Worth Reading: Another Hugo-Based Blog

Bruno Wollmann migrated his blog post to Hugo/GitHub/CloudFlare (the exact toolchain I’m using for one of my personal web sites) and described his choices and improved user- and author experience.

As I keep telling you, always make sure you own your content. There’s absolutely no reason to publish stuff you spent hours researching and creating on legacy platforms like WordPress, third-party walled gardens like LinkedIn, or “free services” obsessed with gathering visitors’ personal data like Medium.

Video: Exposing Kubernetes Services to External Clients

After a brief introduction of Kubernetes service and an overview of services types, Stuart Charlton added the last missing bit: how do you expose Kubernetes services to external clients.

Video: Exposing Kubernetes Services to External Clients

After a brief introduction of Kubernetes service and an overview of services types, Stuart Charlton added the last missing bit: how do you expose Kubernetes services to external clients.

Multihoming Cannot Be Solved within a Network

Henk made an interesting comment that finally triggered me to organize my thoughts about network-level host multihoming¹:

The problems I see with routing are: [hard stuff], host multihoming, [even more hard stuff]. To solve some of those, we should have true identifier/locator separation. Not an after-thought like LISP, but something built into the layer-3 addressing architecture.

Proponents of various clean-slate (RINA) and pimp-my-Internet (LISP) approaches are quick to point out how their solution solves multihoming. I might be missing something, but it seems like that problem cannot be solved within the network.

Multihoming Cannot Be Solved within a Network

Henk made an interesting comment that finally triggered me to organize my thoughts about network-level host multihoming¹:

The problems I see with routing are: [hard stuff], host multihoming, [even more hard stuff]. To solve some of those, we should have true identifier/locator separation. Not an after-thought like LISP, but something built into the layer-3 addressing architecture.

Proponents of various clean-slate (RINA) and pimp-my-Internet (LISP) approaches are quick to point out how their solution solves multihoming. I might be missing something, but it seems like that problem cannot be solved within the network.

BGP in ipSpace.net Design Clinic

The ipSpace.net Design Clinic has been running for a bit over than a year. We covered tons of interesting technologies and design challenges, resulting in over 13 hours of content (so far), including several BGP-related discussions:

• BGP route servers
• Redundant BGP-Based Internet Access
• Secure BGP Configuration on Customer Routers
• Enterprise WAN Routing Design

All the Design Clinic discussions are available with Standard or Expert ipSpace.net Subscription, and anyone can submit new design/discussion challenges.

BGP in ipSpace.net Design Clinic

The ipSpace.net Design Clinic has been running for a bit over than a year. We covered tons of interesting technologies and design challenges, resulting in over 13 hours of content (so far), including several BGP-related discussions:

• BGP route servers
• Redundant BGP-Based Internet Access
• Secure BGP Configuration on Customer Routers
• Enterprise WAN Routing Design

All the Design Clinic discussions are available with Standard or Expert ipSpace.net Subscription, and anyone can submit new design/discussion challenges.

BGP Unnumbered Duct Tape

Every time I mention unnumbered BGP sessions in a webinar, someone inevitably asks “and how exactly does that work?” I always replied “gee, that’s a blog post I should write one of these days,” and although some readers might find it long overdue, here it is ;)

We’ll work with a simple two-router lab with two parallel unnumbered links between them. Both devices will be running Cumulus VX 4.4.0 (FRR 8.4.0 container generates almost identical printouts).

BGP Unnumbered Duct Tape

Every time I mention unnumbered BGP sessions in a webinar, someone inevitably asks “and how exactly does that work?” I always replied “gee, that’s a blog post I should write one of these days,” and although some readers might find it long overdue, here it is ;)

We’ll work with a simple two-router lab with two parallel unnumbered links between them. Both devices will be running Cumulus VX 4.4.0 (FRR 8.4.0 container generates almost identical printouts).

netlab VXLAN Router-on-a-Stick Example

In October 2022 I described how you could build a VLAN router-on-a-stick topology with netlab. With the new features added in netlab release 1.4¹ we can do the same for VXLAN-enabled VLANs – we’ll build a lab where a router-on-a-stick will do VXLAN-to-VXLAN routing.

netlab VXLAN Router-on-a-Stick Example

In October 2022 I described how you could build a VLAN router-on-a-stick topology with netlab. With the new features added in netlab release 1.4¹ we can do the same for VXLAN-enabled VLANs – we’ll build a lab where a router-on-a-stick will do VXLAN-to-VXLAN routing.

Worth Reading: History of Fiber Optics Cables

Geoff Huston published a fantastic history of fiber optics cables, from the first (copper) transatlantic cable to 2.2Tbps coherent optics. Have fun!

Worth Reading: History of Fiber Optics Cables

Geoff Huston published a fantastic history of fiber optics cables, from the first (copper) transatlantic cable to 2.2Tbps coherent optics. Have fun!

Video: Routing Protocols Overview

After discussing network addressing and switching, routing, and bridging in the How Networks Really Work webinar, it was high time for a deep dive into routing protocols, starting (as always) with an overview.

Video: Routing Protocols Overview

After discussing network addressing and switching, routing, and bridging in the How Networks Really Work webinar, it was high time for a deep dive into routing protocols, starting (as always) with an overview.

BGP Route Reflectors in the Forwarding Path

Bela Varkonyi left two intriguing comments on my Leave BGP Next Hops Unchanged on Reflected Routes blog post. Let’s start with:

The original RR design has a lot of limitations. For usual enterprise networks I always suggested to follow the topology with RRs (every interim node is an RR), since this would become the most robust configuration where a link failure would have the less impact.

He’s talking about the extreme case of hierarchical route reflectors, a concept I first encountered when designing a large service provider network. Here’s a simplified conceptual diagram (lines between boxes are physical links as well as IBGP sessions between loopback interfaces):

BGP Route Reflectors in the Forwarding Path

Bela Varkonyi left two intriguing comments on my Leave BGP Next Hops Unchanged on Reflected Routes blog post. Let’s start with:

The original RR design has a lot of limitations. For usual enterprise networks I always suggested to follow the topology with RRs (every interim node is an RR), since this would become the most robust configuration where a link failure would have the less impact.

He’s talking about the extreme case of hierarchical route reflectors, a concept I first encountered when designing a large service provider network. Here’s a simplified conceptual diagram (lines between boxes are physical links as well as IBGP sessions between loopback interfaces):

Using EVPN/VXLAN with MLAG Clusters

There’s no better way to start this blog post than with a widespread myth: we don’t need MLAG now that most vendors have implemented EVPN multihoming.

TL&DR: This myth is close to the not even wrong category.

As we discussed in the MLAG System Overview blog post, every MLAG implementation needs at least three functional components:

Using EVPN/VXLAN with MLAG Clusters

There’s no better way to start this blog post than with a widespread myth: we don’t need MLAG now that most vendors have implemented EVPN multihoming.

TL&DR: This myth is close to the not even wrong category.

As we discussed in the MLAG System Overview blog post, every MLAG implementation needs at least three functional components:

SRv6 as a Host-to-Host Overlay

During the discussion of the On Applicability of MPLS Segment Routing (SR-MPLS) blog post on LinkedIn someone made an off-the-cuff remark that…

SRv6 as an host2host overlay - in some cases not a bad idea

It’s probably just my myopic view, but I fail to see the above idea as anything else but another tiny chapter in the “Solution in Search of a Problem” SRv6 saga¹.