Internet DRAFT - draft-ietf-cdni-footprint-capabilities-semantics
draft-ietf-cdni-footprint-capabilities-semantics
CDNI J. Seedorf
Internet-Draft NEC
Intended status: Standards Track J. Peterson
Expires: November 21, 2016 Neustar
S. Previdi
Cisco
R. van Brandenburg
TNO
K. Ma
Ericsson
May 20, 2016
CDNI Request Routing: Footprint and Capabilities Semantics
draft-ietf-cdni-footprint-capabilities-semantics-20
Abstract
This document captures the semantics of the "Footprint and
Capabilities Advertisement" part of the CDNI Request Routing
interface, i.e., the desired meaning of "Footprint" and
"Capabilities" in the CDNI context, and what the "Footprint and
Capabilities Advertisement Interface (FCI)" offers within CDNI. The
document also provides guidelines for the CDNI FCI protocol. It
further defines a Base Advertisement Object, the necessary registries
for capabilities and footprints, and guidelines on how these
registries can be extended in the future.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
Seedorf, et al. Expires November 21, 2016 [Page 1]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
This Internet-Draft will expire on November 21, 2016.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction and Scope . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Design Decisions for Footprint and Capabilities . . . . . . . 5
2.1. Advertising Limited Coverage . . . . . . . . . . . . . . 5
2.2. Capabilities and Dynamic Data . . . . . . . . . . . . . . 6
2.3. Advertisement versus Queries . . . . . . . . . . . . . . 7
2.4. Avoiding or Handling 'cheating' dCDNs . . . . . . . . . . 7
3. Focusing on Capabilities with Footprint Restrictions . . . . 8
4. Footprint and Capabilities Extension . . . . . . . . . . . . 8
5. Capability Advertisement Object . . . . . . . . . . . . . . . 10
5.1. Base Advertisement Object . . . . . . . . . . . . . . . . 10
5.2. Encoding . . . . . . . . . . . . . . . . . . . . . . . . 11
5.3. Delivery Protocol Capability Object . . . . . . . . . . . 11
5.3.1. Delivery Protocol Capability Object Serialization . . 12
5.4. Acquisition Protocol Capability Object . . . . . . . . . 12
5.4.1. Acquisition Protocol Capability Object Serialization 13
5.5. Redirection Mode Capability Object . . . . . . . . . . . 13
5.5.1. Redirection Mode Capability Object Serialization . . 13
5.6. CDNI Logging Capability Object . . . . . . . . . . . . . 14
5.6.1. CDNI Logging Capability Object Serialization . . . . 15
5.7. CDNI Metadata Capability Object . . . . . . . . . . . . . 15
5.7.1. CDNI Metadata Capability Object Serialization . . . . 16
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
6.1. CDNI Payload Types . . . . . . . . . . . . . . . . . . . 17
6.1.1. CDNI FCI DeliveryProtocol Payload Type . . . . . . . 17
6.1.2. CDNI FCI AcquisitionProtocol Payload Type . . . . . . 18
6.1.3. CDNI FCI RedirectionMode Payload Type . . . . . . . . 18
6.1.4. CDNI FCI Logging Payload Type . . . . . . . . . . . . 18
6.1.5. CDNI FCI Metadata Payload Type . . . . . . . . . . . 18
Seedorf, et al. Expires November 21, 2016 [Page 2]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
6.2. Redirection Mode Registry . . . . . . . . . . . . . . . . 18
7. Security Considerations . . . . . . . . . . . . . . . . . . . 19
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.1. Normative References . . . . . . . . . . . . . . . . . . 20
8.2. Informative References . . . . . . . . . . . . . . . . . 20
Appendix A. Main Use Case to Consider . . . . . . . . . . . . . 21
Appendix B. Semantics for Footprint Advertisement . . . . . . . 22
Appendix C. Semantics for Capabilities Advertisement . . . . . . 24
Appendix D. Acknowledgment . . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction and Scope
The CDNI working group is working on a set of protocols to enable the
interconnection of multiple CDNs. This CDN interconnection (CDNI)
can serve multiple purposes, as discussed in [RFC6770], for instance,
to extend the reach of a given CDN to areas in the network which are
not covered by this particular CDN.
The goal of this document is to achieve a clear understanding about
the semantics associated with the CDNI Request Routing Footprint &
Capabilities Advertisement Interface (from now on referred to as
FCI), in particular the type of information a downstream CDN (dCDN)
'advertises' regarding its footprint and capabilities. To narrow
down undecided aspects of these semantics, this document tries to
establish a common understanding of what the FCI needs to offer and
accomplish in the context of CDNI.
It is explicitly outside the scope of this document to decide on
specific protocols to use for the FCI. However, guidelines for such
FCI protocols are provided.
General assumptions in this document:
o The CDNs participating in the interconnected CDN have already
performed a boot strap process, i.e., they have connected to each
other, either directly or indirectly, and can exchange information
amongst each other.
o The upstream CDN (uCDN) receives footprint and/or capability
advertisements from a set of dCDNs. Footprint advertisement and
capability advertisement need not use the same underlying
protocol.
o The uCDN receives the initial request-routing request from the
endpoint requesting the resource.
Seedorf, et al. Expires November 21, 2016 [Page 3]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
The CDNI Problem Statement [RFC6707] describes the Request Routing
Interface as: "[enabling] a Request Routing function in a uCDN to
query a Request Routing function in a dCDN to determine if the dCDN
is able (and willing) to accept the delegated Content Request". In
addition, RFC6707 says "the CDNI Request Routing interface is also
expected to enable a dCDN to provide to the uCDN (static or dynamic)
information (e.g., resources, footprint, load) to facilitate
selection of the dCDN by the uCDN request routing system when
processing subsequent content requests from User Agents". It thus
considers "resources" and "load" as capabilities to be advertised by
the dCDN.
