ICN Research Group Prakash Suthar
Internet-Draft Milan Stolic
Intended status: Informational Anil Jangam, Ed.
Expires: September 12, 2019 Cisco Systems Inc.
Dirk Trossen
InterDigital Inc.
Ravishankar Ravindran
Huawei Technologies
March 11, 2019
Native Deployment of ICN in LTE, 4G Mobile Networks
draft-irtf-icnrg-icn-lte-4g-03
Abstract
LTE, 4G mobile networks use IP based transport for control plane to
establish the data session and user plane for actual data delivery.
In existing architecture, IP transport used in user plane is not
optimized for data transport, which leads to an inefficient data
delivery. IP unicast routing from server to clients is used for
delivery of multimedia content to User Equipment (UE), where each
user gets a separate stream. From bandwidth and routing perspective
this approach is inefficient. Multicast and broadcast technologies
have emerged recently for mobile networks, but their deployments are
very limited or at an experimental stage due to complex architecture
and radio spectrum issues. ICN is a rapidly emerging technology with
built-in features for efficient multimedia data delivery, however
majority of the work is focused on fixed networks. The main focus of
this draft is on native deployment of ICN in cellular mobile networks
by using ICN in 3GPP protocol stack. ICN has an inherent capability
for multicast, anchorless mobility, security and it is optimized for
data delivery using local caching at the edge. The proposed
approaches in this draft allow ICN to be enabled natively over the
current LTE stack comprising of PDCP/RLC/MAC/PHY or in a dual stack
mode (along with IP) help optimize the mobile networks by leveraging
the inherent benefits of ICN.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions and Terminology . . . . . . . . . . . . . . . 3
1.2. 3GPP Terminology and Concepts . . . . . . . . . . . . . . 3
2. LTE, 4G Mobile Network . . . . . . . . . . . . . . . . . . . 7
2.1. Network Overview . . . . . . . . . . . . . . . . . . . . 7
2.2. QoS Challenges . . . . . . . . . . . . . . . . . . . . . 9
2.3. Data Transport Using IP . . . . . . . . . . . . . . . . . 10
2.4. Virtualizing Mobile Networks . . . . . . . . . . . . . . 11
3. Data Transport Using ICN . . . . . . . . . . . . . . . . . . 11
4. ICN Deployment in 4G and LTE Networks . . . . . . . . . . . . 14
4.1. General ICN Deployment Considerations . . . . . . . . . . 14
4.2. ICN Deployment Scenarios . . . . . . . . . . . . . . . . 14
4.3. ICN Deployment in LTE Control Plane . . . . . . . . . . . 18
4.4. ICN Deployment in LTE User Plane . . . . . . . . . . . . 19
4.4.1. Dual stack ICN Deployments in UE . . . . . . . . . . 20
4.4.2. Native ICN Deployments in UE . . . . . . . . . . . . 23
4.5. ICN Deployment in eNodeB . . . . . . . . . . . . . . . . 24
4.6. ICN Deployment in Packet Core (SGW, PGW) Gateways . . . . 26
4.7. Lab Testing . . . . . . . . . . . . . . . . . . . . . . . 28
5. Security Considerations . . . . . . . . . . . . . . . . . . . 29
6. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 31
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.1. Normative References . . . . . . . . . . . . . . . . . . 31
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8.2. Informative References . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36
1. Introduction
LTE mobile technology is built as all-IP network. It uses IP routing
protocols such as OSPF, ISIS, BGP etc. to establish network routes to
route the data traffic to end user's device. Stickiness of IP
address to a device is the key to get connected to a mobile network
and the same IP address is maintained through the session until the
device gets detached or moves to another network.
One of the key protocols used in 4G and LTE networks is GPRS
Tunneling protocol (GTP). GTP, DIAMETER and other protocols are
built on top of IP. One of the biggest challenges with IP based
routing is that it is not optimized for data transport although it is
the most efficient communication protocol. By native implementation
of Information Centric Networking (ICN) in 3GPP, we can re-architect
mobile network and optimize its design for efficient data transport
by leveraging the caching feature of ICN. ICN also offers an
opportunity to leverage inherent capabilities of multicast,
anchorless mobility management, and authentication. This draft
provides insight into different options for deploying ICN in mobile
networks and how they impact mobile providers and end-users.
1.1. Conventions and Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
1.2. 3GPP Terminology and Concepts
1. Access Point Name
The Access Point Name (APN) is a Fully Qualified Domain Name
(FQDN) and resolves to a set of gateways in an operator's
network. APN identifies the packet data network (PDN) that a
mobile data user wants to communicate with. In addition to
identifying a PDN, an APN may also be used to define the type of
service, QoS and other logical entities inside GGSN, PGW.
2. Control Plane
The control plane carries signaling traffic and is responsible
for routing between eNodeB and MME, MME and HSS, MME and SGW,
SGW and PGW etc. Control plane signaling is required to
authenticate and authorize UE and establish mobility session
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with mobile gateways (SGW/PGW). Functions of the control plane
also include system configuration and management.
3. Dual Address PDN/PDP Type
The dual address Packet Data Network/Packet Data Protocol (PDN/
PDP) Type (IPv4v6) is used in 3GPP context in many cases as a
synonym for dual-stack, i.e. a connection type capable of
serving both IPv4 and IPv6 simultaneously.
4. eNodeB
The eNodeB is a base station entity that supports the Long-Term
Evolution (LTE) air interface.
5. Evolved Packet Core
The Evolved Packet Core (EPC) is an evolution of the 3GPP GPRS
system characterized by a higher-data-rate, lower-latency,
packet-optimized system. The EPC comprises some of the sub
components of the EPS core such as Mobility Management Entity
(MME), Serving Gateway (SGW), Packet Data Network Gateway (PDN-
GW), and Home Subscriber Server (HSS).
6. Evolved Packet System
The Evolved Packet System (EPS) is an evolution of the 3GPP
GPRSsystem characterized by a higher-data-rate, lower-latency,
packet-optimized system that supports multiple Radio Access
Technologies (RATs). The EPS comprises the EPC together with
the Evolved Universal Terrestrial Radio Access (E-UTRA) and the
Evolved Universal Terrestrial Radio Access Network (E-UTRAN).
7. Evolved UTRAN
The Evolved UTRAN (E-UTRAN) is a communications network,
sometimes referred to as 4G, and consists of eNodeBs (4G base
stations). The E-UTRAN allows connectivity between the User
Equipment and the core network.
8. GPRS Tunnelling Protocol
The GPRS Tunnelling Protocol (GTP) [TS29.060] [TS29.274]
[TS29.281] is a tunnelling protocol defined by 3GPP. It is a
network-based mobility protocol and is similar to Proxy Mobile
IPv6 (PMIPv6). However, GTP also provides functionality beyond
mobility, such as in-band signaling related to Quality of
Service (QoS) and charging, among others.
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9. Gateway GPRS Support Node
The Gateway GPRS Support Node (GGSN) is a gateway function in
the GPRS and 3G network that provides connectivity to the
Internet or other PDNs. The host attaches to a GGSN identified
by an APN assigned to it by an operator. The GGSN also serves
as the topological anchor for addresses/prefixes assigned to the
User Equipment.
10. General Packet Radio Service
The General Packet Radio Service (GPRS) is a packet-oriented
mobile data service available to users of the 2G and 3G cellular
communication systems -- the GSM -- specified by 3GPP.
11. Home Subscriber Server
The Home Subscriber Server (HSS) is a database for a given
subscriber and was introduced in 3GPP Release-5. It is the
entity containing the subscription-related information to
support the network entities actually handling calls/sessions.
12. Mobility Management Entity
The Mobility Management Entity (MME) is a network element that
is responsible for control-plane functionalities, including
authentication, authorization, bearer management, layer-2
mobility, etc. The MME is essentially the control-plane part of
the SGSN in the GPRS. The user-plane traffic bypasses the MME.
13. Public Land Mobile Network
The Public Land Mobile Network (PLMN) is a network that is
operated by a single administration. A PLMN (and therefore also
an operator) is identified by the Mobile Country Code (MCC) and
the Mobile Network Code (MNC). Each (telecommunications)
operator providing mobile services has its own PLMN.
14. Policy and Charging Control
The Policy and Charging Control (PCC) framework is used for QoS
policy and charging control. It has two main functions: flow-
based charging, including online credit control and policy
control (e.g., gating control, QoS control, and QoS signaling).
It is optional to 3GPP EPS but needed if dynamic policy and
charging control by means of PCC rules based on user and
services are desired.
