Use iperf to split multiple tcp streams between 2 NIC on same client (similar to IxChariot)

Question

I have 2 PCs connected to each other using two 1 Gbps ethernet link, to have an aggregate data bandwidth of 2 Gbps. In IxChariot, I can create multiple TCP pairs and split them into:

PC1_LAN1 <-> PC2_LAN1 (5 TCP pairs)
PC1_LAN2 <-> PC2_LAN2 (5 TCP pairs)

IxChariot aggregates these as 10 TCP pairs and runs a 2 Gbps throughput test.

I am trying to do something similar using iPerf.

In iPerf, I could run 2 parallel iPerf instances on a single client, 1st instance holding IP of PC2_LAN1 & 2nd instance holding IP of PC2_LAN2. This tries to utilize the 2 ethernet links on the server side. But how can I make,

1st iperf instance send packets on PC1_LAN1 <-> PC2_LAN1 (5 TCP pairs)

> iperf -c PC2_LAN1 -P 5

, and make

2nd iperf instance send packets on PC1_LAN2 <-> PC2_LAN2 (5 TCP pairs).

> iperf -c PC2_LAN2 -P 5

Answer 1

Well that was easy, all we need to do is 'bind' the IP address and/or port to the client. For example,

iperf -c PC2_LAN1 -P 5 -B PC1_LAN1

AND

iperf -c PC2_LAN2 -P 5 -B PC1_LAN2

splits the data on two different LAN connections on the Client PC as well as the Server PC. This is quite useful for WiFi testing of data rate > 1 Gbps.