I need to select a core switch that will connect my access switch to an IP surveillance's server. The point is that in my network I'll have 109 IP camera sending real time traffic to the server and I'm not sure if I have to consider the amount of packets per second (mpps) that can handle the core switch.
Modern switches are generally non-blocking, ie. they can forward as fast as their ports allow them to (large, modular chassis switches may have a lower backplane capacity than the maximum number of the fastest modules would allow).
This holds true for both bandwidth capacity and forwarding capacity. E.g. a switch with 48x 1G and 4x 10G ports should support a maximum throughput of 88 Gbit/s (or 176 Gbit/s aggregating ingress and egress) or 131 Mframes/s (the smallest frame uses 84x8=672 bits on the wire).
Basically, you just need to multiply a camera's average bandwidth (including overhead) with the number of cameras. The number and size of packets doesn't matter. Also, if a camera runs an average of 2 Mbit/s they just add up to 220 Mbit/s which is a piece of cake.