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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 ICN Research Group Prakash Suthar 3 Internet-Draft Milan Stolic 4 Intended status: Informational Anil Jangam 5 Cisco Systems 6 Dirk Trossen 7 InterDigital Inc. 8 Ravishankar Ravindran 9 Huawei Technologies 11 Expires: August 4, 2018 February 1, 2018 13 Native Deployment of ICN in LTE, 4G Mobile Networks 14 draft-irtf-icnrg-icn-lte-4g-00 16 Abstract 18 LTE, 4G mobile networks use IP based transport for control plane to 19 establish the data session and user plane for actual data delivery. 20 In existing architecture, IP transport used in user plane is not 21 optimized for data transport, which leads to an inefficient data 22 delivery. IP unicast routing from server to clients is used for 23 delivery of multimedia content to User Equipment (UE), where each 24 user gets a separate stream. From bandwidth and routing perspective 25 this approach is inefficient. Multicast and broadcast technologies 26 have emerged recently for mobile networks, but their deployments are 27 very limited or at an experimental stage due to complex architecture 28 and radio spectrum issues. ICN is a rapidly emerging technology with 29 built-in features for efficient multimedia data delivery, however 30 majority of the work is focused on fixed networks. The main focus of 31 this draft is on native deployment of ICN in cellular mobile networks 32 by using ICN in 3GPP protocol stack. ICN has an inherent capability 33 for multicast, anchorless mobility, security and it is optimized for 34 data delivery using local caching at the edge. The proposed 35 approaches in this draft allow ICN to be enabled natively over the 36 current LTE stack comprising of PDCP/RLC/MAC/PHY or in a dual stack 37 mode (along with IP) help optimize the mobile networks by leveraging 38 the inherent benefits of ICN. 40 Status of this Memo 42 This Internet-Draft is submitted to IETF in full conformance with the 43 provisions of BCP 78 and BCP 79. 45 Internet-Drafts are working documents of the Internet Engineering 46 Task Force (IETF), its areas, and its working groups. Note that 47 other groups may also distribute working documents as 48 Internet-Drafts. 50 Internet-Drafts are draft documents valid for a maximum of six months 51 and may be updated, replaced, or obsoleted by other documents at any 52 time. It is inappropriate to use Internet-Drafts as reference 53 material or to cite them other than as "work in progress". 55 The list of current Internet-Drafts can be accessed at 56 http://www.ietf.org/1id-abstracts.html 58 The list of Internet-Draft Shadow Directories can be accessed at 59 http://www.ietf.org/shadow.html 61 Copyright and License Notice 63 Copyright (c) 2017 IETF Trust and the persons identified as the 64 document authors. All rights reserved. 66 This document is subject to BCP 78 and the IETF Trust's Legal 67 Provisions Relating to IETF Documents 68 (http://trustee.ietf.org/license-info) in effect on the date of 69 publication of this document. Please review these documents 70 carefully, as they describe your rights and restrictions with respect 71 to this document. Code Components extracted from this document must 72 include Simplified BSD License text as described in Section 4.e of 73 the Trust Legal Provisions and are provided without warranty as 74 described in the Simplified BSD License. 76 Table of Contents 78 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 79 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4 80 1.2 3GPP Terminology and Concepts . . . . . . . . . . . . . . . 4 81 2. LTE, 4G Mobile Network . . . . . . . . . . . . . . . . . . . . 8 82 2.1 Network Overview . . . . . . . . . . . . . . . . . . . . . 8 83 2.2 QoS Challenges . . . . . . . . . . . . . . . . . . . . . . 9 84 2.3 Data Transport Using IP . . . . . . . . . . . . . . . . . . 10 85 2.4 Virtualizing Mobile Networks . . . . . . . . . . . . . . . 11 86 3. Data Transport Using ICN . . . . . . . . . . . . . . . . . . . 12 87 4. ICN Deployment in 4G and LTE Networks . . . . . . . . . . . . 14 88 4.1 General ICN Deployment Considerations . . . . . . . . . . . 14 89 4.2 ICN Deployment Scenarios . . . . . . . . . . . . . . . . . . 14 90 4.3 ICN Deployment in LTE Control Plane . . . . . . . . . . . . 17 91 4.4 ICN Deployment in LTE User Plane . . . . . . . . . . . . . 18 92 4.4.1 Dual stack ICN Deployments in UE . . . . . . . . . . . 19 93 4.4.2 Native ICN Deployments in UE . . . . . . . . . . . . . 22 94 4.5 ICN Deployment in eNodeB . . . . . . . . . . . . . . . . . 23 95 4.6 ICN Deployment in Packet Core (SGW, PGW) Gateways . . . . . 25 96 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 26 97 6. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 98 7 References . . . . . . . . . . . . . . . . . . . . . . . . . . 29 99 7.1 Normative References . . . . . . . . . . . . . . . . . . . 29 100 7.2 Informative References . . . . . . . . . . . . . . . . . . 30 101 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 32 103 1 Introduction 105 LTE mobile technology is built as all-IP network. It uses IP routing 106 protocols such as OSPF, ISIS, BGP etc. to establish network routes to 107 route the data traffic to end user's device. Stickiness of IP address 108 to a device is the key to get connected to a mobile network and the 109 same IP address is maintained through the session until the device 110 gets detached or moves to another network. 