dev@jax-ws.java.net

Re: Metro/JAXWS and network packets...

From: Tony Anecito <adanecito_at_yahoo.com>
Date: Wed, 18 Nov 2009 07:52:29 -0800 (PST)

Hi LeRoy,

Thanks for asking. I filed the bug with Sun and got the standard message of they will look at it in several weeks. I have not gotten any updates with a real bug id.
The issue has been verified by someone else who was curious about it.

Regards,
-Tony

--- On Wed, 11/18/09, LeRoy Hall <leroy_e_hall_at_yahoo.com> wrote:

> From: LeRoy Hall <leroy_e_hall_at_yahoo.com>
> Subject: Re: Metro/JAXWS and network packets...
> To: dev_at_jax-ws.dev.java.net
> Date: Wednesday, November 18, 2009, 7:27 AM
> Hey Tony,
>  
> I was just wondering if you ever got a resolution to
> this?
>  
> LeRoy
>
> --- On Fri, 10/16/09, Tony Anecito
> <adanecito_at_yahoo.com> wrote:
>
>
> From: Tony Anecito <adanecito_at_yahoo.com>
> Subject: Re: Metro/JAXWS and network packets...
> To: dev_at_jax-ws.dev.java.net
> Date: Friday, October 16, 2009, 2:22 PM
>
>
> No Problem LeRoy your
> questions/comments are valid ones.
>
> Since FireFox did not have fragmentation I have like you
> been assuming the jvm has it's own implementaion of the
> OSI layer that disassembles the PDU into packets and that
> may be where the issue is.
>
> I did look for the MSS (Maximum Segment Size) which can
> overide the MTU and in the first sync packet it is set to
> 1460 bytes or the same as the MTU.
>
> Since for FireFox the packets were not fragmented I would
> have to say the router is not fragmenting the packets.
>
> Just to let you know the path for the
> request/response/syn/ack was from the desktop through a
> DLink switch up to the DLink router back down the switch and
> to the Server where my instance of Tomcat is running. So the
> client/server was running on completely separate hardware.
> When I looked at wireshark on both ends the PDU was sent via
> two packets for the request and the response. They should
> have
> been one each. I saw a couple hundred bytes payload in
> each with offsets of 0 for the data within each packet. In
> other words the entire data should have easily fit in a
> single packet like it did for FireFox request/response.
>
> I have no idea why the simple post for the request from the
> java client was not put into a single packet to begin with.
>
> I am like you very interested in Sun's response. If it
> is in the TCP/IP implementation then every communication
> between client and server for every app I know of when it
> communicates with a server will be affected.
> Good thing is the problem is specific to data that fits
> into a packet. Still I suspect people who manage stock or
> bank transactions using java based applications would have a
> very high degree of interest in what I found out.
>
> Regards,
> -Tony
>
> --- On Fri, 10/16/09, LeRoy Hall <leroy_e_hall_at_yahoo.com> wrote:
>
> > From: LeRoy Hall <leroy_e_hall_at_yahoo.com>
> > Subject: Re: Metro/JAXWS and network packets...
> > To: dev_at_jax-ws.dev.java.net
> > Date: Friday, October 16, 2009, 11:58 AM
> > My knowledge of networking is
> > mostly acedemic, just so you don't get the wrong
> > impreression.  
> >  
> > This makes me wonder whether or not the JVM has
> > it's own implementation of TCP/IP, or if it uses
> what
> > is installed on the OS it is running on?? 
> Given
> > your observations, and assuming that your test from
> Firefox
> > and a JVM was on the same machine,
> it would seem that the
> > JVM may have it's own implementation. 
> >  
> > I'm also wondering if the packets are leaving
> your
> > machine fragmented, or are they arriving at the
> destination
> > fragmented?  Like I said, I have learned that it
> is a
> > router on the network that can fragment packets. 
> Could
> > be that the router on your subnet is fragmenting the
> > packets, which is usually done because of a setting on
> the
> > router that sets the maximum size of a packet.
> >  
> > Also, there's a bit in the packet built by either
> > TCP or IP (don't recall) that can prevent
> > fragmentation.  Perhaps the packets from firefox
> are
> > being sent with this bit set.  You can use
> Wireshark to
> > intercept packets to/from your machine to investigate
> this
> > further.
> >  
> > I would like to know what Sun's response is to
> > your bug
> report. 
> >  
> > LeRoy
> >  
> >  
> > --- On Thu, 10/15/09, Tony Anecito
> > <adanecito_at_yahoo.com>
> wrote:
> >
> >
> > From: Tony Anecito <adanecito_at_yahoo.com>
> > Subject: Re: Metro/JAXWS and network packets...
> > To: dev_at_jax-ws.dev.java..net
> > Date: Thursday, October 15, 2009, 10:47 PM
> >
> >
> > Hi LeRoy,
> >
> > I created a simple test where I used the url object to
> send
> > a request for a small file (less than 1460 bytes) and
> the
> > packet issue still appears. I ran it on
> my internal network
> > to isolate the issue. Thus on one subnet I sent a
> request
> > via Firesfox and one packet for send/recieve and then
> again
> > with the simple java program and 2 packets for send
> and
> > recieve.
> > So the issue is not with Metro or JAX-WS and the
> > request/response was not broken up for FireFox but in
> the
> > core code for neworking for the jvm.
> >
> > I created a new bug in Sun's/Oracle's bug
> database.
> > I also had a separate party confirm what I saw.
> >
> > Regards,
> > -Tony
> >
> > --- On Thu, 10/15/09, LeRoy Hall <leroy_e_hall_at_yahoo.com>
> > wrote:
> >
> > > From: LeRoy Hall <leroy_e_hall_at_yahoo.com>
> > > Subject: Re: Metro/JAXWS and network packets...
> > > To: dev_at_jax-ws.dev.java.net
> > > Date: Thursday, October 15, 2009, 8:14 AM
> > > Curious, is it really JAX-WS that is
> > > fragmenting the packets, or is it an
> intermediary
> > device on
> > > the network that is fragmenting them?  I
> know
> > that
> > > routers will sometimes fragment packets when the
> > network
> > > they are forwarding to require smaller packets.
> > >
> > > --- On Thu, 10/15/09, Tony
> > > Anecito
> > > <adanecito_at_yahoo.com>
> > wrote:
> > >
>
> > >
> > > From:
> >  Tony Anecito <adanecito_at_yahoo.com>
> > > Subject: Metro/JAXWS and network packets...
> > > To: "Metro" <users_at_metro..dev.java.net>
> > > Cc: "JWSDP Dev" <dev_at_jax-ws.dev.java.net>
> > > Date: Thursday, October 15, 2009, 2:36 AM
> > >
> > >
> > > I noticed if I send a request via
> > > Metro using a small object that is less than
> 1460
> > bytes
> > > (Maximm Segment Size or MTU Maximum Transport
> Unit
> > size) the
> > > data gets sent/received in
> two packets. If I use
> > Firefox and
> > > request a small html file I only get one packet.
> > >
> > > Any
> >  idea why this is happening? It seems to double
> the
> > > number of packets for communication. The data is
> not
> > > duplicated in the two packets but instead is
> > fragmented.
> > >
> > > I am using a Java Client using jre 1.6.0_16 and
> the
> > Tomcat
> > > Server hosting the web service is also using jdk
> > 1.6.0_16.
> > > All are Windows based OS.
> > >
> > > Regards,
> > > -Tony
> > >
> > >
> > >      
> > >
> > >
> >
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> > >
> > >
> > >
> > >
> > >       
> >
> >
> >
> >
> >
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