New: Disaster Recovery Resources

I wrote dozens of blog posts debunking disaster recovery fairy tales (mostly of the long-distance vMotion and stretched clusters variety) over the years. They are collected and sorted (and polished a bit) in the new Disaster Recovery Resources page. Hope you’ll find them useful.

ITNOG 7 Wrap-up

I attended ITNOG 7 last week, and thoroughly enjoyed a full day of interesting presentations, including how do you run Internet services in a war zone by Elena Lutsenko and Milko Ilari.

The morning was focused primarily on BGP:

ITNOG 7 Wrap-up

I attended ITNOG 7 last week, and thoroughly enjoyed a full day of interesting presentations, including how do you run Internet services in a war zone by Elena Lutsenko and Milko Ilari.

The morning was focused primarily on BGP:

netlab Release 1.5.3: libvirt Public Networks

containerlab release 0.41.0 that came out a few days ago changed a few topology attributes with no backward compatibility, breaking netlab for anyone doing a new installation. The only way out of that conundrum was to push out a new netlab release that uses the new attributes and requires containerlab release 0.41.0 (more about that in a minute).

On a more positive note, netlab release 1.5.3 brings a few interesting features, including:

• Support for public libvirt networks that can be used to connect your labs to the outside world, and reuse of existing libvirt networks
• ‘unknown’ device type that can be used to deploy devices not yet supported by netlab
• MPLS/VPN support on Nokia SR-OS

netlab Release 1.5.3: libvirt Public Networks

containerlab release 0.41.0 that came out a few days ago changed a few topology attributes with no backward compatibility, breaking netlab for anyone doing a new installation. The only way out of that conundrum was to push out a new netlab release that uses the new attributes and requires containerlab release 0.41.0 (more about that in a minute).

On a more positive note, netlab release 1.5.3 brings a few interesting features, including:

• Support for public libvirt networks that can be used to connect your labs to the outside world, and reuse of existing libvirt networks
• ‘unknown’ device type that can be used to deploy devices not yet supported by netlab
• MPLS/VPN support on Nokia SR-OS

Worth Reading: Official Ansible Collection for SR Linux

Roman Dodin wrote an article describing Nokia’s Ansible collection for SR Linux. Although I don’t use SR Linux (even though it was the first container supported by netlab ;), it was still very interesting to read about the design tradeoffs they had to make:

Worth Reading: Official Ansible Collection for SR Linux

Roman Dodin wrote an article describing Nokia’s Ansible collection for SR Linux. Although I don’t use SR Linux (even though it was the first container supported by netlab ;), it was still very interesting to read about the design tradeoffs they had to make:

Service Insertion with BGP FlowSpec

Nicola Modena had an interesting presentation describing how you can use BGP FlowSpec for traffic steering and service insertion during the recent ITNOG 7 event (more about the event in a few days).

One of the slides explained how to use three different aspects of BGP (FlowSpec, MPLS/VPN and multipathing), prompting me to claim the presentation title should be “BGP is the answer, what was the question?” 😉 Hope you’ll enjoy the PDF version of the presentation as much as we did the live one.

Service Insertion with BGP FlowSpec

Nicola Modena had an interesting presentation describing how you can use BGP FlowSpec for traffic steering and service insertion during the recent ITNOG 7 event (more about the event in a few days).

One of the slides explained how to use three different aspects of BGP (FlowSpec, MPLS/VPN and multipathing), prompting me to claim the presentation title should be “BGP is the answer, what was the question?” 😉 Hope you’ll enjoy the PDF version of the presentation as much as we did the live one.

Video: Sample Kubernetes SDN Implementations

Read for more Kubernetes details? How about Container Networking Interface (CNI) described by Stuart Charlton as part of Kubernetes Networking Deep Dive webinar?

Notes:

• You REALLY SHOULD watch Kubernetes SDN architecture and Sample Kubernetes SDN Implementations videos first
• The video (and a large portion of Kubernetes Networking Deep Dive webinar) is available with Free ipSpace.net Subscription.

Video: Kubernetes Container Networking Interface (CNI)

Ready for more Kubernetes details? How about Container Networking Interface (CNI) described by Stuart Charlton as part of Kubernetes Networking Deep Dive webinar?