112 One of the key protocols used in 4G and LTE networks is GPRS 113 Tunneling protocol (GTP). GTP, DIAMETER and other protocols are built 114 on top of IP. One of the biggest challenges with IP based routing is 115 that it is not optimized for data transport although it is the most 116 efficient communication protocol. By native implementation of 117 Information Centric Networking (ICN) in 3GPP, we can re-architect 118 mobile network and optimize its design for efficient data transport 119 by leveraging the caching feature of ICN. ICN also offers an 120 opportunity to leverage inherent capabilities of multicast, 121 anchorless mobility management, and authentication. This draft 122 provides insight into different options for deploying ICN in mobile 123 networks and how they impact mobile providers and end-users. 125 1.1 Terminology 127 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 128 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 129 document are to be interpreted as described in RFC 2119 [RFC2119]. 131 1.2 3GPP Terminology and Concepts 133 Access Point Name 135 The Access Point Name (APN) is a Fully Qualified Domain Name 136 (FQDN) and resolves to a set of gateways in an operator's network. 137 APN identifies the packet data network (PDN) that a mobile data 138 user wants to communicate with. In addition to identifying a PDN, 139 an APN may also be used to define the type of service, QoS and 140 other logical entities inside GGSN, PGW. 142 Control Plane 144 The control plane carries signaling traffic and is responsible for 145 routing between eNodeB and MME, MME and HSS, MME and SGW, SGW and 146 PGW etc. Control plane signaling is required to authenticate and 147 authorize UE and establish mobility session with mobile gateways 148 (SGW/PGW). Functions of the control plane also include system 149 configuration and management. 151 Dual Address PDN/PDP Type 153 The dual address Packet Data Network/Packet Data Protocol 154 (PDN/PDP) Type (IPv4v6) is used in 3GPP context in many cases as a 155 synonym for dual-stack, i.e. a connection type capable of serving 156 both IPv4 and IPv6 simultaneously. 158 eNodeB 160 The eNodeB is a base station entity that supports the Long-Term 161 Evolution (LTE) air interface. 163 Evolved Packet Core 165 The Evolved Packet Core (EPC) is an evolution of the 3GPP GPRS 166 system characterized by a higher-data-rate, lower-latency, packet- 167 optimized system. The EPC comprises some of the sub components of 168 the EPS core such as Mobility Management Entity (MME), Serving 169 Gateway (SGW), Packet Data Network Gateway (PDN-GW), and Home 170 Subscriber Server (HSS). 172 Evolved Packet System 174 The Evolved Packet System (EPS) is an evolution of the 3GPP 175 GPRSsystem characterized by a higher-data-rate, lower-latency, 176 packet-optimized system that supports multiple Radio Access 177 Technologies (RATs). The EPS comprises the EPC together with the 178 Evolved Universal Terrestrial Radio Access (E-UTRA) and the 179 Evolved Universal Terrestrial Radio Access Network (E-UTRAN). 181 Evolved UTRAN The Evolved UTRAN (E-UTRAN) is a communications 182 network, sometimes referred to as 4G, and consists of eNodeBs (4G 183 base stations). The E-UTRAN allows connectivity between the User 184 Equipment and the core network. 186 GPRS Tunnelling Protocol 188 The GPRS Tunnelling Protocol (GTP) [TS.29060] [TS.29274] 189 [TS.29281] is a tunnelling protocol defined by 3GPP. It is a 190 network-based mobility protocol and is similar to Proxy Mobile 191 IPv6 (PMIPv6). However, GTP also provides functionality beyond 192 mobility, such as in-band signaling related to Quality of Service 193 (QoS) and charging, among others. 195 Gateway GPRS Support Node 197 The Gateway GPRS Support Node (GGSN) is a gateway function in the 198 GPRS and 3G network that provides connectivity to the Internet or 199 other PDNs. The host attaches to a GGSN identified by an APN 200 assigned to it by an operator. The GGSN also serves as the 201 topological anchor for addresses/prefixes assigned to the User 202 Equipment. 204 General Packet Radio Service 206 The General Packet Radio Service (GPRS) is a packet-oriented 207 mobile data service available to users of the 2G and 3G cellular 208 communication systems -- the GSM -- specified by 3GPP. 210 Home Subscriber Server 212 The Home Subscriber Server (HSS) is a database for a given 213 subscriber and was introduced in 3GPP Release-5. It is the entity 214 containing the subscription-related information to support the 215 network entities actually handling calls/sessions. 217 Mobility Management Entity 219 The Mobility Management Entity (MME) is a network element that is 220 responsible for control-plane functionalities, including 221 authentication, authorization, bearer management, layer-2 222 mobility, etc. The MME is essentially the control-plane part of 223 the SGSN in the GPRS. The user-plane traffic bypasses the MME. 225 Public Land Mobile Network 227 The Public Land Mobile Network (PLMN) is a network that is 228 operated by a single administration. A PLMN (and therefore also an 229 operator) is identified by the Mobile Country Code (MCC) and the 230 Mobile Network Code (MNC). Each (telecommunications) operator 231 providing mobile services has its own PLMN. 233 Policy and Charging Control 235 The Policy and Charging Control (PCC) framework is used for QoS 236 policy and charging control. It has two main functions: flow- 237 based charging, including online credit control and policy control 238 (e.g., gating control, QoS control, and QoS signaling). It is 239 optional to 3GPP EPS but needed if dynamic policy and charging 240 control by means of PCC rules based on user and services are 241 desired. 