Starting with version 5.13, cFosSpeed can send and receive statistical information about the traffic it is transmitting to other cFosSpeed drivers on the same LAN. The goal is to improve accuracy of multiple cFosSpeed drivers. If cFosSpeed knows about the traffic of other members of your LAN that are sending their traffic over the same router, it can shape more accurately. For instance, the measurement of ping variation depends on the fact that ping times were measured when no one else was transmitting any data.
One other nice advantage of Net_Talk is that you can see in your skin window the overall traffic of other members on your LAN. This might help to understand why a transfer is currectly very slow.
cFosSpeed with Net_Talk enabled will broadcast its statistics to all other members of your LAN 5 times per second. Statistics are transferred so often, so each member has recent data when it is doing shaping decisions. Data is transmitted in one UDP packet of about 1400 bytes in size. The packet is sent with TTL 1 to further insure that it can not be routed outside of your network. If you disable Net_Talk cFosSpeed will still listen for incoming Net_Talk data and use it.
Net_talk packets are never sent to the WAN adapter (Dial-Up networking) or with NDIS 6 to a WWAN adapter. That means that in a LAN, where each machine has cFosSpeed installed, but each connects to the Internet via Dual-Up Networking independently, instead sharing the same router, there will be no Net_Talk support. You do need to use cFosSpeed in "router mode" to use Net_talk and only the PCs that share the same router will participate in Net_talk.
There are some settings around Net_Talk:
To see which other members on the LAN use cFosSpeed, you can use the "spd ts" or "spd talkstat" command. Output looks like this:
address received last version LL method shaper ping offset me 60471 0s ago 5.13.1675 0 pppoe 2 sent blocks: 60471
"LL" shows if that member is using low latency. "ping" means the time from sending a net_talk packet to receiving a ping answer on your LAN (don't confuse this with the ping time to a machine on the Internet.)