Internet Services over ICN in 5G LAN Environments
draft-trossen-icnrg-internet-icn-5glan-00
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| Authors | Dirk Trossen , Chonggang Wang , Sebastian Robitzsch , Martin Reed , Mays AL-Naday , Janne Riihijarvi | ||
| Last updated | 2019-10-31 | ||
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draft-trossen-icnrg-internet-icn-5glan-00
ICNRG D. Trossen
Internet-Draft C. Wang
Intended status: Informational S. Robitzsch
Expires: May 2, 2020 InterDigital Inc.
M. Reed
M. Al-Naday
Essex University
J. Riihijarvi
RWTH Aachen
October 30, 2019
Internet Services over ICN in 5G LAN Environments
draft-trossen-icnrg-internet-icn-5glan-00
Abstract
In this draft, we provide architecture and operations for enabling
Internet services over ICN over (5G-enabled) LAN environments.
Operations include ICN API to upper layers, HTTP over ICN, Service
Proxy Operations, ICN Flow Management, Name Resolution, Mobility
Handling, and Dual Stack Device Support.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on May 2, 2020.
Copyright Notice
Copyright (c) 2019 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
(https://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. 5G Control Plane Services . . . . . . . . . . . . . . . . 5
3.2. HTTP-based Streaming . . . . . . . . . . . . . . . . . . 6
4. 5GLAN in 5G Next Generation Core Network Architecture . . . . 7
4.1. Realization in SDN Transport Networks . . . . . . . . . . 10
4.2. Realization in Other Transport Networks . . . . . . . . . 10
5. Internet Services over ICN over 5GLAN . . . . . . . . . . . . 11
5.1. General Operations . . . . . . . . . . . . . . . . . . . 13
5.2. ICN API to Upper Layers . . . . . . . . . . . . . . . . . 14
5.3. HTTP over ICN . . . . . . . . . . . . . . . . . . . . . . 15
5.3.1. General Mapping Procedures . . . . . . . . . . . . . 15
5.3.2. Realizing Ad-Hoc Multicast Responses for HTTP . . . . 15
5.4. Service Proxy Operations . . . . . . . . . . . . . . . . 16
5.5. ICN Flow Management . . . . . . . . . . . . . . . . . . . 17
5.6. NR Operations . . . . . . . . . . . . . . . . . . . . . . 17
5.7. Mobility Handling . . . . . . . . . . . . . . . . . . . . 17
5.8. Dual Stack Device Support . . . . . . . . . . . . . . . . 17
6. Deployment Considerations . . . . . . . . . . . . . . . . . . 18
7. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 19
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
9. Security Considerations . . . . . . . . . . . . . . . . . . . 19
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19
11. Informative References . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction
As discussed in [I-D.ravi-icnrg-5gc-icn], Information-Centric
Networks (ICN) could be more easily implemented in a Local Area
Network (LAN) environment. In relation to 5G, this specifically
would realize an ICN deployment without requiring integration of ICN
capabilities into the 5G core network itself.
In the currently defined 5G core network, 5GLAN capabilities are
being introduced that provide a LAN abstraction to 5G endpoints,
allowing for Ethernet packets to be sent across a 5G network,
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therefore extending the provisioning of LAN capabilities from fixed
and Wifi-based networks to cellular ones.
Utilizing such ICN realization over 5GLAN, the objective of this
draft is to propose an architecture to enable Internet services over
such ICN-over-LAN environment with the reference architectural
discussions in the 5G core network 3GPP specifications [TS23.501]
[TS23.502] forming the basis of our discussions. This draft also
complements work related to various ICN deployment opportunities
explored in [I-D.irtf-icnrg-deployment-guidelines], where 5G
technology is considered as one of the promising alternatives. In
that, ICN is used as an underlay technology to provide routing
capabilities to Internet services.
Through such replacement of IP routing with ICN routing, we
capitalize on several ICN capabilities:
o Edge Computing: Multi-access Edge Computing (MEC) is located at
the edge of the network and aids several latency sensitive
applications such as augmented and virtual reality (AR/VR), as
well as the ultra reliable and low latency class (URLLC) of
applications such as autonomous vehicles. Enabling edge computing
over an IP converged 5GC comes with the challenge of application
level reconfiguration required to re-initialize a session whenever
it is being served by a non-optimal service instance
topologically. In contrast, named-based networking, as considered
by ICN, naturally supports service-centric networking, which
minimizes network related configuration for applications and
allows fast resolution for named service instances. This
opportunity is realized by interpreting Internet services as
transactions over an ICN routed network with flexible routing to
the nearest execution point for said transaction.
o Edge Storage and Caching: A principal design feature of ICN is the
secured content (or named data) object, which allows location
independent data replication at strategic storage points in the
network, or data dissemination through ICN routers by means of
opportunistic caching. These features benefit both real-time and
non-real-time applications whenever there is spatial and temporal
correlation among content accessed by these users, thereby
advantageous to both high-bandwidth and low-latency applications
such as conferencing, AR/VR, and non-real time applications such
as Video-on-Demand (VOD) and IoT transactions. This opportunity
is realized by the transaction-based model of realizing Internet
service on top of an ICN routed network, where transaction results
can be retrieved from a number of network locations.