243 Packet Data Network 245 The Packet Data Network (PDN) is a packet-based network that 246 either belongs to the operator or is an external network such as 247 the Internet or a corporate intranet. The user eventually accesses 248 services in one or more PDNs. The operator's packet core networks 249 are separated from packet data networks either by GGSNs or PDN 250 Gateways (PGWs). 252 Serving Gateway 254 The Serving Gateway (SGW) is a gateway function in the EPS, which 255 terminates the interface towards the E-UTRAN. The SGW is the 256 Mobility Anchor point for layer-2 mobility (inter-eNodeB 257 handovers). For each UE connected with the EPS, at any given 258 point in time, there is only one SGW. The SGW is essentially the 259 user-plane part of the GPRS's SGSN. 261 Packet Data Network Gateway 263 The Packet Data Network Gateway (PGW) is a gateway function in the 264 Evolved Packet System (EPS), which provides connectivity to the 265 Internet or other PDNs. The host attaches to a PGW identified by 266 an APN assigned to it by an operator. The PGW also serves as the 267 topological anchor for addresses/prefixes assigned to the User 268 Equipment. 270 Packet Data Protocol Context 272 A Packet Data Protocol (PDP) context is the equivalent of a 273 virtual connection between the User Equipment (UE) and a PDN using 274 a specific gateway. 276 Packet Data Protocol Type 278 A Packet Data Protocol Type (PDP Type) identifies the used/allowed 279 protocols within the PDP context. Examples are IPv4, IPv6, and 280 IPv4v6 (dual-stack). 282 Serving GPRS Support Node 284 The Serving GPRS Support Node (SGSN) is a network element that is 285 located between the radio access network (RAN) and the gateway 286 (GGSN). A per-UE point-to-point (p2p) tunnel between the GGSN and 287 SGSN transports the packets between the UE and the gateway. 289 Terminal Equipment 291 The Terminal Equipment (TE) is any device/host connected to the 292 Mobile Terminal (MT) offering services to the user. A TE may 293 communicate to an MT, for example, over the Point to Point 294 Protocol (PPP). 296 UE, MS, MN, and Mobile 298 The terms UE (User Equipment), MS (Mobile Station), MN (Mobile 299 Node), and mobile refer to the devices that are hosts with the 300 ability to obtain Internet connectivity via a 3GPP network. A MS 301 is comprised of the Terminal Equipment (TE) and a Mobile Terminal 302 (MT). The terms UE, MS, MN, and mobile are used interchangeably 303 within this document. 305 User Plane 307 The user plane refers to data traffic and the required bearers for 308 the data traffic. In practice, IP is the only data traffic 309 protocol used in the user plane. 311 2. LTE, 4G Mobile Network 313 2.1 Network Overview 315 With the introduction of LTE, mobile networks moved to all-IP 316 transport for all elements such as eNodeB, MME, SGW/PGW, HSS, PCRF, 317 routing and switching etc. Although LTE network is data-centric, it 318 has support for legacy Circuit Switch features like voice and SMS 319 through transitional CS fallback and flexible IMS deployment 320 [GRAYSON]. For each mobile device attached to the radio (eNodeB) 321 there is a separate overlay tunnel (GPRS Tunneling Protocol, GTP) 322 between eNodeB and Mobile gateways (i.e. SGW, PGW). 324 The GTP tunnel is used to carry user traffic between gateways and 325 mobile devices, this forces data to be only distributed using unicast 326 mechanism. It is also important to understand the overhead of a GTP 327 and IPSec protocols because it has impact on the carried user data 328 traffic. All mobile backhaul traffic is encapsulated using GTP 329 tunnel, which has overhead of 8 bytes on top of IP and UDP [NGMN]. 330 Additionally, if IPSec is used for security (which is often required 331 if the Service provider is using a shared backhaul), it adds overhead 332 based upon IPSec tunneling model (tunnel or transport), and 333 encryption and authentication header algorithm used. If we factor 334 Advanced Encryption Standard (AES) encryption with the packet size, 335 the overhead can be significant, particularly for the smaller 336 payloads [IPSEC2]. 338 When any UE is powered up, it attaches to a mobile network based on 339 its configuration and subscription. After successful attach 340 procedure, UE registers with the mobile core network and IPv4 and/or 341 IPv6 address is assigned. A default bearer is created for each UE and 342 it is assigned to default Access Point Name (APN). 