The range of different footprint definitions and possible
capabilities is very broad. Attempting to define a comprehensive
advertisement solution quickly becomes intractable. The CDNI
requirements draft [RFC7337] lists the specific requirements for the
CDNI Footprint & Capabilities Advertisement Interface in order to
disambiguate footprints and capabilities with respect to CDNI. This
document defines a common understanding of what the terms 'footprint'
and 'capabilities' mean in the context of CDNI, and details the
semantics of the footprint advertisement mechanism and the capability
advertisement mechanism.
1.1. Terminology
This document reuses the terminology defined in [RFC6707].
Additionally, the following terms are used throughout this document
and are defined as follows:
o Footprint: a description of a CDN's coverage area, i.e., the area
from which client requests may originate for, and to which the CDN
is willing to deliver, content. Note: There are many ways to
describe a footprint, for example, by address range (e.g., IPv4/
IPv6 CIDR), by network ID (e.g., ASN), by nation boundaries (e.g.,
country code), by GPS coordinates, etc. This document does not
define or endorse the quality or suitability of any particular
footprint description method; this document only defines a method
for transporting known footprint descriptions in Footprint and
Capabilities Advertisement messages.
o Capability: a feature of a dCDN, upon which a uCDN relies on the
dCDN supporting, when making delegation decisions. Support for a
given feature can change over time and can be restricted to a
limited portion of a dCDN's footprint. Note: There are many
possible dCDN features that could be of interest to a uCDN. This
document does not presume to define them all; this document
describes a scheme for defining new capabilities and how to
Seedorf, et al. Expires November 21, 2016 [Page 4]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
transport them in Footprint and Capabilities Advertisement
messages.
2. Design Decisions for Footprint and Capabilities
A large part of the difficulty in discussing the FCI lies in
understanding what exactly is meant when trying to define footprint
in terms of "coverage" or "reachability." While the operators of
CDNs pick strategic locations to situate surrogates, a surrogate with
a public IPv4 address is reachable by any endpoint on the Internet
unless some policy enforcement precludes the use of the surrogate.
Some CDNs aspire to cover the entire world; we refer to these as
global CDNs. The footprint advertised by such a CDN in the CDNI
environment would, from a coverage or reachability perspective,
presumably cover all prefixes. Potentially more interesting for CDNI
use cases, however, are CDNs that claim a more limited coverage, but
seek to interconnect with other CDNs in order to create a single CDN
fabric which shares resources.
Furthermore, not all capabilities need to be footprint restricted.
Depending upon the use case, the optimal semantics of "footprints
with capability attributes" vs. "capabilities with footprint
restrictions" are not clear.
The key to understanding the semantics of footprint and capability
advertisement lies in understanding why a dCDN would advertise a
limited coverage area, and how a uCDN would use such advertisements
to decide among one of several dCDNs. The following section will
discuss some of the trade-offs and design decisions that need to be
decided upon for the CDNI FCI.
2.1. Advertising Limited Coverage
The basic use case that would motivate a dCDN to advertise a limited
coverage is that the CDN was built to cover only a particular portion
of the Internet. For example, an ISP could purpose-build a CDN to
serve only their own customers by situating surrogates in close
topological proximity to high concentrations of their subscribers.
The ISP knows the prefixes it has allocated to end users and thus can
easily construct a list of prefixes that its surrogates were
positioned to serve.
When such a purpose-built CDN interconnects with other CDNs and
advertises its footprint to a uCDN, however, the original intended
coverage of the CDN might not represent its actual value to the
interconnection of CDNs. Consider an ISP-A and ISP-B that both field
their own CDNs, which they interconnect via CDNI. A given user E,
Seedorf, et al. Expires November 21, 2016 [Page 5]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
who is a customer of ISP-B, might happen to be topologically closer
to a surrogate fielded by ISP-A, if E happens to live in a region
where ISP-B has few customers and ISP-A has many. In this case, is
it ISP-A's CDN that "covers" E? If ISP-B's CDN has a failure
condition, is it up to the uCDN to understand that ISP-A's surrogates
are potentially available as back-ups - and if so, how does ISP-A
advertise itself as a "standby" for E? What about the case where
CDNs advertising to the same uCDN express overlapping coverage (for
example, mixing global and limited CDNs)?
The answers to these questions greatly depend on how much information
the uCDN wants to use to make a selection of a dCDN. If a uCDN has
three dCDNs to choose from that "cover" the IP address of user E,
obviously the uCDN might be interested to know how optimal the
coverage is from each of the dCDNs - coverage need not be binary,
either provided or not provided. dCDNs could advertise a coverage
"score," for example, and provided that they all reported scores
fairly on the same scale, uCDNs could use that to make their
topological optimality decision. Alternately, dCDNs could advertise
the IP addresses of their surrogates rather than prefix "coverage,"
and let the uCDN decide for itself (based on its own topological
intelligence) which dCDN has better resources to serve a given user.
In summary, the semantics of advertising footprint depend on whether
such qualitative metrics for expressing footprint (such as the
coverage 'score' mentioned above) are included as part of the CDNI
FCI, or if the focus is just on 'binary' footprint.
2.2. Capabilities and Dynamic Data
In cases where the apparent footprints of dCDNs overlap, uCDNs might
also want to rely on other factors to evaluate the respective merits
of dCDNs. These include facts related to the surrogates themselves,
to the network where the surrogate is deployed, to the nature of the
resource sought, and to the administrative policies of the respective
networks.
In the absence of network-layer impediments to reaching surrogates,
the choice to limit coverage is necessarily an administrative policy.
Much policy needs to be agreed upon before CDNs can interconnect,
including questions of membership, compensation, volumes, and so on.
