Re: CDI Distribution Draft

["Lisa Amini" <aminil@us.ibm.com>]

Dan, thanks.  I've inserted some responses/questions.
--Lisa

 > Sent by:    owner-webi@equinix.com
 > To:    Lisa Amini/Watson/IBM@IBMUS, cdn@ops.ietf.org,
 > webi@lists.equinix.com
 > cc:
 > Subject:    Re: CDI Distribution Draft
 >
 >
 >
 > Hi, Lisa, I think section 5.5 about relationship with RUP is largely inline
 > with what I expected. Some comments about the ones flagged as still lacking
 > in RUP:
 >
 > >In addition to the metadata fields which were defined for CI-DS, but
 > >    not mapped to an RUP field, CI-DS requires the following
 > >    functionality.
 > >
 > >       Ability to specifically request a Content Set be added or
 > >       withdrawn from the list of objects being serviced. This
 > >       requirement could be covered by adding the ability to dynamically
 > >       define Resource Groups to RUP.
 >
 > This is a no-brainer. Any grouping protocol got to have it. If you find it
 > missing in the RUP draft, it's an editing error. I will add it.
 >
 > >       Specifically, a master Resource Group could be defined which
 > >       would be used as the channel to communicate which Resource Groups
 > >       to be added/withdrawn from service.  The CIG would then establish
 > >       channels to receive cache coherency messages for these Resource
 > >       Groups.
 >
 > Yah, this is a nice architecture point for an end-to-end CDN or inter-CDN
 > system. Good to mention it in your draft.
 >
 > However, it is out side of RUP scope. RUP defines the operation within one
 > channel. How multiple channels are tied together or communicated to a cache
 > is a separate matter, and can potentially use any one of many solutions.
                                                     ^^^^^^^^^^^^^^^^^^^^^
I wasn't aware of any standardized solutions for this -- can you provide
some pointers?

 >
 > >       Ability to update metadata for an object.  While it is possible
 > >       this can be covered by withdrawal and re-add of the Content Set,
 > >       due to the number and types of fields supported, inability to
 > >       update would impact efficiency.
 >
 > Could you explain this a bit more? What kinds of "metadata"? HTTP metadata
 > or CDN metadata or something else?
 >

The metadata is as listed in Section 5.5, item 8.  I believe some of these
fields map well to RUP (such as the Content Set (Resource Group),
Authoritive Source (Content Location)), but others such as the Accounting
Format Accounting Type, Request Routing Type, Time Frame (not the time for
which the object is valid, but instead the time for which distribution
services are being requested), ...).  So, yes, this metadata is important
for interoperability, but some is also specific to CI.

Given the need for interoperability and the fact that the current RUP
document appears to be shifting toward covering both intra- and inter-
domain, I consider it reasonable to specify this info in the RUP document.
However, if it does not, as long as the RUP document does not preclude
metadata being communicated as associated with content or resource
groups, then we could publish a CI-specific document to cover these fields.


 > If it's just arbitrary stuff one can associate with a Resource Group, RUP
 > allows it. RUP has the "option" fields for people to stick anything there
 > as long as the receiving party is equipped to interpret the options.
 >
 > But if it's some specific metadata and you expect interoperability among
 > independent implementations (and operators), then please specify them and
 > RUP can look into incorporating them.
 >
 > Thanks!
 > Dan
 >