One document matched: draft-ietf-cdni-requirements-00.xml
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<front>
<title abbrev="CDNI Requirements">Content Distribution Network
Interconnection (CDNI) Requirements</title>
<author fullname="Kent Leung" initials="K." surname="Leung" role="editor">
<organization abbrev="Cisco">Cisco Systems</organization>
<address>
<postal>
<street>170 West Tasman Drive</street>
<city>San Jose</city>
<code>95134</code>
<region>CA</region>
<country>U.S.A.</country>
</postal>
<phone>+1 408 526 5030</phone>
<email>kleung@cisco.com</email>
</address>
</author>
<author fullname="Yiu Lee" initials="Y." surname="Lee" role="editor">
<organization abbrev="Comcast">Comcast</organization>
<address>
<postal>
<street>One Comcast Center</street>
<city>Philadelphia</city>
<region>PA</region>
<code>19103</code>
<country>U.S.A.</country>
</postal>
<email>yiu_lee@cable.comcast.com</email>
</address>
</author>
<date day="9" month="September" year="2011" />
<abstract>
<t>Content Delivery Networks (CDNs) are frequently used for large-scale
content delivery. As a result, existing CDN providers are scaling up
their infrastructure and many Network Service Providers (NSPs) are
deploying their own CDNs. There is a requirement for interconnecting
standalone CDNs so that their collective CDN footprint can be leveraged
for the end-to-end delivery of content from Content Service Providers
(CSPs) to end users. The Content Distribution Network Interconnection
(CDNI) working group has been chartered to develop an interoperable and
scalable solution for such CDN interconnection.</t>
<t>The goal of the present document is to outline the requirements for
the solution and interfaces to be specified by the CDNI working
group. This draft is a work in progress and requirements may be added, modified, or
removed by the working group. </t>
</abstract>
<note title="Requirements Language">
<t>The key words "High Priority", "Medium Priority" and "Low Priority" in this document are to be
interpreted in the following way:</t>
<t><list style="symbols">
<t>"High Priority" indicates requirements that are to be supported by the
CDNI interfaces. A requirement is stated as "High Priority" when
it is established by the working group that it can be met without compromising the
targeted schedule for WG deliverables, or when it is established
that specifying a solution without meeting this requirement would
not make sense and would justify re-adjusting the WG schedule, or
both. This is tagged as "[HIGH]".</t>
<t>"Medium Priority" indicates requirements that are to be supported by the
CDNI interfaces unless the WG realizes at a later stage
that attempting to meet this requirement would compromise the
overall WG schedule (for example it would involve complexities that
would result in significantly delaying the deliverables). This is tagged as "[MED]".</t>
<t>"Low Priority" indicates requirements that are to be supported by the CDNI
interfaces provided that dedicating WG resources to
this work does not prevent addressing "High Priority" and "Medium Priority"
requirements and that attempting to meet this requirement would not
compromise the overall WG schedule. This is tagged as "[LOW]".</t>
</list></t>
<t></t>
</note>
</front>
<middle>
<section title="Introduction">
<t>The volume of video and multimedia content delivered over the
Internet is rapidly increasing and expected to continue doing so in the
future. In the face of this growth, Content Delivery Networks (CDNs)
provide numerous benefits: reduced delivery cost for cacheable content,
improved quality of experience for end users, and increased robustness
of delivery. For these reasons CDNs are frequently used for large-scale
content delivery. As a result, existing CDN providers are scaling up
their infrastructure and many Network Service Providers (NSPs) are
deploying their own CDNs. It is generally desirable that a given content
item can be delivered to an End User regardless of that End User's
location or attachment network. However, the footprint of a given CDN in
charge of delivering a given content may not expand close enough to the
End User's current location or attachment network to realize the cost
benefit and user experience that a more distributed CDN would provide.
This creates a requirement for interconnecting standalone CDNs so that
their collective CDN footprint can be leveraged for the end-to-end
delivery of content from Content Service Providers (CSPs) to End Users.
The Content Distribution Network Interconnection (CDNI) working group
has been chartered to develop an interoperable and scalable solution
for such CDN interconnection.</t>
<t><xref target="I-D.jenkins-cdni-problem-statement"></xref> outlines
the problem area that the CDNI working group is chartered to address.
<xref target="I-D.bertrand-cdni-use-cases"></xref> discusses the use
cases for CDN Interconnection. <xref
target="I-D.davie-cdni-framework"></xref> discusses the technology
framework for the CDNI solution and interfaces.</t>
<t>The goal of the present document is to document the requirements for
the CDNI solution and interfaces. In order to meet the timelines defined in the working group charter,
the present document categorizes the CDNI requirements as "High Priority",
"Medium Priority", and "Low Priority". (OPEN ISSUE: Should requirements in
each section be ordered by priority?)</t>
<section anchor="terminology" title="Terminology">
<t>This document uses the terminology defined in section 1.1 of <xref
target="I-D.davie-cdni-framework"></xref>.</t>
</section>
</section>
<section anchor="cdni-interfaces" title="CDNI Model and CDNI Interfaces">
<t>For convenience Figure 1 from <xref
target="I-D.davie-cdni-framework"></xref> illustrating the
CDNI problem area and the CDNI protocols is replicated below.</t>
<figure anchor="fig-cdni-model" title="CDNI Model and CDNI Interfaces">
<preamble></preamble>
<artwork><![CDATA[ --------
/ \
| CSP |
\ /
--------
*
*
* /\
* / \
---------------------- |CDNI| ----------------------
/ Upstream CDN \ | | / Downstream CDN \
| +-------------+ | Control Interface| +-------------+ |
|******* Control |<======|====|========>| Control *******|
|* +------*----*-+ | | | | +-*----*------+ *|
|* * * | | | | * * *|
|* +------*------+ | Logging Interface| +------*------+ *|
|* ***** Logging |<======|====|========>| Logging ***** *|
|* * +-*-----------+ | | | | +-----------*-+ * *|
|* * * * | Request Routing | * * * *|
.....*...+-*---------*-+ | Interface | +-*---------*-+...*.*...
. |* * *** Req-Routing |<======|====|========>| Req-Routing *** * *| .
. |* * * +-------------+.| | | | +-------------+ * * *| .
. |* * * . CDNI Metadata | * * *| .
. |* * * +-------------+ |. Interface | +-------------+ * * *| .
. |* * * | Distribution|<==.===|====|========>| Distribution| * * *| .
. |* * * | | | . \ / | | | * * *| .
. |* * * |+---------+ | | . \/ | | +---------+| * * *| .
. |* * ***| +---------+| | ....Request......+---------+ |*** * *| .
. |* *****+-|Surrogate|************************|Surrogate|-+***** *| .
. |******* +---------+| | Acquisition | |+----------+ *******| .
. | +-------------+ | | +-------*-----+ | .
. \ / \ * / .
. ---------------------- ---------*------------ .
. * .
. * Delivery .
. * .
. +--*---+ .
...............Request.............................| User |..Request..
| Agent|
+------+
<==> interfaces inside the scope of CDNI
**** interfaces outside the scope of CDNI
.... interfaces outside the scope of CDNI
]]></artwork>
<postamble></postamble>
</figure>
<t></t>
<t></t>
</section>
<section title="Generic CDNI Requirements">
<t>This section identifies generic requirements independent of the
individual CDNI interfaces. Some of those are expected to affect multiple
or all interfaces.</t>
<t><list counter="gen-reqs" hangIndent="4" style="format GEN-%d">
<t>[MED] Wherever possible, the CDNI interfaces should reuse or leverage
existing IETF protocols.</t>
<t>[HIGH] The CDNI solution shall not require a change, or an upgrade, to
the User Agent to benefit from content delivery through
interconnected CDNs.</t>
<t>[HIGH] The CDNI solution shall not require a change, or an upgrade, to
the Content Service Provider to benefit from content delivery through
interconnected CDNs.</t>
<t>[HIGH] The CDNI solution shall not require intra-CDN information to be
exposed to other CDNs for effective and efficient delivery of the
content. Examples of intra-CDN information include surrogate
topology, surrogate status, cached content, etc.</t>
<t>[HIGH] The CDNI solution shall support delivery to the user agent based
on HTTP <xref target="RFC2616"></xref>. (Note that while delivery
and acquisition "data plane" protocols are out of the CDNI
solution scope, the CDNI solution "control plane" protocols are
expected to participate in enabling, selecting or facilitating
operations of such acquisition and delivery protocols. Hence it is
useful to state requirements on the CDNI solution in terms of
which acquisition and delivery protocols).</t>
<t>[HIGH] The CDNI solution shall support acquisition across CDNs based on
HTTP <xref target="RFC2616"></xref>.</t>
<t>[LOW] The CDNI solution may support delivery to the user agent based
on protocols other than HTTP.</t>
<t>[LOW] The CDNI solution may support acquisition across CDNs based on
protocols other than HTTP.</t>
<t>[MED] The CDNI solution should support cascaded CDN redirection (CDN1
redirects to CDN2 that redirects to CDN3) to an arbitrary number
of levels.(OPEN ISSUE: arbitrary number should more than one level?)</t>
<t>[MED] The CDNI solution should support an arbitrary topology of
interconnected CDNs (i.e. the CDN topology cannot be restricted to
a tree, a loop-free topology, etc.).</t>
<t>[HIGH] The CDNI solution shall prevent looping of any CDNI information
exchange.</t>
<t>[HIGH] When making use of third party reference, the CDNI solution
shall consider the potential issues associated with the use of
various format of third-party references (e.g. NAT or IPv4/IPv6
translation potentially breaking third-party references based on
an IP addresses such as URI containing IPv4 or IPv6 address
litterals, split DNS situations potentially breaking third-party
references based on DNS fully qualified domain names) and wherever
possible avoid, minimize or mitigate the associated risks based on
the specifics of the environments where the reference is used
(e.g. likely or unlikely presence of NAT in the path). In
particular, this applies to situations where the CDNI solution
needs to construct and convey uniform resource identifiers for
directing/redirecting a content request, as well as to situations
where the CDNI solution needs to pass on a third party reference
(e.g. to identify a User Agent) in order to allow another entity
to make a more informed decision (e.g. make a more informed
request routing decision by attempting to derive location
information from the third party reference).</t>
<t>[LOW] The CDNI solution should support virtualization of the
Downstream CDN, so that the Downstream CDN can appear as multiple
logical Downstream CDNs. (OPEN ISSUE: Virtualization is transparent
to CDNI, remove requirement or justify why uCDN/dCDN needs to be aware?)</t>
<t>(OPEN ISSUE: Add HTTP ABR requirements)</t>
</list></t>
</section>
<section title="CDNI Control Interface Requirements">
<t>The primary purpose of the CDNI Control interface is to initiate the
interconnection across CDNs, bootstrap the other CDNI interfaces and
trigger actions into the Downstream CDN by the Upstream CDN (such as
delete object from caches or trigger pre-positioned content
acquisition). We observe that while the CDNI Control interface is
currently discussed as a single "protocol", further analysis will
determine whether the corresponding requirements are to be realized over
a single interface and protocol, or over multiple interfaces and
protocols.</t>
<t><list counter="control-reqs" hangIndent="4" style="format CNTL-%d">
<t>[HIGH] The CDNI Control interface shall allow the Upstream CDN to
request that the Downstream CDN (and, if cascaded CDNs are
supported by the solution, that the potential cascaded Downstream
CDNs) perform the following actions on an object or object set:
<list style="symbols">
<t>Mark an object(s) and/or its CDNI metadata as
“stale” and revalidate them before they are
delivered again</t>
<t>Delete an object(s) and/or its CDNI metadata from the CDN
surrogates and any storage.</t>
</list></t>
<t>[HIGH] The CDNI Control interface shall allow the downstream CDN to
report on the completion of these actions (by itself, and if
cascaded CDNs are supported by the solution, by potential cascaded
Downstream CDNs), in a manner appropriate for the action (e.g.
synchronously or asynchronously).</t>
<t>[HIGH] The CDNI Control interface shall support initiation and control
by the Upstream CDN of pre-positioned CDNI metadata acquisition by
the Downstream CDN.</t>
<t>[MED] The CDNI Control interface should support initiation and control
by the Upstream CDN of pre-positioned content acquisition by the
Downstream CDN.(OPEN ISSUE: how much influence the Upstream CDN
ought to have on pre-positioning of the content on surrogates
inside the Downstream CDN is TBD).</t>
<t>[LOW] The CDNI Control interface may allow a CDN to establish, update
and terminate a CDN interconnection with another CDN whereby one
CDN can act as a Downstream CDN for the other CDN (that acts as an
Upstream CDN).</t>
<t>[LOW] The CDNI Control interface may allow control of the CDNI
interconnection between any two CDNs independently for each
direction (i.e. For the direction where CDN1 is the Upstream CDN
and CDN2 is the Downstream CDN, and for the direction where CDN2
is the Upstream CDN and CDN1 is the Downstream CDN).</t>
<t>[LOW] The CDNI Control interface may allow bootstrapping of the
Request-Routing interface. For example, this can potentially
include:<list style="symbols">
<t>negotiation of the Request-Routing method (e.g. DNS vs
HTTP, if more than one method is specified)</t>
<t>discovery of the Request-Routing protocol endpoints</t>
<t>information necessary to establish secure communication
between the Request-Routing protocol endpoints.</t>
</list></t>
<t>[LOW] The CDNI Control interface may allow bootstrapping of the
CDNI Metadata interface. This information could, for example,
include:<list style="symbols">
<t>discovery of the CDNI Metadata signaling protocol endpoints</t>
<t>information necessary to establish secure communication
between the CDNI Metadata signaling protocol endpoints.</t>
</list></t>
<t>[LOW] The CDNI Control interface may allow bootstrapping of the
Content Acquisition interface. This could, for example, include
exchange and negotiation of the Content Acquisition protocols to
be used across the CDNs (e.g. HTTP, HTTPS, FTP, ATIS C2).</t>
<t>[LOW] The CDNI Control interface may allow exchange and negotiation
of delivery authorization mechanisms to be supported across the
CDNs (e.g. URI signature based validation).</t>
<t>[LOW] The CDNI Control interface may allow bootstrapping of the
CDNI Logging interface. This information could, for example,
include:<list style="symbols">
<t>discovery of the Logging protocol endpoints</t>
<t>information necessary to establish secure communication
between the Logging protocol endpoints</t>
<t>negotiation/definition of the log file format and set of
fields to be exported through the Logging protocol, with some
granularity (e.g. On a per content type basis).</t>
<t>negotiation/definition of parameters related to transaction
Logs export (e.g., export protocol, file compression, export
frequency, directory).</t>
</list></t>
</list></t>
</section>
<section title="CDNI Request Routing Interface Requirements">
<t></t>
<t>The main function of the Request Routing interface is to allow the
Request-Routing systems in interconnected CDNs to communicate to
facilitate redirection of the request across CDNs.</t>
<t><list counter="reqrouting-reqs" hangIndent="4" style="format REQ-%d">
<t>[HIGH] The CDNI Control interface shall allow the Downstream CDN to
communicate to the Upstream CDN coarse information about the
Downstream CDN ability and/or willingness to handle requests from
the Upstream CDN. For example, this could potentially include a
binary signal ("Downstream CDN ready/not-ready to take additional
requests from Upstream CDN”) to be used in case of excessive
load or failure condition in the Downstream CDN. (OPEN ISSUE: Belong to Control Interface section?)</t>
<t>[MED] The CDNI Request-Routing interface should allow the Downstream
CDN to communicate to the Upstream CDN aggregate information to
facilitate CDN selection during request routing, such as
Downstream CDN capabilities, resources and affinities (i.e.
Preferences or cost). This information could, for example,
include:<list style="symbols">
<t>supported content types and delivery protocols</t>
<t>footprint (e.g. layer-3 coverage)</t>
<t>a set of metrics/attributes (e.g. Streaming bandwidth,
storage resources, distribution and delivery priority)</t>
<t>a set of affinities (e.g. Preferences, indication of
distribution/delivery fees)</t>
<t>information to facilitate request redirection (e.g.
Reachability information of Downstream CDN Request Routing
system).</t>
</list>[Note: Some of this information - such as supported
content types and delivery protocols- may also potentially be
taken into account by the distribution system in the Upstream CDN
for pre-positioning of content and/or metadata in the Downstream
CDN in case of pre-positioned content acquisition and/or
pre-positioned CDNI metadata acquisition.]</t>
<t>[MED] In the case of cascaded redirection, the
CDNI Request-Routing interface shall allow the Downstream CDN to
also include in the information communicated to the Upstream CDN,
information on the capabilities, resources and affinities of CDNs
to which the Downstream CDN may (in turn) redirect requests
received by the Upstream CDN. In that case, the CDNI
Request-Routing interface shall prevent looping of such information
exchange.</t>
<t>[LOW] The CDNI Control interface may allow the Downstream CDN to
communicate to the Upstream CDN aggregate information on CDNI
administrative limits and policy. This information can be taken
into account by the Upstream CDN Request Routing system in its CDN
Selection decisions. This information could, for example,
include:<list style="symbols">
<t>maximum number of requests redirected by the Upstream CDN
to be served simultaneously by the Downstream CDN</t>
<t>maximum aggregate volume of content (e.g. in Terabytes) to
be delivered by the Downstream CDN over a time period.</t>
</list></t>
<t>[HIGH] The CDNI Request-Routing architecture and interface shall support
efficient request-routing for small objects. This may, for
example, call for a mode of operation (e.g. DNS-based request
routing) where freshness and accuracy of CDN/Surrogate selection
can be traded-off against reduced request-routing load (e.g. Via
lighter-weight queries and caching of request-routing
decisions). (OPEN ISSUE: Surrogate selection is out of scope?)</t>
<t>[HIGH] The CDNI Request-Routing architecture and interface shall support
efficient request-routing for large objects. This may, for
example, call for a mode of operation (e.g. HTTP-based request
routing) where freshness and accuracy of CDN/Surrogate selection
justifies a per-request decision and a per-request CDNI
Request-Routing protocol call. (OPEN ISSUE: Surrogate selection is out of scope?)</t>
<t>[HIGH] The CDNI Request-Routing architecture shall support recursive
CDNI request routing.</t>
<t>[HIGH] The CDNI Request-Routing architecture shall support iterative
CDNI request routing.</t>
<t>[MED] In case of detection of a request redirection loop, the CDNI
Request-Routing loop prevention mechanism should allow routing of
the request (as opposed to the request loop being simply
interrupted without routing the request). (OPEN ISSUE: Why route a looped request?)</t>
<t>[MED] The CDNI Request-Routing protocol should support a
mechanism allowing enforcment of a limit on the number of
successive CDN redirections for a given request.</t>
<t>[LOW] The CDNI Request-Routing protocol may support a
mechanism allowing an upstream CDN to avoid redirecting a request
to a downstream CDN if that is likely to result in the total
redirection time exceeding some limit.</t>
<t>[HIGH] The CDNI Request-Routing protocol shall allow the Upstream CDN
to include, in the query to the Downstream CDN, the necessary
information to allow the Downstream CDN to process the redirection
query. This could, for example, include:<list style="symbols">
<t>information from which the location of the user-agent that
originated the request can be inferred (e.g. User Agent fully
qualified domain name in case of HTTP-based Request Routing,
DNS Proxy fully qualified domain name in case of DNS-based
Request Routing)</t>
<t>requested resource information (e.g. Resource URI in case
of HTTP-based Request Routing, Resource hostname in case of
DNS-based Request Routing)</t>
<t>additional available request information (e.g. request
headers in case of HTTP-based Request Routing).</t>
</list></t>
<t>[LOW] The CDNI Request-Routing protocol may also allow the Upstream
CDN to convey information pointing to CDNI metadata applicable
(individually or through inheritance) to the requested content.