A uCDN certainly will factor these sorts of considerations into its
decision to select a dCDN, but there is probably little need for
dCDNs to actually advertise them through an interface - they will be
settled out-of-band as a precondition for interconnection.
Other facts about the dCDN would be expressed through the interface
to the uCDN. Some capabilities of a dCDN are static, and some are
Seedorf, et al. Expires November 21, 2016 [Page 6]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
highly dynamic. Expressing the total storage built into its
surrogates, for example, changes relatively rarely, whereas the
amount of storage in use at any given moment is highly volatile.
Network bandwidth similarly could be expressed as either total
bandwidth available to a surrogate, or based on the current state of
the network. A surrogate can at one moment lack a particular
resource in storage, but have it the next.
The semantics of the capabilities interface will depend on how much
of the dCDN state needs to be pushed to the uCDN and qualitatively
how often that information needs to be updated.
2.3. Advertisement versus Queries
In a CDNI environment, each dCDN shares some of its state with the
uCDN. The uCDN uses this information to build a unified picture of
all of the dCDNs available to it. In architectures that share
detailed capability information, the uCDN could perform the entire
request-routing operation down to selecting a particular surrogate in
the dCDN. However, when the uCDN needs to deal with many potential
dCDNs, this approach does not scale, especially for dCDNs with
thousands or tens of thousands of surrogates; the volume of updates
to footprint and capability becomes onerous.
Were the volume of FCI updates from dCDNs to exceed the volume of
requests to the uCDN, it might make more sense for the uCDN to query
dCDNs upon receiving requests (as is the case in the recursive
redirection mode described in [RFC7336]), instead of receiving
advertisements and tracking the state of dCDNs. The advantage of
querying dCDNs would be that much of the dynamic data that dCDNs
cannot share with the uCDN would now be factored into the uCDN's
decision. dCDNs need not replicate any state to the uCDN - uCDNs
could effectively operate in a stateless mode.
The semantics of both footprint and capability advertisement depend
on the service model here: are there cases where a synchronous query/
response model would work better for the uCDN decision than a state
replication model?
2.4. Avoiding or Handling 'cheating' dCDNs
In a situation where more than one dCDN is willing to serve a given
end user request, it might be attractive for a dCDN to 'cheat' in the
sense that the dCDN provides inaccurate information to the uCDN in
order to convince the uCDN to select it over 'competing' dCDNs. It
could therefore be desirable to take away the incentive for dCDNs to
cheat (in information advertised) as much as possible. One option is
to make the information the dCDN advertises somehow verifiable for
Seedorf, et al. Expires November 21, 2016 [Page 7]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
the uCDN. On the other hand, a cheating dCDN might be avoided or
handled by the fact that there will be strong contractual agreements
between a uCDN and a dCDN, so that a dCDN would risk severe penalties
or legal consequences when caught cheating.
Overall, the information a dCDN advertises (in the long run) needs to
be somehow qualitatively verifiable by the uCDN, though possibly
through non-real-time out-of-band audits. It is probably an overly
strict requirement to mandate that such verification be possible
"immediately", i.e., during the request routing process itself. If
the uCDN can detect a cheating dCDN at a later stage, it might
suffice for the uCDN to "de-incentivize" cheating because it would
negatively affect the long-term business relationship with a
particular dCDN.
3. Focusing on Capabilities with Footprint Restrictions
Given the design considerations listed in the previous section, it
seems reasonable to assume that in most cases it is the uCDN that
makes the decision on selecting a certain dCDN for request routing
based on information the uCDN has received from this particular dCDN.
It can be assumed that 'cheating' CDNs will be dealt with via means
outside the scope of CDNI and that the information advertised between
CDNs is accurate. In addition, excluding the use of qualitative
information (e.g., surrogate proximity, delivery latency, surrogate
load) to predict the quality of delivery would further simplify the
use case allowing it to better focus on the basic functionality of
the FCI.
Further understanding that in most cases contractual agreements will
define the basic coverage used in delegation decisions, the primary
focus of FCI is on providing updates to the basic capabilities and
coverage by the dCDNs. As such, FCI has choosen the semantics of
"capabilities with footprint restrictions".
4. Footprint and Capabilities Extension
Other optional "coverage/reachability" types of footprint or
"resource" types of footprint may be defined by future
specifications. To facilitate this, a clear process for specifying
optional footprint types in an IANA registry is specified in the CDNI
Metadata Footprint Types registry (defined in the CDNI Metadata
Interface document [I-D.ietf-cdni-metadata]).
This document also registers CDNI Payload Types [RFC7736] for the
initial capability types (see Section 6):
o Delivery Protocol (for delivering content to the end user)
Seedorf, et al. Expires November 21, 2016 [Page 8]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
o Acquisition Protocol (for acquiring content from the uCDN or
origin server)
o Redirection Mode (e.g., DNS Redirection vs. HTTP Redirection as
discussed in [RFC7336])
o CDNI Logging (i.e., supported logging fields)
o CDNI Metadata (i.e., supported Generic Metadata types)
Each payload type is prefaced with "FCI.". Updates to capability
objects MUST indicate the version of the capability object in a newly
registered payload type, e.g., by appending ".v2". Each capability
type MAY have a list of valid values. Future specifications which
define a given capability MUST define any necessary registries (and
the rules for adding new entries to the registry) for the values
advertised for a given capability type.
The "CDNI Logging record-types" registry [I-D.ietf-cdni-logging]
defines all known record types, including mandatory-to-implement
record-types Advertising support for mandatory-to-implement record-
types would be redundant. CDNs SHOULD NOT advertise support for
mandatory-to-implement record-types.
The "CDNI Logging Fields Names" registry [I-D.ietf-cdni-logging]
defines all known logging fields. Logging fields may be reused by
different record-types and be mandatory-to-implement in some record-
types, but optional in other record-types. CDNs MUST advertise
support for optional logging fields within the context of a specific
record-type. CDNs SHOULD NOT advertise support for mandatory-to-
implement logging fields, for a given record-type. The following
logging fields are defined as optional for the "cdni_http_request_v1"
record-type in the CDNI Logging Interface document
[I-D.ietf-cdni-logging]:
o s-ccid
o s-sid
The CDNI Metadata Interface document [I-D.ietf-cdni-metadata]
requires that CDNs be able to parse all the defined metadata objects,
but does not require dCDNs to support enforcement of non-structural
GenericMetadata objects. Advertising support for mandatory-to-
enforce GenericMetadata types MUST be supported. Advertising support
for non-mandatory-to-enforce GenericMetadata types SHOULD be
supported. Advertisement of non-mandatory-to-enforce GenericMetadata
MAY be necessary, e.g., to signal temporary outages and subsequent
Seedorf, et al. Expires November 21, 2016 [Page 9]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
recovery. It is expected that structural metadata will be supported
at all times.
The notion of optional types of footprint and capabilities implies
that certain implementations might not support all kinds of footprint
and capabilities. Therefore, any FCI solution protocol MUST define
how the support for optional types of footprint/capabilities will be
negotiated between a uCDN and a dCDN that use the particular FCI
protocol. In particular, any FCI solution protocol MUST specify how
to handle failure cases or non-supported types of footprint/
capabilities.
In general, a uCDN MAY ignore capabilities or types of footprints it
does not understand; in this case it only selects a suitable dCDN
based on the types of capabilities and footprint it understands.
Similarly, if a dCDN does not use an optional capability or footprint
which is, however, supported by a uCDN, this causes no problem for
the FCI functionality because the uCDN decides on the remaining
capabilities/footprint information that is being conveyed by the
dCDN.
5. Capability Advertisement Object
To support extensibility, the FCI defines a generic base object
(similar to the CDNI Metadata interface GenericMetadata object)
[I-D.ietf-cdni-metadata] to facilitate a uniform set of mandatory
parsing requirements for all future FCI objects.
Future object definitions (e.g. regarding CDNI Metadata or Logging)
will build off the base object defined here, but will be specified in
separate documents.
Note: In the following sections, the term "mandatory-to-specify" is
used to convey which properties MUST be included when serializing a
given capability object. When mandatory-to-specify is defined as
"Yes" for an individual property, it means that if the object
containing that property is included in an FCI message, then the
mandatory-to-specify property MUST also be included.
5.1. Base Advertisement Object
The FCIBase object is an abstraction for managing individual CDNI
capabilities in an opaque manner.
Property: capability-type
Description: CDNI Capability object type.
Seedorf, et al. Expires November 21, 2016 [Page 10]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
Type: FCI specific CDNI Payload type (from the CDNI Payload
Types registry [RFC7736])
Mandatory-to-Specify: Yes.
Property: capability-value
Description: CDNI Capability object.
Type: Format/Type is defined by the value of capability-type
property above.
Mandatory-to-Specify: Yes.
Property: footprints
Description: CDNI Capability Footprint.
Type: List of CDNI Footprint objects (as defined in
[I-D.ietf-cdni-metadata]).
Mandatory-to-Specify: No.
5.2. Encoding
CDNI FCI objects MUST be encoded using JSON [RFC7159] and MUST also
follow the recommendations of I-JSON [RFC7493]. FCI objects are
composed of a dictionary of (key,value) pairs where the keys are the
property names and the values are the associated property values.
The keys of the dictionary are the names of the properties associated
with the object and are therefore dependent on the specific object
being encoded (i.e., dependent on the CDNI Payload Type of the
capability or the CDNI Metadata Footprint Type of the footprint).
Likewise, the values associated with each property (dictionary key)
are dependent on the specific object being encoded (i.e., dependent
on the CDNI Payload Type of the capability or the CDNI Metadata
Footprint Type of the footprint).
Dictionary keys (properties) in JSON are case sensitive. By
convention, any dictionary key (property) defined by this document
MUST be lowercase.
5.3. Delivery Protocol Capability Object
The Delivery Protocol capability object is used to indicate support
for one or more of the protocols listed in the CDNI Metadata Protocol
Seedorf, et al. Expires November 21, 2016 [Page 11]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
Types registry (defined in the CDNI Metadata Interface document
[I-D.ietf-cdni-metadata]).
Property: delivery-protocols
Description: List of supported CDNI Delivery Protocols.
Type: List of Protocol Types (from the CDNI Metadata Protocol
Types registry [I-D.ietf-cdni-metadata])
Mandatory-to-Specify: Yes.
5.3.1. Delivery Protocol Capability Object Serialization
The following shows an example of Delivery Protocol Capability Object
Serialization, for a CDN that supports only HTTP/1.1 without TLS for
content delivery.
{
"capabilities": [
{
"capability-type": "FCI.DeliveryProtocol",
"capability-value": {
"delivery-protocols": [
"http/1.1",
]
},
"footprints": [
<Footprint objects>
]
}
]
}
5.4. Acquisition Protocol Capability Object
The Acquisition Protocol capability object is used to indicate
support for one or more of the protocols listed in the CDNI Metadata
Protocol Types registry (defined in the CDNI Metadata Interface
document [I-D.ietf-cdni-metadata]).
Property: acquisition-protocols
Description: List of supported CDNI Acquisition Protocols.
Type: List of Protocol Types (from the CDNI Metadata Protocol
Types registry [I-D.ietf-cdni-metadata])
Seedorf, et al. Expires November 21, 2016 [Page 12]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
Mandatory-to-Specify: Yes.
5.4.1. Acquisition Protocol Capability Object Serialization
The following shows an example of Acquisition Protocol Capability
Object Serialization, for a CDN that supports HTTP/1.1 with or
without TLS for content acquisition.
{
"capabilities": [
{
"capability-type": "FCI.AcquisitionProtocol",
"capability-value": {
"acquisition-protocols": [
"http/1.1",
"https/1.1"
]
},
"footprints": [
<Footprint objects>
]
}
]
}
5.5. Redirection Mode Capability Object
The Redirection Mode capability object is used to indicate support
for one or more of the modes listed in the CDNI Capabilities
Redirection Modes registry (see Section 6.2).
Property: redirection-modes
Description: List of supported CDNI Redirection Modes.
Type: List of Redirection Modes (from Section 6.2)
Mandatory-to-Specify: Yes.
5.5.1. Redirection Mode Capability Object Serialization
The following shows an example of Redirection Mode Capability Object
Serialization, for a CDN that supports only iterative (but not
recursive) redirection with HTTP and DNS.
Seedorf, et al. Expires November 21, 2016 [Page 13]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
{
"capabilities": [
{
"capability-type": "FCI.RedirectionMode",
"capability-value": {
"redirection-modes": [
"DNS-I",
"HTTP-I"
]
}
"footprints": [
<Footprint objects>
]
}
]
}
5.6. CDNI Logging Capability Object
The CDNI Logging capability object is used to indicate support for
CDNI Logging record-types, as well as CDNI Logging fields which are
marked as optional for the specified record-types
[I-D.ietf-cdni-logging].
Property: record-type
Description: Supported CDNI Logging record-type.
Type: String corresponding to an entry from the CDNI Logging
record-types registry [I-D.ietf-cdni-logging])
Mandatory-to-Specify: Yes.
Property: fields
Description: List of supported CDNI Logging fields that are
optional for the specified record-type.
Type: List of Strings corresponding to entries from the CDNI
Logging Field Names registry [I-D.ietf-cdni-logging].
Mandatory-to-Specify: No. Default is that all optional fields
are supported. Omission of this field MUST be interpreted as
"all optional fields are supported". An empty list MUST be
interpreted as "no optional fields are supported. Otherwise,
if a list of fields is provided, the fields in that list MUST
be interpreted as "the only optional fields that are
supported".
Seedorf, et al. Expires November 21, 2016 [Page 14]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
5.6.1. CDNI Logging Capability Object Serialization
The following shows an example of CDNI Logging Capability Object
Serialization, for a CDN that supports the optional Content
Collection ID logging field (but not the optional Session ID logging
field) for the "cdni_http_request_v1" record type.
{
"capabilities": [
{
"capability-type": "FCI.Logging",
"capability-value": {
"record-type": "cdni_http_request_v1",
"fields": [ "s-ccid" ]
},
"footprints": [
<Footprint objects>
]
}
]
}
The next example shows the CDNI Logging Capability Object
Serialization, for a CDN that supports all optional fields for the
"cdni_http_request_v1" record type.
{
"capabilities": [
{
"capability-type": "FCI.Logging",
"capability-value": {
"record-type": "cdni_http_request_v1"
},
"footprints": [
<Footprint objects>
]
}
]
}
5.7. CDNI Metadata Capability Object
The CDNI Metadata capability object is used to indicate support for
CDNI GenericMetadata types [I-D.ietf-cdni-metadata].
Property: metadata
Description: List of supported CDNI GenericMetadata types.
Seedorf, et al. Expires November 21, 2016 [Page 15]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
Type: List of Strings corresponding to entries from the CDNI
Payload Type registry [RFC7736]) that correspond to CDNI
GenericMetadata objects.
Mandatory-to-Specify: Yes. An empty list MUST be interpreted
as "no GenericMetadata types are supported", i.e., "only
structural metadata and simple types are supported"; otherwise,
the list must be interpreted as containing "the only
GenericMetadata types that are supported" (in addition to
structural metadata and simple types) [I-D.ietf-cdni-metadata].
5.7.1. CDNI Metadata Capability Object Serialization
The following shows an example of CDNI Metadata Capability Object
Serialization, for a CDN that supports only the SourceMetadata
GenericMetadata type (i.e., it can acquire and deliver content, but
cannot enforce and security policies, e.g., time, location, or
protocol ACLs).
{
"capabilities": [
{
"capability-type": "FCI.Metadata",
"capability-value": {
"metadata": ["MI.SourceMetadata"]
},
"footprints": [
<Footprint objects>
]
}
]
}
The next example shows the CDNI Metadata Capability Object
Serialization, for a CDN that supports only structural metadata
(i.e., it can parse metadata as a transit CDN, but cannot enforce
security policies or deliver content).
Seedorf, et al. Expires November 21, 2016 [Page 16]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
{
"capabilities": [
{
"capability-type": "FCI.Metadata",
"capability-value": {
"metadata": []
},
"footprints": [
<Footprint objects>
]
}
]
}
6. IANA Considerations
6.1. CDNI Payload Types
This document requests the registration of the following CDNI Payload
Types under the IANA CDNI Payload Type registry:
+-------------------------+---------------+
| Payload Type | Specification |
+-------------------------+---------------+
| FCI.DeliveryProtocol | RFCthis |
| | |
| FCI.AcquisitionProtocol | RFCthis |
| | |
| FCI.RedirectionMode | RFCthis |
| | |
| FCI.Logging | RFCthis |
| | |
| FCI.Metadata | RFCthis |
+-------------------------+---------------+
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
6.1.1. CDNI FCI DeliveryProtocol Payload Type
Purpose: The purpose of this payload type is to distinguish FCI
advertisement objects for supported delivery protocols
Interface: FCI
Encoding: see Section 5.3
Seedorf, et al. Expires November 21, 2016 [Page 17]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
6.1.2. CDNI FCI AcquisitionProtocol Payload Type
Purpose: The purpose of this payload type is to distinguish FCI
advertisement objects for supported acquisition protocols
Interface: FCI
Encoding: see Section 5.4
6.1.3. CDNI FCI RedirectionMode Payload Type
Purpose: The purpose of this payload type is to distinguish FCI
advertisement objects for supported redirection modes
Interface: FCI
Encoding: see Section 5.5
6.1.4. CDNI FCI Logging Payload Type
Purpose: The purpose of this payload type is to distinguish FCI
advertisement objects for supported CDNI Logging record-types and
optional CDNI Logging Field Names.