344 +-------+ Diameter +-------+ 345 | HSS |------------| SPR | 346 +-------+ +-------+ 347 | | 348 +------+ +------+ S4 | +-------+ 349 | 3G |---| SGSN |----------------|------+ +------| PCRF | 350 ^ |NodeB | | |---------+ +---+ | | +-------+ 351 +-+ | +------+ +------+ S3 | | S6a | |Gxc | 352 | | | +-------+ | | |Gx 353 +-+ | +------------------| MME |------+ | | | 354 UE v | S1MME +-------+ S11 | | | | 355 +----+-+ +-------+ +-------+ 356 |4G/LTE|------------------------------| SGW |-----| PGW | 357 |eNodeB| S1U +-------+ +--| | 358 +------+ | +-------+ 359 +---------------------+ | | 360 S1U GTP Tunnel traffic | +-------+ | | 361 S2a GRE Tunnel traffic |S2A | ePDG |-------+ | 362 S2b GRE Tunnel traffic | +-------+ S2B |SGi 363 SGi IP traffic | | | 364 +---------+ +---------+ +-----+ 365 | Trusted | |Untrusted| | CDN | 366 |non-3GPP | |non-3GPP | +-----+ 367 +---------+ +---------+ 368 | | 369 +-+ +-+ 370 | | | | 371 +-+ +-+ 372 UE UE 374 Figure-1: LTE, 4G Mobile Network Overview 376 The data delivered to mobile devices is unicast inside GTP tunnel. If 377 we consider combined impact of GTP, IPSec and unicast traffic, the 378 data delivery is not efficient. IETF has developed various header 379 compression algorithms to reduce the overhead associated with IP 380 packets. Some of techniques are robust header compression (ROHC) and 381 enhanced compression of the real-time transport protocol (ECRTP) so 382 that impact of overhead created by GTP, IPsec etc. is reduced to some 383 extent [BROWER]. For commercial mobile networks, 3GPP has adopted 384 different mechanisms for header compression to achieve efficiency in 385 data delivery [TS25.323], and can be adapted to ICN as well. 387 2.2 QoS Challenges 389 During attach procedure, default bearer is created for each UE and it 390 is assigned to the default Access Point Name (APN). The QoS values 391 uplink and downlink bandwidth assigned during initial attach are 392 minimal. Additional dedicated bearer(s) with enhanced QoS parameters 393 is established depending on the specific application needs. 395 While all traffic within a certain bearer gets the same treatment, 396 QoS parameters supporting these requirements can be very granular in 397 different bearers. These values vary for the control, management and 398 user traffic, and depending on the application key parameters, such 399 as latency, jitter (important for voice and other real-time 400 applications), packet loss and queuing mechanism (strict priority, 401 low-latency, fair etc.) can be very different. 403 Implementation of QoS for mobile networks is done at two stages: at 404 content prioritization/marking and transport marking, and congestion 405 management. From the transport perspective, QoS is defined at layer 2 406 as class of service (CoS) and at layer 3 either as DiffServ code 407 point (DSCP) or type of service (ToS). The mapping of CoS to DSCP 408 takes place at layer 2/3 switching and routing elements. 3GPP has 409 specified QoS Class Identifier (QCI) which represents different types 410 of content and equivalent mapping to DSCP at transport layer 411 [TS23.203] [TS23.401]; however, this again requires manual 412 configuration at different elements and if there is misconfiguration 413 at any place in the path it will not work properly. 415 In summary QoS configuration for mobile network for user plane (for 416 user traffic) and transport in IP based mobile network is complex and 417 it requires synchronization of parameters among different platforms. 418 Normally QoS in IP is implemented using DiffServ, which uses hop-by- 419 hop QoS configuration at each router. Any inconsistency in IP QoS 420 configuration at routers in the forwarding path can result in poor 421 subscriber experience (e.g. packet classified as high-priority can go 422 to lower priority queue). By deploying ICN, we intend to enhance the 423 subscriber experience using policy based configuration, which can be 424 associated with the named contents [ICNQoS] at ICN forwarder. Further 425 investigation is needed to understand how QoS in ICN can be 426 implemented to meet the IP QoS requirements [RFC4594]. 428 2.3 Data Transport Using IP 430 The data delivered to mobile devices is unicast inside GTP tunnel 431 from a eNodeB to a PDN gateway (PGW), as described in 3GPP 432 specifications [TS23.401]. While the technology exists to address the 433 issue of possible multicast delivery, there are many difficulties 434 related to multicast protocol implementation on the RAN side of the 435 network. Transport networks in the backhaul and core have addressed 436 the multicast delivery long time ago and have implemented it in most 437 cases in their multi-purpose integrated transport, but the RAN part 438 of the network is still lagging behind due to complexities related to 439 mobility of the clients, handovers, and the fact that the potential 440 gain to the Service Providers may not justify the investment. With 441 that said, the data delivery in the mobility remains greatly unicast. 442 Techniques to handle multicast such as LTE-B or eMBMS have been 443 designed to handle pre-planned content delivery such as live content, 444 which contrasts user behavior today, largely based on content (or 445 video) on demand model. 447 To ease the burden on the bandwidth of the SGi interface, caching is 448 introduced in a similar manner as with many Enterprises. In the 449 mobile networks, whenever possible, a cached data is delivered. 