For illustration, the CDNI metadata pointed to could potentially
include metadata that is applicable to any content, metadata that
is applicable to a content collection (to which the requested
content belongs) and/or metadata that is applicable individually
to the requested content.</t>
<t>[HIGH] The CDNI Request-Routing interface shall allow the Downstream CDN
to include the following information in the response to the
Upstream CDN:<list style="symbols">
<t>status code, in particular indicating acceptance or
rejection of request (e.g. Because the Downstream CDN is
unwilling or unable to serve the request). In case of
rejection, an error code is also to be provided, which allows
the Upstream CDN to react appropriately (e.g. Select another
Downstream CDN, or serve the request itself)</t>
<t>redirection information (e.g. Resource URI in case of
HTTP-based Request Routing, equivalent of a DNS record in case
of DNS-based Request Routing).</t>
</list></t>
</list></t>
</section>
<section title="CDNI Metadata Distribution Interface Requirements">
<t>The primary function of the CDNI Metadata Distribution interface is to
allow the Distribution system in interconnected CDNs to communicate to
ensure Content Distribution Metadata with inter-CDN scope can be
exchanged across CDNs. We observe that while the CDNI Metadata
Distribution protocol is currently discussed as a single "protocol",
further analysis will determine whether the corresponding requirements
are to be realized over a single interface and protocol, or over
multiple interfaces and protocols. For example, a subset of the CDNI
metadata might be conveyed in-band along with the actual content
acquisition across CDNs (e.g. content MD5 in HTTP header) while another
subset might require an out-of-band interface & protocol (e.g.
geo-blocking information).</t>
<t><list counter="meta-reqs" hangIndent="4" style="format META-%d">
<t>[HIGH] The CDNI Metadata Distribution interface shall allow the Upstream
CDN to provide the Downstream CDN with content distribution
metadata of inter-CDN scope.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall support exchange
of CDNI metadata for both the dynamic content acquisition model
and the pre-positioning content acquisition model.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall
support a mode where no, or a subset of, the Metadata is initially
communicated to the Downstream CDN along with information about
how/where to acquire the rest of the CDNI Metadata (i.e. Dynamic
CDNI metadata acquisition). (OPEN ISSUE: Confirm high priority)</t>
<t>[MED] The CDNI Metadata Distribution interface should
support a mode where all the relevant Metadata is initially
communicated to the Downstream CDN (i.e. Pre-positioned CDNI
metadata acquisition). (OPEN ISSUE: Confirm medium priority)</t>
<t>[HIGH] Whether in the pre-positioned content acquisition model or in
the dynamic content acquisition model, the CDNI Metadata
Distribution interface shall provide the necessary information to
allow the Downstream CDN to acquire the content from an upstream
source (e.g. Acquisition protocol and Uniform Resource Identifier
in Upstream CDN- or rules to construct this URI).</t>
<t>[HIGH] The CDNI metadata shall allow signaling of one or more upstream
sources, where each upstream source can be in the Upstream CDN, in
another CDN, the CSP origin server or any arbitrary source
designated by the Upstream CDN. Note that some upstream sources
(e.g. the content origin server) may or may not be willing to
serve the content to the Downstream CDN, if this policy is known
to the upstream CDN then it may omit those sources when exchanging
CDNI metadata.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall allow the Upstream
CDN to request addition and modification of CDNI Metadata into the
Downstream CDN.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall allow removal of
obsolete CDNI Metadata from the Downstream CDN (this could, for
example, be achieved via an explicit removal request from the
Upstream CDN or via expiration of a Time-To-Live associated to the
Metadata).</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall allow association
of CDNI Metadata at the granularity of individual object. This is
necessary to achieve fine-grain Metadata distribution at the level
of an individual object when necessary.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall allow association
of CDNI Metadata at the granularity of an object set. This is
necessary to achieve scalable distribution of metadata when a
large number of objects share the same distribution policy.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall support multiple
levels of inheritance with precedence to more specific metadata.
