Arista 7050X2Earliest product mention is the May 2016 copyright date of a white paper on VXLAN
Here Arista is using the Trident-II+ as a soup'd up version of the Trident-II. They are not using a gear box to group SerDes into 100 Gb/s ports as some other vendors have done.
Arista claims that the Trident-II can route VXLAN encapsulated packets and they are the only manufacturer that knows how to pull that off. They do it by internally recirculating packets through the processing pipeline. This uses extra processing power and the highest port density products need to have some ports disabled to avoid over subscription of the packet processing pipeline. The II+ can route and encapsulate in a single pass through the processing pipeline. Arista thus positions the X2 models as performance varients.
Arista has a packet walk white paper dated January 2017. This is a rewrite of a paper from 2013 that covered only the Trident-II 7050X products.
As of February 2017, there are four X2 models shown below: