Most circuits are full-duplex, ie: they can both transmit and receive at the same time. For example, a T1 which is approximately 1.5Mbps is actually 3Mbps total bandwidth. The same with Ethernet type interfaces, so the total bandwidth on a 1Gbps ethernet interface would be 2Gbps. Go back to the T1, or 1.5Mbps full-duplex. If you were transmitting 1Mbps down and 500Kbps up, you'd be at 50% of your total bandwidth, but at 66% of your download speed and 33% of your upload speed.
Where it can get tricky is with some of these DSL or cable connections. You might have 20Mbps down, but only 1Mbps up, so your total bandwidth would be 21Mbps. So, if you were transmitting 1Mbps down and 1Mbps up, you'd be at 5% of your download speed, but 100% of your upload speed. However, you'd be at ~10% of your total bandwidth.
Half-duplex connections can only have one endpoint transmitting at the same time, otherwise the packets collide and you get a collision. So, with a 10Mbps half-duplex ethernet connection your total bandwidth is still only 10Mbps... Of course if both sides are transmitting, with collisions it would be difficult to get near the 10Mbps...
yes it does. thank you.