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o Opportunistic Multicast: The vast majority of current Internet
traffic is due to unicast delivery of relatively immutable content
such as video or software to very large client groups. This has
resulted in large amount of redundancy in network traffic, as well
as creating capacity bottlenecks both in the core network as well
as the server infrastructure serving the content. Technologies
such as content delivery networks (CDNs) help to spread out the
network load, but are complex to manage, have inherent limits in
terms of how rapidly they can react to changing network and server
conditions, and cannot fundamentally reduce the network overhead
arising from redundant unicast streams. Furthermore, CDNs
traditionally only reach into Points-of-Presence (POP) within
customer networks, therefore not reducing the load of transfer
from said POP to the end customers in that edge network. In
contrast, ICN enables opportunistic multicast delivery of content.
We realize this opportunity by automatically delivering responses
to quasi-concurrent requests in a single lightweight multicast
transmission over the L2 customer network, extending the reach of
CDNs down to the end user. Unlike traditional IP multicast, no
setup time overhead is added and no per-flow state is required in
the network.
In this document, we first outline possible use cases, capitalizing
on the aforementioned ICN capabilities before discussing the proposed
extensions to 5G to support a cellular-based LAN connectivity before
outlining our proposal to support Internet services over an ICN-
routed LAN connectivity in such 5G environments.
2. Terminology
Following are terminologies relevant to this draft:
5G-NextGen Core (5GC): Refers to the new 5G core network
architecture being developed by 3GPP, we specifically refer to the
architectural discussions in [TS23.501] [TS23.502].
5GLAN: Refers to the extensions to the new 5G core network
architecture that provide LAN connectivity to 5G devices connected
via, e.g., new 5G air interfaces.
User Plane Function (UPF): UPF is the generalized logical data
plane function with context of the UE PDU session. UPFs can play
many roles, such as, being a flow classifier, a PDU session
anchoring point, or a branching point.
Packet Data Network (PDN or DN): This refers to service networks
that belong to the operator or third party offered as a service to
the UE.
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Unified Data Management (UDM): Realizes unified data management
for wireless, wireline and any other types of subscribers for M2M,
IOT applications, etc. UDM reports subscriber related vital
information e.g. virtual edge region, list of location visits,
sessions active etc. UDM works as a subscriber anchor point so
that means OSS/BSS systems will have centralized monitoring-of/
access-to of the system to get/set subscriber information.
Authentication Server Function (AUSF): Provides mechanism for
unified authentication for subscribers related to wireless,
wireline and any other types of subscribers such as M2M and IOT
applications. The functions performed by AUSF are similar to HSS
with additional functionalities to related to 5G.
Session Management Function (SMF): Performs session management
functions for attached users equipment (UE) in the 5G Core. SMF
can thus be formed by leveraging the Control and User Plane
Separation (CUPS) feature with control plane session management.
Access Mobility Function (AMF): Perform access mobility management
for attached user equipment (UE) to the 5G core network. The
function includes, network access stratus (NAS) mobility functions
such as authentication and authorization.
Application Function (AF): Helps with influencing the user plane
routing state in 5GC considering service requirements.
Network Slicing: This conceptualizes the grouping for a set of
logical or physical network functions with its own or shared
control, data and service plane to meet specific service
requirements.
3. Use Cases
3.1. 5G Control Plane Services
We exemplify the need for chaining service functions at the level of
a service name through a use case stemming from the current 3GPP
Rel-16 work on Service Based Architecture (SBA) [TS29.500]
[SBA-ENHANCEMENT]. In this work, mobile network control planes are
proposed to be realized by replacing the traditional network function
interfaces with a fully service-based one. HTTP was chosen as the
application layer protocol for exchanging suitable service requests
[TS29.500]. With this in mind, the exchange between, say the 3GPP
(Rel-15) defined Session Management Function (SMF) and the Access and
Mobility management Function (AMF) in a 5G control plane is being
described as a set of web service like requests which are in turn
embedded into HTTP requests. Hence, interactions in a 5G control
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plane can be modelled based on service function chains where the
relationship is between the specific service function endpoints that
implement the necessary service endpoints in the SMF and AMF. The
service functions are exposed through URIs with work ongoing to
define the used naming conventions for such URIs.
This move from a network function model (in pre-Rel 15 systems of
3GPP) to a service-based model is motivated through the proliferation
of data center operations for mobile network control plane services.
In other words, typical IT-based methods to service provisioning, in
particular that of virtualization of entire compute resources, are
envisioned to being used in future operations of mobile networks.
Hence, operators of such future mobile networks desire to virtualize
service function endpoints and direct (control plane) traffic to the
most appropriate current service instance in the most appropriate
(local) data centre, such data centre envisioned as being
interconnected through a software-defined wide area network (SD-WAN).
'Appropriate' here can be defined by topological or geographical
proximity of the service initiator to the service function endpoint.
