Subject: [Dime] receving connections from 3868 with multiple instances.

From: "Valesh Chandu" <[email-masked]>
Date: 19 Sep 2006 09:13:57 -0000

Hi all,

I have a doubt regarding receiving connection requests/listening on port 3868 in case of multiple instances on a single host with one interface.

Snippet from sec 2.1 of RFC 3588:
A Diameter node MAY initiate connections from a source port other   than the one that it declares it accepts incoming connections on, and MUST be prepared to receive connections on port 3868.A given Diameter instance of the peer state machine MUST NOT use more than one transport connection to communicate with a given peer, unless multiple instances exist on the peer in which case a separate connection per process is allowed.
Diameter Node is defined as :
A Diameter node is a host process that implements the Diameter     protocol, and acts either as a Client, Agent or Server.

My understanding of the above section is that multiple instances of the diameter stack is possible on the same host machine.

So, if we have multiple instances on a single host then how it is possible to listen on the same port 3868 from all the instances?

Please any one clarify my doubt? 

Best Regards,
Chandu
  
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---

From: Timothy Smith <[email-masked]>
Date: Wed, 20 Sep 2006 08:50:24 -0400

Hi Chandu,

I think you have touched on an area where there are a couple of unclear 
points.  I also interpret that you can have multiple Diameter nodes on the 
same host.  I think this implies:
1) Each node must listen on a different port as you have pointed out.  So, 
only one of the nodes can use the recommended port 3868.
2) The Origin-Host AVP is also problematic in that its value conflicts in 
a host with multiple Diameter nodes.  The Origin-Host is of type Diameter 
Identity, and "The value of the Origin-Host AVP is guaranteed to be unique 
within a single host".  But also, "DiameterIdentity value is used to 
uniquely identify a Diameter node for purposes of duplicate connection..." 
  These two statements are inconsistent on a host with multiple Diameter 
nodes.  The Diameter Identity is a FQDN which realistically means you can 
only have a single Origin-Host name for all of the nodes on a given host. 
So, the dilemma is that if you have multiple Diameter nodes on host A and 
multiple Diameter nodes on host B, then because of the single connection 
rule, you will only be able to set up one connection between one of the 
nodes on host A and one of the nodes on host B.   This is something that I 
think should be clarified in the BIS document.  My preference would be to 
say that the Origin-Host AVP should be a FQDN, but not that it must be a 
FQDN.  That way, you could assign a unique Origin-Host name to each 
Diameter node on a host.  And any or all nodes on Host A could establish a 
connection to any or all nodes on Host B.

Best Regards,
Timothy Smith

[email-masked]
(919) 254-4723

"Valesh  Chandu" <[email-masked]> 
09/19/2006 05:13 AM
Please respond to
Valesh  Chandu <[email-masked]>

To
[email-masked]
cc

Subject
[Dime] receving connections from 3868 with multiple instances.

Hi all,

I have a doubt regarding receiving connection requests/listening on port 
3868 in case of multiple instances on a single host with one interface.

Snippet from sec 2.1 of RFC 3588:
A Diameter node MAY initiate connections from a source port other  than 
the one that it declares it accepts incoming connections on, and MUST be 
prepared to receive connections on port 3868.A given Diameter instance of 
the peer state machine MUST NOT use more than one transport connection to 
communicate with a given peer, unless multiple instances exist on the peer 
in which case a separate connection per process is allowed.
Diameter Node is defined as :
A Diameter node is a host process that implements the Diameter protocol, 
and acts either as a Client, Agent or Server.

My understanding of the above section is that multiple instances of the 
diameter stack is possible on the same host machine.

So, if we have multiple instances on a single host then how it is possible 
to listen on the same port 3868 from all the instances?

Best Regards,
Chandu

---

From: "Tolga Asveren" <[email-masked]>
Date: Wed, 20 Sep 2006 09:11:46 -0400

Hi Timothy,

Please see below for comments.

  Thanks,
  Tolga

-----Original Message-----
From: Timothy Smith [mailto:[email-masked]]
Sent: Wednesday, September 20, 2006 8:50 AM
To: Valesh Chandu
Cc: [email-masked]
Subject: Re: [Dime] receving connections from 3868 with multiple instances.

Hi Chandu,

I think you have touched on an area where there are a couple of unclear
points.  I also interpret that you can have multiple Diameter nodes on the
same host.  I think this implies:
1) Each node must listen on a different port as you have pointed out.  So,
only one of the nodes can use the recommended port 3868.
[TOLGA]I agree.
2) The Origin-Host AVP is also problematic in that its value conflicts in a
host with multiple Diameter nodes.  The Origin-Host is of type Diameter
Identity, and "The value of the Origin-Host AVP is guaranteed to be unique
within a single host".  But also, "DiameterIdentity value is used to
uniquely identify a Diameter node for purposes of duplicate connection..."
These two statements are inconsistent on a host with multiple Diameter
nodes.  The Diameter Identity is a FQDN which realistically means you can
only have a single Origin-Host name for all of the nodes on a given host.
So, the dilemma is that if you have multiple Diameter nodes on host A and
multiple Diameter nodes on host B, then because of the single connection
rule, you will only be able to set up one connection between one of the
nodes on host A and one of the nodes on host B.   This is something that I
think should be clarified in the BIS document.  My preference would be to
say that the Origin-Host AVP should be a FQDN, but not that it must be a
FQDN.  That way, you could assign a unique Origin-Host name to each Diameter
node on a host.  And any or all nodes on Host A could establish a connection
to any or all nodes on Host B.
[TOLGA]Is this really a problem? A physical host can have multiple FQDN,
where each of them refer to a single Diameter node. I think this is already
covered in definition of Diameter Identity in 4.3.