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15. Packet Data Network
The Packet Data Network (PDN) is a packet-based network that
either belongs to the operator or is an external network such as
the Internet or a corporate intranet. The user eventually
accesses services in one or more PDNs. The operator's packet
core networks are separated from packet data networks either by
GGSNs or PDN Gateways (PGWs).
16. Serving Gateway
The Serving Gateway (SGW) is a gateway function in the EPS,
which terminates the interface towards the E-UTRAN. The SGW is
the Mobility Anchor point for layer-2 mobility (inter-eNodeB
handovers). For each UE connected with the EPS, at any given
point in time, there is only one SGW. The SGW is essentially
the user-plane part of the GPRS's SGSN.
17. Packet Data Network Gateway
The Packet Data Network Gateway (PGW) is a gateway function in
the Evolved Packet System (EPS), which provides connectivity to
the Internet or other PDNs. The host attaches to a PGW
identified by an APN assigned to it by an operator. The PGW
also serves as the topological anchor for addresses/prefixes
assigned to the User Equipment.
18. Packet Data Protocol Context
A Packet Data Protocol (PDP) context is the equivalent of a
virtual connection between the User Equipment (UE) and a PDN
using a specific gateway.
19. Packet Data Protocol Type
A Packet Data Protocol Type (PDP Type) identifies the used/
allowed protocols within the PDP context. Examples are IPv4,
IPv6, and IPv4v6 (dual-stack).
20. Serving GPRS Support Node
The Serving GPRS Support Node (SGSN) is a network element that
is located between the radio access network (RAN) and the
gateway (GGSN). A per-UE point-to-point (p2p) tunnel between
the GGSN and SGSN transports the packets between the UE and the
gateway.
21. Terminal Equipment
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The Terminal Equipment (TE) is any device/host connected to the
Mobile Terminal (MT) offering services to the user. A TE may
communicate to an MT, for example, over the Point to Point
Protocol (PPP).
22. UE, MS, MN, and Mobile
The terms UE (User Equipment), MS (Mobile Station), MN (Mobile
Node), and mobile refer to the devices that are hosts with the
ability to obtain Internet connectivity via a 3GPP network. A
MS is comprised of the Terminal Equipment (TE) and a Mobile
Terminal (MT). The terms UE, MS, MN, and mobile are used
interchangeably within this document.
23. User Plane
The user plane refers to data traffic and the required bearers
for the data traffic. In practice, IP is the only data traffic
protocol used in the user plane.
2. LTE, 4G Mobile Network
2.1. Network Overview
With the introduction of LTE, mobile networks moved to all-IP
transport for all elements such as eNodeB, MME, SGW/PGW, HSS, PCRF,
routing and switching etc. Although LTE network is data-centric, it
has support for legacy Circuit Switch features like voice and SMS
through transitional CS fallback and flexible IMS deployment
[GRAYSON]. For each mobile device attached to the radio (eNodeB)
there is a separate overlay tunnel (GPRS Tunneling Protocol, GTP)
between eNodeB and Mobile gateways (i.e. SGW, PGW).
The GTP tunnel is used to carry user traffic between gateways and
mobile devices, this forces data to be only distributed using unicast
mechanism. It is also important to understand the overhead of a GTP
and IPSec protocols because it has impact on the carried user data
traffic. All mobile backhaul traffic is encapsulated using GTP
tunnel, which has overhead of 8 bytes on top of IP and UDP [NGMN].
Additionally, if IPSec is used for security (which is often required
if the Service provider is using a shared backhaul), it adds overhead
based upon IPSec tunneling model (tunnel or transport), and
encryption and authentication header algorithm used. If we factor
Advanced Encryption Standard (AES) encryption with the packet size,
the overhead can be significant [OLTEANU], particularly for the
smaller payloads.
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When any UE is powered up, it attaches to a mobile network based on
its configuration and subscription. After successful attach
procedure, UE registers with the mobile core network and IPv4 and/or
IPv6 address is assigned. A default bearer is created for each UE
and it is assigned to default Access Point Name (APN).
+-------+ Diameter +-------+
| HSS |------------| SPR |
+-------+ +-------+
| |
+------+ +------+ S4 | +-------+
| 3G |---| SGSN |----------------|------+ +------| PCRF |
^ |NodeB | | |---------+ +---+ | | +-------+
+-+ | +------+ +------+ S3 | | S6a | |Gxc |
| | | +-------+ | | |Gx
+-+ | +------------------| MME |------+ | | |
UE v | S1MME +-------+ S11 | | | |
+----+-+ +-------+ +-------+
|4G/LTE|------------------------------| SGW |-----| PGW |
|eNodeB| S1U +-------+ +--| |
+------+ | +-------+
+---------------------+ | |
S1U GTP Tunnel traffic | +-------+ | |
S2a GRE Tunnel traffic |S2A | ePDG |-------+ |
S2b GRE Tunnel traffic | +-------+ S2B |SGi
SGi IP traffic | | |
+---------+ +---------+ +-----+
| Trusted | |Untrusted| | CDN |
|non-3GPP | |non-3GPP | +-----+
+---------+ +---------+
| |
+-+ +-+
| | | |
+-+ +-+
UE UE
Figure 1: LTE, 4G Mobile Network Overview
The data delivered to mobile devices is unicast inside GTP tunnel.
If we consider combined impact of GTP, IPSec and unicast traffic, the
data delivery is not efficient. IETF has developed various header
compression algorithms to reduce the overhead associated with IP
packets. Some of techniques are robust header compression (ROHC) and
enhanced compression of the real-time transport protocol (ECRTP) so
that impact of overhead created by GTP, IPsec etc. is reduced to some
extent [BROWER]. For commercial mobile networks, 3GPP has adopted
different mechanisms for header compression to achieve efficiency in
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data delivery [TS25.323], and can be adapted to ICN as well
[ICNLOWPAN] [TLVCOMP].
2.2. QoS Challenges
During attach procedure, default bearer is created for each UE and it
is assigned to the default Access Point Name (APN). The QoS values
uplink and downlink bandwidth assigned during initial attach are
minimal. Additional dedicated bearer(s) with enhanced QoS parameters
is established depending on the specific application needs.
While all traffic within a certain bearer gets the same treatment,
QoS parameters supporting these requirements can be very granular in
different bearers. These values vary for the control, management and
user traffic, and depending on the application key parameters, such
as latency, jitter (important for voice and other real-time
applications), packet loss and queuing mechanism (strict priority,
low-latency, fair etc.) can be very different.
Implementation of QoS for mobile networks is done at two stages: at
content prioritization/marking and transport marking, and congestion
management. From the transport perspective, QoS is defined at layer
2 as class of service (CoS) and at layer 3 either as DiffServ code
point (DSCP) or type of service (ToS). The mapping of CoS to DSCP
takes place at layer 2/3 switching and routing elements. 3GPP has
specified QoS Class Identifier (QCI) which represents different types
of content and equivalent mapping to DSCP at transport layer
[TS23.401]; however, this requires manual configuration at different
elements and if there are misconfigurations at any place in the path
it will not work properly.
In summary QoS configuration for mobile network for user plane (for
user traffic) and transport in IP based mobile network is complex and
it requires synchronization of parameters among different platforms.
Normally QoS in IP is implemented using DiffServ, which uses hop-by-
hop QoS configuration at each router. Any inconsistency in IP QoS
configuration at routers in the forwarding path can result in poor
subscriber experience (e.g. packet classified as high-priority can go
to lower priority queue). By deploying ICN, we intend to enhance the
subscriber experience using policy-based configuration, which can be
associated with the named contents [ICNQoS] at ICN forwarder.
Further investigation is needed to understand how QoS in ICN can be
implemented to meet the IP QoS requirements [RFC4594].
Research papers published so far explore the possibility of
classifications based on name prefixes (thus addressing the problem
of IP QoS not being information-aware), or on popularity or placement
(basically, looking at a distance of a content from a requester).
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However, a common limitation of these research efforts is that they
focus on faster routing of Interest request towards the content
rather than the quality of experience based on actual content
delivery. For that to happen, QoS should be implemented and enforced
on the Data packet path.