Alternatively, network or service instance compute load can be used
to direct a request to a more appropriate (in this case less loaded)
instance to reduce possible latency of the overall request. Such
data center centric operation is extended with the trend towards
regionalization of load through a 'regional office' approach, where
micro data centers provide virtualizable resources that can be used
in the service execution, creating a larger degree of freedom when
choosing the 'most appropriate' service endpoint for a particular
incoming service request. This 5G control plane scenario capitalizes
on the edge computing capabilities of ICN by allowing for fast
redirections of HTTP-based transactions to the nearest control plane
service realization within the distributed data centre of the 5G
operator infrastructure.
3.2. HTTP-based Streaming
With the extensive use of "web technology", "distributed services"
and availability of heterogeneous network, HTTP has effectively
transitioned into the common transport or session layer for E2E and
multi-hop communication across the web. Assume clients that are
consuming the same content (such as a TV program) and that this
content has for each block (typically segments worth 2 seconds of
content) a set of outstanding requests from its clients. HTTP
request and response used in media streaming services like HLS, use
HTTP response for delivery of content. In such scenarios, where
semi-synchronous access to the same resource occurs (such as watching
prominent videos over Netflix or similar platforms or live TV over
HTTP), traffic grows linearly with the number of viewers since the
HTTP-based server will provide an HTTP response to each individual
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viewer. To mitigate the load impact, operators often utilize IP
multicast underneath HTTP (for live TV) to create fewer, multicast,
streams; though this comes with the high flow setup and management
cost. This poses a significant burden on operators in terms of costs
and on users in terms of likely degradation of quality.
This problem is not limited to traditional TV broadcasting. Consider
a virtual reality use case where several users are joining a VR
session at the same time, e.g., centered around a joint event.
Hence, due to the temporal correlation of the VR sessions, we can
assume that multiple requests are sent for the same content at any
point, particularly when viewing angles of VR clients are similar or
the same. Due to availability of virtual functions and cloud
technology, the actual end point from where content is delivered may
change. For this type of scenarios, the opportunistic multicast
capability of ICN may be utilized to reduce overall load in the
network, as well as on the server providing the HTTP responses. The
latter also allows constrained resources to serve a higher volume of
demands and therefore incur a higher impact on traffic distribution
in the network.
4. 5GLAN in 5G Next Generation Core Network Architecture
In this section, for brevity purposes, we restrict the discussions to
the 5G extensions currently studied in 3GPP to facilitate a
distributed, cellular-based LAN connectivity to end users, based on
the 5G next generation core network architecture. For more
information on the latter, we refer to [TS23.501] [TS23.502] as well
as [I-D.ravi-icnrg-5gc-icn].
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+------+ +------+ +-----+ +-----+ +-----+ +-----+
| NSSF | | NEF | | NRF | | PCF | | UDM | | AF |
+--o---+ +--o---+ +--o--+ +--o--+ +--o--+ +--o--+
Nnssf| Nnef| Nnrf| Npcf| Nudm| Naf|
-----+-------+-+---------+--+------+-------+-+---------+---------
Nausf| Namf| Nsmf|
+--o--+ +--o--+ +--o--+
| AUSF| | AMF | | SMF |
+-----+ +-+-+-+ +--+--+
/ | |
+---------+ | |
N1 / |N2 N4| +-N9/Nx-+
+------+ | | | |
/ | | | V
+-+--+ +----+----+ N3 +-+--+-------+--+ N6 +----+
| UE +----------------+ (R)AN +------+ UPF +----->+ DN |
+----+ +---------+ +---------------+ +----+
Figure 1: 5G Core Network with Vertical_LAN (5GLAN) Extensions
Figure 1 shows the current 5G Core Network Architecture being
discussed within the scope of the normative work addressing 5GLAN
Type services in the 3GPP System Architecture Working Group 2 (3GPP
SA2), referred formally as "5GS Enhanced support of Vertical and LAN
Services" [SA2-5GLAN]. The goal of this work item is to provide
distributed LAN-based connectivity between two or more terminals or
User Equipment entities (UEs) connected to the 5G network. The SMF
(session management function) provides a registration and discovery
protocol that allows UEs wanting to communicate via a relevant 5GLAN
group towards one or more UEs also members of this 5GLAN group, to
determine the suitable forwarding information after each UE
previously registered suitable identifier information with the SMF
responsible to manage the paths across UEs in a 5GLAN group. UEs
register and discover (obtain) suitable identifiers during the
establishment of a Protocol Data Unit (PDU) Session or PDU Session
Modification procedure. Suitable identifier information, according
to [SA2-5GLAN], are Ethernet MAC addresses as well as IP addresses
(the latter is usually assigned during the session setup through the
SMF, i.e., the session management function).
The SMF that manages the path across UEs in a 5GLAN group, then
establishes the suitable procedures to ensure the forwarding between
the required UPFs (user plane functions) to ensure the LAN
connectivity between the UEs (user equipments) provided in the
original request to the SMF. When using the N9 interface to the UPF,
this forwarding will rely on a tunnel-based approach between the UPFs
along the path, while the Nx interface uses path-based forwarding
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between UPFs, while LAN-based forwarding is utilized between the
final UPF and the UE (utilizing the N3 interface towards the
destination UE).
