AWS Automatic EC2 Instance Recovery

On March 30th 2022, AWS announced automatic recovery of EC2 instances. Does that mean that AWS got feature-parity with VMware High Availability, or that VMware got it right from the very start? No and No.

Automatic Instance Recover Is Not High Availability

Reading the AWS documentation (as opposed to the feature announcement) quickly reveals a caveat or two. The automatic recovery is performed if an instance becomes impaired because of an underlying hardware failure or a problem that requires AWS involvement to repair.

Keep Blogging, Some of Us Still Read

I stumbled upon a sad tweet a few days ago…

… and not surprisingly, a lot of people chimed in saying “don’t give up, we still prefer reading”. Unfortunately, it does seem like the amount of worthy content is constantly decreasing, and way too many quality blogs disappeared over the years, so I’ll try to lift the veil of depression a bit ;)

Keep Blogging, Some of Us Still Read

I stumbled upon a sad tweet a few days ago…

… and not surprisingly, a lot of people chimed in saying “don’t give up, we still prefer reading”. Unfortunately, it does seem like the amount of worthy content is constantly decreasing, and way too many quality blogs disappeared over the years, so I’ll try to lift the veil of depression a bit ;)

Creating VRF Lite Labs With netsim-tools

I always found VRF lab setups a chore. On top of the usual IPAM tasks you have to create VRFs, assign route targets and route distinguishers, do that on every PE-router in your lab… before you can start working on interesting things.

I tried to remove as much friction as I could with the netsim-tools VRF configuration module – let me walk you through a few simple examples¹ which will also serve to illustrate the VRF configuration differences between Cisco IOS and Arista EOS.

Creating VRF Lite Labs With netlab

I always found VRF lab setups a chore. On top of the usual IPAM tasks you have to create VRFs, assign route targets and route distinguishers, do that on every PE-router in your lab… before you can start working on interesting things.

I tried to remove as much friction as I could with the netlab VRF configuration module – let me walk you through a few simple examples¹ which will also serve to illustrate the VRF configuration differences between Cisco IOS and Arista EOS.

Worth Reading: Full-Stack Network Automation

Lívio Zanol Puppim published a series of blog posts describing a full-stack network automation, including GitOps with GitLab, handling secrets with Hashicorp Vault, using Ansible and AWX to run automation scripts, continuous integration with Gitlab CI Runner, and topped it off with a REST API and React-based user interface.

You might not want to use the exact same components, but it’s probably worthwhile going through his solution and explore the source code. He’s also looking for any comments or feedback you might have on how to improve what he did.

Worth Reading: Full-Stack Network Automation

Lívio Zanol Puppim published a series of blog posts describing a full-stack network automation, including GitOps with GitLab, handling secrets with Hashicorp Vault, using Ansible and AWX to run automation scripts, continuous integration with Gitlab CI Runner, and topped it off with a REST API and React-based user interface.

You might not want to use the exact same components, but it’s probably worthwhile going through his solution and explore the source code. He’s also looking for any comments or feedback you might have on how to improve what he did.

Worth Reading: The AI Illusion

Russ White’s Weekend Reads are full of gems, including a recent pointer to the AI Illusion – State-of-the-Art Chatbots Aren’t What They Seem article. It starts with “Artificial intelligence is an oxymoron. Despite all the incredible things computers can do, they are still not intelligent in any meaningful sense of the word.” and it only gets better.

While the article focuses on natural language processing (GPT-3 model), I see no reason why we should expect better performance from AI in networking (see also: AI/ML in Networking – The Good, the Bad, and the Ugly).

Worth Reading: The AI Illusion

Russ White’s Weekend Reads are full of gems, including a recent pointer to the AI Illusion – State-of-the-Art Chatbots Aren’t What They Seem article. It starts with “Artificial intelligence is an oxymoron. Despite all the incredible things computers can do, they are still not intelligent in any meaningful sense of the word.” and it only gets better.

While the article focuses on natural language processing (GPT-3 model), I see no reason why we should expect better performance from AI in networking (see also: AI/ML in Networking – The Good, the Bad, and the Ugly).

Video: IPv6 Trust Model

After discussing the basics of IPv6 security in the hands-on part of IPv6 security webinar webinar, Christopher Werny focused on the IPv6 trust model (aka “we’re all brothers and sisters on link-local").

Video: IPv6 Trust Model

After discussing the basics of IPv6 security in the hands-on part of IPv6 security webinar webinar, Christopher Werny focused on the IPv6 trust model (aka “we’re all brothers and sisters on link-local”).

