I am ordering a few new C8300-2N2S-6T routers as SBC peering to PSTN

[Kevin_CBP]

as do we need A-FLEX-STD-CUBE license for this purpose. 

1) Do we need A-FLEX-STD-CUBE license? That license does not appear on the  C8300-2N2S-6T CCW page. So I wonder do I still need it given I already have the DNA advantage license?

2) Also how Cisco count the sessions? each call has two legs as below

 --- outgoing leg --- C8300-2N2S-6T—incoming leg

 Each call per VoIP has 2 legs so I think they count as 1 session, right? or Two?

[b.winter · Accepted solution]

1) Yes, you need SIP trunk licenses (A-FLEX-CUBE-STD, ...)
2) 1 call (2 call legs) is 1 license