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On Wed, 24 Apr 2002, Wensong Zhang wrote:
>
>
> Hello,
>
> On Wed, 24 Apr 2002, 8923517 wrote:
>
> > > On Mon, 15 Apr 2002, motse wrote:
> > >
> > > > Yes. At real server have another kernel module that can rebuild
> > the
> > > > connection base on the packet that contains URLs. The DRWS-filter is
> > the
> > > > module at real server. You can see the mechanism in the slides.
> > > >
> > >
> > > I just read the slides and some of your code.
> > >
> > > I see that there may be some problems in your method, for example, there
> > > is a long HTTP request which is sent through two packets, how can it be
> > > handled in your method? Maybe I miss something.
> > if two packets,the first packet will redirect by it's header. The
> > second packet or any following packets, I redirect them to the same real
> > server.
> >
>
> No, you probably didn't understand my question. You cannot redirect the
> first packet because its header (URL) is not finished, this is a long URL
> overlap packet. OK, I give you a detailed example, the requested URL
> is "GET /directory/image/picture.gif", the first packet has data "... GET
> /directory/image/picture.g" and the second one has data "if ...", how
> could you forward the first packet when the requested URL is not
> complete? It is broken. I think that the situation above is quite
> possible.
>
> Regards,
>
> Wensong
I think I need to buffer enough packets to figure out the request's
content type. A very long URL or small packet size will cause this
problem. A Foundry's agent told us that their serveriron has a special
feature that they can solve the problem you mention above. And he told us
other products such as BigIP, they can't solve this problem. But, I had no
time to test. I don't sure that the words is right or not.
Ping Tsai
>
> > >
> > > The other problem is that when there are more servers (e.g. 4), in most
> > > cases, the director cannot forward the request to the right server
> > ("guess
> > > right"), then the director send RST to the former server. It will bring
> > > more overhead to both the director and the real servers.
> > When the pcket filter at the real server receives the RST packet, it
> > will not send the RST packet to the kernel. It is just a signal to tell
> > the
> > packet filter "the connection has moved to another real server", and the
> > real server will keep silent. But, after 10~15 sceonds, no other requests
> > come to this real server using the same connection. The pakcet filter must
> > close the connection.
> >
> > Ping Tsai
> > >
> > > For a high-performance Layer-7 switching, maybe it can be constructured
> > as
> > > one IPVS and many KTCPVS (that can be running as real servers, just like
> > > that you install filter modules on real servers).
> > >
> > > Regards,
> > >
> > > Wensong
> > >
> >
> >
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> >
>
>
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