In the following, path-based forwarding is assumed, i.e., the usage
of the Nx interface and the utilization of a path identifier for the
end-to-end LAN communication. Here, the path between the source and
destination UPFs is encoded through a bitfield, provided in the
packet header. Each bit position in said bitfield represents a
unique link in the network. Upon receiving an incoming packet, each
UPF inspects said bitfield for the presence of any local link that is
being served by one of its output ports. Such presence check is
implemented via a simple binary AND and CMP operation. If no link is
being found, the packet is dropped. Such bitfield-based path
representation also allows for creating multicast relations in an ad
hoc manner by combining two or more path identifiers through a binary
OR operation. Note that due to the assignment of a bit position to a
link, path identifiers are bidirectional and can therefore be used
for request/response communication without incurring any need for
path computation on the return path.
For sending a packet from one Layer 2 device (UE) connected to one
UPF (via a RAN) to a device connected to another UPF, we provide the
MAC address of the destination and perform a header re-write by
providing the destination MAC address of the ingress UPF when sending
from source device to ingress and placing the end destination MAC
address in the payload. Upon arrival at the egress UPF, after having
applied the path-based forwarding between ingress and egress UPF, the
end destination address is restored while the end source MAC is
placed in the payload with the egress L2 forwarder one being used as
the L2 source MAC for the link-local transfer. At the end device (or
proxy device), the end source MAC address is restored as the source
MAC, providing an abstraction of a link-local L2 communication
between the end source and destination devices.
+---------+---------+----------+-----------+-----------+
| Src MAC | Dst MAC | pathID | NAME_ID | Payload |
+---------+---------+----------------------+-----------+
Figure 2: General Packet Structure
For this end-to-end transfer, the general packet structure of
Figure 2 is used. The Name_ID field is being used for the ICN
operations, while the payload contains the information related to the
transaction-based flow management described in Section 5.6 and the
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PATH_ID is the bitfield-based path identifier for the path-based
forwarding.
4.1. Realization in SDN Transport Networks
An emerging technology for Layer 2 forwarding that suits the 5GLAN
architecture in Figure 1 is that of Software-Defined networking (SDN)
[SDN-DEFINITION], which allows for programmatically forwarding
packets at Layer 2. Switch-based rules are being executed with such
rules being populated by the SDN controller. Rules can act upon so-
called matching fields, as defined by the OpenFlow protocol
specification [OpenFlowSwitch]. Those fields include Ethernet MAC
addresses, IPv4/6 source and destination addresses and other well-
known Layer 3 and even 4 transport fields.
As shown in [Reed], efficient path-based forwarding can be realized
in SDN networks by placing the aforementioned path identifiers into
the IPv6 source/destination fields of a forwarded packet. Utilizing
the IPv6 source/destination fields allows for natively supporting 256
links in a transport network. Larger topologies can be supported by
extension schemes but are left out of this paper for brevity of the
presentation. During network bootstrapping, each link at each switch
is assigned a unique bitnumber in the bitfield. In order to forward
based on such bitfield path information, the SDN controller is
instructed to insert a suitable wildcard matching rule into the SDN
switch. This wildcard at a given switch is defined by the bitnumber
that has been assigned to a particular link at that switch during
bootstrapping. Wildcard matching as a generalization of longest
prefix matching is natively supported by SDN-based switches since the
OpenFlow v1.3 specification, efficiently implemented through TCAM
based operations. With that, SDN forwarding actions only depend on
the switch-local number of output ports, while being able to
transport any number of higher-layer flows over the same transport
network without specific flow rules being necessary. This results in
a constant forwarding table size while no controller-switch
interaction is necessary for any flow setup; only changes in
forwarding topology (resulting in a change of port to bit number
assignment) will require suitable changes of forwarding rules in
switches.
4.2. Realization in Other Transport Networks
Although we focus the methods in this draft on Layer 2 forwarding
approaches and realization of Internet-over-ICN over a 5G LAN enabled
network, path-based transport networks can also be established as an
overlay over otherwise Layer 2 networks. For instance, the BIER (Bit
Indexed Explicit Replication) [RFC8279] efforts within the Internet
Engineer Task Force (IETF) establish such path-based forwarding
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transport as an overlay over existing, e.g., MPLS networks. The
path-based forwarding identification is similar to the aforementioned
SDN realization although the bitfield represents ingress/egress
information rather than links along the path.
Yet another transport network example is presented in [Khalili],
utilizing flow aggregation over SDN networks. The flow aggregation
again results in a path representation that is independent from the
specific flows traversing the network.
The proposed traffic engineering extensions to BIER, presented in
[I-D.ietf-bier-te-arch], directly align with the SDN-based
realization presented in Section 4.1, by proposing the same
bitposition per transport link assignment being used, resulting in
BIER bitstrings in which a dedicated forwarding path is encoded as a
unique bitpattern containing said bitpositions of the chosen
forwarding links. The BIER-TE controller plays a similar role as the
northbound SDN controller application utilized for the solution in
Section 4.1.
