OSPF Inter-Process Route Selection

The traditional wisdom claimed that a Cisco IOS router cannot compare routes between different OSPF routing processes. The only parameter to consider when comparing routes coming from different routing processes is the admin distance, and unless you change the default admin distance for one of the processes, the results will be random.

Following Vladislav’s comment to a decade-old blog post, I decided to do a quick test, and found out that code changes tend to invalidate traditional wisdom. OSPF inter-process route selection is no exception. That’s why it’s so stupid to rely on undefined behavior in your network design, memorize such trivia, test the memorization capabilities in certification labs, or read decades-old blog posts describing arcane behavior.

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OSPF Inter-Process Route Selection

The traditional wisdom claimed that a Cisco IOS router cannot compare routes between different OSPF routing processes. The only parameter to consider when comparing routes coming from different routing processes is the admin distance, and unless you change the default admin distance for one of the processes, the results will be random.

Following Vladislav’s comment to a decade-old blog post, I decided to do a quick test, and found out that code changes tend to invalidate traditional wisdom. OSPF inter-process route selection is no exception. That’s why it’s so stupid to rely on undefined behavior in your network design, memorize such trivia, test the memorization capabilities in certification labs, or read decades-old blog posts describing arcane behavior.

Read more …

A startup makes IoT sensors, no batteries necessary

A startup founded by two MIT grads says that it can deploy self-powering sensors to handle low-intensity IoT tasks, eliminating the need for batteries or wired electrical supplies, adding a new level of flexibility to IoT deployments.Ben Calhoun and Dave Wentzloff are the founders of Everactive, an IoT-device manufacturing startup whose sensor modules can create their own power from a variety of sources, including indoor solar, thermal gradient differential, and vibrations. The sensors can monitor for temperature, humidity, light levels, vibration, movement, sound, pressure and gas, among other things.To read this article in full, please click here

The uselessness of bash

The way I write automation for personal projects nowadays seems to follow a common pattern:

  1. A command line, that’s getting a bit long
  2. A bash script
  3. Rewrite in Go

Occasionally I add a step between 2 and 3 where I write it in Python, but it’s generally not actually gaining me anything. Python’s concurrency primitives are pretty bad, and it’s pretty wasteful.

Maybe there’s an actually good scripting language somewhere.

I should remember that writing a bash script (step 2) seems to almost never be worth it. If it’s so complicated that it doesn’t fit on one line, then it’ll become complicated enough to not work with bash.

There are two main things that don’t work well. Maybe there are good solutions to these problems, but I’ve not found them.

1. Concurrency

There are no good primitives. Basically only xargs -P and &. It’s annonying when you have an embarrassingly parallelizable problem where you want to run exactly nproc in parallel.

Especially error handling becomes terrible here.

2. Error handling

You can handle errors in bash scripts in various ways:

  1. || operator. E.g. gzip -9 < a > a.gz || (echo "handling error…")
  2. set -e at the top Continue reading

It’s Most Complicated than You Think

It’s not unusual in the life of a network engineer to go entire weeks, perhaps even months, without “getting anything done.” This might seem odd for those who do not work in and around the odd combination of layer 1, layer 3, layer 7, and layer 9 problems network engineers must span and understand, but it’s normal for those in the field. For instance, a simple request to support a new application might require the implementation of some feature, which in turn requires upgrading several thousand devices, leading to the discovery that some number of these devices simply do not support the new software version, requiring a purchase order and change management plan to be put in place to replace those devices, which results in … The chain of dominoes, once it begins, never seems to end.

Or, as those who have dealt with these problems many times might say, it is more complicated than you think. This is such a useful phrase, in fact, it has been codified as a standard rule of networking in RFC1925 (rule 8, to be precise).

