I've recently spent hours trying to work out why certain traffic types have been dropped over VXLAN. Particularly when wifi traffic traversed the campus wide network but also certain streaming services. After a hunch I worked out the commonality amongst failing traffic types was packet size. Large packets were being silently dropped. This was a... Continue Reading →
Upgrading Aruba CX VSX Pairs
Aruba AOS-CX contains a technology for logically linking a pair of switches so that they exchange specific types of information and states. A typical use case is to have two physical switches act as a single LACP partner (MC-LAG). Config and other info can be kept in sync automatically if desired. When using this technology... Continue Reading →
Aruba AOS-CX Internal VLANs
First, an easy CCNA level question: How many VLANs can you configure on a standard switch? If you answered 4094 and you run anything other than AOS-CX then you are maybe correct. If you run AOS-CX the answer (by default) is 4040. Thats right, Aruba have stolen 54 VLANs. Aruba CX have a concept of... Continue Reading →
Scheduled reboot on CX
It is a common task to need to reboot a switch at a pre-defined time, such as early in the morning. The most common reason being to invoke an upgrade. This can be achieved using network automation if done at scale but it may also be necessary for a single switch. This post describes the... Continue Reading →
Renaming Interfaces in bulk in Netbox
Netbox has a handy feature in the interface section that permits the bulk edit of interface names. This is really handy when you have switch stacks and want the name to represent the full port name so the CLI and netbox agree. In my example I have member 2 of a stack. When created ports... Continue Reading →
Aruba AOS-CX packet capture including VXLAN decoding
This post shows you how you can capture packets directly on an Aruba CX switch using the linux tcpdump utility. When you start using the CX CLI you'll see it is very much built on Linux and allows for a lot of the same commands. If you run the diagnostics command you unlock a set... Continue Reading →
ACL Scaling on HPE Comware
This post will be of zero interest to anyone who doesn't need to create very large ACLs on HPE Comware switches. If you are normal, look away now. I had a need to understand the ACL scaling limits on HP5130 switches. ACLs elsewhere on the network consist of a handful of rules to permit/deny specific... Continue Reading →
Is Cisco certification essential for career progression?
I've read the discussions over the last half a decade that Cisco's grip on the certification market, and the grip of certification on the job market, has dwindled. I believed what people were saying that such traditions had been replaced by a broader vendor outlook from employers together with the requirement to demonstrate broader skills... Continue Reading →
loop protection the the DC
Intro: Broadcast Loops v Broadcast Storms Wherever there is a broadcast domain there exists the opportunity for some idiot to create a loop. It happens in the simplest of environments where a misunderstanding or mis-configuration creates a logical loop where BUM traffic (broadcast, unknown-unicast, multicast) is allowed to go round and round like a merry-go-round.... Continue Reading →
Creating a Blog on GitHub Pages v WordPress
This post is a copy of the content at https://constantpinger.github.io/github/GH_pages.html This is the first page written within GitHub Pages and falls around the 4 hour point in the journey to understanding the technology. Upon hearing about the concept I thought this would be a brilliant way to produce content about code I've written or tech... Continue Reading →
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