5. Internet Services over ICN over 5GLAN
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+-------------------------------+
| Forwarding Network | .... Control
| +--------------------------+ |
| | . NR . | | **** Data
| +-.----------------------.-+ |
+--------------+ | . . | +--------------+
| App | | +-.---------+ +---------.-+ | | App |
+-----+----+---+ | | . ******* | | ******* . | | +--------------+
|HTTP*|TCP*|IP.| | | . * UPF * | | * UPF * . | | |.IP|*TCP|*HTTP|
+----*+---*+--.+ | +-.-*-----*-+ +-*-----*-.-+ | +.--+*---+*----+
|ICN * * .| | . * * * * . | |. * * ICN|
+----*----*---.+ +---+ . * ******** * . +---+ +.---*----*----+
|L2 * * ....|RAN+.. * * ..+RAN|.... * * |
| ********************** ********************** |
+--------------+ +---+ . * * . +---+ +--------------+
| . * * . |
| +-.-*-----+ +-----*-.+ |
+--| . * RAN|------|RAN * .|--+
+-.-*-----+ +-----*-.+
. * * .
. ******* ******* .
Legacy Service ....... * * ....... Service
Device Proxy . * * . Proxy
+-----+ +-------------------+ . * * . +-------------------+
|APP *| | ********* | . * * . | ********** |
+----*+ +----*+ * | . * * . | * +*----+
|HTTP*| |HTTP*|******* | . * * . | ********|*HTTP|
+----*+ +----*-+ * | . * * . | * +*----+
|TCP *| |TCP * |****** | . * * . | *******| * TCP|
+----*+ +----*--+ +*------+ . * * . +-----*+ +---*----+ +-------+
|IP *| |IP * |***|* ICN .| . * * . |.ICN *|***| * IP| | IP |
+----*+ +----*--+---+*-----.+ . * * . +.----*+---+---*----+ |Peering|
|L2 *| | * L2 * .... * * .... * * | |Network|
| ********* ************ *********** ************ |
+-----+ +-------------------+ +-------------------+ +-------+
Figure 3: Internet Services over ICN over 5GLAN
Figure 3 shows the protocol layering for realizing Internet protocols
over an ICN over 5GLAN transport, assuming an end-to-end LAN
connectivity provided by solutions such as 5GLAN.
Note that such LAN connectivity can also be found in environments
such as localized LAN-based deployments in smart cities, enterprises
and others, with the UPF representing, e.g., an SDN switch (utilizing
the methods outlined in Section 4.1). Hence, the solutions described
in this section also applies to those deployments.
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Key to the approach is that Internet services are being interpreted
as the main unit of transfer in the architecture shown in Figure 3.
For this, any Internet service is treated as a Named Service
Transaction (NST) which is in turn suitably routed over an ICN layer
in one or more other devices. As a result of this name-based
interpretation of any Internet service, the protocol stack in end
devices flattens to four layers with Internet services and ICN, with
ICN acting as a name-based routing layer for all IP protocols
implemented atop, with Layer 1 and 2 realizing the end-to-end packet
forwarding outlined in Section 4 (over a 5G environment) or a general
LAN environment provided through WiFi or fixed Ethernet technologies.
The general ICN operations are presented in Section 5.1 before
discussing the assumed (strawman) API to the ICN layer in
Section 5.2, which is used in turn to define the mapping of HTTP
transactions to operations at the ICN layer in Section 5.3 for the
example of HTTP. As explained in that section, the ICN layer uses an
interaction with the NR to register and discover HTTP-based services
for determining the suitable end-to-end packet forwarding
information.
Interfaces to legacy devices and peering networks are preserved
through service proxy devices, which terminate a traditional Internet
protocol stack communication and translate it into a resulting flat
protocol transaction. Termination here can be based on well-known
port numbers for specific Internet protocols, ultimately falling back
to the IP datagram service being the minimal service being mapped.
The operations of said service proxy devices is described in
Section 5.4.
An important aspect of the architecture is the mapping of the end-to-
end flow semantic established in many Internet services onto the flat
protocol stack. Section 5.5 outlines the flow management that exists
between the end devices.
The mapping of protocol identifiers onto ICN forwarding relations,
i.e., the operations of the name resolver (NR), shown in Figure 3, is
described in Section 5.6, followed by the procedures for handling
mobility of service providers and consumers in Section 5.7. Finally,
the support for dual-stack devices, not requiring a service proxy
device yet being able to also connect to existing IP routed networks,
is described in Section 5.8.
5.1. General Operations
The semantics of our name-based routing is that of a publish-
subscribe system over a name. The intention to receive packets with
a certain name is expressed through a subscription while sending
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packets to a name is expressed through a publication. The matching
of a sender to a receiver is realized through NR in Figure 3. The
exact nature of the matching is defined through the semantics of the
service and, therefore, through the nature of the name provided. For
instance, HTTP and raw Internet services are matched to exactly one
subscriber only, providing an anycast capability, while IP multicast
services are matched against any subscriber (with the IP multicast
address being the name).
Structured names are used with the root specific to the (Internet)
service name, such as URL, and therefore deriving the matching
semantics directly from the name.
The subscription to a name is realized through a registration
protocol between end device and NR. Hence, any end device exposing a
certain Internet service registers the suitable name with the NR,
which in turn stores reachability information that is suitable for
path calculation between the ingress and egress L2 forwarders between
which the communication eventually will take place. In our current
realization, we utilize shortest paths only although other link
weights can be utilized for, e.g., delay-constrained and other
policies.
