Bandwidth allocation sizing

Originally appeared in January 2015

When trying to calculate bandwidth allocation for a particular protocol, you would need to understand what the size of the actual payload/data is, then calculate what the bottom layer headers would add as overhead. Also, you would need to know what a particular data/payload would measure on Data Links (Layer 2), e.g. Ethernet, Ethernet 801.1Q (VLAN), HDLC, PPP, Frame Relay, Fiber

The typical example is a G.729 voice packet. Just the payload of the packet is 8 kbits, then we add the overheads of the lower layers:

Overhead Byes/sec	Total
G729	20	20
Layer 5	RTP	12	32
Layer 4	UDP	8	40
Layer 3	IP	20	60
Layer 2	Ethernet	38	98

Some links I came across: