Hi Richard,

Thanks a lot for your updates that all perfectly address my comments and 
clarify a lot.  I have inserted suggestions inline, on your update on "[Page 
27] §8.5.3 Example" and leave it up to you to use them. Their purpose is to 
clarify from the beginning the fact that a Cost Type name is local to an IRD 
and the names listed in the "meta" member are not necessarily supported by all 
applicable resources entries.
Thanks
Sabine


De : [email protected] [mailto:[email protected]] De la part de Y. 
Richard Yang
Envoyé : lundi 1 juillet 2013 06:17
À : RANDRIAMASY, SABINE (SABINE)
Cc : [email protected]
Objet : Re: [alto] draft-ietf-alto-protocol-16 - minor comments

Hi Sabine,

Thanks a lot for the excellent comments! Please see below.

On Mon, Jun 24, 2013 at 1:02 PM, RANDRIAMASY, SABINE (SABINE) 
<[email protected]<mailto:[email protected]>>
 wrote:
Dear all,

While going through the latest update, I have listed some minor comments and 
typos and  suggest some re-phrasings below, in particular in paragraphs on new 
features such as the new cost type and the in/re-direction to other IRDs. I 
also attached a text file with the comments.
Hoping it helps.
Sabine


---------------------------------------
COMMENTS ON draft-ietf-alto-protocol-16
---------------------------------------


- everything in ++ indicates ADDED text, including white space
- everything in -- indicated REMOVED text


[Page 27] §8.5.3 Example
The example IRD exposes a capability called "cost-type-name" that is not 
introduced before and it would help to add some sentences to better distinguish 
the roles of "cost-type-name" and "cost-type". Especially as the combination of 
cost metric and cost mode into cost type is new to people who already coded an 
ALTO Client. Besides, the field "cost-type" of the meta member defines the cost 
type names but also specifies their members. So I propose to add some text 
after the example IRD and before sentence "Specifically, the "meta" member of 
the example IRD defines....", that would look like:

"When an ALTO Client wants to fetch the Cost Types supported at the uris listed 
in the ALTO Server, it should look after string "cost-type-names". The values 
of "cost-type-names" indicate Cost Types whose Cost Metric and Cost Mode are 
specified in the field "cost-type" of member "meta" of the IRD. Specifically 
etc. ...".

Good comment. Here is the new text based on your suggestion:

      Specifically, the "meta" member of the example IRD defines a
      field named "cost-types", which defines the names of cost
      types[  +for this IRD+   ]  . For example, "num-routing" in the example 
is the name
      that refers to a Cost Type with Cost Mode being "numerical" and
      Cost Metric being "routingcost".  The value of "cost-types" is
      of type IRDMetaCostTypes defined below; see  Section 9.6 for the 
definition of CostType.

      The names defined in "cost-types" can be used in [   -the -  ] [  +one or 
more+   ]
      "resources" entries. For example, the second entry of
      "resources" defines a Cost Map.  The "cost-type-names" of its
      "capabilities" specifies that this resource supports a Cost Type
      named as "num-routing". The ALTO Client looks up the name
      "num-routing" in "cost-types" of the IRD to obtain the Cost Type
      named as "num-routing". The last entry of "resources" uses all
      four names defined in "cost-types".

[Page 28] § 8.5.4 Delegation and Multiple Choices
Redirection to another IRD is another new feature so like in the previous 
section, I suggest to add text on the media-type. A proposal for the first 
paragraph:
"... In the example above, the -- +fourth uri/entry+ provides additional 
Network and Cost Maps via a separate subdomain, 
"custom.alto.example.com<http://custom.alto.example.com>". +This re/indirection 
is indicated by the media-type "application/alto-directory+json"+. In 
particular etc. ... ".

Good suggestion. Here is the new text based on your suggestion:

     Consider the preceding example.  The fourth entry of
      "resources" provides additional Network and Cost Maps via a
      separate subdomain: 
"custom.alto.example.com<http://custom.alto.example.com>". This delegation
      is indicated by the media-type
      "application/alto-directory+json". The ALTO Client can discover
      the maps available at 
"custom.alto.example.com<http://custom.alto.example.com>" by successfully
      performing a request to
      "http://custom.alto.example.com/maps":



[Page 30] § 8.5.5.1 ALTO Client
text says: "In general, it is preferred for ALTO Clients to use GET requests 
where appropriate, since it is more likely for responses to be cachable."

As the ECS seems as attractive as the Cost Map Service in many use cases, I'd 
prefer to mention preferences for both CostMap and ECS with a text like:

"An ALTO Client may prefer to use GET requests for cacheable information. It 
may on the other hand prefer POST requests for example to get ALTO costs or 
properties on a restricted set of PIDs or Endpoints or to update cached 
information previously acquired via GET requests."

Here is the revised text to add the POST part f your suggestion:

       In general, it is preferred for ALTO Clients to use GET
        requests where appropriate, since it is more likely for
        responses to be cachable. However, an ALTO Client may need to
        use POST, for example, to get ALTO costs or properties that
        are for a restricted set of PIDs or Endpoints, or to update
        cached information previously acquired via GET requests."

[Page 37] § 9.6. Cost Type
text says: "The combinaton of CostType and a CostMode defines a CostType"
Given the latest specs in §6.1 and the IRD examples, the sentence should be 
"The combinaton of +a+ Cost++Type and a Cost++Mode defines a Cost++Type"

The object CostType specified in this section contains a field called 
"CostModel" where I believe the "l" should be removed to give "CostMode-l-".

Fixed both:
       The combination of a CostMetric and a CostMode defines a
      CostType:
object {
  CostMetric cost-metric;
  CostMode   cost-mode;
  [JSONString description;]
} CostType;



[Page 38] § 10 Protocol Specification: Service Information Resources
A "d" should be added in sentence, to have: "This section documents.... 
define+d+ ... document".

Good catch. Fixed.



[Page 40] Section 10.1.1.6 Example
In paragraph after the example, in following part of 2nd sentence: "such as 
transforming the Network Map into a IP trie": should it be "tree"?

I see the ambiguity. Here is a new text:

 If lookup efficiency at runtime is crucial, then the returned
         Cost Map and Network Map can be transformed into data
         structures offering more efficient lookup. For example, one
         may store the Cost Map as a matrix, and the Network Map as a
         trie-based data structure, which may allow efficient
         longest-prefix matching of IP addresses.

Please let us know if they address your comments.

Thanks again.

Richard




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