Why powerline adapter are faster with multiple tcp connections?

[mgiammarco]

Hello,
I see in tests that several powerline hd adapters reach 300mbps but only with multiple tcp streams running.

Why? I need to reach max speed with only one tcp connection.... can I?

Thanks in advance for any reply!

Mario

 

[thiggins]

I don't know the technical explanation. But the effect is also seen with 802.11n wireless networks.

You can't reach the same total speed for multiple connections with a single connection.

 

[stevech]

Hello,
I see in tests that several powerline hd adapters reach 300mbps but only with multiple tcp streams running.

Why? I need to reach max speed with only one tcp connection.... can I?

Thanks in advance for any reply!

Mario

It's because of (a) the half-duplex protocol used for power line and WiFi and (b) the PCs doing the transfer cannot keep the "pipe" full for one TCP connection, but several in parallel will fill the pipe (bandwidth capacity of the medium).

Check out my prior posting (sticky here). It shows what I measured for parallel connections.

 

[mgiammarco]

Great!

So if I can make the connection full duplex I can get greater speeds!

BTW: there are several ways to make two half duplex connections work as one full duplex.

I can bond them using routing protocol:

http://www.ubnt.com/forum/showthread.php?t=34428

Or I can bond them with a new linux (of pfsense?!?) bonding algorithm that sends upstream packets on one link and downstream on another link (I cannot find the link grrrrr)

Link found:
http://www.dd-wrt.com/wiki/index.php/Bonding#duplex

 

[thiggins]

Good luck with that. Let us know if you succeed.