So when I’ve done most of my searching on these technologies so far, Google has auto-directed me to IOS XE when it comes to Cisco platforms. Looking at certification blueprints, it seems like the certification expectations are that you know how these technologies work across all three of Cisco’s primary network OSes (IOS + XE + XR).
I must fully admit my experience with the platforms that run these network OSes is pretty limited. My roles so far have mostly focused around specific cases where the network OS was not something I could control.
That said, I want to get a better understanding for when I should be leveraging a given network OS in a given scenario. I think I have a general understanding of the architecture of each of the Cisco-specific ones I’ve listed so far, but I feel like the hardware platforms these typically run on are going to have massively different specs.
And if my question seems super off-base, let’s direct the energy into what I should be asking! I feel like I’m almost in the “don’t know what you don’t know” category here, and every little bit will get me pushing in the right direction.
With the Catalyst 9k series, Cisco has been unifying many of their platforms. So IOS is pretty much just going to be IOS-XE, with NX for data center, XR for carrier, FXOS for Firepower, UCS for… UCS…
Carrier gear is almost always Cisco, Juniper, Ciena, Nokia, and increasingly Arista.
The technologies are pretty much the same, so the hardware and OS doesn’t really matter as long as it does what you want. EVPN is EVPN, regardless of if it’s a Cisco box or not.
The answer depends on scale and features.
“MPLS VPN” is only the tip of the iceberg to pick a platform/OS.
Think of how much bandwidth you need, how many VPNs, how many routes per VPN, if this is a PE or a P device, is this L3VPN, L2VPN, VPLS.
IOS-XE boxes are generally more for enterprise applications, few VRFs here and there.
IOS-XR are Service Provider oriented, where you need hundreds of VRFs on a PE for example. Or massive throughput requirements.
In the IOS-XR platforms there will be devices focused on aggregation vs core or even RR with a ton of RAM for millions of BGP routes.