2.3. Data Transport Using IP
The data delivered to mobile devices is unicast inside GTP tunnel
from an eNodeB to a PDN gateway (PGW), as described in 3GPP
specifications [TS23.401]. While the technology exists to address
the issue of possible multicast delivery, there are many difficulties
related to multicast protocol implementation on the RAN side of the
network. Transport networks in the backhaul and core have addressed
the multicast delivery long time ago and have implemented it in most
cases in their multi-purpose integrated transport, but the RAN part
of the network is still lagging behind due to complexities related to
mobility of the clients, handovers, and the fact that the potential
gain to the Service Providers may not justify the investment. With
that said, the data delivery in the mobility remains greatly unicast.
Techniques to handle multicast such as LTE-B or eMBMS have been
designed to handle pre-planned content delivery such as live content,
which contrasts user behavior today, largely based on content (or
video) on demand model.
To ease the burden on the bandwidth of the SGi interface, caching is
introduced in a similar manner as with many Enterprises. In the
mobile networks, whenever possible, a cached data is delivered.
Caching servers are placed at a centralized location, typically in
the Service Provider's Data Center, or in some cases lightly
distributed in the Packet Core locations with the PGW nodes close to
the Internet and IP services access (SGi interface). This is a very
inefficient concept because traffic has to traverse the entire
backhaul path for the data to be delivered to the end-user. Other
issues, such as out-of-order delivery contribute to this complexity
and inefficiency, which needs to be addressed at the application
level.
The data delivered to mobile devices is unicast inside a GTP tunnel.
If we consider combined impact of GTP, IPSec and unicast traffic, the
end-to-end data delivery is not efficient. By deploying ICN, we
intend to either terminate GTP tunnel at the mobility anchoring point
by leveraging control and user plane separation or replace it with
the native ICN protocols.
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2.4. Virtualizing Mobile Networks
The Mobile packet core deployed in a major service provider network
is either based on dedicated hardware or large capacity x86 platforms
in some cases. With adoption of Mobile Virtual Network Operators
(MVNO), public safety network, and enterprise mobility network, we
need elastic mobile core architecture. By deploying mobile packet
core on a commercially off the shelf (COTS) platform using
virtualized infrastructure (NFVI) framework and end-to-end
orchestration, we can simplify new deployments and provide optimized
total cost of ownership (TCO).
While virtualization is growing, and many mobile providers use hybrid
architecture consisting of dedicated and virtualized infrastructures,
the control and data delivery planes are still the same. There is
also work underway to separate control plane and user plane so that
the network can scale better. Virtualized mobile networks and
network slicing with control and user plane separation provide
mechanism to evolve GTP-based architecture to open-flow SDN-based
signaling for LTE and proposed 5G core. Some of early architecture
work for 5G mobile technologies provides mechanism for control and
user plane separation and simplifies mobility call flow by
introduction of open- flow based signaling [ICN5G]. This has been
considered by 3GPP [EPCCUPS] and is also described in [SDN5G].
3. Data Transport Using ICN
For mobile devices, the edge connectivity to the network is between
radio and a router or mobile edge computing (MEC) [MECSPEC] element.
MEC has the capability of processing client requests and segregating
control and user traffic at the edge of radio rather than sending all
requests to the mobile gateway.
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+----------+
| Content +----------------------------------------+
| Publisher| |
+---+---+--+ |
| | +--+ +--+ +--+ |
| +--->|R1|------------>|R2|---------->|R4| |
| +--+ +--+ +--+ |
| | Cached |
| v content |
| +--+ at R3 |
| +========|R3|---+ |
| # +--+ | |
| # | |
| v v |
| +-+ +-+ |
+---------------| |-------------| |-------------+
+-+ +-+
Consumer-1 Consumer-2
UE UE
===> Content flow from cache
---> Content flow from publisher
Figure 2: ICN Architecture
MEC transforms radio into an intelligent service edge that is capable
of delivering services directly from the edge of the network, while
providing the best possible performance to the client. MEC can be an
ideal candidate for ICN forwarder in addition to its usual function
of managing mobile termination. In addition to MEC, other transport
elements, such as routers, can work as ICN forwarders.
Data transport using ICN is different compared to IP-based transport.
It evolves the Internet infrastructure by introducing uniquely named
data as a core Internet principle. Communication in ICN takes place
between content provider (producer) and end user (consumer) as
described in Figure 2.
Every node in a physical path between a client and a content provider
is called ICN forwarder or router, and it has the ability to route
the request intelligently and to cache the content so that it can be
delivered locally for subsequent request from any other client. For
mobile network, transport between a client and a content provider
consists of radio network + mobile backhaul and IP core transport +
Mobile Gateways + Internet + content data network (CDN).
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In order to understand suitability of ICN for mobile networks, we
will discuss the ICN framework describing protocols architecture and
different types of messages, and then consider how we can use this in
a mobile network for delivering content more efficiently. ICN uses
two types of packets called "interest packet" and "data packet" as
described in Figure 3.
+------------------------------------+
Interest | +------+ +------+ +------+ | +-----+
+-+ ---->| CS |---->| PIT |---->| FIB |--------->| CDN |
| | | +------+ +------+ +------+ | +-----+
+-+ | | Add | Drop | | Forward
UE <--------+ Intf v Nack v |
Data | |
+------------------------------------+
+------------------------------------+
+-+ | Forward +------+ | +-----+
| | <-------------------------------------| PIT |<---------| CDN |
+-+ | | Cache +--+---+ | Data +-----+
UE | +--v---+ | |
| | CS | v |
| +------+ Discard |
+------------------------------------+
Figure 3: ICN Interest, Data Packet and Forwarder
In an LTE network, when a mobile device wants to get certain content,
it will send an Interest message to the closest eNodeB. Interest
packet follows the TLV format [CCNxTLV] and contains mandatory fields
such as name of the content and content matching restrictions
(KeyIdRestr and ContentObjectHashRestr) forming the tuple [CCNxSem].
The content matching tuple uniquely identifies the correlation
between an Interest and data packet. Another attribute called
HopLimit is used to detect looping Interest messages. Interest
looping is not prevented, and looped Interest packets are eventually
discarded at the expiry of HopLimit.
An ICN router will receive Interest packet and perform lookup if
request for such content has come earlier from any other client. If
yes, it is served from the local cache, otherwise request is
forwarded to the next-hop ICN router. Each ICN router maintains
three data structures, namely Pending Interest Table (PIT),
Forwarding Information Base (FIB), and Content Store (CS). The
Interest packet travels hop-by-hop towards content provider. Once
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the Interest reaches the content provider it will return a Data
packet containing information such as content name, signature, signed
key and data.
Data packet travels in reverse direction following the same path
taken by the interest packet so routing symmetry is maintained.
Details about algorithms used in PIT, FIB, CS and security trust
models are described in various resources [CCN], here we explained
the concept and its applicability to the LTE network.
4. ICN Deployment in 4G and LTE Networks
4.1. General ICN Deployment Considerations
In LTE/4G mobile networks, both user and control plane traffic have
to be transported from the edge to the mobile packet core via IP
transport. The evolution of existing mobile packet core using CUPS
[TS23.714] enables flexible network deployment and operation, by
distributed deployment and the independent scaling between control
plane and user plane functions - while not affecting the
functionality of the existing nodes subject to this split.
In the CUPS architecture, there is an opportunity to shorten the path
for user plane traffic by deploying offload nodes closer to the edge
[OFFLOAD]. With this major architecture change, User Plane Function
(UPF) node is placed close to the edge so traffic no longer needs to
traverse the entire backhaul path to reach the EPC. In many cases,
where feasible, UPF can be collocated with the eNodeB, which is also
a business decision based on the user demand. Placing a Publisher
close to the offload site, or at the offload site, provides for a
significant improvement in user experience, especially with the
latency-sensitive applications. This optimization allows for the
introduction of ICN and amplifies its advantages. This section
analyzes the potential impact of ICN on control and user plane
traffic for centralized and disaggregate CUPS based mobile network
architecture.
4.2. ICN Deployment Scenarios
Deployment of ICN provides an opportunity to further optimize the
existing data transport in LTE/4G mobile networks. The various
deployment options that ICN and IP provide are somewhat analogous to
the deployment scenarios when IPv6 was introduced to inter operate
with IPv4, except with ICN the whole IP stack is being replaced. We
have reviewed [RFC6459] and analyzed the impact of ICN on control
plane signaling and user plane data delivery. In general, ICN can be
deployed by natively replacing IP transport (IPv4 and IPv6) or as an
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overlay protocol. Figure 4 describes a modified protocol stack to
support ICN deployment scenarios.
