Re: [Dime] [RFC3588bis-34] - Host-IP-Address AVP

[Glen Zorn <[e-mail]>]

On 09/17/2012 07:09 PM, VITON HORCAJO, Pedro (Pedro) wrote:
> Glen,
>
>   Thanks for answering.
> Maybe my original mail was too long, and I  might have not have been clear enough.
>
> Let me rephase my questions, in a shorter way:
>
> 1.- The current text for Host-IP-Address AVP indicates the value to send when transporting over SCTP.
> But which value should be sent when transporting over TCP?

I think that a TCP pseudo-connection can only have two end-points, so 
the value should probably be the IP address of the sender.  I suppose 
that it could be different, though, in some load balancing scheme: "I'm 
sending this from address 'A', but from now on I'll be using address 
'B'"; of course, the connection w/that address would need to be 
authenticated, etc.

>
> 2.- What should a Diameter implementation do when receiving the Host-IP-Address AVP?

Any thing it likes, I suppose ;-).

>
> Best Regards,
>    Pedro
>
>>> -----Original Message-----
>>> From: Glen Zorn [mailto:[e-mail]]
>>> Sent: Monday, September 17, 2012 1:06 PM
>>> To: VITON HORCAJO, Pedro (Pedro)
>>> Cc: [e-mail]; [e-mail]
>>> Subject: Re: [Dime] [RFC3588bis-34] - Host-IP-Address AVP
>>>
>>>
>>> On 09/17/2012 04:02 PM, VITON HORCAJO, Pedro (Pedro) wrote:
>>>> Hi:
>>>> After reviewing original RFC3588 and the lastest draft for
>>> 3588bis-34,
>>>> I have a couple of comments/questions related to the
>>> Host-IP-Address AVP
>>>> 1.- I don't have clear the behavior of a diameter peer
>>> when SENDING
>>>> the Host-IP-Address AVP in the CER/CEA messages, if using TCP to
>>>> transport Diameter.
>>>> In sections 5.3.1 (CER), 5.3.2(CEA) and 5.3.5
>>> (Host-IP-Address AVP),
>>>> it indicates the behavior with respect to that AVP when
>>> using SCTP or
>>>> DTLS/SCTP as transport mechanism.
>>>>      The Host-IP-Address AVP (AVP Code 257) is of type
>>> Address and is used
>>>>      to inform a Diameter peer of the sender's IP address.
>>> All source
>>>>      addresses that a Diameter node expects to use with
>>> SCTP [RFC4960] or
>>>>      DTLS/SCTP [RFC6083] MUST be advertised in the CER and
>>> CEA messages by
>>>>      including a Host-IP-Address AVP for each address.
>>>>      When Diameter is run over SCTP [RFC4960] or DTLS/SCTP
>>> [RFC6083],
>>>>      which allow connections to span multiple interfaces,
>>> hence, multiple
>>>>      IP addresses, the Capabilities-Exchange-Answer message
>>> MUST contain
>>>>      one Host-IP-Address AVP for each potential IP address
>>> that MAY be
>>>>      locally used when transmitting Diameter messages.
>>>> That might lead to think that if using TCP, that AVP
>>> might/needs not
>>>> be sent.
>>>> However, not sending it would be a contradiction with the
>>> CER/CEA ABNF
>>>> message format, that states that the Host-IP-Address AVP is a
>>>> mandatory AVP with at least 1 ocurrence :
>>>> <CER> ::= < Diameter Header: 257, REQ >
>>>>                     { Origin-Host }
>>>>                     { Origin-Realm }
>>>>                  1* { Host-IP-Address } <------------
>>>> ...
>>>> I think it would be a good idea to clarify:
>>>> A.- whether Host-IP-Address MUST/SHOULD/MAY included in CER/CEA
>>>> messages if using TCP
>>> As you point out, the command definition for the CER
>>> requires at least
>>> on instance of the AVP.  What is unclear?
>>>
>>> ...
>>>