wdiff rfc9138.original rfc9138.txt

ICN

Internet Research Group Task Force (IRTF) J. Hong
Internet-Draft
Request for Comments: 9138 T. You
Intended status:
Category: Informational ETRI
Expires: 29 January 2022
ISSN: 2070-1721 L. Dong
C. Westphal
Futurewei Technologies Inc.
B. Ohlman
Ericsson
28 July
November 2021

Design Considerations for Name Resolution Service in ICN
draft-irtf-icnrg-nrs-requirements-06 Information-Centric
Networking (ICN)

Abstract

This document provides the functionalities and design considerations
for a Name Resolution Service (NRS) in ICN. An Information-Centric Networking
(ICN). The purpose of an NRS in ICN is to translate an object name
into some other information such as a locator, another name, etc. for forwarding in
order to forward the object request. This document is a product of
the Information-Centric Networking Research Group (ICNRG).

Status of This Memo

This Internet-Draft document is submitted in full conformance with not an Internet Standards Track specification; it is
published for informational purposes.

This document is a product of the
provisions Internet Research Task Force
(IRTF). The IRTF publishes the results of BCP 78 Internet-related research
and BCP 79.

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This Internet-Draft will expire on 29 January 2022.
https://www.rfc-editor.org/info/rfc9138.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Name Resolution Service in ICN . . . . . . . . . . . . . . . 4
2.1. Explicit name resolution approach . . . . . . . . . . . . 4 Name Resolution Approach
2.2. Name-based routing approach . . . . . . . . . . . . . . . 4 Name-Based Routing Approach
2.3. Hybrid approach . . . . . . . . . . . . . . . . . . . . . 5 Approach
2.4. Comparisons of name resolution approaches . . . . . . . . 5 Name Resolution Approaches
3. Functionalities of NRS in ICN . . . . . . . . . . . . . . . . 6
3.1. Support heterogeneous name types . . . . . . . . . . . . 7 Heterogeneous Name Types
3.2. Support producer mobility . . . . . . . . . . . . . . . . 8 Producer Mobility
3.3. Support scalable routing system . . . . . . . . . . . . . 9 Scalable Routing System
3.4. Support off-path caching . . . . . . . . . . . . . . . . 10 Off-Path Caching
3.5. Support nameless object . . . . . . . . . . . . . . . . . 10 Nameless Object
3.6. Support manifest . . . . . . . . . . . . . . . . . . . . 11 Manifest
3.7. Support metadata . . . . . . . . . . . . . . . . . . . . 11 Metadata
4. Design considerations Considerations for NRS in ICN . . . . . . . . . . . . 11
4.1. Resolution response time . . . . . . . . . . . . . . . . 11 Response Time
4.2. Response accuracy . . . . . . . . . . . . . . . . . . . . 12 Accuracy
4.3. Resolution guarantee . . . . . . . . . . . . . . . . . . 12 Guarantee
4.4. Resolution fairness . . . . . . . . . . . . . . . . . . . 12 Fairness
4.5. Scalability . . . . . . . . . . . . . . . . . . . . . . . 13
4.6. Manageability . . . . . . . . . . . . . . . . . . . . . . 14
4.7. Deployed system . . . . . . . . . . . . . . . . . . . . . 14 System
4.8. Fault tolerance . . . . . . . . . . . . . . . . . . . . . 14 Tolerance
4.9. Security and privacy . . . . . . . . . . . . . . . . . . 14 Privacy
4.9.1. Confidentiality . . . . . . . . . . . . . . . . . . . 14
4.9.2. Authentication . . . . . . . . . . . . . . . . . . . 15
4.9.3. Integrity . . . . . . . . . . . . . . . . . . . . . . 15
4.9.4. Resiliency and availability . . . . . . . . . . . . . 15 Availability
5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 16
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
8.1. Normative References . . . . . . . . . . . . . . . . . . 16
8.2. Informative References . . . . . . . . . . . . . . . . . 16
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19

1. Introduction

The current Internet is based upon a host-centric networking
paradigm, where hosts are identified with IP addresses and
communication is possible between any pair of hosts. Thus,
information in the current Internet is identified by the name of the
host (or server) where the information is stored. In contrast to host-
centric
host-centric networking, the primary communication objects in Information-
centric networking
Information-Centric Networking (ICN) are the named data objects (NDOs)
(NDOs), and they are uniquely identified by location-independent
names. Thus, ICN aims for the efficient dissemination and retrieval
of NDOs at a global scale, scale and has been identified and acknowledged as
a promising technology for a future Internet architecture to overcome
the limitations of the current Internet Internet, such as scalability and
mobility [Ahlgren] [Xylomenos]. ICN also has emerged as a candidate
architecture in the IoT Internet of Things (IoT) environment since IoT
focuses on data and information [Baccelli] [Amadeo] [Quevedo]
[Amadeo2] [ID.Zhang2].

Since naming data independently from its current location (where it
is stored) is a primary concept of ICN, how to find any NDO using a
location-independent name is one of the most important design
challenges in ICN. Such ICN routing may comprise three steps
[RFC7927]:

(1) Name resolution: matches/translates a content name to the
locator of the content producer or source that can provide the
content.

(2) Content request routing: routes the content request towards the
content's location either based either on its name or locator.

(3) Content delivery: transfers the content to the requester.

Among the three steps of ICN routing, this document investigates only
the name resolution step step, which translates a content name to the
content locator. In addition, this document covers various possible
types of name resolution in ICN such as one name to another name,
name to locator, name to manifest, name to metadata, etc.

