Should You Build or Buy a Router?

Patrik Schindler sent me an interesting comment to my Open-Source DMVPN Alternatives blog post:

Welcome to the build-or-buy dilemma, router edition.

Should You Build or Buy a Router?

Patrik Schindler sent me an interesting comment to my Open-Source DMVPN Alternatives blog post:

Welcome to the build-or-buy dilemma, router edition.

Worth Reading: Do We Need Segment Routing?

Etienne-Victor Depasquale sent me a pointer to an interesting NANOG discussion: why would we need Segment Routing. It’s well worth reading the whole thread (until it devolves into “that is not how MPLS works” arguments), which happens to be somewhat aligned with my thinking:

• SR-MPLS makes perfect sense (excluding the migration-from-LDP fun)
• SRv6 (in whatever incantation) is mostly a vendor ploy to sell new chipsets.

Enjoy!

Worth Reading: Do We Need Segment Routing?

Etienne-Victor Depasquale sent me a pointer to an interesting NANOG discussion: why would we need Segment Routing. It’s well worth reading the whole thread (until it devolves into “that is not how MPLS works” arguments), which happens to be somewhat aligned with my thinking:

• SR-MPLS makes perfect sense (excluding the migration-from-LDP fun)
• SRv6 (in whatever incantation) is mostly a vendor ploy to sell new chipsets.

Enjoy!

Graceful Restart and Other Control Plane Protocols

In the Graceful Restart 101 blog post, I promised to discuss the ugly parts of this concept in a follow-up post. It turns out we’ll need more than one; today, we’ll focus on other control plane protocols in an access network scenario.

Imagine an access router with multiple uplinks serving a bunch of non-redundantly-connected customers:

Graceful Restart and Other Control Plane Protocols

In the Graceful Restart 101 blog post, I promised to discuss the ugly parts of this concept in a follow-up post. It turns out we’ll need more than one; today, we’ll focus on other control plane protocols in an access network scenario.

Imagine an access router with multiple uplinks serving a bunch of non-redundantly-connected customers:

Feedback: Mastering Cloud Networking

Most of the public cloud training seems focused on developers. No surprise there, they are the usual beachhead public cloud services need to get into large organizations. Unfortunately, once the production applications start getting deployed into public cloud infrastructure, someone has to take over operations, and that’s where the fun starts.

For whatever reason, there aren’t that many resources helping the infrastructure operations teams understand how to deal with this weird new world, at least according to the feedback Jawed left on Azure Networking webinar:

Feedback: Mastering Cloud Networking

Most of the public cloud training seems focused on developers. No surprise there, they are the usual beachhead public cloud services need to get into large organizations. Unfortunately, once the production applications start getting deployed into public cloud infrastructure, someone has to take over operations, and that’s where the fun starts.

For whatever reason, there aren’t that many resources helping the infrastructure operations teams understand how to deal with this weird new world, at least according to the feedback Jawed left on Azure Networking webinar:

Video: Public Cloud Networking Is Different

Even though you need plenty of traditional networking constructs to deploy a complex application stack in a public cloud (packet filters, firewalls, load balancers, VPN, BGP…), once you start digging deep into the bowels of public cloud virtual networking, you’ll find out it’s significantly different from the traditional Ethernet+IP implementations common in enterprise data centers.

For an overview of the differences watch the Public Cloud Networking Is Different video (part of Introduction to Cloud Computing webinar), for more details start with AWS Networking 101 and Azure Networking 101 blog posts, and continue with corresponding cloud networking webinars.

Video: Public Cloud Networking Is Different

Even though you need plenty of traditional networking constructs to deploy a complex application stack in a public cloud (packet filters, firewalls, load balancers, VPN, BGP…), once you start digging deep into the bowels of public cloud virtual networking, you’ll find out it’s significantly different from the traditional Ethernet+IP implementations common in enterprise data centers.

For an overview of the differences watch the Public Cloud Networking Is Different video (part of Introduction to Cloud Computing webinar), for more details start with AWS Networking 101 and Azure Networking 101 blog posts, and continue with corresponding cloud networking webinars.

