Subject: [AAA-WG]: More about Dynamic HA at visited domain and reducing delay

From: "Haseeb Akhtar" <[email-masked]>
Date: Fri, 16 Mar 2001 16:57:40 -0600

Hello all,

The following is the detail of the proposal that I mentioned last 
week that deals with allocating an HA at the visited network.

Of course, this proposal only uses two messages (namely AMR and
AAR) through out this entire process.

FA --AMR(1)------>AAAF----AMR(2)--->AAAH

HA <--AMA(4)------AAAF<---AMA(3)----AAAH

FA <---AMA(6)-----AAAF<---AMA(5)----HA

(1) The FA sends an AMR to AAAF (Destination Realm = AAAH, Origin
    FQDN = FA, MIP Feature Vector = HA_in_Foreign_Network).

(2) AAAF receives the message and forwards it to AAAH based on the
    Destination Realm (Destination Realm = AAAH, Origin
    FQDN = FA, MIP Feature Vector = HA_in_Foreign_Network).

(3) The AAAH receives the message, sees the MIP Feature Vector
    and does other necessary functions. It then sends an AMA to the
    AAAF with rest of the keys and so forth. It attaches the MIP
    Feature Vector into the AMA and copies the Origin FQDN into
    a new AVP called FA FQDN (Destination Realm = AAAF,
    MIP Feature Vector = HA_in_Foreign_Network, FA FQDN = FA).

(4) The AAAF now receives an AMA and sees the MIP Feature Vector
    to contain HA_in_Foreign_Network and the Destination Realm is
    same as its own realm. Therefore, it knows to select an HA
    (at the visited network) and hence forwards pretty much
    the same AMA to a selected HA (Destination Realm = AAAF, 
    MIP Feature Vector = HA_in_Foreign_Network, 
    FA FQDN = FA).

(5) The HA does its thing and forwards the AMA to the AAAF with
    Destination FQDN = FA. This will also allow multiple FAs to
    interface with single AAAF and the everybody in the route will
    exactly know as to what FA the final message needs to go to
    (Destination Realm = AAAF, Destination FQDN = FA).

(6) The AAAF looks at the Destination FQDN of the AMA and then
    ships it to the appropriate FA (Destination Realm = AAAF).

The only time that the AAAF/AAAH needs to behave differently, that is
do different things from the current implementation, is when it receives
the MIP Feature Vector as HA_in_Foreign_Network, and the Destination 
Realm contains its own Realm (as in step 4 above).

As I mentioned earlier, a new AVP FA FQDN is needed to scale multiple
FAs with one AAAF server. 

Regards,

Haseeb