When I come across the S6a interface we are using IMEI AVP for International Mobile Equipment Identity.
But when I come across the Gy interface we are using a Grouped AVP named as User-Equipment-Info AVP which contain User-Equipment-Info-Value and User-Equipment-Info-Type.
My query is why we need to use two different Diameter AVPs across the EPC network which gives the same result , let say IMEI in this case.