In our realization, we use network domain unique host identifiers
that are being assigned to end devices during the connectivity setup.
Sending a packet of a given Internet service is realized through a
discovery protocol, which returns a suitable pathID, i.e., the
forwarding information between ingress and egress L2 forwarder, and
the destination MAC address of the hosting end device. It is this
pathID and MAC address that is being used in the general packet
structure of Figure 2 to forward the packet to the destination.
To reduce latency in further communication, the forwarding
information is locally cached at the end device, while the cached
information is being maintained through path updates sent by the NR
in case of hosting end devices having moved or de-registered,
therefore avoiding stale forwarding information.
5.2. ICN API to Upper Layers
The operations of the ICN layer are exposed to upper layers in
Figure 1 through the following API calls, being exemplary here for
the further explanation of operations in the next sub-sections:
o conn = send(name, payload)
o send(conn, payload)
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o conn = receive(name, &payload)
o receive(conn, &payload)
The first send() call is used for initiating a send operation to a
name with a connection handle returned, while the second send() is
used for return calls, using a connection parameters that is being
received with the receive() call to an incoming connection or for
subsequence outgoing calls after an initial request to a name has
been made. A return send() is being received at the other (client)
side through the second receive() call where the conn parameter is
obtained by the corresponding send() call for the outgoing call.
With these API functions, we provide means for providing name-based
transactions with return responses association provided natively.
The conn parameter represents the bitfield used for path-based
forwarding in the remote host case or the hash of the local MAC
address in case of link-local connections.
5.3. HTTP over ICN
5.3.1. General Mapping Procedures
To realize the flat device nature, Internet service layers, such as
the HTTP protocol stack or the TCP protocol stack, will need to be
adapted to run atop this new API, implementing the semantics of the
respective Internet protocol through suitable transactions at the
name level. In the example of HTTP, the standard operations of DNS
resolution for the server to be contacted and opening of a TCP socket
are altogether replaced by a single send(FQDN, HTTP request) call,
while the response will be sent by the server, which received the
request through a receive(FQDN, &payload) call, using the returned
conn parameter to send the response with the second send() API call.
Note that the use of bidirectional pathIDs, no NR lookup is performed
at the HTTP serving endpoint.
5.3.2. Realizing Ad-Hoc Multicast Responses for HTTP
The basis of a named service transaction allows to deliver the same
HTTP responses to several requestees in efficient multicast (see
[I-D.ietf-bier-multicast-http-response] for use cases in a BIER-based
transport network environment).
This opportunity is realized by sending the same payload (i.e., an
HTTP response to the same resource across a number of pending
requests) through a combination of several conn parameters received
in the incoming requests via the receive() function.
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What is required in the HTTP stack implementation is a logic to
decide that two or more outstanding requests are possible to be
served by one response. For this, upon receiving an incoming
request, the HTTP stack determines any outstanding request to the
same resource. 'Same' here is defined as URI-specific combination of
the request URI and URI-specific header fields, such as browsing
agent or similar, called requestID in the following.
Once such determination is made that two requests are relating to the
same resource, i.e., are having the same request ID, the HTTP stack
maintains a temporary mapping of the request ID to the respective
conn parameters delivered by the receive() call. Upon receiving the
HTTP response from its application-level logic, the HTTP stack will
generate the suitable send(conn, payload) call where the provided
conn parameter is bitwise OR of all previously stored conn parameters
received in the receive() call. The ICN layer will recognize the use
of those ad-hoc created conn parameters and set the destination MAC
address in the general packet structure of Figure 2 to the Ethernet
broadcast MAC address as the destination address, leading to sending
the response to all end devices at the egress L2 forwarders to which
the response will be forwarded based on the combined conn parameter.
Alternatively, one could request IEEE assignment for a specific
Ethernet multicast address for this scheme instead of using the
broadcast address. For the local end device to determine the
relevance of the response received at the broadcast channel, the HTTP
stack of the serving endpoint includes the aforementioned requestID
into the payload of the packet (see Figure 2), while the originating
endpoint maintains an internal table with the requestID of pending
requests and its associated conn handle. If no matching requestID is
found, the packet is not being delivered to the ICN layer of the
incoming device. If a request is found, the ICN layer delivers the
response via the receive() call, using the conn handle stored in the
pending request table. Note that this filtering mechanism can easily
be implemented in hardware upon standardizing the appropriate payload
and header fields.
5.4. Service Proxy Operations
The service proxy in Figure 3 serves the integration of legacy
devices, i.e., with regular IP protocol stack, and the
interconnection to IP-based peering networks. It registers suitable
identifiers with the NR to ensure the reception of (ICN) packets,
while providing suitable protocol termination for the various
supported protocols. For instance, for HTTP, the service proxy
towards the peering network will register a wildcard name to the NR
to receive any HTTP request not destined to a network-locally
registered FQDN, operating as an HTTP proxy towards the peering
network.
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5.5. ICN Flow Management
EDITOR NOTE: left for future draft updates.
