacts with network devices in any way1 is called an SDN controller. Let’s try to throw some minimal amount of taxonomy into that mess based on how these controllers interact with network elements (physical or virtual).
Christoph Jaggi, the author of Ethernet Encryption webinar, published a new version of Ethernet Encryptor Market Overview including:
Christoph Jaggi, the author of Ethernet Encryption webinar, published a new version of Ethernet Encryptor Market Overview including:
I started preparing the materials for the SDN – 10 years later webinar, and plan to publish a series of blog posts documenting what I found on various aspects of what could be considered SDN1. I’m pretty sure I missed quite a few things; your comments are most welcome.
Let’s start with an easy one: software/hardware disaggregation in network devices.
I found several widely-used open-source2 network operating systems:
I started preparing the materials for the SDN – 10 years later webinar, and plan to publish a series of blog posts documenting what I found on various aspects of what could be considered SDN1. I’m pretty sure I missed quite a few things; your comments are most welcome.
Let’s start with an easy one: software/hardware disaggregation in network devices.
I found several widely-used open-source2 network operating systems:
Another interesting column by Geoff Huston: performance of TCP congestion control protocols when using Low-Earth Orbit or Geosynchronous Orbit satellites for Internet access.
Another interesting column by Geoff Huston: performance of TCP congestion control protocols when using Low-Earth Orbit or Geosynchronous Orbit satellites for Internet access.
The last part of Network Addressing section of How Networks Really Work webinar covered other addressing-related topics starting with address assignment mechanisms.
The last part of the Network Addressing section of How Networks Really Work webinar covered other addressing-related topics starting with address assignment mechanisms.
Here’s another “do these things ever disappear?” question from Enrique Vallejo:
Regarding storage, is Fibre Channel still a thing in 2022, or most people employ SATA over Ethernet and NVMe over fabrics?
TL&DR: Yes. So is COBOL.
To understand why some people still use Fibre Channel, we have to start with an observation made by Howard Marks: “Storage is different.” It’s OK to drop a packet in transit. It’s NOT OK to lose data at rest.
Here’s another “do these things ever disappear?” question from Enrique Vallejo:
Regarding storage, is Fibre Channel still a thing in 2022, or most people employ SATA over Ethernet and NVMe over fabrics?
TL&DR: Yes. So is COBOL.
To understand why some people still use Fibre Channel, we have to start with an observation made by Howard Marks: “Storage is different.” It’s OK to drop a packet in transit. It’s NOT OK to lose data at rest.
Here’s a short list of major goodies included in netsim-tools release 1.2.2:
More details in the release notes.
To upgrade netsim-tools, use pip3 install --upgrade netsim-tools; if you’re starting from scratch, read the installation instructions.
Here’s a short list of major goodies included in netsim-tools release 1.2.2:
More details in the release notes.
Recent news from the Department of Unintended Consequences: RFC 6724 changed the IPv4/IPv6 source/destination address selection rules a decade ago, and it seems that the common interpretation of those rules makes IPv6 Unique Local Addresses (ULA) less preferred than the IPv4 addresses, at least according to the recent Unintended Operational Issues With ULA draft by Nick Buraglio, Chris Cummings and Russ White.
End result: If you use only ULA addresses in your dual-stack network1, IPv6 won’t be used at all. Even worse, if you use ULA addresses together with global IPv6 addresses (GUA) as a fallback mechanism, there might be hidden gotchas that you won’t discover until you turn off IPv4. Looks like someone did a Truly Great Job, and ULA stands for Useless Local Addresses.
Recent news from the Department of Unintended Consequences: RFC 6724 changed the IPv4/IPv6 source/destination address selection rules a decade ago, and it seems that the common interpretation of those rules makes IPv6 Unique Local Addresses (ULA) less preferred than the IPv4 addresses, at least according to the recent Unintended Operational Issues With ULA draft by Nick Buraglio, Chris Cummings and Russ White.
End result: If you use only ULA addresses in your dual-stack network1, IPv6 won’t be used at all. Even worse, if you use ULA addresses together with global IPv6 addresses (GUA) as a fallback mechanism, there might be hidden gotchas that you won’t discover until you turn off IPv4. Looks like someone did a Truly Great Job, and ULA stands for Useless Local Addresses.
A friend of mine working for a mid-sized networking vendor sent me an intriguing question:
We have a product using an old ASIC that has 12K forwarding entries, and would like to extend its lifetime. I know you were mentioning some useful tricks, would you happen to remember what they were?
This challenge has no perfect solution, but there are at least three tricks I’ve encountered so far (as always, comments are most welcome):
A friend of mine working for a mid-sized networking vendor sent me an intriguing question:
We have a product using an old ASIC that has 12K forwarding entries, and would like to extend its lifetime. I know you were mentioning some useful tricks, would you happen to remember what they were?
This challenge has no perfect solution, but there are at least three tricks I’ve encountered so far (as always, comments are most welcome):
Erik Auerswald sent me a pointer to a blog post by Dave Taht: The state of fq_codel and sch_cake worldwide. It’s so nice to see what a huge impact Dave made since he started the Bufferbloat project.
Hint: if you have no idea what Bufferbloat or fq_codel are, you REALLY SHOULD explore Dave’s web site.
Erik Auerswald sent me a pointer to a blog post by Dave Taht: The state of fq_codel and sch_cake worldwide. It’s so nice to see what a huge impact Dave made since he started the Bufferbloat project.
Hint: if you have no idea what Bufferbloat or fq_codel are, you REALLY SHOULD explore Dave’s web site.