Hi Wendy, Sorry for the belated reply. Please see below.
On Thu, Jul 18, 2013 at 1:31 PM, Wendy Roome <[email protected]>wrote: > I like the idea of reserving the id "default-network-map" (say) for the > server's "default" or "general purpose" network map. Clients would use > that map unless explicitly configured to use a different one. > > However, I think default-network-map should be optional. The server should > offer one only if it is a truly a general-purpose map. Why? Because I can > imagine an ALTO server that provides nothing but specialized network maps. > Yes. I agree that an ALTO Service that provides only specialized network maps can already provide value. For example, one network map lists the mapping from access technology (e.g., ADSL, Fiber, LTE...) to its pool of IP addresses... Another network map lists each country/city code and the lists of IP addresses... Such maps can provide information to some applications. I agree that in such a setting, there may not be a general-purpose network map: every network map is specialized, and we do not have to force the ALTO Service Provider to single one out as the "default". > Clients of that server should be configured with the desired network map > id. Clients that try to use the default map should fail. > > This does imply that any ALTO server returned by the discovery protocol > must provide default-network-map. > > Not sure I understand why must return a default-network-map? > If anyone objects to reserving an id name, we could add an optional > "default-network-map-id" attribute to the IRD's metadata. > I feel that an attribute makes more sense. But increasingly, I feel less convinced that an ALTO Service needs to provide a default attribute to a network map. My understanding of the context where a default map can help is default behaviors of an application programming API design. Let's consider the origin application context. It is a P2P app who wants to fetch the routingcost. The default API should look for the (or the first) cost map resource in the IRD with routingcost as the cost metric. This resource will list the network map that the cost map uses. Hence, if we want to help this case, and for the case where there are multiple cost maps of "routingcost", we mark one of these as the default (or a numerical priority value). Another solution is to specify the "semantics" that the first entry of the same type of resource is the default. This is less robust, but avoids new syntax. A third solution is to assign a preference value of the same type of resource to give them an ordering. Hence, it is a more general solution than marking a single one as default. What do you think? Richard > Because "routingcost" is the implicit default cost metric, I don't think > reserving an id for a default cost map would provide any benefit. > > - Wendy Roome > > On 07/17/2013 17:57, "[email protected]" <[email protected]> > wrote: > > >Message: 1 > >Date: Wed, 17 Jul 2013 21:03:18 +0100 > >From: Ben Niven-Jenkins <[email protected]> > >To: Wendy Roome <[email protected]> > >Cc: alto <[email protected]> > >Subject: Re: [alto] Clarifying Cost Map Dependencies on a Network Map > >Message-ID: <[email protected]> > >Content-Type: text/plain; charset=us-ascii > > > >We can reserve an id for a 'default' map the clients can fallback to. If > >there's demand for multiple maps and they provide value clients will > >provide hooks to select a map. If there isn't then none of this matters > >:-) Ben > > > > > _______________________________________________ > alto mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/alto >
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