Next Hops of BGP Routes Reflected by Arista EOS

Imagine a suboptimal design in which:

• A BGP route reflector also servers as an AS edge (PE) router¹;
• You want to use next-hop-self on AS edge routers.

Being exposed to Cisco IOS for decades, I considered that to be a no-brainer. After all, section 10 of RFC 4456 is pretty specific:

In addition, when a RR reflects a route, it SHOULD NOT modify the following path attributes: NEXT_HOP, AS_PATH, LOCAL_PREF, and MED.

Arista EOS is different – a route reflector happily modifies NEXT_HOP on reflected routes (but then, did you notice the “SHOULD NOT” wording?²)

Next Hops of BGP Routes Reflected by Arista EOS

Imagine a suboptimal design in which:

• A BGP route reflector also servers as an AS edge (PE) router¹;
• You want to use next-hop-self on AS edge routers.

Being exposed to Cisco IOS for decades, I considered that to be a no-brainer. After all, section 10 of RFC 4456 is pretty specific:

In addition, when a RR reflects a route, it SHOULD NOT modify the following path attributes: NEXT_HOP, AS_PATH, LOCAL_PREF, and MED.

Arista EOS is different – a route reflector happily modifies NEXT_HOP on reflected routes (but then, did you notice the “SHOULD NOT” wording?²)

Opinion: Do You Care about MPLS in 2022?

One of my readers asked for my opinion about this question…

… and I promised something longer than 280 characters.

Opinion: Do You Care about MPLS in 2022?

One of my readers asked for my opinion about this question…

… and I promised something longer than 280 characters.

BGP Labeled Unicast Interoperability Challenges

Jeff Tantsura left me tantalizing hint after reading the BGP Labeled Unicast on Cisco IOS blog post:

Read carefully “Relationship between SAFI-4 and SAFI-1 Routes” section in RFC 8277

The start of that section doesn’t look promising (and it gets worse):

It is possible that a BGP speaker will receive both a SAFI-1¹ route for prefix P and a SAFI-4² route for prefix P. Different implementations treat this situation in different ways.

Now for the details:

BGP Labeled Unicast Interoperability Challenges

Jeff Tantsura left me tantalizing hint after reading the BGP Labeled Unicast on Cisco IOS blog post:

Read carefully “Relationship between SAFI-4 and SAFI-1 Routes” section in RFC 8277

The start of that section doesn’t look promising (and it gets worse):

It is possible that a BGP speaker will receive both a SAFI-1¹ route for prefix P and a SAFI-4² route for prefix P. Different implementations treat this situation in different ways.

Now for the details:

netsim-tools, MPLS Edition

netsim-tools release 1.2.0 adds full-blown MPLS and MPLS/VPN support:

• VRF definitions and layer-3 VRFs
• VRF-aware OSPF, IS-IS and BGP
• Traditional MPLS with LDP (SR-MPLS was already available)
• BGP Labeled Unicast
• MPLS/VPN: VPNv4 and VPNv6 address family support

It’s never been easier to build full-blown MPLS/VPN labs ;)… if you’re OK with using Cisco IOS or Arista EOS. Please feel free to submit a PR to add support for other platforms.

You might want to start with the VRF tutorial to see how simple it is to define VRFs, and follow the installation guide to set up your lab – if you’re semi-fluent in Linux (and don’t care about data plane quirks), the easiest option would be to run Arista cEOS.

netlab MPLS Support

netlab release 1.2.0 adds full-blown MPLS and MPLS/VPN support:

• VRF definitions and layer-3 VRFs
• VRF-aware OSPF, IS-IS and BGP
• Traditional MPLS with LDP (SR-MPLS was already available)
• BGP Labeled Unicast
• MPLS/VPN: VPNv4 and VPNv6 address family support

It’s never been easier to build full-blown MPLS/VPN labs ;)… if you’re OK with using Cisco IOS or Arista EOS. Please feel free to submit a PR to add support for other platforms.

You might want to start with the VRF tutorial to see how simple it is to define VRFs, and follow the installation guide to set up your lab – if you’re semi-fluent in Linux, the easiest option would be to run Arista cEOS.

Worth Reading: Higher Levels of Address Aggregation

Every now and then someone tells me how much better the global Internet would be if only we were using recursive layers (RINA) and hierarchical addresses. I always answer “that’s a business problem, not a technical one, and you cannot solve business problems by throwing technology at them”, but of course that has never persuaded anyone who hasn’t been running a large-enough business for long enough.

Geoff Huston is doing a much better job in the March 2022 ISP Column – read the Higher Levels of Address Aggregation, and if you still need more technical details, there’s 30+ pages of RFC 4984.