+----------------+ +-----------------+
| ICN App (new) | |IP App (existing)|
+---------+------+ +-------+---------+
| |
+---------+----------------+---------+
| Transport Convergence Layer (new) |
+------+---------------------+-------+
| |
+------+------+ +------+-------+
|ICN function | | IP function |
| (New) | | (Existing) |
+------+------+ +------+-------+
| |
(```). (```).
( ICN '`. ( IP '`.
( Cloud ) ( Cloud )
` __..'+' ` __..'+'
Figure 4: IP/ICN Convergence and Deployment Scenarios
As shown in Figure 4, for applications running either in UE or in
content provider system to use the new transport option, we propose a
new transport convergence layer (TCL). This transport convergence
layer helps determine what type of transport (e.g. ICN or IP), as
well as type of radio interface (e.g. LTE or WiFi or both), is used
to send and receive the traffic based on preference e.g. content
location, content type, content publisher, congestion, cost, quality
of service etc. It helps to configure and decide the type of
connection as well as the overlay mode (ICNoIP or IPoICN) between
application and the protocol stack (IP or ICN) to be used.
The ICN function together with existing IP function provides the
support for either native ICN and/or the dual stack (ICN/IP)
transport functionality. More elaborate description on these
functional layers are provided in Section 4.4.1.
TCL can use a number of mechanisms for the selection of transport.
It can use a per application configuration through a management
interface, possibly even a user-facing setting realized through a
user interface, similar to those used today that select cellular over
WiFi being used for selected applications. In another option, it
might use a software API, which an adapted IP application could use
to specify e.g. an ICN transport for obtaining its benefits.
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Another potential application of TCL is in implementation of network
slicing, where it can have a slice management capability locally or
it can interface to an external slice manager through an API [GALIS].
This solution can enable network slicing for IP and ICN transport
selection from the UE itself. The TCL could apply slice settings to
direct certain traffic (or applications) over one slice and others
over another slice, determined by some form of 'slicing policy'.
Slicing policy can be obtained externally from slice manager or
configured locally on UE.
From the perspective of the applications either on UE or content
provider, following options are possible for the deployment of ICN
natively and/or with IP.
1. IP over IP
In this scenario UE uses applications tightly integrated with the
existing IP transport infrastructure. In this option, the TCL
has no additional function since the packets are directly
forwarded using IP protocol stack, which in turn sends the
packets over the IP transport.
2. ICN over ICN
Similar to case 1 above, ICN applications tightly integrate with
the ICN transport infrastructure. The TCL has no additional
responsibility since the packets are directly forwarded using ICN
protocol stack, which in turn sends the packets over the ICN
transport.
3. ICN over IP (ICNoIP)
In ICN over IP scenario, the underlying IP transport
infrastructure is not impacted (i.e. ICN is implemented, as an
IP overlay, between user equipment (UE) and content provider).
IP routing is used from Radio Access Network (eNodeB) to mobile
backhaul, IP core and Mobile Gateway (SGW/PGW). UE attaches to
Mobile Gateway (SGW/PGW) using IP address. Also, the data
transport between Mobile Gateway (SGW/PGW) and content publisher
uses IP. Content provider is capable of serving content either
using IP or ICN, based on UE request.
An approach to implement ICN in mobile backhaul networks is
described in [MBHICN]. It implements a GTP-U extension header
option to encapsulate ICN payload in GTP tunnel. However, as
this design runs ICN as an overlay over IP, it would complement
only ICNoIP use case scenario described in this draft. In
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addition, the design assumes a proxy function at the edge, to
perform ICN data retrieval on behalf of a non-ICN end device.
Detailed deployment of use cases is described in section 4.4.
Application conveys the preference to the TCL, which in turn
sends the ICN data packets using the IP transport.
4. IP over ICN (IPoICN)
H2020 project [H2020] provides an architectural framework for
deployment of IP as an overlay over ICN protocol [IPoICN].
Implementing IP services over ICN provides an opportunity
leveraging benefit of ICN in the transport infrastructure and
there is no impact on end devices (UE and access network) as they
continue to use IP. IPoICN however, will require an inter-
working function (IWF/Border Gateway) to translate various
transport primitives. IWF function will provide a mechanism for
protocol translation between IPoICN and native IP deployment for
mobile network. After reviewing [IPoICN], we understand and
interpret that ICN is implemented in the transport natively;
however, IP is implemented in UE, eNodeB, and Mobile gateway
(SGW/PGW), which is also called as network attach point (NAP).
For this, said NAP receives an incoming IP or HTTP packet (the
latter through TCP connection termination) and publishes the
packet under a suitable ICN name (i.e. the hash over the
destination IP address for an IP packet or the hash over the FQDN
of the HTTP request for an HTTP packet) to the ICN network. In
the HTTP case, the NAP maintains a pending request mapping table
to map returning responses to the terminated TCP connection.
5. Hybrid ICN (hICN)
An alternative approach to implement ICN over IP is provided in
Hybrid ICN [HICN]. It describes a novel approach to integrate
ICN into IPv6 without creating overlays with a new packet format
as an encapsulation. HICN address the content by encoding a
location independent name in an IPv6 address. It uses two name
components, namely name prefix and name suffix, which identify
the source of data and the data segment within the scope of name
prefix respectively.
From the perspective of this draft, HICN provides an alternative
transport layer, to be used by the UE and mobile core network
nodes, which can be selected by the TCL.
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4.3. ICN Deployment in LTE Control Plane
In this section we analyze signaling messages which are required for
different procedures, such as attach, handover, tracking area update
etc. The goal of analysis is to see if there is any benefit to
replace IP-based protocols with ICN for LTE signaling in the current
architecture. It is important to understand the concept of point of
attachment (POA). When UE connects to a network it has following
POAs:
1. eNodeb managing location or physical POA
2. Authentication and Authorization (MME, HSS) managing identity or
authentication POA
3. Mobile Gateways (SGW, PGW) managing logical or session management
POA
In current architecture IP transport is used for all the messages
associated with Control Plane for mobility and session management.
IP is embedded very deeply into these messages and TLV carrying
additional attributes as a layer 3 transport. Physical POA in eNodeB
handles both mobility and session management for any UE attached to
4G, LTE network. The number of mobility management messages between
different nodes in an LTE network per signaling procedure are shown
in Table 1.
Normally two types of UE devices attach to LTE network: SIM based
(need 3GPP mobility protocol for authentication) or non-SIM based
(which connect to WiFi network), and authentication is required for
both of these device types. For non-SIM based devices, AAA is used
for authentication. We do not propose to change UE authentication or
mobility management messaging for user data transport using ICN. A
separate study would be required to analyze impact of ICN on mobility
management messages structures and flows. We are merely analyzing
the viability of implementing ICN as a transport for Control plane
messages.
It is important to note that even if MME and HSS do not support ICN
transport, they still need to support UE capable of dual stack or
native ICN. When UE initiates attach request using the identity as
ICN, MME must be able to parse that message and create a session.
MME forwards UE authentication to HSS so HSS must be able to
authenticate an ICN capable UE and authorize create session
[TS23.401].
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+---------------------------+-----+-----+-----+-----+------+
| LTE Signaling Procedures | MME | HSS | SGW | PGW | PCRF |
+---------------------------+-----+-----+-----+-----+------+
| Attach | 10 | 2 | 3 | 2 | 1 |
| Additional default bearer | 4 | 0 | 3 | 2 | 1 |
| Dedicated bearer | 2 | 0 | 2 | 2 | 0 |
| Idle-to-connect | 3 | 0 | 1 | 0 | 0 |
| Connect-to-Idle | 3 | 0 | 1 | 0 | 0 |
| X2 handover | 2 | 0 | 1 | 0 | 0 |
| S1 handover | 8 | 0 | 3 | 0 | 0 |
| Tracking area update | 2 | 2 | 0 | 0 | 0 |
| Total | 34 | 2 | 14 | 6 | 3 |
+---------------------------+-----+-----+-----+-----+------+
Table 1: Signaling Messages in LTE Gateways
Anchorless mobility [ALM] provides a fully decentralized, control-
plane agnostic solution to handle producer mobility in ICN. Mobility
management at layer-3 level makes it access agnostic and transparent
to the end device or the application. The solution discusses about
handling of mobility without having to depend on the core network
functions (e.g. MME); however, location update to the core network
may still be required to support legal compliance requirements such
as lawful intercept and emergency services. These aspects are open
for further study.
The main advantage of ICN is in caching and reusing the content,
which does not apply to the transactional signaling exchange. After
analyzing LTE signaling call flows [TS23.401] and messages inter-
dependencies Table 1, our recommendation is that it is not beneficial
to deploy ICN for control plane and mobility management functions.
