From hvp at info.fundp.ac.be Mon Oct 25 23:53:10 2004 From: hvp at info.fundp.ac.be (Hugues Van Peteghem) Date: Mon Oct 25 23:54:05 2004 Subject: [tg] UDP issue Message-ID: <200410260853.10035.hvp@info.fundp.ac.be> Dear all, I got a light problem with the 'tg' generator. As I want to generate large UDP packets, the maximum a receiver can get is 8188 bytes packets : Experience 1, emitting packets of 8187 bytes length : ------------------------------------------------------------------------------- SENDER 2.005671 Setup 2.005925 Transmit 10.0.2.2.50000 0 8187 2.055706 Transmit 10.0.2.2.50000 1 8187 ... RECEIVER 0.009376 Setup 2.020474 Receive 10.0.0.6.32801 0 8187 2.069666 Receive 10.0.0.6.32801 1 8187 ... Experience 2, emitting packets of 8189 bytes length : ------------------------------------------------------------------------------- SENDER 2.005671 Setup 2.005925 Transmit 10.0.2.2.50000 0 8189 2.055706 Transmit 10.0.2.2.50000 1 8189 ... RECEIVER 0.009376 Setup 2.020474 Receive 10.0.0.6.32801 0 8188 2.069666 Receive 10.0.0.6.32801 1 8188 ... Can anybody help me ? Best regards : H PS : I have just looked on the 'tg' official site and it seems that none of my prevous remarks (mail of the 2004-04-28) have been taken into account. Is it normal ? -- Hugues Van Peteghem Institut d'Informatique - FUNDP -------------------------------- Web : http://www.info.fundp.ac.be/~hvp From b_a_denny at yahoo.com Thu Oct 28 09:29:40 2004 From: b_a_denny at yahoo.com (Barbara Denny) Date: Thu Oct 28 09:30:09 2004 Subject: [tg] UDP issue In-Reply-To: <200410260853.10035.hvp@info.fundp.ac.be> Message-ID: <20041028162940.71126.qmail@web14326.mail.yahoo.com> Hi, For users who would like to send very large user datagrams, try modifying MAX_PKT_SIZE in config.h. The current maximum size is set to 8192. When you add the unsigned long, which tg uses to record a sequence number for udp, you get the results of the second run. All the bytes should be received by the end of the run. barbara --- Hugues Van Peteghem wrote: > Dear all, > > I got a light problem with the 'tg' generator. As I > want to generate large UDP > packets, the maximum a receiver can get is 8188 > bytes packets : > > Experience 1, emitting packets of 8187 bytes length > : > ------------------------------------------------------------------------------- > SENDER > 2.005671 Setup > 2.005925 Transmit 10.0.2.2.50000 0 > 8187 > 2.055706 Transmit 10.0.2.2.50000 1 > 8187 > ... > > RECEIVER > 0.009376 Setup > 2.020474 Receive 10.0.0.6.32801 0 > 8187 > 2.069666 Receive 10.0.0.6.32801 1 > 8187 > ... > > Experience 2, emitting packets of 8189 bytes length > : > ------------------------------------------------------------------------------- > SENDER > 2.005671 Setup > 2.005925 Transmit 10.0.2.2.50000 0 > 8189 > 2.055706 Transmit 10.0.2.2.50000 1 > 8189 > ... > > RECEIVER > 0.009376 Setup > 2.020474 Receive 10.0.0.6.32801 0 > 8188 > 2.069666 Receive 10.0.0.6.32801 1 > 8188 > ... > > Can anybody help me ? > > Best regards : > > H > > PS : I have just looked on the 'tg' official site > and it seems that none of my > prevous remarks (mail of the 2004-04-28) have been > taken into account. Is it > normal ? > -- > Hugues Van Peteghem > Institut d'Informatique - FUNDP > -------------------------------- > Web : http://www.info.fundp.ac.be/~hvp > > _______________________________________________ > tg mailing list > tg@postel.org > http://www.postel.org/mailman/listinfo/tg > __________________________________ Do you Yahoo!? Yahoo! Mail Address AutoComplete - You start. We finish. http://promotions.yahoo.com/new_mail From m.brescia at comcast.net Thu Oct 28 12:13:47 2004 From: m.brescia at comcast.net (Mike Brescia) Date: Thu Oct 28 12:14:10 2004 Subject: [tg] UDP issue In-Reply-To: <20041028162940.71126.qmail@web14326.mail.yahoo.com> References: <20041028162940.71126.qmail@web14326.mail.yahoo.com> Message-ID: At 9:29 AM -0700 10/28/04, Barbara Denny wrote: >For users who would like to send very large user >datagrams, try modifying MAX_PKT_SIZE in config.h. >The current maximum size is set to 8192. That sets the size for receiving and buffering. In my (FreeBSD) unix, there's a kernel limit on sending datagram size (perhaps also receive re-assembly?) set in parameter "net.inet.udp.maxdgram" (9216 in mine). Examine and set this with sysctl(8). >When >you add the unsigned long, which tg uses to >record a sequence number for udp, you get the >results of the second run. All the bytes should >be received by the end of the run. Also, thanks to Barbara for explaining the off-by-4 discrepancy. >--- Hugues Van Peteghem wrote: > > I got a light problem with the 'tg' generator. As I > > want to generate large UDP >> packets, the maximum a receiver can get is 8188 > > bytes packets : Good hunting, -- Mike From b_a_denny at yahoo.com Fri Oct 29 13:22:26 2004 From: b_a_denny at yahoo.com (Barbara Denny) Date: Fri Oct 29 13:23:15 2004 Subject: [tg] UDP issue In-Reply-To: Message-ID: <20041029202226.85845.qmail@web14310.mail.yahoo.com> Thanks Mike for elaborating on the kernel limitation. The constant, MAX_PKT_SIZE, is a misleading name. It is only the buffer size for the reads and writes to the kernel. barbara .--Mike Brescia wrote: > At 9:29 AM -0700 10/28/04, Barbara Denny wrote: > >For users who would like to send very large user > >datagrams, try modifying MAX_PKT_SIZE in config.h. > >The current maximum size is set to 8192. > > That sets the size for receiving and buffering. In > my (FreeBSD) > unix, there's a kernel limit on sending datagram > size (perhaps also > receive re-assembly?) set in parameter > "net.inet.udp.maxdgram" (9216 > in mine). Examine and set this with sysctl(8). > > > >When > >you add the unsigned long, which tg uses to > >record a sequence number for udp, you get the > >results of the second run. All the bytes should > >be received by the end of the run. > > Also, thanks to Barbara for explaining the off-by-4 > discrepancy. > > >--- Hugues Van Peteghem > wrote: > > > I got a light problem with the 'tg' generator. > As I > > > want to generate large UDP > >> packets, the maximum a receiver can get is 8188 > > > bytes packets : > > Good hunting, > -- Mike > _______________________________________________ > tg mailing list > tg@postel.org > http://www.postel.org/mailman/listinfo/tg > __________________________________ Do you Yahoo!? Yahoo! Mail Address AutoComplete - You start. We finish. http://promotions.yahoo.com/new_mail