Take, for instance, the problem of sending documents through electronic mail—in the real world, there are various Continue reading

Tech Bytes: Digital Experience Management For Distributed Workforces (Sponsored)

Today's Tech Bytes podcast dives into Digital Experience Management, or DEM. With distributed and remote work becoming more accepted, IT orgs are looking for better ways to monitor and manage user experience. We talk about DEM with sponsor Palo Alto Networks. Our guest is Anupam Uphadhyaya, Senior Director, Product Management at Palo Alto Networks.

The post Tech Bytes: Digital Experience Management For Distributed Workforces (Sponsored) appeared first on Packet Pushers.

Announcing VMware HCX 4.1

VMware HCX is a crucial component of the modernization journey for many VMware customers as they transform their data centers into SDDCs, both on-premises and in the public cloud. HCX, an application mobility platform, simplifies application migration, workload rebalancing, and business continuity across data centers and clouds, and enables large-scale migration of workloads to modern environments.

With the HCX 4.0 release, we rolled out some major updates. Now, the journey continues steadily forward with the release of HCX 4.1. Let’s dive in and see what’s new.

What’s New

Migrations Estimations: Predictive Estimations for Bulk Migrations

One key capability that was launched in HCX 4.0 was Migration Estimation — which provides real-time predictions for bulk migrations. With the HCX 4.1 release, customers will see a more accurate predictive estimate for bulk migrations in draft stage before wave execution.

Seed Checkpoint for Bulk Migration​

In the past, failed replication-based migrations, like bulk migrations with HCX, automatically executed a cleanup process, which would lead to a total loss of replicated data. To the customer, this entailed losing all migration progress, while for larger VM profiles this meant the loss of many days of replication progress.

The seed checkpoint Continue reading

Network Break 337: Hey, You Dropped Some Bitcoin; Fastly Recovers From Outage…Fastly

On this week's Network Break deployment of virtual donuts and tech commentary, Fastly takes out much of the Web but recovers quickly, AWS suffers an outage at a German data center, US law enforcement reclaims a large chunk of Bitcoin ransom, Bosch unveils a new fab to make silicon wafers for automotive chips, and more.

The post Network Break 337: Hey, You Dropped Some Bitcoin; Fastly Recovers From Outage…Fastly appeared first on Packet Pushers.

The Week in Internet News: Twitter Deletes Tweet, Nigeria Bans the Whole Platform

No more tweets: After Twitter removed a tweet by Nigerian President Muhammadu Buhari, the federal government there banned the platform, at least temporarily, because of “the persistent use of the platform for activities that are capable of undermining Nigeria’s corporate existence,” DW.com reports. Some Nigerians are tweeting anyway, but they risk arrest for doing so, […]

The post The Week in Internet News: Twitter Deletes Tweet, Nigeria Bans the Whole Platform appeared first on Internet Society.

IoT cloud services: How they stack up against DIY

Eager to cash in on the massive potential for IoT-based data storage and analytics, public-cloud vendors are diving headlong into the IoT market, offering enterprises everything from individual building blocks to fully managed services and every combination in between. Tech Spotlight: Cloud Computing Cloud or bust: IT leaders go all in on cloud computing (CIO) Migrating to hosted Exchange: Do’s and don’ts (Computerworld) AWS, Google Cloud Platform and Azure: How their security features compare (CSO) From legacy to the cloud: The 3 stages of enterprise modernization (InfoWorld) IoT cloud services: How they stack up against DIY (Network World) The amount of data that is expected to be generated by IoT devices is staggering. IDC predicts that by 2025, there will be 55.9 billion connected devices worldwide, 75% of which will be connected to an IoT platform. IDC estimates the amount of data generated from IoT devices will be 79.4 zettabytes by 2025.To read this article in full, please click here

ipSpace.net Subscription for System Administrators

One of our subscribers sent me this question:

I am a system administrator working primarily on server/storage virtualization. How would you recommend I take full advantage of the subscription while not being in networking full-time?

Let’s start with the webinars focused on technologies and fundamentals:

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