Among the features of ICN design such as, Interest aggregation and
content caching is not applicable to control plane signaling
messages. Control plane messages are originated and consumed by the
applications and they canot be shared.
4.4. ICN Deployment in LTE User Plane
We will consider Figure 1 to discuss different mechanisms to deploy
ICN in mobile networks. In section 4.2 we discussed generi
deployment scenarios of ICN. In this section, we shall see the
specific use cases of native ICN deployment in LTE user plane. We
consider the following options:
1. Dual stack ICN deployment in UE
2. Native ICN Deployments in UE
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3. ICN Deployment in eNodeB
4. ICN Deployment in mobile gateways (SGW/PGW)
4.4.1. Dual stack ICN Deployments in UE
The control and user plane communications in LTE, 4G mobile networks
are specified in 3GPP documents [TS23.203] and [TS23.401]. It is
important to understand that UE can be either consumer (receiving
content) or publisher (pushing content for other clients). The
protocol stack inside mobile device (UE) is complex as it has to
support multiple radio connectivity access to eNodeB(s).
Figure 5 provides high level description of a protocol stack, where
IP is defined at two layers: (1) at user plane communication, (2)
Transport layer. User plane communication takes place between Packet
Data Convergence Protocol (PDCP) and Application layer, whereas
transport layer is at GTP protocol stack.
The protocol interactions and impact of supporting tunneling of ICN
packet into IP or to support ICN natively are described in Figure 5
and Figure 6 respectively.
+--------+ +--------+
| App | | CDN |
+--------+ +--------+
|Transp. | | | | |Transp. |
|Converg.|.|..............|...............|............|.|Converge|
+--------+ | | | +--------+ | +--------+
| |.|..............|...............|.| |.|.| |
| ICN/IP | | | | | ICN/IP | | | ICN/IP|
| | | | | | | | | |
+--------+ | +----+-----+ | +-----+-----+ | +-----+--+ | +--------+
| |.|.| | |.|.| | |.|.| | | | | |
| PDCP | | |PDCP|GTP-U| | |GTP-U|GTP-U| | |GTP-U| | | | L2 |
+--------+ | +----------+ | +-----------+ | +-----+ | | | |
| RLC |.|.|RLC | UDP |.|.| UDP | UDP |.|.|UDP |L2|.|.| |
+--------+ | +----------+ | +-----------+ | +-----+ | | | |
| MAC |.|.| MAC| L2 |.|.| L2 | L2 |.|.| L2 | | | | |
+--------+ | +----------+ | +-----------+ | +--------+ | +--------+
| L1 |.|.| L1 | L1 |.|.| L1 | L1 |.|.| L1 |L1|.|.| L1 |
+--------+ | +----+-----+ | +-----+-----+ | +-----+--+ | +--------+
UE | BS(enodeB) | SGW | PGW |
Uu S1U S5/S8 SGi
Figure 5: Dual stack ICN Deployment in UE
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The protocols and software stack used inside LTE capable UE support
both 3G and LTE software interworking and handover. Latest 3GPP
Rel.13 onward specification describes the use of IP and non-IP
protocols to establish logical/session connectivity. We intend to
leverage the non-IP protocol-based mechanism to deploy ICN protocol
stack in UE as well as in eNodeB and mobile gateways (SGW, PGW).
1. Existing application layer can be modified to provide options for
new ICN based application and existing IP based applications. UE
can continue to support existing IP based applications or host
new applications developed either to support native ICN as
transport, ICNoIP or IPoICN based transport. Application layer
has the option of selecting either ICN or IP transport layer as
well as radio interface to send and receive data traffic.
Our proposal is to provide a common Application Programming
Interface (API) to the application developers such that there is
no impact on the application development when they choose either
ICN or IP transport for exchanging the traffic with the network.
As mentioned in section 4.2, the transport convergence layer
(TCL) function handles the interaction of application with the
multiple transport options.
2. The transport convergence layer helps determine what type of
transport (e.g. ICN, hICN, or IP) as well as type of radio
interface (e.g. LTE or WiFi or both), is used to send and
receive the traffic. Application layer can make the decision to
select a specific transport based on preference e.g. content
location, content type, content publisher, congestion, cost,
quality of service etc. There can be an Application Programming
Interface (API) to exchange parameters required for transport
selection. The southbound interactions of Transport Convergence
Layer (TCL) will be either to IP or ICN at the network layer.
When selecting the IPoICN mode, the TCL is responsible for
receiving an incoming IP or HTTP packet and publishing the packet
under a suitable ICN name (i.e. the hash over the destination IP
address for an IP packet or the hash over the FQDN of the HTTP
request for an HTTP packet) to the ICN network. In the HTTP
case, the TCL maintains a pending request mapping table to map
returning responses to the originating HTTP request. The common
API will provide a common 'connection' abstraction for this HTTP
mode of operation, returning the response over said connection
abstraction, akin to the TCP socket interface, while implementing
a reliable transport connection semantic over the ICN from the UE
to the receiving UE or the PGW. If the HTTP protocol stack
remains unchanged, therefore utilizing the TCP protocol for
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transfer, the TCL operates in local TCP termination mode,
retrieving the HTTP packet through said local termination.
+----------------+ +-----------------+
| ICN App (new) | |IP App (existing)|
+---------+------+ +-------+---------+
| |
+---------+----------------+---------+
| Transport Convergence Layer (new) |
+------+---------------------+-------+
| |
+------+------+ +------+-------+
|ICN function | | IP function |
| (New) | | (Existing) |
+------+------+ +------+-------+
| |
+------+---------------------+-------+
| PDCP (updated to support ICN) |
+-----------------+------------------+
|
+-----------------+------------------+
| RLC (Existing) |
+-----------------+------------------+
|
+-----------------+------------------+
| MAC Layer (Existing) |
+-----------------+------------------+
|
+-----------------+------------------+
| Physical L1 (Existing) |
+------------------------------------+
Figure 6: Dual stack ICN protocol interactions
3. ICN function (forwarder) is introduced in parallel to the
existing IP layer. ICN forwarder contains functional
capabilities to forward ICN packets, e.g. Interest packet to
eNodeB or response "data packet" from eNodeB to the application.
4. For dual stack scenario, when UE is not supporting ICN at
transport layer, we use IP underlay to transport ICN packets.
ICN function will use IP interface to send Interest and Data
packets for fetching or sending data using ICN protocol function.
This interface will use ICN overlay over IP using any overlay
tunneling mechanism.
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5. To support ICN at network layer in UE, PDCP layer has to be aware
of ICN capabilities and parameters. PDCP is located in the Radio
Protocol Stack in the LTE Air interface, between IP (Network
layer) and Radio Link Control Layer (RLC). PDCP performs
following functions [TS36.323]:
1. Data transport by listening to upper layer, formatting and
pushing down to Radio Link Layer (RLC)
2. Header compression and decompression using ROHC (Robust
Header Compression)
3. Security protections such as ciphering, deciphering and
integrity protection
4. Radio layer messages associated with sequencing, packet drop
detection and re-transmission etc.
6. No changes are required for lower layer such as RLC, MAC and
Physical (L1) because they are not IP aware.
One key point to understand in this scenario is that ICN is deployed
as an overlay on top of IP.
4.4.2. Native ICN Deployments in UE
We propose to implement ICN natively in UE by modifying PDCP layer in
3GPP protocols. Figure 7 provides a high-level protocol stack
description where ICN is used at following different layers:
1. at user plane communication
2. at transport layer
User plane communication takes place between PDCP and application
layer, whereas transport layer is a substitute of GTP protocol.
Removal of GTP protocol stack is significant change in mobile
architecture because GTP is used not just for routing but for
mobility management functions such as billing, mediation, policy
enforcement etc.
If we implement ICN natively in UE, communication between UE and
eNodeB will change. Also, this will avoid tunneling the user plane
traffic from eNodeB to mobile packet core (SGW, PGW) using GTP
tunnel.
For native ICN deployment, an application will be configured to use
ICN forwarder so there is no need for Transport Convergence. Also,
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to support ICN at network layer in UE, we need to modify existing
PDCP layer. PDCP layer has to be aware of ICN capabilities and
parameters.
Native implementation will also provide opportunities to develop new
use cases leveraging ICN capabilities such as seamless mobility, UE
to UE content delivery using radio network without traversing the
mobile gateways, etc.