Interface: FCI
Encoding: see Section 5.6
6.1.5. CDNI FCI Metadata Payload Type
Purpose: The purpose of this payload type is to distinguish FCI
advertisement objects for supported CDNI GenericMetadata types.
Interface: FCI
Encoding: see Section 5.7
6.2. Redirection Mode Registry
The IANA is requested to create a new "CDNI Capabilities Redirection
Modes" registry in the "Content Delivery Networks Interconnection
(CDNI) Parameters" category. The "CDNI Capabilities Redirection
Modes" namespace defines the valid redirection modes that can be
advertised as supported by a CDN. Additions to the Redirection Mode
namespace conform to the "IETF Review" policy as defined in
[RFC5226].
The following table defines the initial Redirection Modes:
Seedorf, et al. Expires November 21, 2016 [Page 18]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
+------------------+----------------------------------+---------+
| Redirection Mode | Description | RFC |
+------------------+----------------------------------+---------+
| DNS-I | Iterative DNS-based Redirection | RFCthis |
| | | |
| DNS-R | Recursive DNS-based Redirection | RFCthis |
| | | |
| HTTP-I | Iterative HTTP-based Redirection | RFCthis |
| | | |
| HTTP-R | Recursive HTTP-based Redirection | RFCthis |
+------------------+----------------------------------+---------+
[RFC Editor: Please replace RFCthis with the published RFC number for
this document.]
7. Security Considerations
This specification describes the semantics for capabilities and
footprint advertisement objects across interconnected CDNs. It does
not, however, specify a concrete protocol for transporting those
objects. Specific security mechanisms can only be selected for
concrete protocols that instantiate these semantics. This document
does, however, place some high-level security constraints on such
protocols.
All protocols that implement these semantics are REQUIRED to provide
integrity and authentication services. Without authentication and
integrity, an attacker could trivially deny service by forging a
footprint advertisement from a dCDN which claims the network has no
footprint or capability. This would prevent the uCDN from delegating
any requests to the dCDN. Since a pre-existing relationship between
all dCDNs and uCDNs is assumed by CDNI, the exchange of any necessary
credentials could be conducted before the FCI interface is brought
online. The authorization decision to accept advertisements would
also follow this pre-existing relationship and any contractual
obligations that it stipulates.
All protocols that implement these semantics are REQUIRED to provide
confidentiality services. Some dCDNs are willing to share
information about their footprint or capabilities with a uCDN but not
with other, competing dCDNs. For example, if a dCDN incurs an outage
that reduces footprint coverage temporarily, that could be
information the dCDN would want to share confidentially with the
uCDN.
As specified in this document, the security requirements of the FCI
could be met by transport-layer security mechanisms coupled with
domain certificates as credentials (e.g., TLS transport for HTTP as
Seedorf, et al. Expires November 21, 2016 [Page 19]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
per [RFC2818] and [RFC7230], with usage guidance from [RFC7525])
between CDNs. There is no apparent need for further object-level
security in this framework, as the trust relationships it defines are
bilateral relationships between uCDNs and dCDNs rather than
transitive relationships.
8. References
8.1. Normative References
[I-D.ietf-cdni-logging]
Faucheur, F., Bertrand, G., Oprescu, I., and R.
Peterkofsky, "CDNI Logging Interface", draft-ietf-cdni-
logging-25 (work in progress), April 2016.
[I-D.ietf-cdni-metadata]
Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
"CDN Interconnection Metadata", draft-ietf-cdni-
metadata-16 (work in progress), April 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <http://www.rfc-editor.org/info/rfc7159>.
[RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
"Framework for Content Distribution Network
Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
August 2014, <http://www.rfc-editor.org/info/rfc7336>.
[RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493,
DOI 10.17487/RFC7493, March 2015,
<http://www.rfc-editor.org/info/rfc7493>.
8.2. Informative References
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000,
<http://www.rfc-editor.org/info/rfc2818>.
Seedorf, et al. Expires November 21, 2016 [Page 20]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
[RFC6707] Niven-Jenkins, B., Le Faucheur, F., and N. Bitar, "Content
Distribution Network Interconnection (CDNI) Problem
Statement", RFC 6707, DOI 10.17487/RFC6707, September
2012, <http://www.rfc-editor.org/info/rfc6707>.
[RFC6770] Bertrand, G., Ed., Stephan, E., Burbridge, T., Eardley,
P., Ma, K., and G. Watson, "Use Cases for Content Delivery
Network Interconnection", RFC 6770, DOI 10.17487/RFC6770,
November 2012, <http://www.rfc-editor.org/info/rfc6770>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014,
<http://www.rfc-editor.org/info/rfc7230>.
[RFC7337] Leung, K., Ed. and Y. Lee, Ed., "Content Distribution
Network Interconnection (CDNI) Requirements", RFC 7337,
DOI 10.17487/RFC7337, August 2014,
<http://www.rfc-editor.org/info/rfc7337>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <http://www.rfc-editor.org/info/rfc7525>.
