IETF Logo Mail Archive

RE: timeout value in TCP implementation

Mark Allman <mallman@grc.nasa.gov> Mon, 21 April 2003 14:11 UTC

Message-Id: <200304211411.KAA89438@guns.lerc.nasa.gov>
To: tcp-impl@grc.nasa.gov
From: Mark Allman <mallman@grc.nasa.gov>
Reply-To: bodhi@jack.see.plymouth.ac.uk
Subject: RE: timeout value in TCP implementation
Organization: BBN Technologies/NASA GRC
Song-of-the-Day: Outshine
Date: Mon, 21 Apr 2003 10:11:48 -0400
Sender: owner-tcp-impl@grc.nasa.gov
Precedence: bulk
Status: RO
Content-Length: 1446
Lines: 51

 

------- Forwarded Message

From: Bogdan Ghita <bodhi@jack.see.plymouth.ac.uk>
To: "'kunchanl '" <kunchanl@pollux.usc.edu>
Cc: "'tcp-impl@lerc.nasa.gov'" <tcp-impl@lerc.nasa.gov>
Subject: RE: timeout value in TCP implementation
Date: Sun, 20 Apr 2003 18:45:56 +0100

Hello Kun-chan,

3 seconds is the recomended initial value for the TCP timeout timer (RTO).
See RFC1122 (section 4.2.3.1) for details.

Cheers,
Bogdan


- -----Original Message-----
From: kunchanl
To: tcp-impl@lerc.nasa.gov
Sent: 20/04/03 17:57
Subject: timeout value in TCP implementation

Hi,

    I've observed quiet a few of connections in my tcpdump trace
has the SYN packet re-transmitted after about 3 seconds (as
the example below). I'm wondering if this 3-second is related
some particular timeout value in some tcp implementaton. Can
anybody shed me some light?

Thanks
Kun-chan Lan

1036626828.477241 10.0.0.1.2355 > 192.168.0.2.80: S 12193306:12193306(0)
win 8192 <mss 1460,nop,nop,sackOK> (DF)
1036626831.460768 10.0.0.1.2355 > 192.168.0.2.80: S 12193306:12193306(0)
win 8192 <mss 1460,nop,nop,sackOK> (DF)
1036626831.784822 10.0.0.1.2355 > 192.168.0.2.80: . ack 3335637810 win
8760 (DF)
1036626831.792048 10.0.0.1.2355 > 192.168.0.2.80: P 0:758(758) ack 1 win
8760 (DF)
1036626831.852406 10.0.0.1.2355 > 192.168.0.2.80: . ack 124 win 8638
(DF)
1036626831.852423 10.0.0.1.2355 > 192.168.0.2.80: R 12194065:12194065(0)
win 0 (DF)


------- End of Forwarded Message

v2.23.0 | Report a Bug | By Email