The focus of this document is a Name Resolution Service (NRS) itself
as a service or a system in ICN ICN, and it provides the functionalities
and the design considerations for an NRS in ICN as well as the
overview of the NRS approaches in ICN. On the other hand, its
companion document [NRSarch] describes considerations from the
perspective of the ICN architecture and routing system when using an
NRS in ICN.

This document represents the consensus of the Information-Centric
Networking Research Group (ICNRG). It has been reviewed extensively
by the Research Group (RG) members who are actively involved in the
research and development of the technology covered by this document.
It is not an IETF product and is not a standard.

2. Name Resolution Service in ICN

A Name Resolution Service (NRS) in ICN is defined as the service that
provides the name resolution function for translating an object name
into some other information such as a locator, another name,
metadata, next hop next-hop info, etc. that is used for forwarding the object
request. In other words, an NRS is a service that can be provided by
the ICN infrastructure to help a consumer to reach a specific piece of
information (or named data object). The consumer provides an NRS
with a persistent name name, and the NRS returns a name or locator (or
potentially multiple names and locators) that can reach a current
instance of the requested object.

The name resolution is a necessary process in ICN routing routing, although
the name resolution either can be separated from the content request
routing as an explicit process or can be integrated with the content
request routing as an implicit process. The former is referred to as
explicit
an "explicit name resolution approach, approach", and the latter is referred to
as name-
based a "name-based routing approach approach" in this document.

2.1. Explicit name resolution approach Name Resolution Approach

An NRS could take the explicit name resolution approach to return the
locators of the content to the client, which will be used by the
underlying network as the identifier to route the client's request to
one of the producers or to a copy of the content. There are several
ICN projects that use the explicit name resolution approach approach, such as
DONA
Data-Oriented Network Architecture (DONA) [Koponen], PURSUIT
[PURSUIT], NetInf Network of Information (NetInf) [SAIL], MobilityFirst
[MF], IDNet [Jung], etc. In addition, the explicit name resolution
approach has been allowed for 5G control planes [SA2-5GLAN].

2.2. Name-based routing approach Name-Based Routing Approach

An NRS could take the name-based routing approach, which integrates
the
name resolution with the content request message routing as in
NDN [NDN]/CCNx Named Data
Networking / Content-Centric Networking (NDN/CCNx) [NDN] [CCNx].

In the case that cases where the content request also specifies the reverse path,
as in NDN/CCNx, the name resolution mechanism also derives the
routing path for the data. This adds a requirement on to the name
resolution service to propagate the request in a way that is
consistent with the subsequent data forwarding. Namely, the request
must select a path for the data based upon finding a copy of the content,
content but also properly delivering the data.

2.3. Hybrid approach Approach

An NRS could also take hybrid approach. For instance, it can attempt
the name-based routing approach first. If this fails at a certain
router, the router can go back to the explicit name resolution
approach. The hybrid NRS approach also works the other way around around:
first by performing explicit name resolution first to find the locators of
routers. And
routers, then it can carry out the name-based by routing approach
of the client's request. request using the name-based
routing approach.

A hybrid approach would combine name resolution over a subset of
routers on the path with some tunneling in between (say, across an
administrative domain) so that only a few of the nodes in the ICN
network perform name resolution in the name-based routing approach.

2.4. Comparisons of name resolution approaches Name Resolution Approaches

The following compares the explicit name resolution and the name-
based routing approaches for in several aspects:

* Overhead due to the maintenance of the content location: The
content reachability is dynamic and includes new content being
cached or content being expired from a cache, content producer
mobility, etc. Maintaining a consistent view of the content
location across the network requires some overhead that differs
for the name resolution approaches. The name-based routing
approach may require flooding parts of the network for update
propagation. In the worst case, the name-based routing approach
may flood the whole network (but mitigating techniques may be used
to scope the flooding). However, the explicit name resolution
approach only requires updating propagation in part of the name
resolution system (which could be an overlay with a limited number
of nodes).

* Resolution capability: The explicit name resolution approach, if
designed and deployed with sufficient robustness, can offer at
least weak guarantees that resolution will succeed for any content
name in the network if it is registered to the name resolution
overlay. In the name-based routing approach, content resolution
depends on the flooding scope of the content names (i.e. (i.e., content
publishing message and the resulting name-based routing tables).
For example, when a content is cached, the router may only notify
this information to
its direct neighbors. neighbors of this information. Thus, only those
neighboring routers can build a named based name-based entry for this cached
content. But if the neighboring routers continue to propagate
this information, the other nodes are able to direct to this
cached copy as well.

* Node failure impact: Nodes involved in the explicit name
resolution approach are the name resolution overlay servers (e.g.
Resolution Handlers (e.g.,
resolution handlers in DONA), while the nodes involved in the
name-based routing approach are routers which that route messages based
on the name-based routing tables (e.g. (e.g., NDN routers). Node
failures in the explicit name resolution approach may cause some
content request routing to fail even though the content is
available. This problem does not exist in the name-based routing
approach because other alternative paths can be discovered to
bypass the failed ICN routers, given the assumption that the
network is still connected.

* Maintained databases: The storage usage for the explicit name
resolution approach is different from that of the name-based
routing approach. The explicit name resolution approach typically
needs to maintain two databases: name to locator name-to-locator mapping in the
name resolution overlay and routing tables in the routers on the
data forwarding plane. The name-based routing approach needs to
maintain only the name-based routing tables.

Additionally, some other intermediary step may be included in the
name resolution, namely resolution -- namely, the mapping of one name to other names, names --
in order to facilitate the retrieval of named content, content by way of a
manifest [Westphal] [Mosko]. [RFC8569]. The manifest is resolved using one of
the two above approaches, and it may include further mapping of names
to content and location. The steps for name resolution then become:
first become
the following: first, translate the manifest name into a location of
a copy of the
manifest; the manifest manifest, which includes further names of the content
components,
components and potentially locations for the content. The content
is content, then retrieved retrieve
the content by using these names and/or location, potentially
resulting in additional name resolutions.

Thus, no matter which approach is taken by an NRS in ICN, the name
resolution is the essential function that shall be provided by the
ICN infrastructure.

3. Functionalities of NRS in ICN

This section presents the functionalities of an NRS in ICN.

3.1. Support heterogeneous name types Heterogeneous Name Types

In ICN, a name is used to identify the data object and is bound to it
[RFC7927]. ICN requires uniqueness and persistency of the name of
the data object to ensure the reachability of the object within a
certain scope. There are heterogeneous approaches to designing ICN
naming schemes [Bari]. Ideally, a name can include any form of
identifier, which can be flat or hierarchical, and human readable or non-
readable.

Although there are diverse types of naming schemes proposed in the
literature, they all need to provide basic functions for identifying
a data object, supporting named data lookup lookup, and routing. An NRS may
combine the better aspects of different schemes. Basically, an NRS
should be able to support a generic naming schema so that it can
resolve any type of content name, irrespective of whether it is flat,
hierarchical, attribute-based attribute based, or anything else.

In PURSUIT [PURSUIT], names are flat flat, and the rendezvous functions
are defined for an NRS, which is implemented by a set of Rendezvous Nodes rendezvous
nodes (RNs), known as the Rendezvous Network rendezvous network (RENE). Thus, a name
consists of a sequence of scope IDs IDs, and a single rendezvous ID is
routed by the RNs in RENE. Thus, PURSUIT decouples name resolution
and data routing, where the NRS is performed by the RENE.

In MobilityFirst [MF], a name called known as a Global "Global Unique IDentifier
(GUID) Identifier
(GUID)", derived from a human-readable name via a global naming service
service, is a flat typed 160-bits 160-bit string with self-certifying
properties. Thus, MobilityFirst defines a Global Name Resolution
Service (GNRS) (GNRS), which resolves GUIDs to network addresses and
decouples name resolution and data routing similarly to PURSUIT.

In NetInf [Dannewitz], information objects are named using ni-naming Named
Information (NI) names [RFC6920], which consist of an authority part
and digest part (content hash). The ni NI names can be flat as the
authority part is optional. Thus, the NetInf architecture also
includes a Name Resolution System (NRS) (NRS), which can be used to resolve ni-names
NI names to addresses in an underlying routable network layer.

In NDN [NDN] and CCNx [CCNx], names are hierarchical and may be
similar to URLs. Each name component can be anything, including a
human-readable string or a hash value. NDN/CCNx adopts the name-
based routing approach. The NDN router forwards the request by doing
the longest-match lookup in the Forwarding Information Base (FIB)
based on the content name name, and the request is stored in the Pending
Interest Table (PIT).

3.2. Support producer mobility Producer Mobility

ICN natively inherently supports mobility management. by consumers. Namely, consumer or
client mobility is handled by re-requesting the content in case the
mobility event (say, handover) occurred before receiving the
corresponding content from the network. Since ICN can ensure that
content reception continues without any disruption in ICN
applications, seamless mobility from the consumer's point of view can
be easily supported.

However, producer mobility does not emerge naturally from the ICN
forwarding model as does consumer mobility. If a producer moves into
a different network location or a different name domain, which is
assigned by another authoritative publisher, it would be difficult
for the mobility management to update RIB Routing Information Base (RIB)
and FIB entries in ICN routers with the new forwarding path in a very
short time. Therefore, various ICN architectures in the literature
have proposed
to adopt adopting an NRS to achieve the producer or publisher
mobility, where the NRS can be implemented in different ways such as
rendezvous points and/or overlay mapping systems.

In NDN [Zhang2], for producer mobility support, rendezvous mechanisms
have been proposed to build interests interest rendezvous (RV) with data
generated by a mobile producer (MP). This can be classified into two
approaches: chase mobile producer; producer and rendezvous data. Regarding MP
chasing, rendezvous acts as a mapping service that provides the
mapping from the name of the data produced by the MP to the name of
the MP's current point of attachment (PoA). Alternatively, the RV
serves as a home agent as in IP mobility support, so the RV enables
the consumer's interest Interest message to tunnel towards the MP at the PoA.
Regarding rendezvous data, the solution involves moving the data
produced by the MP to a data depot instead of forwarding interest Interest
messages. Thus, a consumer's interest Interest message can be forwarded to
stationary place as called data rendezvous, a "data rendezvous", so it would either
return the data or fetch it using another mapping solution.
Therefore, RV or other mapping functions are in the role of an NRS in
NDN.

In [Ravindran], forwarding-label the forwarding label (FL) object is referred used to enable
identifier (ID) and locator (LID) namespaces to be split in ICN.
Generally, IDs are managed by applications, while locators are
managed by a network administrator, administrator so that IDs are mapping mapped to
heterogeneous name schemes and LIDs are mapping mapped to the network domains
or to specific network elements. Thus, the proposed FL object acts
as a locator (LID) and provides the flexibility to forward Interest
messages through a mapping service between IDs and LIDs. Therefore,
the mapping service in control plane infrastructure can be considered
as an NRS in this draft.

In MobilityFirst [MF], both consumer and publisher mobility can be
primarily handled by the global name resolution service (GNRS) (GNRS), which
resolves GUIDs to network addresses. Thus, the GNRS must be updated
for mobility support when a network attached network-attached object changes its point
of attachment, which differs from NDN/CCNx.

In NetInf [Dannewitz], mobility is handled by an NRS in a very
similar way to MobilityFirst.

Besides the consumer and producer mobility, ICN also has to face faces challenges
to support the other dynamic features such as multi-
homing, multi-homing,
migration, and replication of named resources such as content,
devices, and services. Therefore, an NRS can help to support these
dynamic features.

3.3. Support scalable routing system Scalable Routing System

In ICN, the name of data objects is used for routing by either a name
resolution step or a routing table lookup. Thus, routing information
for each data object should be maintained in the routing base, such
as Routing Information Base (RIB) RIB and Forwarding Information Base
(FIB). FIB. Since the number of data objects would be very
large, the size of information bases would be significantly larger as
well [RFC7927].

The hierarchical namespace used in CCNx [CCNx] and NDN [NDN]
architectures reduces the size of these tables through name
aggregation and improves the scalability of the routing system. A
flat naming scheme, on the other hand, would aggravate the
scalability problem of the routing system. The non-aggregated name
prefixes injected to into the Default Route Free Zone (DFZ) of ICN would
create a more serious scalability problem when compared to the
scalability issues of the IP routing system. Thus, an NRS may play
an important role in the reduction of the routing scalability problem
regardless of the types of namespaces.

In [Afanasyev], in order to address the routing scalability problem
in NDN's DFZ, a well-known concept of Map-and-Encap called "map-and-encap" is applied
to provide a simple and secure namespace mapping solution. In the
proposed map-and-encap design, data whose name prefixes do not exist
in the DFZ forwarding table can be retrieved by a distributed mapping
system called NDNS, which maintains and lookups looks up the mapping
information from a name to its globally routed prefixes, where NDNS
is a kind of an NRS.

3.4. Support off-path caching Off-Path Caching

Caching in-network is considered to be a basic architectural
component of an ICN architecture. It may be used to provide a level
of Quality-of-Service quality-of-service (QoS) experience to users, users to reduce the overall
network traffic, to prevent network congestion and Denial-of-
Service denial-of-service
(DoS) attacks attacks, and to increase availability. Caching approaches can
be categorized into off-path caching and on-path caching based on the
location of caches in relation to the forwarding path from the
original server to the consumer. Off-path caching, also referred to
as content replication "content replication" or content storing, "content storing", aims to replicate
content within a network in order to increase availability,
regardless of the relationship of the location to the forwarding
path. Thus, finding off-path cached objects is not trivial in name-
based routing of ICN. In order to support off-path caches, replicas
are usually advertised into a name-based routing system or into an
NRS.

In [Bayhan], an NRS is used to find off-path copies in the network,
which may not be accessible via name-based routing mechanisms. Such
a capability can be helpful for an Autonomous System (AS) to avoid
the costly inter-AS traffic for external content more, to yield
higher bandwidth efficiency for intra-AS traffic, and to decrease the
data access latency for a pleasant user experience.

3.5. Support nameless object Nameless Object

In CCNx 1.0 [Mosko2], the concept of a "Nameless Objects" that are Object", which is a
Content Object without a Name name, is introduced to provide a means to
move Content content between storage replicas without having to rename or re-
sign the content objects Content Objects for the new name. Nameless Objects can be
addressed by the ContentObjectHash that ContentObjectHash, which is to restrict Content
Object matching by using a SHA-256 hash.

An Interest message would still carry a Name name and a ContentObjectHash,
where a Name name is used for routing, while a ContentObjectHash is used
for matching. However, on the reverse path, if the Content Object's
name is missing, it is a "Nameless Object" and only matches against
the ContentObjectHash. Therefore, a consumer needs to resolve the
proper name and hashes through an outside system, which can be
considered as an NRS.

3.6. Support manifest Manifest

For collections of data objects which that are organized as large and file file-
like contents [FLIC], manifests are used as data structures to
transport this information. Thus, manifests may contain hash digests
of signed content objects Content Objects or other manifests, manifests so that large content
objects which Content
Objects that represent a large piece of application data can be
collected by using such a manifest.

In order to request content objects, Content Objects, a consumer needs to know a
manifest root name to acquire the manifest. In the case of FLIC, File-Like
ICN Collections (FLIC), a manifest name can be represented by a
nameless root manifest, manifest so that an outside system such as an NRS may
be involved to give this information to the consumer.

3.7. Support metadata Metadata

When resolving the name of a content object, Content Object, NRS could return a rich
set of metadata in addition to returning a locator. The metadata
could include alternative object locations, supported object transfer
protocol(s), caching policy, security parameters, data format, hash
of object data, etc. The consumer could use this metadata for the
selection of object transfer protocol, security mechanism, egress
interface, etc. An example of how metadata can be used in this way
is provided by the NEO Networked Object (NEO) ICN architecture [NEO].

4. Design considerations Considerations for NRS in ICN

This section presents the design considerations for NRS in ICN.

4.1. Resolution response time Response Time

The name resolution process should provide a response within a
reasonable amount of time. The response should be either a proper
mapping of the name to a copy of the content, content or an error message
stating that no such object exists. If the name resolution does not
map to a location, the system may not issue any response, and the
client should set a timer when sending a request, request so as to consider
the resolution incomplete when the timer expires.

The acceptable response delay could be of the order of a round trip round-trip
time between the client issuing the request and the NRS servers that
provides
provide the response. While this RTT may vary greatly depending on
the proximity between the two end points, some upper bound need needs to
be used. Especially, Especially in some delay-sensitive scenarios such as
industrial Internet and telemedicine, the upper bound of the response
delay must be guaranteed.

The response time includes all the steps of the resolution, including
potentially a hop-by-hop resolution or a hierarchical forwarding of
the resolution request.

4.2. Response accuracy Accuracy

An NRS must provide an accurate response, namely response -- namely, a proper binding
of the requested name (or prefix) with a location. The response can
be either a (prefix, location) pair, pair or the actual forwarding of a
request to a node holding the content, which is then transmitted in
return.

An NRS must provide an up-to-date response, namely response -- namely, an NRS should
be updated within a reasonable time when new copies of the content
are being stored in the network. While every transient cache addition/
eviction
addition/eviction should not trigger an NRS update, some origin
servers may move and require the NRS to be updated.

An NRS must provide mechanisms to update the mapping of the content
with its location. Namely, an NRS must provide a mechanism for a
content provider to add new content, revoke old/dated/obsolete
content, and modify existing content. Any content update should then
be propagated through the NRS system within reasonable delay.

Content that is highly mobile may require to specify specifying some type of
anchor that is kept at the NRS, NRS instead of the content location.

4.3. Resolution guarantee Guarantee

An NRS must ensure that the name resolution is successful with high
probability if the name matching name-matching content exists in the network,
regardless of its popularity and the number of cached copies existing
in the network. As per Per Section 4.1, some resolution resolutions may not occur in a
timely manner. However, the probability of such an event should be
minimized. The NRS system may provide a probability (say, five 9s, (five 9s or five sigmas
sigmas, for instance) that a resolution will be satisfied.

4.4. Resolution fairness Fairness

An NRS could provide this service for all content in a fair manner,
independently of the specific content properties (content producer,
content popularity, availability of copies, content format, etc.).
Fairness may be defined as a per request per-request delay to complete the NRS
steps that is not agnostic to the properties of the content itself.
Fairness may be defined as well as the number of requests answered
per unit of time.

However, it is notable that content (or their associated producer)
may request a different level of QoS from the network (see [RFC9064] [RFC9064],
for instance), and this may include the NRS as well, in which case
considerations of fairness may be restricted to content within the
same class of service.

4.5. Scalability

The NRS system must scale up to support a very large user population
(including human users as well as machine-to-machine communications).
As an idea of the scale, it is expected that 50 billion devices will
be connected in 2025 (per ITU projections). The system must be able
to respond to a very large number of requests per unit of time.
Message forwarding and processing, routing table building-up buildup, and name
records
record propagation must be efficient and scalable.

The NRS system must scale up with the number of pieces of content
(content names) and should be able to support a content catalog that
is extremely large. Internet traffic is of the order of the zettabytes
per year (10^21 bytes). Since NRS is associated with actual traffic,
the number of pieces of content should scale with the amount of
traffic. Content size may vary from a few bytes to several GB, so
the NRS should be expected scale up to a catalog of the size of 10^21
in the near future, and larger beyond.

The NRS system must be able to scale up, namely up -- namely, to add NRS servers
to the NRS system, system in a way that is transparent to the users. Addition The
addition of a new server should have a limited negative impact on the
other NRS servers (or should have a negative impact on only a small
subset of the NRS servers). The impact of adding new servers may
induce some overhead at the other servers to rebuild a hierarchy or
to exchange messages to include the new server within the service.
Further, data may be shared among the new servers, servers for load balancing
or tolerance to failure. These steps should not disrupt the service
provided by the NRS and should in the long run improve the quality of the
service. service in
the long run.

The NRS system may support access from a heterogeneity of connection
methods and devices. In particular, the NRS system may support
access from constrained devices devices, and interactions with the NRS system
would not be too costly. An IoT node node, for instance instance, should be able
to access the NRS system as well as a more powerful node.

The NRS system should scale up in its responsiveness to the increased
request rate that is expected from applications such as IoT or M2M,
machine-to-machine (M2M), where data is being frequently generated
and/or frequently requested.

4.6. Manageability

The NRS system must be manageable since some parts of the system may
grow or shrink dynamically and an NRS system node may be added or
deleted frequently.

The NRS system may support an NRS management layer that allows for
adding or subtracting NRS nodes. In order to infer the circumstance,
the management layer can measure the network status.

4.7. Deployed system System

The NRS system must be deployable since deployability is important
for a real-world system. The NRS system must be deployable in
network edges and cores so that the consumers as well as ICN routers
can perform name resolution in a very low latency.

4.8. Fault tolerance Tolerance

The NRS system must ensure resiliency in the event of NRS server
failures. The failure of a small subset of nodes should not impact
the NRS performance significantly.

After an NRS server fails, the NRS system must be able to recover
and/or restore the name records stored in the NRS server.

4.9. Security and privacy Privacy

On utilizing an NRS in ICN, there are some security considerations
for the NRS servers/nodes and name mapping records stored in the NRS
system. This subsection describes them.

4.9.1. Confidentiality

The name mapping records in the NRS system must be assigned with
proper access rights such that the information contained in the name
mapping records would not be revealed to unauthorized users.

The NRS system may support access control for certain name mapping
records. Access control can be implemented with a reference monitor
that uses client authentication, so only users with appropriate
credentials can access these records, and they are not shared with
unauthorized users. Access control can also be implemented by
encryption-based techniques using control of keys to control the
propagations of the mappings.

The NRS system may support obfuscation and/or encryption mechanisms
so that the content of a resolution request may not be accessible by
third parties outside of the NRS system.

