Subject: [alto] Duplicate entries in resource directory?

From: "Scharf, Michael (Michael)" <[email-masked]>
Date: Mon, 29 Apr 2013 12:54:14 +0200

Hi all,

draft -14 states regarding multiple entries in the directory:
   
   It is possible that multiple entries in the directory match a desired
   Information Resource.  For instance, in the example in Section 7.6.3,
   a full Cost Map with "numerical" Cost Mode and "routingcost" Cost
   Type could be retrieved via a GET request to
   "http://alto.example.com/costmap/num/routingcost", or via a POST
   request to "http://custom.alto.example.com/costmap/filtered".

Is my understanding correct that a directory response with duplicate entries for the exactly same service (including the same cost mode etc.) is allowed as well?

Example for network map:

   HTTP/1.1 200 OK
   Content-Length: 1472
   Content-Type: application/alto-directory+json

   {
     "resources" : [
       {
         "uri" : "http://alto.example.com/networkmap",
         "media-types" : [ "application/alto-networkmap+json" ]
       },
       {
         "uri" : "http://alto2.example.com/alternative/networkmap,
         "media-types" : [ "application/alto-networkmap+json" ]
       }
     ]
   }

We just wonder what an ALTO client should do if it gets such a response - probably it would pick a random URI. This could actually achieve some simple load balancing.

Thanks

Michael