[RFC7736] Ma, K., "Content Delivery Network Interconnection (CDNI)
Media Type Registration", RFC 7736, DOI 10.17487/RFC7736,
December 2015, <http://www.rfc-editor.org/info/rfc7736>.
Appendix A. Main Use Case to Consider
Focusing on a main use case that contains a simple (yet somewhat
challenging), realistic, and generally imaginable scenario can help
in narrowing down the requirements for the CDNI FCI. To this end,
the following (simplified) use case can help in clarifying the
semantics of footprint and capabilities for CDNI. In particular, the
intention of the use case is to clarify what information needs to be
exchanged on the CDNI FCI, what types of information need to be
supported in a mandatory fashion (and which can be considered
optional), and what types of information need to be updated with
respect to a priori established CDNI contracts.
Use case: A given uCDN has several dCDNs. It selects one dCDN for
delivery protocol A and footprint 1 and another dCDN for delivery
protocol B and footprint 1. The dCDN that serves delivery protocol B
has a further, transitive (level-2) dCDN, that serves delivery
protocol B in a subset of footprint 1 where the first-level dCDN
Seedorf, et al. Expires November 21, 2016 [Page 21]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
cannot serve delivery protocol B itself. What happens if
capabilities change in the transitive level-2 dCDN that might affect
how the uCDN selects a level-1 dCDN (e.g., in case the level-2 dCDN
cannot serve delivery protocol B anymore)? How will these changes be
conveyed to the uCDN? In particular, what information does the uCDN
need to be able to select a new first-level dCDN, either for all of
footprint 1 or only for the subset of footprint 1 that the transitive
level-2 dCDN served on behalf of the first-level dCDN?
Appendix B. Semantics for Footprint Advertisement
Roughly speaking, "footprint" can be defined as "ability and
willingness to serve" by a dCDN. However, in addition to simple
"ability and willingness to serve", the uCDN could want additional
information to make a dCDN selection decision, e.g., "how well" a
given dCDN can actually serve a given end user request. The "ability
and willingness" to serve SHOULD be distinguished from the subjective
qualitative measurement of "how well" it was served. One can imagine
that such additional information is implicitly associated with a
given footprint, due to contractual agreements, SLAs, business
relationships, or past perceptions of dCDN quality. As an
alternative, such additional information could also be explicitly
tagged along with the footprint.
It is reasonable to assume that a significant part of the actual
footprint advertisement will happen in contractual agreements between
participating CDNs, prior to the advertisement phase using the CDNI
FCI. The reason for this assumption is that any contractual
agreement is likely to contain specifics about the dCDN coverage
(footprint) to which the contractual agreement applies. In
particular, additional information to judge the delivery quality
associated with a given dCDN footprint might be defined in
contractual agreements, outside of the CDNI FCI. Further, one can
assume that dCDN contractual agreements about the delivery quality
associated with a given footprint will probably be based on high-
level aggregated statistics and not too detailed.
Given that a large part of footprint advertisement will actually
happen in contractual agreements, the semantics of CDNI footprint
advertisement refer to answering the following question: what exactly
still needs to be advertised by the CDNI FCI? For instance, updates
about temporal failures of part of a footprint can be useful
information to convey via the CDNI request routing interface. Such
information would provide updates on information previously agreed in
contracts between the participating CDNs. In other words, the CDNI
FCI is a means for a dCDN to provide changes/updates regarding a
footprint it has prior agreed to serve in a contract with a uCDN.
Seedorf, et al. Expires November 21, 2016 [Page 22]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
Generally speaking, one can imagine two categories of footprint to be
advertised by a dCDN:
o Footprint could be defined based on "coverage/reachability", where
coverage/reachability refers to a set of prefixes, a geographic
region, or similar boundary. The dCDN claims that it can cover/
reach 'end user requests coming from this footprint'.
o Footprint could be defined based on "resources", where resources
refers to surrogates a dCDN claims to have (e.g., the location of
surrogates/resources). The dCDN claims that 'from this footprint'
it can serve incoming end user requests.
For each of these footprint types, there are capabilities associated
with a given footprint:
o capabilities such as delivery protocol, redirection mode, and
metadata, which are supported in the coverage area for a
"coverage/reachability" defined footprint, or
o capabilities of resources, such as delivery protocol, redirection
mode, and metadata, which apply to a "resource" defined footprint.
"Resource" types of footprints are more specific than "coverage/
reachability" types of footprints, where the actual coverage/
reachability are extrapolated from the resource location (e.g.,
netmask applied to resource IP address to derive IP-prefix). The
specific methods for extrapolating coverage/reachability from
resource location are beyond the scope of this document. In the
degenerate case, the resource address could be specified as a
coverage/reachability type of footprint, in which case no
extrapolation is necessary. Resource types of footprints could
expose the internal structure of a CDN network which could be
undesirable. As such, the resource types of footprints are not
considered mandatory to support for CDNI.
Footprints can be viewed as constraints for delegating requests to a
dCDN: A dCDN footprint advertisement tells the uCDN the limitations
for delegating a request to the dCDN. For IP prefixes or ASN(s), the
footprint signals to the uCDN that it should consider the dCDN a
candidate only if the IP address of the request routing source falls
within the prefix set (or ASN, respectively). The CDNI
specifications do not define how a given uCDN determines what address
ranges are in a particular ASN. Similarly, for country codes a uCDN
should only consider the dCDN a candidate if it covers the country of
the request routing source. The CDNI specifications do not define
how a given uCDN determines the country of the request routing
source. Multiple footprint constraints are additive: the
Seedorf, et al. Expires November 21, 2016 [Page 23]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
advertisement of different types of footprint narrows the dCDN
candidacy cumulatively.