Notes:

• You REALLY SHOULD watch Kubernetes SDN architecture and Sample Kubernetes SDN Implementations videos first
• The video (and a large portion of Kubernetes Networking Deep Dive webinar) is available with Free ipSpace.net Subscription.

MLAG Clusters without a Physical Peer Link

With the widespread deployment of Ethernet-over-something technologies, it became possible to build MLAG clusters without a physical peer link, replacing it with a virtual link across the core fabric. Avaya was one of the first vendors to implement virtual peer links with Provider Backbone Bridging (PBB) transport, and some data center switching vendors (example: Cisco) offer similar functionality with VXLAN transport.

MLAG Clusters without a Physical Peer Link

With the widespread deployment of Ethernet-over-something technologies, it became possible to build MLAG clusters without a physical peer link, replacing it with a virtual link across the core fabric. Avaya was one of the first vendors to implement virtual peer links with Provider Backbone Bridging (PBB) transport, and some data center switching vendors (example: Cisco) offer similar functionality with VXLAN transport.

Is ChatGPT an Efficiency Multiplier?

I got this comment on one of my ChatGPT-related posts:

It does save time for things like converting output to YAML (I do not feed it proprietary information), or have it write scripts in various languages, converting configs from one vendor to another, although often they are not complete or correct they save time so regardless of what we think of it, it is an efficiency multiplier.

I received similar feedback several times, but found that the real answer (as is too often the case) is It Depends.

Is ChatGPT an Efficiency Multiplier?

I got this comment on one of my ChatGPT-related posts:

It does save time for things like converting output to YAML (I do not feed it proprietary information), or have it write scripts in various languages, converting configs from one vendor to another, although often they are not complete or correct they save time so regardless of what we think of it, it is an efficiency multiplier.

I received similar feedback several times, but found that the real answer (as is too often the case) is It Depends.

Modifying BGP Behavior with xBGP API

When I reposted a link to xBGP: Faster Innovation in Routing Protocols paper, someone immediately replied

Quite interesting, but it feels like this could become the proverbial 15th standard.

xBGP is an API that allows BGP users to implement routing policies (route selection, filtering, or propagation) that use attributes or mechanisms defined in newer IETF RFCs or drafts, so the proverbial 15th standard is not that far off the mark. However, we must remember that what we call BGP is more than just a set of competing standards.

Modifying BGP Behavior with xBGP API

When I reposted a link to xBGP: Faster Innovation in Routing Protocols paper, someone immediately replied

Quite interesting, but it feels like this could become the proverbial 15th standard.

xBGP is an API that allows BGP users to implement routing policies (route selection, filtering, or propagation) that use attributes or mechanisms defined in newer IETF RFCs or drafts, so the proverbial 15th standard is not that far off the mark. However, we must remember that what we call BGP is more than just a set of competing standards.

Building a DMVPN Test Lab with netlab

I always love to hear about real-life netlab use cases, and try to make them even easier to implement with new netlab features – that’s how netlab got custom Vagrant configuration templates and per-node configuration templates.

When Anne Baretta sent me his initial DMVPN solution, we quickly figured out we could make it even cleaner if netlab supported tunnel interfaces; you can enjoy the results in release 1.5.2, and explore Anne’s solution on GitHub.

Building a DMVPN Test Lab with netlab

I always love to hear about real-life netlab use cases, and try to make them even easier to implement with new netlab features – that’s how netlab got custom Vagrant configuration templates and per-node configuration templates.

When Anne Baretta sent me his initial DMVPN solution, we quickly figured out we could make it even cleaner if netlab supported tunnel interfaces; you can enjoy the results in release 1.5.2, and explore Anne’s solution on GitHub.

MUST READ: End-to-End Arguments in System Design

In case you ever wondered how old the “keep network simple and do complex stuff at the endpoints” approach is, read the End-to-End Arguments in System Design article from 1981.

For whatever reason (hint: profits), networking vendors keep ignoring those arguments, turning the network into a kitchen sink of complexity.

Fun tidbit: the article describes a variant of relying on layer-2 checksums will corrupt your data. Some things never change.