5.6. NR Operations
The NR in Figure 3 combines the operations of the SMF and the PMF in
5GLAN (see Figure 1), by allowing for registering IP protocol
identifiers for discovery and subsequent path computation by
resolving the destination(s) to a suitable pathID and destination MAC
address for forwarding. This will require extensions to the
operations of the SMF to allow for such higher layer identifiers to
be registered (and discovered), in addition to the already supported
Ethernet and IP addresses.
5.7. Mobility Handling
EDITOR NOTE: left for future draft updates.
5.8. Dual Stack Device Support
Figure 3 outlines a protocol stack for the user equipment that
realizes Internet services on top of the proposed name-based routing
layer as a single stack device. However, [I-D.irtf-icnrg-icn-lte-4g]
outlines the possibility of supporting dual-stack devices for 4G LTE
networks by allowing IP as well as ICN protocol stacks to be deployed
with the operation of IP and ICN based applications.
[I-D.ravi-icnrg-5gc-icn] outlines the same dual-stack device
realization for a 5G ICN realization. For both environments, a
convergence layer is described that selects the appropriate data path
for each ICN or IP application, e.g., based on configuration per
application (similar to selecting network interfaces such as WiFi
over cellular).
As a possible data path selection, [I-D.irtf-icnrg-icn-lte-4g] and
[I-D.ravi-icnrg-5gc-icn] envision the realization of Internet-over-
ICN (Section 4.2 in [I-D.irtf-icnrg-icn-lte-4g]) in which the
convergence layer would realize similar mapping functions as
described in this draft. Hence, we foresee the utilization of such
dual-stack devices connected to an Internet services over ICN over
5GLAN environment. When utilizing the service proxy, IP applications
that are configured to use the IP data path only could still utilize
the ICN-based forwarding in the network. In that case, functionality
such as the opportunistic multicast in Section 5.3.2 would only reach
up to the service proxy with unicast traffic continuing along the
data path towards the user equipment.
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6. Deployment Considerations
The work in [I-D.irtf-icnrg-deployment-guidelines] outlines a
comprehensive set of considerations related to the deployment of ICN.
We now relate the solutions proposed in this draft to the two main
aspects covered in the deployment considerations draft, namely the
'deployment configuration' (covered in Section 3 of
[I-D.irtf-icnrg-deployment-guidelines]) that is being realized and
the 'deployment migration paths' (covered in Section 4 of
[I-D.irtf-icnrg-deployment-guidelines]) that are being provided.
The solutions proposed in this draft relate to those "deployment
configuration" as follows:
o The realization of Internet service on top of an ICN routing
capabilities, as proposed in Section 5, follows the "ICN-as-an-
Underlay" categorization, interpreting the ICN routing as an
underlay to the Internet services with the path-based forwarding
being compatible with the 5GLAN forwarding capabilities currently
discussed in 3GPP and therefore providing an underlay integration
capability for the ICN forwarding used in the proposed solution.
o The deployment of 5GLAN based ICN capabilities can be realized
following the "ICN-as-a-Slice" deployment configuration, i.e., the
5GLAN connectivity is provided to a "vertical 5G customer" which
in turn provides the ICN capability over 5GLAN within said network
(and compute) slice at the endpoints of the 5GLAN connectivity, as
proposed in Section 3.
In relation of the 'deployment migration paths', the solutions in
this draft relate as follows:
o The integration with the 5GLAN capability, as proposed in
Section 5, facilitates "edge network migration" (interpreting the
cellular sub-system here as an edge network albeit a possibly
geographically large one.
o The single stack realization, as proposed in Figure 3, as well as
the dual-stack deployment, as proposed in Section 5.8, facilitate
"application and services migration" through not only supporting
ICN applications but also Internet applications through the
proposed Internet-over-ICN mapping in the terminal.
o The Internet over ICN over 5GLAN deployment, possibly combined
with an ICN-as-a-Slice deployment, facilitates the "content
delivery networks migration" through a deployment of Internet-
over-ICN-based 5GLAN connected CDN elements in (virtualized) edge
network nodes or POP locations in the customer (5G) network.
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7. Conclusion
In this draft, we explored the feasibility of enabling Internet
services directly over ICN network over (5G)LAN environments. We
proposed the architecture and discussed corresponding operations of
mapping Internet services onto name-based transactions, with the
specific example of HTTP-based transactions. We described the flow
management, the realization of opportunistic multicast responses for
HTTP as well as the realization of dual-stack user equipment. Future
updates to the draft will provide more details to the flow management
in terms of reliable transport between Internet-overIP-ICN enabled
end-systems as well as mobility handling. We also described the
deployment scenario for supporting Internet services over ICN over
5GLAN.
8. IANA Considerations
This document requests no IANA actions.
9. Security Considerations
Editor Note: to be added in future drafts.
10. Acknowledgments
Work towards developing the solutions outlined in this draft have
been funded under grants of the [H2020POINT] and [H2020FLAME]
projects.
11. Informative References
[H2020FLAME]
H2020, "The FLAME Project", https://www.ict-flame.eu/ .
[H2020POINT]
H2020, "The POINT Project", https://www.point-h2020.eu/ .
[I-D.galis-anima-autonomic-slice-networking]
Galis, A., Makhijani, K., Yu, D., and B. Liu, "Autonomic
Slice Networking", draft-galis-anima-autonomic-slice-
networking-05 (work in progress), September 2018.