For example, the CDNI Metadata Distribution protocol may support
metadata that is applicable to any content, metadata that is
applicable to a content collection and metadata that is applicable
to an individual content where content level metadata overrides
content collection metadata that overrides metadata for any
content.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall ensure that
conflicting metadata with overlapping scope are prevented or
deterministically handled.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall provide indication
by the Downstream CDN to the Upstream CDN of whether the CDNI
metadata (and corresponding future request redirections) is
accepted or rejected. When rejected, the CDNI Metadata
Distribution protocol Must allow the Downstream CDN to provide
information about the cause of the rejection.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall allow signaling of
content distribution control policies. For example, this could
potentially include:<list style="symbols">
<t>geo-blocking information (i.e. Information defining
geographical areas where the content is to be made available
or blocked)</t>
<t>availability windows (i.e. Information defining time
windows during which the content is to be made available or
blocked; expiration time may also be included to remove content)
(OPEN ISSUE: Expiration time needed?)</t>
<t>delegation whitelist/blacklist (i.e. Information defining
which downstream CDNs the content may/may not be delivered
through)</t>
</list></t>
<t>[HIGH] The CDNI Metadata interface shall be able to exchange a set of
well-accepted metadata elements with specified semantics (e.g. start of time window, end of time window).</t>
<t>[HIGH] The CDNI Metadata interface shall allow exchange of opaque metadata element, whose semantic is
not defined in CDNI but established by private CDN agreement.</t>
<t>[HIGH] The CDNI Metadata Distribution interface shall allow signaling of
authorization checks and validation that are to be performed by
the surrogate before delivery. For example, this could potentially
include:<list style="symbols">
<t>need to validate URI signed information (e.g. Expiry time,
Client IP address).</t>
</list></t>
<t>[LOW] The CDNI Metadata Distribution interface may allow signaling of
CDNI-relevant surrogate cache behavior parameters. For example,
this could potentially include:<list style="symbols">
<t>control of whether the query string of HTTP URI is to be
ignored by surrogate cache</t>
<t>content revalidation parameters (e.g. TTL)</t>
</list></t>
</list></t>
</section>
<section title="CDNI Logging Interface Requirements">
<t>This section identifies the requirements related to the CDNI Logging
interface. We observe that while the CDNI Logging interface is currently
discussed as a single "protocol", further analysis will determine
whether the corresponding requirements are to be realized over a single
interface and protocol, or over multiple interfaces and protocols.</t>
<t><list counter="log-reqs" hangIndent="4" style="format LOG-%d">
<t>[HIGH] The CDNI logging architecture and interface shall ensure reliable
logging of CDNI events.</t>
<t>[HIGH] The CDNI Logging interface shall provide logging of deliveries to
User Agents performed by the Downstream CDN as a result of request
redirection by the Upstream CDN.</t>
<t>[MED] In the case of cascaded CDNs, the CDNI Logging interface shall
allow the Downstream CDN to report to the Upstream CDN logging for
deliveries performed by the Downstream CDN itself as well as
logging for deliveries performed by cascaded CDNs on behalf of the
Downstream CDN.</t>
<t>[HIGH] The CDNI Logging interface shall provide logging of distribution
performed by the Upstream CDN as a result of acquisition request
by the Downstream CDN.</t>
<t>[HIGH] The CDNI Logging interface shall support batch/offline exchange
of logging records.</t>
<t>[MED] The CDNI Logging interface should also support additional timing
constraints for some types of logging records (e.g. near-real time
for monitoring and analytics applications)</t>
<t>[HIGH] The CDNI Logging interface shall define a log file format and a
set of fields to be exported through the Logging protocol, with
some granularity (e.g. On a per content type basis).</t>
<t>[HIGH] The CDNI Logging interface shall define a transport mechanisms to
exchange CDNI Logging files.</t>