Best Regards,
Timothy Smith

[email-masked]
(919) 254-4723

"Valesh  Chandu" <[email-masked]>
09/19/2006 05:13 AM Please respond to
Valesh  Chandu <[email-masked]>

[email-masked]
cc
Subject[Dime] receving connections from 3868 with multiple instances.

Hi all,

A Diameter node MAY initiate connections from a source port other  than the
one that it declares it accepts incoming connections on, and MUST be

Best Regards,
Chandu

---

From: Timothy Smith <[email-masked]>
Date: Wed, 20 Sep 2006 16:41:18 -0400

Hi Tolga,

Thanks for your note.  I think I was stuck in a rut.  From your note, I 
would assume that we can update a DNS server with any number of aliases to 
provide a unique FQDN for each node on the same host, correct? 

Best Regards,
Timothy Smith

[email-masked]
(919) 254-4723

"Tolga Asveren" <[email-masked]> 
09/20/2006 09:11 AM

To
Timothy Smith/Raleigh/IBM@IBMUS, "Valesh Chandu" 
<[email-masked]>
cc
<[email-masked]>
Subject
RE: [Dime] receving connections from 3868 with multiple instances.

Hi Timothy,

  Thanks,
  Tolga

-----Original Message-----
From: Timothy Smith [mailto:[email-masked]]
Sent: Wednesday, September 20, 2006 8:50 AM
To: Valesh Chandu
Cc: [email-masked]
Subject: Re: [Dime] receving connections from 3868 with multiple 
instances.

Hi Chandu,

a
Diameter
node on a host.  And any or all nodes on Host A could establish a 
connection
where each of them refer to a single Diameter node. I think this is 
already

Best Regards,
Timothy Smith

[email-masked]
(919) 254-4723

[email-masked]
cc

Hi all,

the

Best Regards,
Chandu

---

From: Andreas Fredriksson <[email-masked]>
Date: Thu, 21 Sep 2006 09:27:06 +0200

Timothy Smith wrote:
>
> Hi Chandu,
>
> I think you have touched on an area where there are a couple of 
> unclear points.  I also interpret that you can have multiple Diameter 
> nodes on the same host.  I think this implies:
> 1) Each node must listen on a different port as you have pointed out. 
>  So, only one of the nodes can use the recommended port 3868.
> 2) The Origin-Host AVP is also problematic in that its value conflicts 
> in a host with multiple Diameter nodes.  The Origin-Host is of type 
> Diameter Identity, and "The value of the Origin-Host AVP is guaranteed 
> to be unique within a single host".  But also, "DiameterIdentity value 
> is used to uniquely identify a Diameter node for purposes of duplicate 
> connection..."   These two statements are inconsistent on a host with 
> multiple Diameter nodes.  The Diameter Identity is a FQDN which 
> realistically means you can only have a single Origin-Host name for 
> all of the nodes on a given host.  So, the dilemma is that if you have 
> multiple Diameter nodes on host A and multiple Diameter nodes on host 
> B, then because of the single connection rule, you will only be able 
> to set up one connection between one of the nodes on host A and one of 
> the nodes on host B.   This is something that I think should be 
> clarified in the BIS document.  My preference would be to say that the 
> Origin-Host AVP should be a FQDN, but not that it must be a FQDN. 
>  That way, you could assign a unique Origin-Host name to each Diameter 
Hi,
I think the port 3868 restriction helps when you're doing dynamic peer 
discovery. If an implementation sees an unknown diameter identity it 
could try the various discovery options outlined in the RFC (e.g. DNS 
lookups). These do not include a port anywhere IIRC and if there are 
multiple stacks running on a single IP messages could end up on the 
wrong stack.

However, it's perfectly fine to use several IP addresses (using ethernet 
aliases) on a single box which map to different FQDNs. This removes the 
above limitation and is fine as far as the RFC goes.

Best regards,
Andreas

---

From: "Tolga Asveren" <[email-masked]>
Date: Thu, 21 Sep 2006 09:19:57 -0400

Hi Andreas,

For a truly dynamic discovery, wouldn't the "Port" in SRV lookup result
address your concern of not being able to distinguish between multiple
instances on the same host?

    Thanks,
    Tolga

> From: Andreas Fredriksson [mailto:[email-masked]]
> Sent: Thursday, September 21, 2006 3:27 AM
> To: Timothy Smith
> Cc: [email-masked]; Valesh Chandu

---

From: "Tolga Asveren" <[email-masked]>
Date: Thu, 21 Sep 2006 09:07:17 -0400

Hi Tim,

Yes, multiple FQDN can resolve to the same IP.

   Thanks,
   Tolga
-----Original Message-----
From: Timothy Smith [mailto:[email-masked]]
Sent: Wednesday, September 20, 2006 4:41 PM
To: Tolga Asveren
Cc: Valesh Chandu; [email-masked]
Subject: RE: [Dime] receving connections from 3868 with multiple instances.

Hi Tolga,

Best Regards,
Timothy Smith

[email-masked]
(919) 254-4723

"Tolga Asveren" <[email-masked]>
09/20/2006 09:11 AM ToTimothy Smith/Raleigh/IBM@IBMUS, "Valesh Chandu"
<[email-masked]>
cc<[email-masked]>
SubjectRE: [Dime] receving connections from 3868 with multiple instances.

Hi Timothy,

 Thanks,
 Tolga

-----Original Message-----
From: Timothy Smith [mailto:[email-masked]]
Sent: Wednesday, September 20, 2006 8:50 AM
To: Valesh Chandu
Cc: [email-masked]
Subject: Re: [Dime] receving connections from 3868 with multiple instances.

Hi Chandu,

Best Regards,
Timothy Smith

[email-masked]
(919) 254-4723

[email-masked]
cc

Hi all,

Best Regards,
Chandu