Subject: [AAA-WG]: Redirect-server and transport

From: Mark Eklund <[email-masked]>
Date: Mon, 26 Feb 2001 13:39:53 -0500 (EST)

All,

Now that Diameter MAY use TCP, should the Redirect-Host AVP
contain an AVP specifying Transport?  If not, how does one know
what transport to use when connecting with the Redirect Server?

This question was based off of draft-calhoun-diameter-18.txt.

Thanks,

-mark

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From: David Frascone <[email-masked]>
Date: Mon, 26 Feb 2001 12:48:57 -0600

I would assume that the redirecting host would not have any idea of the
relationship between the sending host and the host it's being redirected to.

I can barely read the above sentance :).  Let me try again:  IN my opinion,
the redirect server should not try to enforce a particular transport, just
a location.

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From: Mark Eklund <[email-masked]>
Date: Mon, 26 Feb 2001 14:07:11 -0500 (EST)

David,

> the redirect server should not try to enforce a particular transport, just

Currently you can either send a Redirect-Host-Address AVP by
itself, or a Redirect-Host AVP of type group which contains a
Redirect-Host-Address AVP and a Redirect-Host-Port AVP.  If the
redirect server shouldn't enforce a transport, why should it
enforce a port?

Or how about this.  If I can handle both TCP and SCTP and am
told to redirect my request to a.b.c.d.  How do I know what
transport to use?

-mark

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From: Pat Calhoun <[email-masked]>
Date: Mon, 26 Feb 2001 15:18:10 -0800 (PST)

Good question. The agreement at the Interim meeting was that NASes MUST
support TCP (and may need to support SCTP in the future), while servers MUST
support both TCP and SCTP. Therefore, a NAS can use whatever transport it
prefers, since a redirect will cause the NAS to talk to a server.

PatC

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From: Mark Eklund <[email-masked]>
Date: Mon, 26 Feb 2001 18:38:29 -0500 (EST)

Thanks for the explanation.
-mark

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From: "Bernard Aboba" <[email-masked]>
Date: Tue, 27 Feb 2001 09:10:20 -0800

>Now that Diameter MAY use TCP

To quote from the interim meeting minutes:

"AAA Servers MUST support TCP & SCTP. NASes MUST support TCP,
MAY support SCTP. The specification will state that "SCTP
MAY be required in the future."   TCP is required on NASes
because not all NASes have SCTP in their protocol stacks, because
SCTP has problems getting past firewalls, and because neither
TLS nor IPSEC is fully defined for SCTP."

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From: Richard Perlman <[email-masked]>
Date: Tue, 27 Feb 2001 09:15:46 -0800 (PST)

Q.

Does anyone know if Java supports SCTP yet?

Richard

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From: Randy Bush <[email-masked]>
Date: Tue, 27 Feb 2001 09:28:36 -0800

[ no ad hat ]

> MAY be required in the future."

that last MAY probably is a may.  i.e. it in itself is not actually
a requirement.

> TCP is required on NASes because not all NASes have SCTP in their
> protocol stacks, because SCTP has problems getting past
> firewalls, and because neither TLS nor IPSEC is fully defined for
> SCTP."

sctp does not have an inherent problem with firewalls.  it's just
that firewalls have not needed to be sctp-aware yet.  they will be.

randy