450 Caching servers are placed at a centralized location, typically in 451 the Service Provider's Data Center, or in some cases lightly 452 distributed in the Packet Core locations with the PGW nodes close to 453 the Internet and IP services access (SGi interface). This is a very 454 inefficient concept because traffic has to traverse the entire 455 backhaul path for the data to be delivered to the end-user. Other 456 issues, such as out-of-order delivery contribute to this complexity 457 and inefficiency but they could be addressed at the IP transport 458 level. 460 The data delivered to mobile devices is unicast inside a GTP tunnel. 461 If we consider combined impact of GTP, IPSec and unicast traffic, the 462 end-to-end data delivery is not efficient. By deploying ICN, we 463 intend to either terminate GTP tunnel at the mobility anchoring point 464 by leveraging control and user plane separation or replace it with 465 the native ICN protocols. 467 2.4 Virtualizing Mobile Networks 469 The Mobile packet core deployed in a major service provider network 470 is either based on dedicated hardware or large capacity x86 platforms 471 in some cases. With adoption of Mobile Virtual Network Operators 472 (MVNO), public safety network, and enterprise mobility network, we 473 need elastic mobile core architecture. By deploying mobile packet 474 core on a commercially off the shelf (COTS) platform using 475 virtualized infrastructure (NFVI) framework and end-to-end 476 orchestration, we can simplify new deployments and provide optimized 477 total cost of ownership (TCO). 479 While virtualization is growing and many mobile providers use hybrid 480 architecture consisting of dedicated and virtualized infrastructures, 481 the control and data delivery planes are still the same. There is 482 also work underway to separate control plane and user plane so that 483 the network can scale better. Virtualized mobile networks and network 484 slicing with control and user plane separation provide mechanism to 485 evolve GTP-based architecture to open-flow SDN-based signaling for 486 LTE and proposed 5G core. Some of early architecture work for 5G 487 mobile technologies provides mechanism for control and user plane 488 separation and simplifies mobility call flow by introduction of open- 489 flow based signaling [5GICN]. This has been considered by 3GPP 490 [EPCCUPS] and is also described in [SDN5G]. 492 3. Data Transport Using ICN 494 For mobile devices, the edge connectivity to the network is between 495 radio and a router or mobile edge computing (MEC) [MECSPEC] element. 496 MEC has the capability of processing client requests and segregating 497 control and user traffic at the edge of radio rather than sending all 498 requests to the mobile gateway. 500 +----------+ 501 | Content +----------------------------------------+ 502 | Publisher| | 503 +---+---+--+ | 504 | | +--+ +--+ +--+ | 505 | +--->|R1|------------>|R2|---------->|R4| | 506 | +--+ +--+ +--+ | 507 | | Cached | 508 | v content | 509 | +--+ at R3 | 510 | +========|R3|---+ | 511 | # +--+ | | 512 | # | | 513 | v v | 514 | +-+ +-+ | 515 +---------------| |-------------| |-------------+ 516 +-+ +-+ 517 Consumer-1 Consumer-2 518 UE UE 520 ===> Content flow from cache 521 ---> Content flow from publisher 523 Fig. 2. ICN Architecture 525 MEC transforms radio into an intelligent service edge that is capable 526 of delivering services directly from the edge of the network, while 527 providing the best possible performance to the client. MEC can be an 528 ideal candidate for ICN forwarder in addition to its usual function 529 of managing mobile termination. In addition to MEC, other transport 530 elements, such as routers, can work as ICN forwarders. 532 Data transport using ICN is different compared to IP-based transport. 533 It evolves the Internet infrastructure by introducing uniquely named 534 data as a core Internet principle. Communication in ICN takes place 535 between content provider (producer) and end user (consumer) as 536 described in figure 2. 538 Every node in a physical path between a client and a content provider 539 is called ICN forwarder or router, and it has the ability to route 540 the request intelligently and also cache the content so that it can 541 be delivered locally for subsequent request from any other client. 542 For mobile network, transport between a client and a content provider 543 consists of radio network + mobile backhaul and IP core transport + 544 Mobile Gateways + Internet + content data network (CDN). 546 In order to understand suitability of ICN for mobile networks, we 547 will discuss the ICN framework describing protocols architecture and 548 different types of messages, and then consider how we can use this in 549 a mobile network for delivering content more efficiently. ICN uses 550 two types of packets called "interest packet" and "data packet" as 551 described in figure 3. 