Subject: [AAA-WG]: [issue] Purpose of MIP-Foreign-Agent-Host

From: Johan Johansson <[email-masked]>
Date: Sun, 10 Mar 2002 02:20:13 +0100

Subject: [issue] Purpose of MIP-Foreign-Agent-Host

Submitter name: Johan Johansson
Submitter email address: [email-masked]
Date first submitted: March 10, 2002
Reference:
Document: Mip
Comment type: T
Priority: 2
Section: 4.8 + ABNFs and occurence rules

Rationale/Explanation of issue

The MIP-Foreign-Agent-Host avp is mandatory in both the HAR and the HAA. 
The only text covering this avp is

  The MIP-Foreign-Agent-Host AVP (AVP Code 330) is of type
    DiameterIdentity and contains the identity of the foreign agent. This
    AVP is copied from the value of the Origin-Host AVP in the AMR.

If we start with its presence in the HAA, this can't possibly serve any 
purpose since the AAAH already knows the identity of the FA. It was 
after all the one who sent it to the HA in the first place.

But why would the HA want it at all and badly enough for it to be 
mandatory in the HAR at that? The avp is of type DiameterIdentity which 
is a strong indication that it is for the consumption of a Diameter 
entity and not a mobile ip entity. If the mobile node is supposed to 
carry this information for some reason there is ample opportunity for 
the FA to provide it directly to the mobile node.

The avp is not present in accounting messages.

I am quite ignorant about CMS, but it seems unlikely that the HA could 
have a conceivable need to establish a DSA with the FA.

The avp must come from somewhere though since it must have been actively 
introduced. Can someone please shed some light on why it was defined?

Requested change:

Explain the avp's use or remove it.

j