Draft: draft-ietf-capport-architecture

Commentary: This rephrases the " Evaluating an Identifier " section ( 3.3 ) to refer to identifier types , rather than identifiers . We now draw the distinction between the type of an identifier , and an identifier itself , to avoid ambiguity . Fixes Issue 
 I 'd appreciate it if a reviewer could go over the surrounding text to make sure the distinction is obvious , and we 're not misusing the ' type ' term . 
 A reviewer writes , I think we should rewrite this section to be about evaluating types of identifiers or sources of identifiers . 
 Agreed . It 's ambiguous as to whether we 're describe how to evaluate equals , or whether we 're talking about the types ( ip vs ethernet ) 
 Not yet sure this is is all that 's needed , but on its own it 's clarifying I think .
To evaluate whether an identifier is appropriate, one should consider
every recommended property from the perspective of interactions among
the components in the architecture.  When comparing identifiers,
choose the one which best satisfies all of the recommended
properties.  The architecture does not provide an exact measure of
how well an identifier satisfies a given property; care should be
taken in performing the evaluation.
This section provides some examples of identifiers, along with some
evaluation of whether they are good identifiers.  The list of
identifiers is not exhaustive.  Other identifiers may be used.  An
important point to note is that whether the identifiers are good
depends heavily on the capabilities of the components and where in
the network the components exist.
The physical interface by which the User Equipment is attached to the
network can be used to identify the User Equipment.  This identifier
has the property of being extremely difficult to spoof: the User
Equipment is unaware of the property; one User Equipment cannot
manipulate its interactions to appear as though it is another.
Further, if only a single User Equipment is attached to a given
physical interface, then the identifier will be unique.  If multiple
User Equipment is attached to the network on the same physical
interface, then this property is not appropriate.
To evaluate whether a type of identifier is appropriate, one should
consider every recommended property from the perspective of
interactions among the components in the architecture.  When
comparing identifier types, choose the one which best satisfies all
of the recommended properties.  The architecture does not provide an
exact measure of how well an identifier type satisfies a given
property; care should be taken in performing the evaluation.
This section provides some example identifier types, along with some
evaluation of whether they are suitable types.  The list of
identifier types is not exhaustive.  Other types may be used.  An
important point to note is that whether a given identifier type is
suitable depends heavily on the capabilities of the components and
where in the network the components exist.
The physical interface by which the User Equipment is attached to the
network can be used to identify the User Equipment.  This identifier
type has the property of being extremely difficult to spoof: the User
Equipment is unaware of the property; one User Equipment cannot
manipulate its interactions to appear as though it is another.
Further, if only a single User Equipment is attached to a given
physical interface, then the identifier will be unique.  If multiple
User Equipment is attached to the network on the same physical
interface, then this type is not appropriate.
A natural identifier to consider is the IP address of the User
Equipment.  At any given time, no device on the network can have the
same IP address without causing the network to malfunction, so it is
appropriate from the perspective of uniqueness.
A natural identifier type to consider is the IP address of the User
Equipment.  At any given time, no device on the network can have the
same IP address without causing the network to malfunction, so it is
appropriate from the perspective of uniqueness.