553 +------------------------------------+ 554 Interest | +------+ +------+ +------+ | +-----+ 555 +-+ ---->| CS |---->| PIT |---->| FIB |--------->| CDN | 556 | | | +------+ +------+ +------+ | +-----+ 557 +-+ | | Add | Drop | | Forward 558 UE <--------+ Intf v Nack v | 559 Data | | 560 +------------------------------------+ 562 +------------------------------------+ 563 +-+ | Forward +------+ | +-----+ 564 | | <-------------------------------------| PIT |<---------| CDN | 565 +-+ | | Cache +--+---+ | Data +-----+ 566 UE | +--v---+ | | 567 | | CS | v | 568 | +------+ Discard | 569 +------------------------------------+ 571 Fig. 3. ICN Interest, Data Packet and Forwarder 573 In an LTE network, when a mobile device wants to get certain content, 574 it will send an Interest message to the closest eNodeB. Interest 575 packet follows the TLV format [CCNxTLV] and contains mandatory fields 576 such as name of the content and content matching restrictions 577 (KeyIdRestr and ContentObjectHashRestr) forming the tuple [CCNxSem]. 578 The content matching tuple uniquely identifies the correlation 579 between an Interest and data packet. Another attribute called 580 HopLimit is used to detect looping Interest messages. Interest 581 looping is not prevented and looped Interest packets are eventually 582 discarded at the expiry of HopLimit. 584 First ICN router will receive Interest packet and perform lookup if 585 request for such content has come earlier from any other client. If 586 yes, it is served from the local cache, otherwise request is 587 forwarded to the next-hop ICN router. Each ICN router maintains three 588 data structures, namely Pending Interest Table (PIT), Forwarding 589 Information Base (FIB), and Content Store (CS). The Interest packet 590 travels hop-by-hop towards content provider. Once the Interest 591 reaches the content provider it will return a Data packet containing 592 information such as content name, signature, signed key and data. 594 Data packet travels in reverse direction following the same path 595 taken by the interest packet so routing symmetry is maintained. 596 Details about algorithms used in PIT, FIB, CS and security trust 597 models are described in various resources [CCN], here we explained 598 the concept and its applicability to the LTE network. 600 4. ICN Deployment in 4G and LTE Networks 602 4.1 General ICN Deployment Considerations 604 In LTE/4G mobile networks, both user and control plane traffic have 605 to be transported from the edge to the mobile packet core via IP 606 transport. The evolution of existing mobile packet core using CUPS 607 [TS23.714] enables flexible network deployment and operation, by 608 distributed deployment and the independent scaling between control 609 plane and user plane functions - while not affecting the 610 functionality of the existing nodes subject to this split. 612 In the CUPS architecture, there is an opportunity to shorten the path 613 for user plane traffic by deploying offload nodes closer to the edge 614 [OFFLOAD]. This optimization allows for the introduction of ICN and 615 amplifies its advantages. This section analyzes the potential impact 616 of ICN on control and user plane traffic for centralized and 617 disaggregate CUPS based mobile network architecture. 619 4.2 ICN Deployment Scenarios 621 Deployment of ICN provides an opportunity to further optimize the 622 existing data transport in LTE/4G mobile networks. The various 623 deployment options that ICN and IP provide are somewhat analogous to 624 the deployment scenarios when IPv6 was introduced to inter operate 625 with IPv4, except with ICN the whole IP stack is being replaced. We 626 have reviewed [RFC6459] and analyzed the impact of ICN on control 627 plane signaling and user plane data delivery. In general ICN can be 628 deployed natively replacing IP transport (IPv4 and IPv6) or as an 629 overlay protocol. Figure 4 describes a modified protocol stack to 630 support ICN deployment scenarios. 632 As shown in figure 4, for applications running either in UE or in 633 content provider system to use the new transport option, we propose a 634 new transport convergence layer (TCL). This transport convergence 635 layer helps determine what type of transport (e.g. ICN or IP), as 636 well as type of radio interface (e.g. LTE or WiFi or both), is used 637 to send and receive the traffic based on preference e.g. content 638 location, content type, content publisher, congestion, cost, quality 639 of service etc. It helps to configure and decide the type of 640 connection as well as the overlay mode (ICNoIP or IPoICN) between 641 application and the protocol stack (IP or ICN) to be used. 643 The ICN function together with existing IP function provides the 644 support for either native ICN and/or the dual stack (ICN/IP) 645 transport functionality. More elaborate description on these 646 functional layers is provided in Section 4.4.1. 648 +----------------+ +-----------------+ 649 | ICN App (new) | |IP App (existing)| 650 +---------+------+ +-------+---------+ 651 | | 652 +---------+----------------+---------+ 653 | Transport Convergence Layer (new) | 654 +------+---------------------+-------+ 655 | | 656 +------+------+ +------+-------+ 657 |ICN function | | IP function | 658 | (New) | | (Existing) | 659 +------+------+ +------+-------+ 660 | | 661 (```). (```). 662 ( ICN '`. ( IP '`. 663 ( Cloud ) ( Cloud ) 664 ` __..'+' ` __..'+' 666 Fig. 4. IP/ICN Convergence and Deployment Scenarios 668 TCL can use a number of mechanisms for the selection of transport. It 669 can use a per application configuration through a management 670 interface, possibly even a user-facing setting realized through a 671 user interface, similar to those used today that select cellular over 672 WiFi being used for selected applications. In another option, it 673 might use a software API, which an adapted IP application could use 674 to specify e.g. an ICN transport for obtaining its benefits. 