+--------+ +--------+
| App | | CDN |
+--------+ +--------+
|Transp. | | | | | |Transp. |
|Converge|.|..............|..............|..............|.|Converge|
+--------+ | | | | +--------+
| |.|..............|..............|..............|.| |
| ICN/IP | | | | | | |
| | | | | | | |
+--------+ | +----+-----+ | +----------+ | +----------+ | | ICN/IP |
| |.|.| | | | | | | | | | | |
| PDCP | | |PDCP| ICN |.|.| ICN |.|.| ICN |.|.| |
+--------+ | +----+ | | | | | | | | | |
| RLC |.|.|RLC | | | | | | | | | | |
+--------+ | +----------+ | +----------+ | +----------+ | +--------+
| MAC |.|.| MAC| L2 |.|.| L2 |.|.| L2 |.|.| L2 |
+--------+ | +----------+ | +----------+ | +----------+ | +--------+
| L1 |.|.| L1 | L1 |.|.| L1 |.|.| L1 |.|.| L1 |
+--------+ | +----+-----+ | +----------+ | +----------+ | +--------+
UE | BS(enodeB) | SGW | PGW |
Uu S1u S5/S8 SGi
Figure 7: Native ICN Deployment in UE
4.5. ICN Deployment in eNodeB
eNodeB is physical point of attachment for UE, where radio protocols
are converted into IP transport protocol as depicted in Figure 6 and
Figure 7 for dual stack/overlay and native ICN respectively. When UE
performs attach procedures, it is assigned an identity either as IP,
dual stack (IP and ICN), or ICN. UE can initiate data traffic using
any of the follwing options:
1. Native IP (IPv4 or IPv6)
2. Native ICN
3. Dual stack IP (IPv4/IPv6) or ICN
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UE encapsulates user data transport request into PDCP layer and sends
the information on air interface to eNodeB. eNodeB receives the
information and using PDCP [TS36.323], de-encapsulates air-interface
messages and converts them to forward to core mobile gateways (SGW,
PGW). As shown in Figure 8, in order to support ICN natively in
eNodeB, it is proposed to provide transport convergence layer (TCL)
capabilities in eNodeB (similar to as provided in UE), which provides
following functions:
1. It decides the forwarding strategy for user data request coming
from UE. The strategy can make decision based on preference
indicated by the application such as congestion, cost, quality of
service, etc.
2. eNodeB to provide open Application Programming Interface (API) to
external management systems, to provide capability to eNodeB to
program the forwarding strategies.
+---------------+ |
| UE request | | ICN +---------+
+---> | content using |--+--- transport -->| |
| |ICN protocol | | | |
| +---------------+ | | |
| | | |
| +---------------+ | | |
+-+ | | UE request | | IP |To mobile|
| |---+---> | content using |--+--- transport -->| GW |
+-+ | | IP protocol | | |(SGW,PGW)|
UE | +---------------+ | | |
| | | |
| +---------------+ | | |
| | UE request | | Dual stack | |
+---> | content using |--+--- IP+ICN -->| |
|IP/ICN protocol| | transport +---------+
+---------------+ |
eNodeB S1u
Figure 8: Native ICN Deployment in eNodeB
3. eNodeB shall be upgraded to support three different types of
transport: IP, ICN, and dual stack IP+ICN towards mobile
gateways, as depicted in Figure 8. It is also recommended to
deploy IP and/or ICN forwarding capabilities into eNodeB for
efficient transfer of data between eNodeB and mobile gateways.
There are following choices for forwarding data request towards
mobile gateways:
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1. Assuming eNodeB is IP-enabled and UE requests IP transfer,
eNodeB forwards data over IP.
2. Assuming eNodeB is ICN-enabled and UE requests ICN transfer,
eNodeB forwards data over ICN.
3. Assuming eNodeB is IP-enabled and UE requests ICN, eNodeB
overlays ICN on IP and forwards the user plane traffic over
IP.
4. Assuming eNodeB is ICN-enabled and UE requests IP, eNodeB
overlays IP on ICN and forwards the user plane traffic over
ICN [IPoICN].
4.6. ICN Deployment in Packet Core (SGW, PGW) Gateways
Mobile gateways a.k.a. Evolved Packet Core (EPC) include SGW, PGW,
which perform session management for UE from the initial attach to
disconnection. When UE is powered on, it performs NAS signaling and
after successful authentication it attaches to PGW. PGW is an
anchoring point for UE and responsible for service creations,
authorization, maintenance etc. Entire functionality is managed
using IP address(es) for UE.
In order to implement ICN in EPC, the following functions are needed.
1. Insert ICN attributes in session management layer as additional
functionality with IP stack. Session management layer is used
for performing attach procedures and assigning logical identity
to user. After successful authentication by HSS, MME sends
create session request (CSR) to SGW and SGW to PGW.
2. When MME sends Create Session Request message (step 12 in
[TS23.401]) to SGW or PGW, it contains Protocol Configuration
Option Information Element (PCO IE) containing UE capabilities.
We can use PCO IE to carry ICN related capabilities information
from UE to PGW. This information is received from UE during the
initial attach request in MME. Details of available TLV, which
can be used for ICN are given in subsequent sections. UE can
support either native IP, or ICN+IP, or native ICN. IP is
referred to as both IPv4 and IPv6 protocols.
3. For ICN+IP capable UE, PGW assigns the UE both IP address and ICN
identity. UE selects either of the identities during the initial
attach procedures and registers with network for session
management. For ICN-capable UE it will provide only ICN
attachment. For native IP-capable UE there is no change.
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4. In order to support ICN-capable attach procedures and use ICN for
user plane traffic, PGW needs to have full ICN protocol stack
functionalities. Typical ICN capabilities include functions such
as content store (CS), Pending Interest Table (PIT), Forwarding
Information Base (FIB) capabilities etc. If UE requests ICN in
PCO IE, then PGW registers UE with ICN names. For ICN
forwarding, PGW caches content locally using CS functionality.
5. PCO IE described in [TS24.008] (see Figure 10.5.136 on page 598)
and [TS24.008] (see Table 10.5.154 on page 599) provide details
for different fields.
1. Octet 3 (configuration protocols define PDN types) which
contains details about IPv4, IPv6, both or ICN.
2. Any combination of Octet 4 to Z can be used to provide
additional information related to ICN capability. It is most
important that PCO IE parameters are matched between UE and
mobile gateways (SGW, PGW) so that they can be interpreted
properly and UE can attach successfully.
6. Deployment of ICN functionalities in SGW and PGW should be
matched with UE and eNodeB because they will exchange ICN
protocols and parameters.
7. Mobile gateways SGW, PGW will also need ICN forwarding and
caching capability. This is especially important if CUPS is
implemented. User Plane Function (UPF), comprising the SGW and
PGW user plane, will be located at the edge of the network and
close to the end-user. ICN-enabled gateway means that this UPF
would serve as a forwarder and should be capable of caching, as
is the case with any other ICN-enabled node.
8. The transport between PGW and CDN provider can be either IP or
ICN. When UE is attached to PGW with ICN identity and
communicates with an ICN-enabled CDN provider, it will use ICN
primitives to fetch the data. On other hand, for a UE attached
with an ICN identity, if PGW has to communicate with an IP-
enabled CDN provider, it will have to use an ICN-IP interworking
gateway to perform conversion between ICN and IP primitives for
data retrieval. In the case of CUPS implementation with an
offload close to the edge, this interworking gateway can be
collocated with the UPF at the offload site to maximize the path
optimization. Further study is required to understand how this
ICN to IP (and vice versa) interworking gateway would function.
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4.7. Lab Testing
To further test the modifications proposed above in different
scenarios, a simple lab has been set up as shown in Figure 9.
+------------------------------------------+
| +-----+ +------+ (```). +------+ | (````). +-----+
| | SUB |-->| EMU |--(x-haul'.-->| EPC |--->( PDN ).-->| CDN |
| +-----+ +------+ `__..'' +------+ | `__...' +-----+
+------------------------------------------+
Figure 9: Native ICN deployment lab setup
The following test scenarios can be set up with VM-based deployment:
1. SUB: ICN simulated client (using ndnSIM), a client application on
workstation requesting content.
2. EMU: test unit emulating eNodeB and UE. This will be a test node
allowing for UE attachment and routing the traffic subsequently
from the Subscriber to the Publisher.