Independent of the exact type of a footprint, a footprint might also
include the connectivity of a given dCDN to other CDNs that are able
to serve content to users on behalf of that dCDN, to cover cases with
cascaded CDNs. Further, the dCDN needs to be able to express its
footprint to an interested uCDN in a comprehensive form, e.g., as a
data set containing the complete footprint. Making incremental
updates, however, to express dynamic changes in state is also
desirable.
Appendix C. Semantics for Capabilities Advertisement
In general, the dCDN needs to be able to express its general
capabilities to the uCDN. These general capabilities could express
if the dCDN supports a given service, for instance, HTTP vs HTTPS
delivery. Furthermore, the dCDN needs to be able to express
particular capabilities for the delivery in a particular footprint
area. For example, the dCDN might in general offer HTTPS but not in
some specific areas, either for maintenance reasons or because the
surrogates covering this particular area cannot deliver this type of
service. Hence, in certain cases footprint and capabilities are tied
together and cannot be interpreted independently from each other. In
such cases, i.e., where capabilities need to be expressed on a per
footprint basis, it could be beneficial to combine footprint and
capabilities advertisement.
A high-level and very rough semantic for capabilities is thus the
following: Capabilities are types of information that allow a uCDN to
determine if a dCDN is able (and willing) to accept (and properly
handle) a delegated content request. In addition, Capabilities are
characterized by the fact that this information can change over time
based on the state of the network or surrogates.
At a first glance, several broad categories of capabilities seem
useful to convey via an advertisement interface, however, advertising
capabilities that change highly dynamically (e.g., real-time delivery
performance metrics, CDN resource load, or other highly dynamically
changing QoS information) is beyond the scope for CDNI FCI. First,
out of the multitude of possible metrics and capabilities, it is hard
to agree on a subset and the precise metrics to be used. Second, it
seems infeasible to specify such highly dynamically changing
capabilities and the corresponding metrics within a reasonable time-
frame.
Useful capabilities refer to information that does not change highly
dynamically and which in many cases is absolutely necessary to decide
Seedorf, et al. Expires November 21, 2016 [Page 24]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
on a particular dCDN for a given end user request. For instance, if
an end user request concerns the delivery of a video file with a
certain protocol, the uCDN needs to know if a given dCDN has the
capability of supporting this delivery protocol.
Similar to footprint advertisement, it is reasonable to assume that a
significant part of the actual (resource) capabilities advertisement
will happen in contractual agreements between participating CDNs,
i.e., prior to the advertisement phase using the CDNI FCI. The role
of capability advertisement is hence rather to enable the dCDN to
update a uCDN on changes since a contract has been set up (e.g., in
case a new delivery protocol is suddenly being added to the list of
supported delivery protocols of a given dCDN, or in case a certain
delivery protocol is suddenly not being supported anymore due to
failures). Capabilities advertisement thus refers to conveying
information to a uCDN about changes/updates of certain capabilities
with respect to a given contract.
Given these semantics, it needs to be decided what exact capabilities
are useful and how these can be expressed. Since the details of CDNI
contracts are not known at the time of this writing (and the CDNI
interface are better off being agnostic to these contracts anyway),
it remains to be seen what capabilities will be used to define
agreements between CDNs in practice. One implication for
standardization could be to initially only specify a very limited set
of mandatory capabilities for advertisement and have on top of that a
flexible data model that allows exchanging additional capabilities
when needed. Still, agreement needs to be found on which
capabilities (if any) will be mandatory among CDNs.
It is not feasible to enumerate all the possible options for the
mandatory capabilities listed above (e.g., all the potential delivery
protocols or metadata options) or anticipate all the future needs for
additional capabilities. It would be unreasonable to burden the CDNI
FCI specification with defining each supported capability. Instead,
the CDNI FCI specification should define a generic protocol for
conveying any capability information (e.g. with common encoding,
error handling, and security mechanism; further requirements for the
CDNI FCI Advertisement Interface are listed in [RFC7337]).
Appendix D. Acknowledgment
Jan Seedorf is partially supported by the GreenICN project (GreenICN:
Architecture and Applications of Green Information Centric
Networking), a research project supported jointly by the European
Commission under its 7th Framework Program (contract no. 608518) and
the National Institute of Information and Communications Technology
(NICT) in Japan (contract no. 167). The views and conclusions
Seedorf, et al. Expires November 21, 2016 [Page 25]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
contained herein are those of the authors and should not be
interpreted as necessarily representing the official policies or
endorsements, either expressed or implied, of the GreenICN project,
the European Commission, or NICT.
Martin Stiemerling provided initial input to this document and
valuable comments to the ongoing discussions among the authors of
this document. Thanks to Francois Le Faucheur and Scott Wainner for
providing valuable comments and suggestions to the text.
Authors' Addresses
Jan Seedorf
NEC
Kurfuerstenanlage 36
Heidelberg 69115
Germany
Phone: +49 6221 4342 221
Fax: +49 6221 4342 155
Email: seedorf@neclab.eu
Jon Peterson
NeuStar
1800 Sutter St Suite 570
Concord CA 94520
USA
Email: jon.peterson@neustar.biz
Stefano Previdi
Cisco Systems
Via Del Serafico 200
Rome 0144
Italy
Email: sprevidi@cisco.com
Seedorf, et al. Expires November 21, 2016 [Page 26]
Internet-Draft CDNI RR Footprint/Capabilities Semantics May 2016
Ray van Brandenburg
TNO
Brassersplein 2
Delft 2612CT
The Netherlands
Phone: +31-88-866-7000
Email: ray.vanbrandenburg@tno.nl
Kevin J. Ma
Ericsson
43 Nagog Park
Acton, MA 01720
USA
Phone: +1 978-844-5100
Email: kevin.j.ma@ericsson.com
Seedorf, et al. Expires November 21, 2016 [Page 27]