676 Another potential application of TCL is in implementation of network 677 slicing, where it can have a slice management capability locally or 678 it can interface to an external slice manager through an API [GALIS]. 679 This solution can enable network slicing for IP and ICN transport 680 selection from the UE itself. The TCL could apply slice settings to 681 direct certain traffic (or applications) over one slice and others 682 over another slice, determined by some form of 'slicing policy'. 683 Slicing policy can be obtained externally from slice manager or 684 configured locally on UE. 686 From the perspective of the applications either on UE or content 687 provider, four different options are possible for the deployment of 688 ICN natively and/or with IP. 690 1. IP over IP 692 In this scenario UE uses applications tightly integrated with 693 the existing IP transport infrastructure. In this option, the 694 TCL has no additional function since the packets are directly 695 forwarded using IP protocol stack, which in turn sends the 696 packets over the IP transport. 698 2. ICN over ICN 700 Similar to case 1 above, ICN applications tightly integrate 701 with the ICN transport infrastructure. The TCL has no 702 additional responsibility since the packets are directly 703 forwarded using ICN protocol stack, which in turn sends the 704 packets over the ICN transport. 706 3. ICN over IP (ICNoIP) 708 In ICN over IP scenario, the underlying IP transport 709 infrastructure is not impacted (i.e. ICN is implemented, as an 710 IP overlay, between user equipment (UE) and content provider). 711 IP routing is used from Radio Access Network (eNodeB) to mobile 712 backhaul, IP core and Mobile Gateway (SGW/PGW). UE attaches to 713 Mobile Gateway (SGW/PGW) using IP address. Also, the data 714 transport between Mobile Gateway (SGW/PGW) and content 715 publisher uses IP. Content provider is capable of serving 716 content either using IP or ICN, based on UE request. 718 An alternative approach to implement ICN over IP is provided in 719 Hybrid ICN [HICN], which implements ICN over IP by mapping of 720 ICN names to the IPv4/IPv6 addresses. 722 Detailed deployment of use cases is described in section 4.4. 723 Application conveys the preference to the TCL, which in turn 724 sends the ICN data packets using the IP transport. 726 4. IP over ICN (IPoICN) 728 H2020 project [H2020] provides an architectural framework for 729 deployment of IP as an overlay over ICN protocol [IPoICN]. 730 Implementing IP services over ICN provides an opportunity 731 leveraging benefit of ICN in the transport infrastructure and 732 there is no impact on end devices (UE and access network) as 733 they continue to use IP. IPoICN however, will require an inter- 734 working function (IWF/Border Gateway) to translate various 735 transport primitives such as transport of tunnel mode. IWF 736 function will provide a mechanism for protocol translation 737 between IPoICN and native IP deployment for mobile network. 738 After reviewing [IPICN], we understand and interpret that ICN 739 is implemented in the transport natively; however, IP is 740 implemented in UE, eNodeB, and Mobile gateway (SGW/PGW), which 741 is also called as network attach point (NAP). 743 4.3 ICN Deployment in LTE Control Plane 745 In this section we analyze signaling messages which are required for 746 different procedures, such as attach, handover, tracking area update 747 etc. The goal of analysis is to see if there is any benefit to 748 replace IP-based protocols with ICN for LTE signaling in the current 749 architecture. It is important to understand the concept of point of 750 attachment (POA). When UE connects to a network it has at least three 751 POAs: 753 1. eNodeb managing location or physical POA 755 2. Authentication and Authorization (MME, HSS) managing identity 756 or authentication POA 758 3. Mobile Gateways (SGW, PGW) managing logical or session 759 management POA. 761 In current architecture IP transport is used for all the messages 762 associated with Control Plane for mobility and session management. IP 763 is embedded very deeply into these messages and TLV carrying 764 additional attributes as a layer 3 transport . Physical POA in eNodeB 765 handles both mobility and session management for any UE attached to 766 4G, LTE network. The number of mobility management messages between 767 different nodes in an LTE network per signaling procedure are given 768 below in figure 5. 770 Normally two types of UE devices attach to LTE network: SIM based 771 (need 3GPP mobility protocol for authentication) or non-SIM based 772 (which connect to WiFi network), and authentication is required for 773 both of these device types. For non-SIM based devices, AAA is used 774 for authentication. We do not propose to change UE authentication or 775 mobility management messaging for user data transport using ICN. A 776 separate study would be required to analyze impact of ICN on mobility 777 management messages structures and flows. We are merely analyzing the 778 viability of implementing ICN as a transport for Control plane 779 messages. 