I apparently wasn't very clear. In the layered approach to multiple vendors, you would (obviously) choose your layer definitions to avoid such delicate interdependence. Regardless of my failure to fully explain, I'm curious as to how mixing vendors at the same layer is seen to be less problematic than assigning vendors specific roles? ----

My Android sent this< http://chrisgrundemann.com

On Dec 28, 2016 11:13 PM, "David Barak" <thegameiam@yahoo.com> wrote: On Dec 28, 2016, at 5:34 PM, Randy Bush <randy@psg.com> wrote:

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An alternative multi-vendor approach is to use 1 vendor per stack layer, but alternate layer to layer. That is; Vendor A edge router, Vendor B firewall, Vendor A/C switches, Vendor D anti-SPAM software, etc. This doesn't address the bug impact issue as well as it alleviates the vendor "ownership" issue though...

i think this is where i say that i hope my competitors do this. it is a recipe for a complex set of delicate dependencies and great fun debugging.

One of the more spectacular failures I've seen was a bug in a network core router that caused bad into to be carried by all of that same vendor's routers across the core to the edges (made by a different vendor) which promptly barfed and locked up. So I'd be cautious about saying "vendor X for one layer, vendor Y for adjacent layer" as a multi-vendor strategy. David Barak Sent from mobile device, please excuse autocorrection artifacts