The NRS system must keep confidentiality to prevent sensitive name
mapping records from being reached by unauthorized data requesters.
This is more required in IoT environments where a lot of sensitive
data is produced.

The NRS system must also keep confidentiality of meta-data metadata as well as
NRS usage to protect the privacy of the users. For instance, a
specific user's NRS requests should not be shared outside the NRS
system (with the exception of legal intercept).

4.9.2. Authentication

* NRS server authentication: Authentication of the new NRS servers/
nodes that want to be registered with the NRS system must be
required so that only authenticated entities can store and update
name mapping records. The NRS system should detect an attacker
attempting to act as a fake NRS server to cause service disruption
or manipulate name mapping records.

* Producer authentication: The NRS system must support
authentication of the content producers to ensure that
update/addition/removal of name mapping records requested by
content producers are actually valid and that content producers
are authorized to modify (or revoke) these records or add new
records.

* Mapping record authentication: The NRS should verify new mapping
records that are being registered so that it cannot be polluted
with falsified information or invalid records.

4.9.3. Integrity

The NRS system must be prevented protected from malicious users attempting to
hijack or corrupt the name mapping records.

4.9.4. Resiliency and availability Availability

The NRS system should be resilient against denial of service denial-of-service attacks
and other common attacks to isolate the impact of the attacks and
prevent collateral damage to the entire system. Therefore, if a part
of the NRS system fails, the failure should only affect a local
domain. And fast recovery mechanisms need to be in place to bring
the service back to normal.

5. Conclusion

ICN routing may comprise three steps: name resolution, content
request routing, and content delivery. This document investigates
the name resolution step, which is the first and most important to be
achieved for ICN routing to be successful. A Name Resolution Service
(NRS) in ICN is defined as the service that provides such a function
of name resolution for translating an object name into some other
information such as a locator, another name, metadata, next hop next-hop info,
etc. that is used for forwarding the object request.

This document classifies and analyzes the NRS approaches according to
whether the name resolution step is separated from the content
request routing as an explicit process or not. This document also
explains the NRS functions used to support heterogeneous name types,
producer mobility, scalable routing system, off-path caching,
nameless object, manifest, and metadata. Finally, this document
presents design considerations for NRS in ICN, which include
resolution response time and accuracy, resolution guarantee,
resolution fairness, scalability, manageability, deployed system, and
fault tolerance.

6. IANA Considerations

There are

This document has no IANA considerations related to this document. actions.

7. Security Considerations

A discussion of security guidelines was is provided in section Section 4.9.

8. References

8.1. Normative References

[RFC7927] Kutscher, D., Ed., Eum, S., Pentikousis, K., Psaras, I.,
Corujo, D., Saucez, D., Schmidt, T., and M. Waehlisch,
"Information-Centric Networking (ICN) Research
Challenges", RFC 7927, DOI 10.17487/RFC7927, July 2016,
<https://www.rfc-editor.org/info/rfc7927>.

8.2. Informative References

[Afanasyev]
Afanasyev, A. et al., "SNAMP: Secure Namespace Mapping to
Scale NDN Forwarding", 2015 IEEE Conference on Computer
Communications Workshops,
DOI 10.1109/INFCOMW.2015.7179398, April 2015,
<https://doi.org/10.1109/INFCOMW.2015.7179398>.

[Ahlgren] Ahlgren, B., Dannewitz, C., Imbrenda, C., Kutscher, D.,
and B. Ohlman, "A Survey of Information-Centric
Networking", IEEE Communications Magarzine Vol.50, Magazine, Vol. 50, Issue
7, 2012.

[Xylomenos]
Xylomenos, G., Ververidis, C. N., Siris, V. A., Fotiou,
N., Tsilopoulos, C., Vasilako, X., Katsaros, K. V., and G.
C. Polyzos, "A Survey of Information-Centric Networking
Research,Communications Surveys and Tutorials", IEEE
Communications Surveys and Tutorials vol. 16, no. 2, 2014.

[Baccelli] Baccelli, E., Mehlis, C., Hahm, O., Schmidt, T., and M.
Wahlisch, "Information Centric Networking in the IoT:
Experiments with NDN in the Wild", ACM ICN 2014, 2014. DOI 10.1109/MCOM.2012.6231276, July 2012,
<https://doi.org/10.1109/MCOM.2012.6231276>.

[Amadeo] Amadeo, M., Campolo, C., Iera, A., and A. Molinaro, "Named
data networking for IoT: An architectural perspective",
European Conference on Networks and Communications
(EuCNC) , 2014.

[Quevedo] Quevedo, J., Corujo, D., and R. Aguiar, "A case for ICN
usage in IoT environments", IEEE GLOBECOM , 2014.
(EuCNC), DOI 10.1109/EuCNC.2014.6882665, June 2014,
<https://doi.org/10.1109/EuCNC.2014.6882665>.

[Amadeo2] Amadeo, M. et al., "Information-centric networking for the
internet of things: challenges and opportunitiesve", opportunities", IEEE
Network vol.
Network, Vol. 30, no. No. 2, July 2016.

[ID.Zhang2]
Ravindran, R. et al., "Design Considerations for Applying
ICN to IoT", draft-zhang-icnrg-icniot-03 , May 2019.

[Koponen] Koponen, DOI 10.1109/MNET.2016.7437030,
March 2016, <https://doi.org/10.1109/MNET.2016.7437030>.

[Baccelli] Baccelli, E., Mehlis, C., Hahm, O., Schmidt, T., Chawla, M., Chun, B., Ermolinskiy, A., Kim,
K. H., Shenker, S., and I. Stoica, "A Data-Oriented (and
Beyond) Network Architecture", ACM SIGCOMM 2007 pp.
181-192, 2007.

[PURSUIT] "FP7 PURSUIT project.",
http://www.fp7-pursuit.eu/PursuitWeb/ .

[SAIL] "FP7 SAIL project.", http://www.sail-project.eu/ .

[NDN] "NSF Named Data Networking project.",
http://www.named-data.net .

[CCNx] "Content M.
Wählisch, "Information Centric Networking project.",
https://wiki.fd.io/view/Cicn .

[MF] "NSF Mobility First project.",
http://mobilityfirst.winlab.rutgers.edu/ .

[Jung] Jung, H. et al., "IDNet: Beyond All-IP Network", ETRI
Jouranl vol. 37, no. 5, October 2015.

[SA2-5GLAN]
3gpp-5glan, "SP-181129, Work Item Description,
Vertical_LAN(SA2), 5GS Enhanced Support of Vertical and
LAN Services", 3GPP ,
http://www.3gpp.org/ftp/tsg_sa/TSG_SA/TSGS_82/Docs/SP-
181120.zip. in the IoT:
Experiments with NDN in the Wild", ACM-ICN 2014,
DOI 10.1145/2660129.2660144, 2014,
<https://doi.org/10.1145/2660129.2660144>.

[Bari] Bari, M. F., M.F., Chowdhury, S. R., S.R., Ahmed, R., Boutaba, R., and
B. Mathieu, "A Survey of Naming and Routing in
Information-Centric Networks", IEEE Communications
Magazine
Magazine, Vol. 50, No. 12, P.44-53, 2012.

[Westphal] Westphal, C. and E. Demirors, "An IP-based Manifest
Architecture for ICN", ACM ICN , 2015.

[Mosko] Mosko, M., Scott, G., Solis, I., and C. Wood, "CCNx
Manifest Specification", draft-wood-icnrg-
ccnxmanifests-00 , July 2015.

[RFC6920] Farrell, S., Kutscher, D., Dannewitz, C., Ohlman, B.,
Keranen, A., and P. Hallam-Baker, "Naming Things with
Hashes", RFC6920, pp. 44-53,
DOI 10.17487/RFC6920,
https://rfc-editor.org/rfc/rfc6920.txt , April 2013.

[Zhang2] Zhang, Y. 10.1109/MCOM.2012.6384450, December 2012,
<https://doi.org/10.1109/MCOM.2012.6384450>.

[Bayhan] Bayhan, S. et al., "A Survey of Mobility Support "On Content Indexing for Off-Path
Caching in Named
Data Networking", IEEE Conference on Computer
Communications Workshops , 2016. Information-Centric Networks", ACM-ICN 2016,
DOI 10.1145/2984356.2984372, September 2016,
<https://doi.org/10.1145/2984356.2984372>.

[CCNx] "CICN", <https://wiki.fd.io/view/Cicn>.

[Dannewitz]
Dannewitz, C. et al., "Network of Information (NetInf)-An
information centric (NetInf) -
An information-centric networking architecture", Computer
Communications vol.
Communications, Vol. 36, no. Issue 7,
DOI 10.1016/j.comcom.2013.01.009, April 2013.

[Ravindran]
Ravindran, R. et al., "Forwarding-Label support 2013,
<https://doi.org/10.1016/j.comcom.2013.01.009>.

[FLIC] Tschudin, C., Wood, C. A., Mosko, M., and D. Oran, "File-
Like ICN Collections (FLIC)", Work in CCN
Protocol", draft-ravi-icnrg-ccn-forwarding-label-02 ,
March 2018.

[Afanasyev]
Afanasyev, Progress, Internet-
Draft, draft-irtf-icnrg-flic-03, 7 November 2021,
<https://datatracker.ietf.org/doc/html/draft-irtf-icnrg-
flic-03>.

[ID.Zhang2]
Ravindran, R., Zhang, Y., Grieco, L. A., Lindgren, A.,
Burke, J., Ahlgren, B., and A. Azgin, "Design
Considerations for Applying ICN to IoT", Work in Progress,
Internet-Draft, draft-irtf-icnrg-icniot-03, 2 May 2019,
<https://datatracker.ietf.org/doc/html/draft-irtf-icnrg-
icniot-03>.

[Jung] Jung, H. et al., "SNAMP: Secure Namespace Mapping to
Scale NDN Forwarding", IEEE Global "IDNet: Beyond All-IP Network", ETRI
Journal, Vol. 37, Issue 5, DOI 10.4218/etrij.15.2415.0045,
October 2015,
<https://doi.org/10.4218/etrij.15.2415.0045>.

[Koponen] Koponen, T., Chawla, M., Chun, B., Ermolinskiy, A., Kim,
K.H., Shenker, S., and I. Stoica, "A Data-Oriented (and
Beyond) Network Architecture", ACM SIGCOMM 2007, pp.
181-192, DOI 10.1145/1282380.1282402, August 2007,
<https://doi.org/10.1145/1282380.1282402>.

[MF] "MobilityFirst Future Internet Symposium ,
April 2015. Architecture Project
Overview", <http://mobilityfirst.winlab.rutgers.edu>.

[Mosko2] Mosko, M., "Nameless Objects", IRTF ICNRG , ICNRG, January 2016.

[Bayhan] Bayhan, S. et al., "On Content Indexing for Off-Path
Caching in Information-Centric Networks", ACM ICN ,
September 2016.

