[alto] Review on draft-ietf-alto-unified-props-new-04

[Kai GAO <[e-mail]>]

Hi everyone,

Below is a review on the unified property map extension:

1. In Sec 2.1, the first sentence reads "The entity is an extended concept
of the endpoint ...". Here the word "extended" may not be very precise, and
the term "generalization" (which is also used in the abstract) sounds
better. Generalization indicates that an endpoint is essentially an entity
while extension could be misleading and even incorrect. For example, in
certain languages, A extends B indicates that A is also B.

2. In Sec 2.2, an entity domain is defined as "a set of entities". This
seems odd because then one can say a set of two entities
{"ipv4:190.0.2.34", "pid:PID1"} is also a domain, which doesn't make sense.
An entity domain should be a generalization of endpoint address type, which
must define the syntax and semantics of the entity addresses in this
domain. Thus, borrowed from the definition of a domain in math, it could be
"the complete set of all possible values of a given address type". Here the
"given address type" is uniquely represented by the domain name, which
indicates the "semantics" for this domain, while syntax for "all possible
values" is defined by the "domain-specific entity addresses".

I also feel Sec 2 can be slightly rearranged for better clarity. Right now
there are a lot of cross-references between different concepts. I suggest
having a short section introducing the terms and then using a paragraph to
specify their relations, for example,

(domain name, domain-specific address type, hierarchies, relations)
-(1:1)-> domain -(1:n)-> entity address -(1:1)-> entity -(1:m)-> property
<-(1:1)- (property type, property value)

3. I think the draft should make it clear that the uniqueness of an entity
address only applies in the same unified property map. For example,
"pid:PID1" could point to different entities when two UPMs depend on two
different network maps, both have the PID "PID1".

Best,
Kai