[I-D.ietf-bier-multicast-http-response]
Trossen, D., Rahman, A., Wang, C., and T. Eckert,
"Applicability of BIER Multicast Overlay for Adaptive
Streaming Services", draft-ietf-bier-multicast-http-
response-01 (work in progress), June 2019.
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[I-D.ietf-bier-te-arch]
Eckert, T., Cauchie, G., and M. Menth, "Traffic
Engineering for Bit Index Explicit Replication (BIER-TE)",
draft-ietf-bier-te-arch-04 (work in progress), October
2019.
[I-D.irtf-icnrg-deployment-guidelines]
Rahman, A., Trossen, D., Kutscher, D., and R. Ravindran,
"Deployment Considerations for Information-Centric
Networking (ICN)", draft-irtf-icnrg-deployment-
guidelines-07 (work in progress), September 2019.
[I-D.irtf-icnrg-icn-lte-4g]
suthar, P., Stolic, M., Jangam, A., Trossen, D., and R.
Ravindran, "Native Deployment of ICN in LTE, 4G Mobile
Networks", draft-irtf-icnrg-icn-lte-4g-04 (work in
progress), September 2019.
[I-D.muscariello-intarea-hicn]
Muscariello, L., Carofiglio, G., Auge, J., and M.
Papalini, "Hybrid Information-Centric Networking", draft-
muscariello-intarea-hicn-03 (work in progress), October
2019.
[I-D.ravi-icnrg-5gc-icn]
Ravindran, R., suthar, P., Trossen, D., Wang, C., and G.
White, "Enabling ICN in 3GPP's 5G NextGen Core
Architecture", draft-ravi-icnrg-5gc-icn-04 (work in
progress), May 2019.
[I-D.white-icnrg-ipoc]
White, G., Shannigrahi, S., and C. Fan, "Internet Protocol
Tunneling over Content Centric Mobile Networks", draft-
white-icnrg-ipoc-02 (work in progress), June 2019.
[Khalili] Khalili, R., Poe, W., Despotovic, Z., and A. Hecker,
"Reducing State of SDN Switches in Mobile Core Networks by
Flow Rule Aggregation", IEEE ICCCN 2016, Hawaii, USA,
August 2016.
[OpenFlowSwitch]
Open Networking Foundation, available at
https://www.opennetworking.org/wp-content/uploads/2014/10/
openflow-switch-v1.5.1.pdf, "OpenFlow Switch Specification
V1.5.1", 2018.
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[Reed] Reed, M., AI-Naday, M., Thomos, N., Trossen, D.,
Petropoulos, G., and S. Spirou, "Stateless Multicast
Switching in Software Defined Networks", IEEE ICC 2016,
Kuala Lumpur, Maylaysia, 2016.
[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>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>.
[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.
[SBA-ENHANCEMENT]
3gpp-sba-enhancement, "S2-182904, New SID for Enhancements
to the Service-Based 5G System Architecture.", 3GPP ,
February 2018 (http://www.3gpp.org/ftp/tsg_sa/WG2_Arch/
TSGS2_126_Montreal/Docs/S2-182904.zip).
[SDN-DEFINITION]
Open Networking Foundation, available at
https://www.opennetworking.org/sdn-definition/, "Software-
Defined Networking (SDN) Definition", 2018.
[TS23.501]
3gpp-23.501, "Technical Specification Group Services and
System Aspects; System Architecture for the 5G System;
Stage 2 (Rel.15)", 3GPP , December 2018.
[TS23.502]
3gpp-23.502, "Technical Specification Group Services and
System Aspects; Procedures for the 5G System; Stage 2
(Rel. 15)", 3GPP , January 2019.
[TS29.500]
3gpp-29.500, "Technical Realization of Service Based
Architecture.", 3GPP , January 2018.
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Authors' Addresses
Dirk Trossen
InterDigital Inc.
64 Great Eastern Street, 1st Floor
London EC2A 3QR
United Kingdom
Email: Dirk.Trossen@InterDigital.com
URI: http://www.InterDigital.com/
Chonggang Wang
InterDigital Inc.
1001 E Hector St, Suite 300
Conshohocken PA 19428
United States
Email: Chonggang.Wang@InterDigital.com
URI: http://www.InterDigital.com/
Sebastian Robitzsch
InterDigital Inc.
64 Great Eastern Street, 1st Floor
London EC2A 3QR
United Kingdom
Email: Sebastian.Robitzsch@InterDigital.com
URI: http://www.InterDigital.com/
Martin Reed
Essex University
Colchester
United Kingdom
Email: mjreed@essec.ac.uk
URI: https://www.essex.ac.uk/people/reedm58703/martin-reed
Mays Al-Naday
Essex University
Colchester
United Kingdom
Email: mfhaln@essec.ac.uk
URI: https://www.essex.ac.uk/people/alned81405/mays-al-naday
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Janne Riihijarvi
RWTH Aachen
Aachen
Germany
Email: jariihij@googlemail.com
URI: https://www.inets.rwth-aachen.de/about-us/janne-riihijaervi/
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