Re: [leaf-user] Bering Tweaks

[Charles S. <ch...@st...>]

Matt Russell wrote:
> Are there any tweaks for bering that I can use to pick up my cable
> connection? i downloaded an ipconfig.lrp package but i cannot get it to
> change the recieve window (one of the main things that the mtu patch does
> for windows to increase speed). is there something that i am missing?

If you are referring to the TCP recieve window size, that is a property 
particular to the TCP/IP stack of the system in question (windows, in 
your case), and is not affected by intermediate routers.

Essentially, this value is the amount of memory allocated for storing 
incoming packets, and represents the maximum amount of TCP data the far 
end can send without getting a ACK back from your box.  Windows assumes 
everyone is on a very high-speed local area network, so the default TCP 
settings provide sub-optimal results when run over high-latency networks 
(like the public internet or a corperate WAN).

There's no way getting around having to tweak the registry settings for 
all your windows boxes if you want to make the most of your cable-modem 
speed across high-latency links (besides switching to linux, or some 
other OS with a better TCP/IP implementation :-)

NOTE:  There is another TCP parameter that *CAN* be controlled by the 
new 2.4 iptables settings in bering, related to the path MTU.  Windows 
also does not properly perform path-MTU discovery, which means it 
continues to send full-size ethernet packets, even if an intermediate 
link in the route to the target system does not support that size 
without fragmentation (ie: the packets go through a VPN or PPPoE 
connection that "wrapps" the original data and reduces the effective 
MTU).  This causes lots of unnecessary packet fragmentation which can 
have nasty effects on overall latency and link throughput.  This doesn't 
sound like what you're looking for, however.

-- 
Charles Steinkuehler
ch...@st...