Throughput limits switching capacity
01-14-2020 12:26 PM
Just to know if my understanding is correct. According to this post which makes sense to me, a switch needs to be able to forward 1488095 packets per second (1.488 million packets per second) to reach 1 Gbps per port (taking into account an Ethernet frame length of 64 bytes):
According to the 2930F 24G 4SFP+ datasheet, the switching capacity is 128 Gbps, which matches (24 x 1Gbps + 4 x 10Gbps) x 2, and the throughput is 95.2 Mbps, which is OK to have the switch at full speed since (24 x 1Gbps + 4 x 10Gbps) x 1.488 = 95.2 Mpps.
However, the 2930F 48G 4SFP+ datasheet says the switching capacity is 176 Gbps, which matches (48 x 1Gbps + 4 x 10Gbps) x 2, but the throughput is 112 Mpps, which is NOT OK to have the switch at full speed since (48 x 1Gbps + 4 x 10Gbps) x 1.488 = 130.9 Mpps. Then, the switch needs a throughput of 130.9 Mpps for not having problems at full speed, but the throughput is only 112 Mpps, which is less.
Does then the throughput limit the switching capacity?
Re: Throughput limits switching capacity
01-21-2020 06:14 AM
Average packet size will be a lot larger than 64 bytes, so you will not see a network pushing gigabits per second of 64 byte packets.
Yes, I know the 64 bytes length is the minimum Ethernet frame length and is the worst case, it will not happen in the real world. But if I made this in a lab with Ethernet frames of 64 bytes, would the switch reach its maximum switching capacity?