Nagle's Algorithm disabling

Hi all,
I am currently checking the Nagle's algorithm which is by default
enabled in TCP/IP implementation. But I want to see difference in
packet transfer by disabling it and enabling it (By capturing the
packet and analyzing them) using setsockopt()'s TCP_NODELAY option.

I have a constraint here I want to check all this in a Fast LAN
connection. As we all know the effect of Nagles algorithm is bettter
seen in a WAN network as there exist a very high RTT time hence the
corrsponding ACK takes enough time to reach the sender side.

So how can I introduce high RTT time in the network which in turn make
the ACK reach late for any small packet sent by sender.

Congesting the network would be a bad idea as it may not work
everytime. Also modifying the TCP stack to send the ACK late is
discouraged.

So please help if there is any other way we can do this.

Thanks
Lalatendu Das

> Congesting the network would be a bad idea as it may not work
> everytime. Also modifying the TCP stack to send the ACK late is
> discouraged.

Overload the machine?


Stefan

Seems you also asked this question over in comp.protocols.tcp-ip, but
didn't make the more-correct cross-posting:

One can specify more than one newsgroup in the Newsgroups: line. The
format would look like this:

Newsgroups: group1,group2,group3

with no spaces in the grouplist. This has several advantages (so long
as it is not abused by posting messages to inappropriate groups). Only
one copy of your message must traverse the Internet, saving network
bandwidth; only one copy of your message must be stored on each news
server on the Internet, saving many MB of space world-wide; you only
have to enter the news posting once, saving you time; people only have
to read/skip your post once, saving them time; all responses in any
group can be seen in all groups, keeping everyone up to date with the
conversation.

Also, you can add a Followup-to: header line which will direct all the
follow-ups to a particular group, making it easier for you to look for
responses.

I hope you find this helpful. If you do, please pass it along to your
peers as you see them needing the same advice.

sincerely,

rick jones
--
firebug n, the idiot who tosses a lit cigarette out his car window
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

2007-10-17, 03:28(-07), Lalatendu Das:
> Hi all,
> I am currently checking the Nagle's algorithm which is by default
> enabled in TCP/IP implementation. But I want to see difference in
> packet transfer by disabling it and enabling it (By capturing the
> packet and analyzing them) using setsockopt()'s TCP_NODELAY option.
>
> I have a constraint here I want to check all this in a Fast LAN
> connection. As we all know the effect of Nagles algorithm is bettter
> seen in a WAN network as there exist a very high RTT time hence the
> corrsponding ACK takes enough time to reach the sender side.
>
> So how can I introduce high RTT time in the network which in turn make
> the ACK reach late for any small packet sent by sender.
>
> Congesting the network would be a bad idea as it may not work
> everytime. Also modifying the TCP stack to send the ACK late is
> discouraged.
[...]

See the netem queueing discipline. You can delay packets this way.

Google qdisc netem delay

--
Stéphane

On Oct 17, 10:20 pm, Rick Jones <rick.jon...@hp.com> wrote:
> Seems you also asked this question over in comp.protocols.tcp-ip, but
> didn't make the more-correct cross-posting:
>
> One can specify more than one newsgroup in the Newsgroups: line. The
> format would look like this:
>
> Newsgroups: group1,group2,group3
>
> with no spaces in the grouplist. This has several advantages (so long
> as it is not abused by posting messages to inappropriate groups). Only
> one copy of your message must traverse the Internet, saving network
> bandwidth; only one copy of your message must be stored on each news
> server on the Internet, saving many MB of space world-wide; you only
> have to enter the news posting once, saving you time; people only have
> to read/skip your post once, saving them time; all responses in any
> group can be seen in all groups, keeping everyone up to date with the
> conversation.
>
> Also, you can add a Followup-to: header line which will direct all the
> follow-ups to a particular group, making it easier for you to look for
> responses.
>
> I hope you find this helpful. If you do, please pass it along to your
> peers as you see them needing the same advice.
>
> sincerely,
>
> rick jones
> --
> firebug n, the idiot who tosses a lit cigarette out his car window
> these opinions are mine, all mine; HP might not want them anyway...
> feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

Thanks for the advice Rick. Actulally I am not aware of this.
Hence forth I will take care of the same.
I will try the options you have mentioned in the "comp.protocols.tcp-
ip".
thanks to everyone for there answers. I will try them and bug you
people if fail somewhere