3. EPC: Cisco evolved Packet Core in a single instance (vPC-SI).
4. CDN: content delivery by a Publisher server.
For the purpose of this testing, ICN emulating code (when available)
can be inserted in the test code in EMU to emulate ICN-capable UE
and/or eNodeB. An example of the code to be used is NS3 in its LTE
model. Effect of such traffic on EPC and CDN can be observed and
documented. In a subsequent phase, EPC code supporting ICN can be
tested when available.
Another option is to simulate the UE/eNodeB and EPC functions using
NS3's LTE [NS3LTE] and EPC [NS3EPC] models respectively. LTE model
includes the LTE Radio Protocol stack, which resides entirely within
the UE and the eNB nodes. This capability shall provide the
simulation of UE and eNodeB deployment use cases. Similarly, EPC
model includes core network interfaces, protocols and entities, which
resides within the SGW, PGW and MME nodes, and partially within the
eNB nodes.
Even with its current limitations (i.e. IPv4 only, lack of
integration with ndnSIM, no support for UE idle state etc.) LTE
simulation may be a very useful tool. In any case, both control and
user plane traffic should be tested independently according to the
deployment model discussed in sections 4.4 through 4.6.
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5. Security Considerations
To ensure only authenticated UEs are connected to the network, LTE
mobile network implements various security mechanisms. From
perspective of ICN deployment in user plane, it needs to take care of
the following security aspects:
1. UE authentication and authorization
2. Radio or air interface security
3. Denial of service attacks on mobile gateway, services
4. Content positioning either in transport or servers
5. Content cache pollution attacks
6. Secure naming, routing, and forwarding
7. Application security
Security over the LTE air interface is provided through cryptographic
technique. When UE is powered up, it performs key exchange between
UE's USIM and HSS/Authentication Center using NAS messages including
ciphering and integrity protections between UE and MME. Details of
secure UE authentication, key exchange, ciphering and integrity
protections messages are given in 3GPP call flow [TS23.401].
LTE is an all-IP network and uses IP transport in its mobile backhaul
(e.g. between eNodeB and core network). In case of provider owned
backhaul, it may not implement security mechanisms; however, they are
necessary in case it uses shared or a leased network. The native IP
transport continues to leverage security mechanism such as Internet
key exchange (IKE) and the IP security protocol (IPsec). More
details of mobile backhaul security are provided in 3GPP network
security [TS33.310] and [TS33.320]. When mobile backhaul is upgraded
to support dual stack (IP+ICN) or native ICN, it is required to
implement security techniques which are deployed in mobile backhaul.
When ICN forwarding is enabled on mobile transport routers, we need
to deploy security practices based on [RFC7476] and [RFC7927].
Some of the key functions supported by LTE mobile gateway (SGW, PGW)
are content based billing, deep packet inspection (DPI), and lawful
intercept (LI). For ICN-based user plane traffic, it is required to
integrate ICN security for session between UE and gateway; however,
in ICN network, since only consumers who are in possession of
decryption keys can access the content, some of the services provided
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by mobile gateways mentioned above may not work. Further research in
this area is needed.
6. Summary
In this draft, we have discussed complexities of LTE network and key
dependencies for deploying ICN in user plane data transport.
Different deployment options described cover aspects such as inter-
operability and multi-technology, which is a reality for any service
provider. In section Section 4.7, we provide details of an
experimental setup for evaluation of ICN deployment scenarios,
described in section 4. One can use LTE gateway software and ICN
simulator and deploy ICN data transport in user plane either as an
overlay, dual stack (IP + ICN), hICN, or natively (by integrating ICN
with CDN, eNodeB, SGW, PGW and transport network etc.). Notice that
for above discussed deployment scenarios, additional study is
required for lawful interception, billing/mediation, network slicing,
and provisioning APIs.
Mobile Edge Computing (MEC) [CHENG] provides capabilities to deploy
functionalities such as Content Delivery Network (CDN) caching and
mobile user plane functions (UPF) [TS23.501]. Recent research for
delivering real-time video content [MPVCICN] using ICN has also been
proven to be efficient [NDNRTC] and can be used towards realizing the
benefits of ICN deployment in eNodeB, MEC, mobile gateways (SGW, PGW)
and CDN. The key aspect for ICN is in its seamless integration in
LTE and 5G networks with tangible benefits so that we can optimize
content delivery using simple and scalable architecture. Authors
will continue to explore how ICN forwarding in MEC could be used in
efficient data delivery from mobile edge.
Based on our study of control plane signaling it is not beneficial to
deploy ICN with existing protocols unless further changes are
introduced in the control protocol stack itself. As mentioned in
[TS23.501], 5G network architecture proposes simplification of
control plane messages and can be a candidate for use of ICN.
As a starting step towards ICN user plane deployment, it is
recommended to incorporate protocol changes in UE, eNodeB, SGW/PGW
for data transport. ICN has inherent capabilities for mobility and
content caching, which can improve the efficiency of data transport
for unicast and multicast delivery. Authors welcome the
contributions and suggestions including those related to further
validations of the principles by implementing prototype and/or proof
of concept in the lab and in production environment.
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7. Acknowledgements
We thank all contributors, reviewers and the chairs for the valuable
time in providing the comments and feedback, which has helped to
improve this draft.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[TS24.008]
3GPP, "Mobile radio interface Layer 3 specification; Core
network protocols; Stage 3", 3GPP TS 24.008 3.20.0,
December 2005,
<http://www.3gpp.org/ftp/Specs/html-info/24008.htm>.
[TS25.323]
3GPP, "Packet Data Convergence Protocol (PDCP)
specification", 3GPP TS 25.323 3.10.0, September 2002,
<http://www.3gpp.org/ftp/Specs/html-info/25323.htm>.
[TS29.274]
3GPP, "3GPP Evolved Packet System (EPS); Evolved General
Packet Radio Service (GPRS) Tunnelling Protocol for
Control plane (GTPv2-C); Stage 3", 3GPP TS 29.274 10.11.0,
June 2013,
<http://www.3gpp.org/ftp/Specs/html-info/29274.htm>.
[TS29.281]
3GPP, "General Packet Radio System (GPRS) Tunnelling
Protocol User Plane (GTPv1-U)", 3GPP TS 29.281 10.3.0,
September 2011,
<http://www.3gpp.org/ftp/Specs/html-info/29281.htm>.
[TS36.323]
3GPP, "Evolved Universal Terrestrial Radio Access
(E-UTRA); Packet Data Convergence Protocol (PDCP)
specification", 3GPP TS 36.323 10.2.0, January 2013,
<http://www.3gpp.org/ftp/Specs/html-info/36323.htm>.
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8.2. Informative References
[ALM] Auge, J., Carofiglio, G., Grassi, G., Muscariello, L.,
Pau, G., and X. Zeng, "Anchor-Less Producer Mobility in
ICN", Proceedings of the 2Nd ACM Conference on
Information-Centric Networking, ACM-ICN'15, ACM DL,
pp.189-190, September 2013,
<https://dl.acm.org/citation.cfm?id=2812601>.
[BROWER] Brower, E., Jeffress, L., Pezeshki, J., Jasani, R., and E.
Ertekin, "Integrating Header Compression with IPsec",
MILCOM 2006 - 2006 IEEE Military Communications
conference IEEE Xplore DL, pp.1-6, October 2006,
<https://ieeexplore.ieee.org/document/4086687>.
[CCN] "Content Centric Networking", <http://www.ccnx.org>.
[CCNxSem] Mosko, M., Solis, I., and C. Wood, "CCNx Semantics",
draft-irtf-icnrg-ccnxsemantics-09 (work in progress), June
2018.
[CCNxTLV] Mosko, M., Solis, I., and C. Wood, "CCNx Messages in TLV
Format", draft-irtf-icnrg-ccnxmessages-08 (work in
progress), July 2018.
[CHENG] Liang, C., Yu, R., and X. Zhang, "Information-centric
network function virtualization over 5g mobile wireless
networks", IEEE Network Journal vol. 29, number 3, pp.
68-74, June 2015,
<https://ieeexplore.ieee.org/document/7113228>.
[EPCCUPS] Schmitt, P., Landais, B., and F. Yong Yang, "Control and
User Plane Separation of EPC nodes (CUPS)", 3GPP The
Mobile Broadband Standard, July 2017,
<http://www.3gpp.org/news-events/3gpp-news/1882-cups>.
[GALIS] Galis, A., Makhijani, K., Yu, D., and B. Liu, "Autonomic
Slice Networking", draft-galis-anima-autonomic-slice-
networking-05 (work in progress), September 2018.