Reusing Underlay Network for Infrastructure Services

Boris Lazarov sent me an excellent question:

Does it make sense and are there any inherent problems from design perspective to use the underlay not only for transport of overlay packets, but also for some services. For example: VMWare cluster, vMotion, VXLAN traffic, and some basic infrastructure services that are prerequisite for the rest (DNS).

Before answering it, let’s define some terminology which will inevitably lead us to the it’s tunnels all the way down endstate.

Reusing Underlay Network for Infrastructure Services

Boris Lazarov sent me an excellent question:

Does it make sense and are there any inherent problems from design perspective to use the underlay not only for transport of overlay packets, but also for some services. For example: VMWare cluster, vMotion, VXLAN traffic, and some basic infrastructure services that are prerequisite for the rest (DNS).

Before answering it, let’s define some terminology which will inevitably lead us to the it’s tunnels all the way down endstate.

Watch Out: ISR Performance License

Bill Dagy sent me an annoying ISR gotcha. In his own words:

Since you have a large audience I thought I would throw this out here. Maybe it will help someone avoid spending 80 man hours troubleshooting network slowdowns.

Here’s the root cause of that behavior:

Cisco is now shipping routers that have some specified maximum throughput, but you have to buy a “boost license” to run them unthrottled. Maybe everyone already knew this but it sure took us by surprise.

Don’t believe it? Here’s a snapshot from Cisco 4000 Family Integrated Services Router Data Sheet:

Watch Out: ISR Performance License

Bill Dagy sent me an annoying ISR gotcha. In his own words:

Since you have a large audience I thought I would throw this out here. Maybe it will help someone avoid spending 80 man hours troubleshooting network slowdowns.

Here’s the root cause of that behavior:

Cisco is now shipping routers that have some specified maximum throughput, but you have to buy a “boost license” to run them unthrottled. Maybe everyone already knew this but it sure took us by surprise.

Don’t believe it? Here’s a snapshot from Cisco 4000 Family Integrated Services Router Data Sheet:

Graceful Restart 101

In the Non-Stop Forwarding (NSF) article, I mentioned that the routers adjacent to the device using NSF have to play along to make the idea work. That capability is called Graceful Restart. Today we’ll explore its intricate details, be diplomatic, and leave the shortcomings and tradeoffs for the next blog post.

The Problem

Imagine an access (provider edge) router providing connectivity services to its clients and running a routing protocol with one or more upstream devices.

Graceful Restart (GR) 101

In the Non-Stop Forwarding (NSF) article, I mentioned that the routers adjacent to the device using NSF have to play along to make the idea work. That capability is called Graceful Restart. Today we’ll explore its intricate details, be diplomatic, and leave the shortcomings and tradeoffs for the next blog post.

The Problem

Imagine an access (provider edge) router providing connectivity services to its clients and running a routing protocol with one or more upstream devices.

State of IT Security in 2021

Patrik Schindler sent me his views on code quality and resulting security nightmares after reading the Cisco SD-WAN SQL Injection saga. Enjoy!

I think we have a global problem with code quality. Both from a security perspective, and from a less problematic but still annoying bugs-everywhere perspective. I’m not sure if the issue is largely ignored, or we’ve given up on it (see also: Cloud Complexity Lies or Cisco ACI Complexity).

State of IT Security in 2021

Patrik Schindler sent me his views on code quality and resulting security nightmares after reading the Cisco SD-WAN SQL Injection saga. Enjoy!

I think we have a global problem with code quality. Both from a security perspective, and from a less problematic but still annoying bugs-everywhere perspective. I’m not sure if the issue is largely ignored, or we’ve given up on it (see also: Cloud Complexity Lies or Cisco ACI Complexity).

Worth Reading: Breaking Down Silos

Here’s another masterpiece by Charity Majors: Why I hate the phrase “breaking down silos”. A teaser in case you can’t decide whether to click the link:

When someone says they are “breaking down silos”, whether in an interview, a panel, or casual conversation, it tells me jack shit about what they actually did.

Enjoy ;)

Worth Reading: Breaking Down Silos

Here’s another masterpiece by Charity Majors: Why I hate the phrase “breaking down silos”. A teaser in case you can’t decide whether to click the link:

When someone says they are “breaking down silos”, whether in an interview, a panel, or casual conversation, it tells me jack shit about what they actually did.

Enjoy ;)