Trunk to Access – Will It Work?

Recently a posted a question to Twitter about connecting two Cisco Catalyst switches. One switch has already booted and has the following configuration:

interface GigabitEthernet0/0
 description SW02
 switchport mode trunk
 switchport trunk allowed vlan 1,10,20,30
 switchport nonegotiate

The other switch is connected to Gi1/0/48 and has just been powered on. It has no configuration so it is booting with the default configuration. The intention is to onboard a new switch via Catalyst Center using Plug and Play (PNP).

Based on the responses not many people were able to describe what would happen and why or why not this scenario would work. There are some interesting details here and before running into this scenario myself I thought that it might work. Before we can answer if it will work, let’s list what we know at this point in time about the two switches, SW01, and SW02. For SW01 we know that:

  • The port is configured as a trunk.
  • The VLANs allowed on the trunk are 1,10,20, and 30.
  • DTP has been disabled.
  • The native VLAN is 1.

For SW02 we know that:

  • It will boot with all ports enabled.
  • Those ports will be in VLAN 1.
  • DTP is enabled on the Continue reading

Technology Short Take 171

Welcome to Technology Short Take #171! This is the next installation in my semi-regular series that shares links and articles from around the interwebs on various technology areas of interest. Let the linking begin!

Networking

The networking section this time around is focused on application level protocols…but hey, they’re still networking protocols, right?

Security

Cloud Computing/Cloud Management

HN713: Network Automation: Where Are We, And Where Can We Go?

Today’s show is roundtable conversation on the state of automation in the networking industry. We discuss takeaways from the recent AutoCon event on network automation, and get into issues such as sources of truth and the role of abstractions in automation. We also talk about the learning, cultural, and business challenges of network automation--and how to get beyond them.

The post HN713: Network Automation: Where Are We, And Where Can We Go? appeared first on Packet Pushers.

Weekend Reads 120923


Google has revealed a new multilingual text vectorizer called RETVec (short for Resilient and Efficient Text Vectorizer) to help detect potentially harmful content such as spam and malicious emails in Gmail.


Carding has been around since the 1980s but has evolved to the point that even less experienced cybercriminals can now launch campaigns.


Enter Cilium’s advanced Border Gateway Protocol (BGP) implementation, powered by the GoBGP control plane, a solution that not only addresses these challenges but also adds unprecedented flexibility to your network configurations.


The most curious part of this is how people working inside the macroculture are the only folks who don’t understand what’s going on.


Efforts to convince remote workers to return to corporate offices appear to have stalled, based on data from the government, academia, and private-sector organizations.


Once in your home, different individuals have differing authority based on who they are. Family members have access to your whole home.


HP is squeezing more margin out of print customers, the result of a multi-year strategy to convert unprofitable business into something more lucrative, and says its subscription model is “locking” in people.


Microsoft helped Chinese state-run media outlets disseminate propaganda as part of previously unreported partnership agreements, Continue reading

Hedge 205: OId Engineering Quotes

For this month’s roundtable, Eyvonne, Tom, and I return to Addresses to Engineering Students by Harrington and Waddell. This book, published in 1912, is a “product of its time,” and hence deserves some trigger warnings. But it is also interesting to see how advice given to engineering students over 100 years ago holds up for today. Have engineering challenges, and the engineering life, changed all that much? What kinds of advice stand the test of time, what kinds do not?

download

Video: netlab IP Address Management (IPAM)

Did you know that netlab includes full-blown IP address management? You can define address pools (or use predefined ones) and get IPv4 and IPv6 prefixes from those pools assigned to links, interfaces, and loopbacks. You can also assign static prefixes to links, use static IP addresses, interface addresses as an offset within the link subnet, or use unnumbered interfaces.

For an overview of netlab IPAM, watch the netlab address management video (part of the Network Automation Tools webinar), for more details read the netlab addressing tutorial.

Watch the video
You need Free ipSpace.net Subscription to watch the video and Standard ipSpace.net Subscription to watch the rest of the webinar.

Video: netlab IP Address Management (IPAM)

Did you know that netlab includes full-blown IP address management? You can define address pools (or use predefined ones) and get IPv4 and IPv6 prefixes from those pools assigned to links, interfaces, and loopbacks. You can also assign static prefixes to links, use static IP addresses, interface addresses as an offset within the link subnet, or use unnumbered interfaces.

For an overview of netlab IPAM, watch the netlab address management video (part of the Network Automation Tools webinar), for more details read the netlab addressing tutorial.

Watch the video
You need Free ipSpace.net Subscription to watch the video and Standard ipSpace.net Subscription to watch the rest of the webinar.

Life is Life

The initial idea behind this blog was to have a medium to store and share notes on the different technologies I worked on in an searchable manner. I have decided to step back from work and take a year out so this new life tab of the blog will be for all things non-IT related. I still plan to write technology based blogs over this time (got a few automation projects and Azure tips to share), however this is unlikely to start happening until later into next year.

While you sleep, Automate resolving Dynatrace problem alerts and report them to ServiceNow!

Integrating observability tools with automation is paramount in the realm of modern IT operations, as it fosters a symbiotic relationship between visibility and efficiency. Observability tools provide deep insights into the performance, health, and behavior of complex systems, enabling organizations to proactively identify and rectify issues before they escalate. 

When seamlessly integrated with automation frameworks, these tools empower businesses to not only monitor but also respond to dynamic changes in real time. This synergy between observability and automation enables IT teams to swiftly adapt to evolving conditions, minimize downtime, and optimize resource utilization. By automating responses based on observability data, organizations can enhance their agility, reduce manual intervention, and maintain a robust and resilient infrastructure. In essence, using observability with automation is indispensable for achieving a proactive, responsive, and streamlined operational environment in the fast-paced and complex landscape of today’s technology.

In this blog post, we will look at a common use case involving the monitoring of processes on both bare metal and virtual machines. Our exploration will focus on utilizing Dynatrace's OneAgent, a deployed binary file on hosts that encompasses a suite of specialized services meticulously configured for environment monitoring. These services actively gather telemetry metrics, capturing insights into Continue reading

ML Ops Platform at Cloudflare

ML Ops Platform at Cloudflare

We've been relying on ML and AI for our core services like Web Application Firewall (WAF) since the early days of Cloudflare. Through this journey, we've learned many lessons about running AI deployments at scale, and all the tooling and processes necessary. We recently launched Workers AI to help abstract a lot of that away for inference, giving developers an easy way to leverage powerful models with just a few lines of code. In this post, we’re going to explore some of the lessons we’ve learned on the other side of the ML equation: training.

Cloudflare has extensive experience training models and using them to improve our products. A constantly-evolving ML model drives the WAF attack score that helps protect our customers from malicious payloads. Another evolving model power bot management product to catch and prevent bot attacks on our customers. Our customer support is augmented by data science. We build machine learning to identify threats with our global network. To top it all off, Cloudflare is delivering machine learning at unprecedented scale across our network.

Each of these products, along with many others, has elevated ML models — including experimentation, training, and deployment — to a crucial position within Continue reading

AMS-IX Outage: Layer-2 Strikes Again

On November 22nd, 2023, AMS-IX, one of the largest Internet exchanges in Europe, experienced a significant performance drop lasting more than four hours. While its peak performance is around 10 Tbps, it dropped to about 2.1 Tbps during the outage.

AMS-IX published a very sanitized and diplomatic post-mortem incident summary in which they explained the outage was caused by LACP leakage. That phrase should be a red flag, but let’s dig deeper into the details.

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