[GRAYSON] Grayson, M., Shatzkamer, M., and S. Wainner, "Cisco Press
book "IP Design for Mobile Networks"", Cisco
Press Networking Technology series, June 2009,
<http://www.ciscopress.com/store/
ip-design-for-mobile-networks-9781587058264>.
[H2020] H2020, "The POINT Project", <https://www.point-h2020.eu/>.
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[HICN] Muscariello, L., Carofiglio, G., Auge, J., and M.
Papalini, "Hybrid Information-Centric Networking", draft-
muscariello-intarea-hicn-01 (work in progress), December
2018.
[ICN5G] Ravindran, R., suthar, P., Trossen, D., and G. White,
"Enabling ICN in 3GPP's 5G NextGen Core Architecture",
draft-ravi-icnrg-5gc-icn-02 (work in progress), July 2018.
[ICNLOWPAN]
Gundogan, C., Schmidt, T., Waehlisch, M., Scherb, C.,
Marxer, C., and C. Tschudin, "ICN Adaptation to LowPAN
Networks (ICN LoWPAN)", draft-irtf-icnrg-icnlowpan-02
(work in progress), March 2019.
[ICNQoS] Al-Naday, M., Bontozoglou, A., Vassilakis, G., and M.
Reed, "Quality of Service in an Information-Centric
Network", 2014 IEEE Global Communications Conference IEEE
Xplore DL, pp. 1861-1866, December 2014,
<https://ieeexplore.ieee.org/document/7037079>.
[IPoICN] Trossen, D., Read, M., Riihijarvi, J., Georgiades, M.,
Fotiou, N., and G. Xylomenos, "IP over ICN - The better
IP?", 2015 European Conference on Networks and
Communications (EuCNC) IEEE Xplore DL, pp. 413-417, June
2015, <https://ieeexplore.ieee.org/document/7194109>.
[MBHICN] Carofiglio, G., Gallo, M., Muscariello, L., and D. Perino,
"Scalable mobile backhauling via information-centric
networking", The 21st IEEE International Workshop on Local
and Metropolitan Area Networks, Beijing, pp. 1-6, April
2015, <https://ieeexplore.ieee.org/document/7114719>.
[MECSPEC] "Mobile Edge Computing (MEC); Framework and Reference
Architecture", ETSI European Telecommunication Standards
Institute (ETSI) MEC specification, March 2016,
<https://www.etsi.org/deliver/etsi_gs/
MEC/001_099/003/01.01.01_60/gs_MEC003v010101p.pdf>.
[MPVCICN] Jangam, A., Ravindran, R., Chakraborti, A., Wan, X., and
G. Wang, "Realtime multi-party video conferencing service
over information centric network", IEEE International
Conference on Multimedia and Expo Workshops (ICMEW) Turin,
Italy, pp. 1-6, June 2015,
<https://ieeexplore.ieee.org/document/7169810>.
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[NDNRTC] Gusev, P., Wang, Z., Burke, J., Zhang, L., Yoneda, T.,
Ohnishi, R., and E. Muramoto, "Real-time Streaming Data
Delivery over Named Data Networking,", IEICE Transactions
on Communications vol. E99.B, pp. 974-991, May 2016,
<https://doi.org/10.1587/transcom.2015AMI0002>.
[NGMN] Robson, J., "Data Offloading Techniques in Cellular
Networks: A Survey", Next Generation Mobile Networks, LTE-
Advanced Transport Provisioning, V0.0.14, October 2015,
<https://www.ngmn.org/fileadmin/user_upload/150929_NGMN_P-
SmallCells_Backhaul_for_LTE-Advanced_and_Small_Cells.pdf>.
[NS3EPC] Baldo, N., "The ns-3 EPC module", NS3 EPC Model,
<https://www.nsnam.org/docs/models/html/
lte-design.html#epc-model>.
[NS3LTE] Baldo, N., "The ns-3 LTE module", NS3 LTE Model,
<https://www.nsnam.org/docs/models/html/
lte-design.html#lte-model>.
[OFFLOAD] Rebecchi, F., Dias de Amorim, M., Conan, V., Passarella,
A., Bruno, R., and M. Conti, "Data Offloading Techniques
in Cellular Networks: A Survey", IEEE Communications
Surveys and Tutorials, IEEE Xplore DL, vol:17, issue:2,
pp.580-603, November 2014,
<https://ieeexplore.ieee.org/document/6953022>.
[OLTEANU] Olteanu, A. and P. Xiao, "Fragmentation and AES Encryption
Overhead in Very High-speed Wireless LANs", Proceedings of
the 2009 IEEE International Conference on Communications
ICC'09, ACM DL, pp.575-579, June 2009,
<http://dl.acm.org/citation.cfm?id=1817271.1817379>.
[RFC4594] Babiarz, J., Chan, K., and F. Baker, "Configuration
Guidelines for DiffServ Service Classes", RFC 4594,
DOI 10.17487/RFC4594, August 2006,
<https://www.rfc-editor.org/info/rfc4594>.
[RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen,
T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
Partnership Project (3GPP) Evolved Packet System (EPS)",
RFC 6459, DOI 10.17487/RFC6459, January 2012,
<https://www.rfc-editor.org/info/rfc6459>.
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[RFC7476] Pentikousis, K., Ed., Ohlman, B., Corujo, D., Boggia, G.,
Tyson, G., Davies, E., Molinaro, A., and S. Eum,
"Information-Centric Networking: Baseline Scenarios",
RFC 7476, DOI 10.17487/RFC7476, March 2015,
<https://www.rfc-editor.org/info/rfc7476>.
[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>.
[SDN5G] Page, J. and J. Dricot, "Software-defined networking for
low-latency 5G core network", 2016 International
Conference on Military Communications and Information
Systems (ICMCIS) IEEE Xplore DL, pp. 1-7, May 2016,
<https://ieeexplore.ieee.org/document/7496561>.
[TLVCOMP] Mosko, M., "Header Compression for TLV-based Packets",
ICNRG Buenos Aires IETF 95, April 2016,
<https://datatracker.ietf.org/meeting/interim-2016-icnrg-
02/materials/slides-interim-2016-icnrg-2-7>.
[TS23.203]
3GPP, "Policy and charging control architecture", 3GPP
TS 23.203 10.9.0, September 2013,
<http://www.3gpp.org/ftp/Specs/html-info/23203.htm>.
[TS23.401]
3GPP, "General Packet Radio Service (GPRS) enhancements
for Evolved Universal Terrestrial Radio Access Network
(E-UTRAN) access", 3GPP TS 23.401 10.10.0, March 2013,
<http://www.3gpp.org/ftp/Specs/html-info/23401.htm>.
[TS23.501]
3GPP, "System Architecture for the 5G System", 3GPP
TS 23.501 15.2.0, June 2018,
<http://www.3gpp.org/ftp/Specs/html-info/23501.htm>.
[TS23.714]
3GPP, "Technical Specification Group Services and System
Aspects: Study on control and user plane separation of EPC
nodes", 3GPP TS 23.714 0.2.2, June 2016,
<http://www.3gpp.org/ftp/Specs/html-info/23714.htm>.
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[TS29.060]
3GPP, "General Packet Radio Service (GPRS); GPRS
Tunnelling Protocol (GTP) across the Gn and Gp interface",
3GPP TS 29.060 3.19.0, March 2004,
<http://www.3gpp.org/ftp/Specs/html-info/29060.htm>.
[TS33.310]
3GPP, "Network Domain Security (NDS); Authentication
Framework (AF)", 3GPP TS 33.310 10.7.0, December 2012,
<http://www.3gpp.org/ftp/Specs/html-info/33310.htm>.
[TS33.320]
3GPP, "Security of Home Node B (HNB) / Home evolved Node B
(HeNB)", 3GPP TS 33.320 10.5.0, June 2012,
<http://www.3gpp.org/ftp/Specs/html-info/33320.htm>.
Authors' Addresses
Prakash Suthar
Cisco Systems Inc.
Rosemont, Illinois
USA
Email: psuthar@cisco.com
Milan Stolic
Cisco Systems Inc.
Rosemont, Illinois
USA
Email: mistolic@cisco.com
Anil Jangam (editor)
Cisco Systems Inc.
San Jose, California
USA
Email: anjangam@cisco.com
Dirk Trossen
InterDigital Inc.
London
United Kingdom
Email: Dirk.Trossen@InterDigital.com
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Ravishankar Ravindran
Huawei Technologies
Santa Clara, California
USA
Email: ravi.ravindran@huawei.com
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