Tag: cisco

Well… It will reboot your whole switch stack at once, In case you were wondering. But it has a neat feature of automatic rollback to the previous IOS XE version if something goes south with the newly upgraded switches.

The same goes for non-stacked Cisco Catalyst C9200 and C9300 switches, but the question was, and the answer is hard to find if the stack would reload members sequentially or it would just reload all members at once. The answer is of course the least good option which makes the upgrade impossible without network outage even if other devices are connected to the stack redundantly (to two or more stack members).

The whole procedure is fairly simple:

Switch Upgrade install mode

New Cisco switches are now usually shipped with install mode configuration for software installation. The other (older) bundle mode was simply a boot variable on the switch config that stated where the .bin files is saved on the switch flash and if multiple .bin files which one to load upon switch reboot.

It was a year of big changes in every way. I was fortunate enough to be surrounded by great professionals working on huge projects and then even to get the chance to switch to some completely new technologies that I never really worked with before. It was great, it is still very intense and from my perspective, all changes were for the better.

But as with all periods with a lot of action, all those draft articles on this blog’s queue didn’t yield as much new material as I wanted. It was a year of almost no writing but a lot of learning, adapting and real-life collaboration with other fellow engineers in different fields and different places across the world.

Consequently, all that work and collaboration on projects with great tech people made this year’s nomination for Cisco Champion possible again. In the end, even this BLOGs awards nomination and TOP25 ranking was also mostly because of the support from colleagues and friends that voted for this material of mine.

Thanks!

Doing a lot on Nexus 9000 series datacenter boxes (N9K) lately? Sure you’re missing the good old ‘wr’ command to save your last startup-config into running-config.

NXOS architecture guys decided that you should be really well concentrated when deciding to save your nice new configuration to survive device reboot and type: N9K_1(config)# copy running-config startup-config. Just typing ‘wr’ into the console would be too nice right? Let’s use the alias configuration and bring that command back to the box.

It’s one of those articles aimed at the people with Cisco ACI experience who don’t bother with reading all the install and other guides again while going through n’th time of building and ACI fabric, like me. When it comes to Cisco ACI, you really should.

There’s a small change with the physical build of the third generation of APIC server where 10G SFP interfaces from APIC towards the Leaf switches (used for fabric discovery and later for the in-band controller to fabric communication) where 4x10G card is built in the server and not like 2x10G on M2/L2 and other first and second generation of APICs.

When you see those 4x10G ports on the server, the logical thing to do will be to use the first two ports on each APIC and connect them to two Leafs (for redundancy and stuff). It ended up being that is not really how Cisco intended those interfaces to be used and it will end up blowing your fabric stability and management. I was able to discover the fabric and register the fabric leaf and spines. It was even possible to configure the whole thing up to the functional fabric and L2-L3 functions but the APIC cluster was always unstable and going in and out of configuration stale and data diverged statuses on cluster view.

SDDC – Software-Defined Data Centers

Times of Software Defined everything has long since arrived, the need to implement many appliances, two or more for each network function, is not so popular anymore. The possibility to manage packet forwarding, load balancing and security of network traffic inside the datacenter from one simple web console is showing finally that things can be managed in a simpler way after all. All vendors in the networking world tried to come up with their own way of centralizing data center management, as it ends up, all of them did it, some better than the others. As always, it’s not a surprise that some vendors are better in creating hardware-based forwarding solutions and some others in software solutions (in this case, software for packet forwarding).

Requirements

It seems that we have basically only a few good options when wanting to select a complete SDDC solution. The data center needs to provide a large number of server access ports in the form of networking devices that are configured and managed as simply and promptly as possible. Datacenter network needs to be configured in a way to provide robustness and stability of packet forwarding at almost line rate and all that at 10-100, even 400Gbps speeds.