[FLIC] Tschudin, C. et al., "File-Like ICN Collection (FLIC)",
draft-irtf-icnrg-flic-02 , November 2019. 2016,
<https://datatracker.ietf.org/meeting/interim-2016-icnrg-
01/materials/slides-interim-2016-icnrg-1-7.pdf>.

[NDN] "Named Data Networking", <http://www.named-data.net>.

[NEO] Eriksson, A. and A. M. A.M. Malik, "A DNS-based information-
centric network architecture open to multiple protocols
for transfer of data objects", 21st Conference on
Innovation in Clouds, Internet and Networks and Workshops
(ICIN), pp. 1-8, 2018. DOI 10.1109/ICIN.2018.8401595, February
2018, <https://doi.org/10.1109/ICIN.2018.8401595>.

[NRSarch] Hong, J. et al., J., You, T., and V. Kafle, "Architectural
Considerations of ICN using Name Resolution Service", Work
in Progress, Internet-Draft, draft-irtf-icnrg-nrsarch-
considerations-06 ,
considerations-06, 12 February 2021. 2021,
<https://datatracker.ietf.org/doc/html/draft-irtf-icnrg-
nrsarch-considerations-06>.

[PURSUIT] "FP7 PURSUIT", <https://www.fp7-pursuit.eu/>.

[Quevedo] Quevedo, J., Corujo, D., and R. Aguiar, "A case for ICN
usage in IoT environments", IEEE GLOBECOM,
DOI GLOCOM.2014.7037227, December 2014,
<https://doi.org/GLOCOM.2014.7037227>.

[Ravindran]
Ravindran, R., Chakraborti, A., and A. Azgin, "Forwarding
Label support in CCN Protocol", Work in Progress,
Internet-Draft, draft-ravi-icnrg-ccn-forwarding-label-02,
5 March 2018, <https://datatracker.ietf.org/doc/html/
draft-ravi-icnrg-ccn-forwarding-label-02>.

[RFC6920] Farrell, S., Kutscher, D., Dannewitz, C., Ohlman, B.,
Keranen, A., and P. Hallam-Baker, "Naming Things with
Hashes", RFC 6920, DOI 10.17487/RFC6920, April 2013,
<https://www.rfc-editor.org/info/rfc6920>.

[RFC8569] Mosko, M., Solis, I., and C. Wood, "Content-Centric
Networking (CCNx) Semantics", RFC 8569,
DOI 10.17487/RFC8569, July 2019,
<https://www.rfc-editor.org/info/rfc8569>.

[RFC9064] Oran, D., "Considerations in the development Development of a QoS
Architecture for CCNx-like ICN protocols", RFC9064,
https://datatracker.ietf.org/doc/rfc9064/ , CCNx-Like Information-Centric Networking
Protocols", RFC 9064, DOI 10.17487/RFC9064, June 2021. 2021,
<https://www.rfc-editor.org/info/rfc9064>.

[SA2-5GLAN]
3GPP, "New WID: 5GS Enhanced support of Vertical and LAN
Services", TSG SA Meeting #SP-82, December 2018,
<http://www.3gpp.org/ftp/tsg_sa/TSG_SA/TSGS_82/Docs/SP-
181120.zip>.

[SAIL] "Scalable and Adaptive Internet Solutions (SAIL)",
<http://www.sail-project.eu/>.

[Westphal] Westphal, C. and E. Demirors, "An IP-Based Manifest
Architecture for ICN", ACM-ICN 2015,
DOI 10.1145/2810156.2812614, September 2015,
<https://doi.org/10.1145/2810156.2812614>.

[Xylomenos]
Xylomenos, G., Ververidis, C., Siris, V., Fotiou, N.,
Tsilopoulos, C., Vasilakos, X., Katsaros, K., and G.
Polyzos, "A Survey of Information-Centric Networking
Research", IEEE Communications Surveys and Tutorials, Vol.
16, Issue 2, DOI 10.1109/SURV.2013.070813.00063, 2014,
<https://doi.org/10.1109/SURV.2013.070813.00063>.

[Zhang2] Zhang, Y. et al., "A Survey of Mobility Support in Named
Data Networking", IEEE Conference on Computer
Communications Workshops,
DOI 10.1109/INFCOMW.2016.7562050, April 2016,
<https://doi.org/10.1109/INFCOMW.2016.7562050>.

Acknowledgements

The authors would like to thank Dave Oran, Dirk Kutscher, Ved Kafle,
Vincent Roca, Marie-Jose Montpetit, Stephen Farrell, Mirja Kuhlewind, Kühlewind,
and Colin Perkins for very useful reviews, comments comments, and improvement
on improvements
to the document.

Authors' Addresses

Jungha Hong
ETRI
218 Gajeong-ro,
Yuseung-Gu
218 Gajeong-ro
Daejeon
34129
Republic of Korea

Email: jhong@etri.re.kr

Tae-Wan You
ETRI
218 Gajeong-ro,
Yuseung-Gu
218 Gajeong-ro
Daejeon
34129
Republic of Korea

Email: twyou@etri.re.kr

Lijun Dong
Futurewei Technologies Inc.
10180 Telesis Court
San Diego, CA 92121
United States of America

Email: lijun.dong@futurewei.com

Cedric Westphal
Futurewei Technologies Inc.
2330 Central Expressway
Santa Clara, CA 95050
United States of America

Email: cedric.westphal@futurewei.com

Borje

Börje Ohlman
Ericsson Research
S-16480
SE-16480 Stockholm
Sweden

Email: Borje.Ohlman@ericsson.com