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Dear all,
see my comments below.
Best regards
Michael

Michael Tuexen Tel.: +49 89 722 47210
Siemens AG Fax: +49 89 722 48212
ICN WN CS SE 5 E-mail:
Michael.Tuexen AT icn.siemens.de

> -----Original Message-----
> From: Michael Mueller
> [SMTP:bhu5nji AT yahoo.com]
> Sent: Wednesday, August 29, 2001 3:33 PM
> To:
> discussion AT sctp.de
> Subject: [SCTP-Discussion] sctpd, sctplib, and IPC
>
> My impression of sctpd is that it is a daemon that manages multiple
> SCTP instances for clients through a UDP interfaces. Is this
> correct?
[Tuexen Michael] Yes.
> The User Manual, mentions that it is possible to run multiple
> instances of SCTP using different IP addresses. Is this the only
> method for managing multiple IP addresses with sctplib?
[Tuexen Michael] No. All instances are able to
handle multipe IP-Addresses (IPv4/IPv6). The point
is that you can not run multiple instances of the
library with common IP-Addresses.
>
> How does sctpd transfer chunks to other processes? Is it
> implementation dependent? Here is how I think that it would be
> done:
[Tuexen Michael] It uses a UDP based communication.
> Consider a system with two daemons where one is running sctplib
> (called d-sctp to differentiate it from sctpd) and the other is
> running a user application (called d-ua). The two processes
> communicate with each other using UDP sockets. Do the following
> sctplib design choices make sense in this situation?
>
> 1. d-sctp uses helper function sctp_registerUdpCallback() to cause
> sctp_eventLoop() to create/bind/watch for UDP input on
> 127.0.0.0:50023. The callback function transfers information from
> the UDP datagram to an SCTP stream.
[Tuexen Michael] What is wrong with this?
> 2. d-sctp will create/bind a UDP socket on 127.0.0.0:50024.
[Tuexen Michael] This seems not to be necessary.
> 3. d-ua sends to d-sctp on 127.0.0.0:50023 and receives from d-sctp
> on 127.0.0.0:50024.
[Tuexen Michael] The d-sctp could only use one
UDP socket.
> 4. d-sctp has a function defined for function pointer
> (*dataArriveNotif)() that will transfer all incoming SCTP chunks to
> 127.0.0.0:50024 if the socket is write-ready; if the socket is not
> write ready, then the chunk is placed into a queue.
[Tuexen Michael] That is OK, isn't it?
> 5. d-sctp uses the Timer helper functions to periodically service
> the IPC queue mentioned in 4 above. If the queue has chunk entries,
> then they will be sent to d-ua if the socket is write-ready.
[Tuexen Michael] Seem reasonable. You have to avoid
the blocking of a system call if you use the callback
interface.
> Thanks again,
> Mike
[Tuexen Michael] Maybe we get some info why multiple UDP
sockets are used from the developers of the sctpd?

Best regards
Michael
> _______________________________________________
> discussion mailing list
> discussion AT sctp.de
> http://www.sctp.de/mailman/listinfo/discussion

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• [SCTP-Discussion] sctpd, sctplib, and IPC, Michael Mueller, 08/29/2001
  • <Possible follow-up(s)>
  • RE: [SCTP-Discussion] sctpd, sctplib, and IPC, Tuexen Michael, 08/29/2001
  • RE: [SCTP-Discussion] sctpd, sctplib, and IPC, Sim Woon Chiat ICM CA MS MI E7 Extern, 08/29/2001
    • Re: [SCTP-Discussion] sctpd, sctplib, and IPC, Michael Mueller, 08/29/2001
  • RE: [SCTP-Discussion] sctpd, sctplib, and IPC, Sim Woon Chiat ICM CA MS MI E7 Extern, 08/30/2001

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