<t>[LOW] The CDNI Logging interface may allow a CDN to query another CDN
for relevant current logging records (e.g. For on-demand access to
real-time logging information).</t>
</list></t>
<t> [Editor's note: should we add a requirement for support of
aggregate/summarized logs (e.g. total bytes delivered for a content
regardless of individual User Agents to which it was delivered)]
(OPEN ISSUE: LOW for aggregate/summarized logs)</t>
</section>
<section anchor="sec" title="CDNI Security Requirements">
<t>This section identifies the requirements related to the CDNI
security. Some of those are expected to affect multiple or all
protocols.</t>
<t><list counter="sec-reqs" hangIndent="4" style="format SEC-%d">
<t>[HIGH] All the CDNI interface shall support secure operation over
unsecured IP connectivity (e.g. The Internet). This includes
authentication, confidentiality, integrity protection as well as
protection against spoofing and replay.</t>
<t>[HIGH] The CDNI solution shall provide sufficient protection against
Denial of Service attacks. This includes protection against
spoofed delivery requests sent by user agents directly to a
Downstream CDN attempting to appear as if they had been redirected
by a given Upstream CDN when they have not.</t>
<t>[MED] The CDNI solution should be able to ensure that for any given
request redirected to a Downstream CDN, the chain of CDN
Delegation (leading to that request being served by that CDN) can
be established with non-repudiation.</t>
<t>[MED] The CDNI solution should be able to ensure that the Downstream
CDN cannot spoof a transaction log attempting to appear as if it
corresponds to a request redirected by a given Upstream CDN when
that request has not been redirected by this Upstream CDN. This
ensures non-repudiation by the Upstream CDN of transaction logs
generated by the Downstream CDN for deliveries performed by the
Downstream CDN on behalf of the Upstream CDN.</t>
<t>[LOW] The CDNI solution may provide a mechanism allowing an Upstream
CDN that has credentials to acquire content from the CSP origin
server (or another CDN), to allow establishment of credentials
authorizing the Downstream CDN to acquire the content from the CSP
origin server (or the other CDN) (e.g. In case the content cannot
be acquired from the Upstream CDN).</t>
</list></t>
</section>
<section anchor="IANA" title="IANA Considerations">
<t>This document makes no request of IANA.</t>
<t>Note to RFC Editor: this section may be removed on publication as an
RFC.</t>
</section>
<section anchor="Security" title="Security Considerations">
<t>This document discusses CDNI security requirements in <xref
target="sec"></xref>.</t>
</section>
<section title="Authors">
<t>This document reflects the contributions from the following authors:</t>
<t><list style="hanging">
<t hangText="Francois Le Faucheur"></t>
<t>Cisco Systems</t>
<t>flefauch@cisco.com</t>
<t hangText="Mahesh Viveganandhan"></t>
<t>Cisco Systems</t>
<t>mvittal@cisco.com</t>
<t hangText="Grant Watson"></t>
<t>BT</t>
<t>grant.watson@bt.com</t>
</list></t>
</section>
<section anchor="Acknowledgements" title="Acknowledgements">
<t>This document leverages the earlier work of the IETF CDI working
group in particular as documented in <xref
target="I-D.cain-request-routing-req"></xref>, <xref
target="I-D.amini-cdi-distribution-reqs"></xref> and <xref
target="I-D.gilletti-cdnp-aaa-reqs"></xref>.</t>
<t>The authors would like to thank Gilles Bertrand, Christophe Caillet,
Bruce Davie, Phil Eardly, Ben Niven-Jenkins, Agustin Schapira, Emile Stephan, Eric Burger,
Susan He, and Kevin Ma for their input.</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc
?>
<?rfc include='reference.I-D.jenkins-cdni-problem-statement'
?>
<?rfc include='reference.I-D.bertrand-cdni-use-cases'
?>
<?rfc include="reference.RFC.2616"?>
<?rfc include='reference.I-D.davie-cdni-framework'
?>
<?rfc ?>
<?rfc ?>
</references>
<references title="Informative References">
<?rfc include='reference.I-D.cain-request-routing-req'
?>
<?rfc include='reference.I-D.amini-cdi-distribution-reqs'
?>
<reference anchor="I-D.gilletti-cdnp-aaa-reqs">
<front>
<title>CDI AAA Requirements,
draft-gilletti-cdnp-aaa-reqs-01.txt</title>
<date month="June" year="2001" />
<abstract>
<t />
</abstract>
</front>
</reference>
</references>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-23 05:06:33 |