781 It is important to note that even if MME and HSS do not support ICN 782 transport, they still need to support UE capable of dual stack or 783 native ICN. When UE initiates attach request using the identity as 784 ICN, MME must be able to parse that message and create a session. MME 785 forwards UE authentication to HSS so HSS must be able to authenticate 786 an ICN capable UE and authorize create session [TS23.401]. 788 +---------------------------+-------+-------+-------+-------+------+ 789 | LTE Signaling Procedures | MME | HSS | SGW | PGW | PCRF | 790 +------------------------------------------------------------------+ 791 | Attach | 10 | 2 | 3 | 2 | 1 | 792 | Additional default bearer | 4 | 0 | 3 | 2 | 1 | 793 | Dedicated bearer | 2 | 0 | 2 | 2 | 1 | 794 | Idle-to-connect | 3 | 0 | 1 | 0 | 0 | 795 | Connect-to-Idle | 3 | 0 | 1 | 0 | 0 | 796 | X2 handover | 2 | 0 | 1 | 0 | 0 | 797 | S1 handover | 8 | 0 | 3 | 0 | 0 | 798 | Tracking area update | 2 | 0 | 0 | 0 | 0 | 799 | Total | 34 | 2 | 14 | 6 | 3 | 800 +---------------------------+-------+-------+-------+-------+------+ 802 Fig. 5. Signaling Messages in LTE Gateways 804 Anchorless mobility [ALM] has made some important comments on how 805 mobility management is done in ICN. Author comments about handling 806 mobility without having a dependency on the core network function 807 e.g. MME. However, location update to the core network would still be 808 required to support some of the legal compliance requirements such as 809 lawful intercept and emergency services. 811 The main advantage of ICN is in caching and reusing the content, 812 which does not apply to the transactional signaling exchange. After 813 analyzing LTE signaling call flows [TS23.401] and messages inter- 814 dependencies [Fig 4], our recommendation is that it is not beneficial 815 to deploy ICN for control plane and mobility management functions. 817 4.4 ICN Deployment in LTE User Plane 819 We will consider figure 1 to discuss different mechanisms to deploy 820 ICN in mobile networks. In section 4.2 we discussed generic 821 deployment scenarios of ICN. In this section, we shall see the 822 specific use cases of native ICN deployment in LTE user plane. We 823 consider the following options: 825 1. Dual stack ICN deployment in UE 827 2. Native ICN Deployments in UE 829 3. ICN Deployment in eNodeB 831 4. ICN Deployment in mobile gateways (SGW/PGW) 833 4.4.1 Dual stack ICN Deployments in UE 835 The control and user plane communications in LTE, 4G mobile networks 836 are specified in 3GPP documents [TS23.203] [TS23.401]. It is 837 important to understand that UE can be either consumer (receiving 838 content) or publisher (pushing content for other clients). The 839 protocol stack inside mobile device (UE) is complex as it has to 840 support multiple radio connectivity access to eNodeB(s). 842 +--------+ +--------+ 843 | App | | CDN | 844 +--------+ +--------+ 845 |Transp. | | | | |Transp. | 846 |Converg.| |..............|...............|............|.|Converge| 847 +--------+ | | | +--------+ | +--------+ 848 | |.|..............|...............|.| |.|.| | 849 | ICN/IP | | | | | ICN/IP | | | ICN/IP| 850 | | | | | | | | | | 851 +--------+ | +----+-----+ | +-----+-----+ | +-----+--+ | +--------+ 852 | |.|.| | |.|.| | |.|.| | | | | | 853 | PDCP | | |PDCP|GTP-U| | |GTP-U|GTP-U| | |GTP-U| | | | L2 | 854 +--------+ | +----------+ | +-----------+ | +-----+ | | | | 855 | RLC |.|.|RLC | UDP |.|.| UDP | UDP |.|.|UDP |L2|.|.| | 856 +--------+ | +----------+ | +-----------+ | +-----+ | | | | 857 | MAC |.|.| MAC| L2 |.|.| L2 | L2 |.|.| L2 | | | | | 858 +--------+ | +----------+ | +-----------+ | +--------+ | +--------+ 859 | L1 |.|.| L1 | L1 |.|.| L1 | L1 |.|.| L1 |L1|.|.| L1 | 860 +--------+ | +----+-----+ | +-----+-----+ | +-----+--+ | +--------+ 861 UE | BS(enodeB) | SGW | PGW | 862 Uu S1U S5/S8 SGi 864 Fig. 6. Dual stack ICN Deployment in UE 866 Figure 6 provides high level description of a protocol stack, where 867 IP is defined at two layers: (1) at user plane communication, (2) 868 Transport layer. User plane communication takes place between Packet 869 Data Convergence Protocol (PDCP) and Application layer, whereas 870 transport layer is at GTP protocol stack. 872 The protocol interactions and impact of supporting tunneling of ICN 873 packet into IP or to support ICN natively are described in figure 6 874 and figure 7 respectively. 876 The protocols and software stack used inside LTE capable UE support 877 both 3G and LTE software interworking and handover. Latest 3GPP 878 Rel.13 onward specification describes the use of IP and non-IP 879 protocols to establish logical/session connectivity. We intend to 880 leverage the non-IP protocol based mechanism to deploy ICN protocol 881 stack in UE as well as in eNodeB and mobile gateways (SGW, PGW). 883 +----------------+ +-----------------+ 884 | ICN App (new) | |IP App (existing)| 885 +---------+------+ +-------+---------+ 886 | | 887 +---------+----------------+---------+ 888 | Transport Convergence Layer (new) | 889 +------+---------------------+-------+ 890 | | 891 +------+------+ +------+-------+ 892 |ICN function | | IP function | 893 | (New) | | (Existing) | 894 +------+------+ +------+-------+ 895 | | 896 +------+---------------------+-------+ 897 | PDCP (updated to support ICN) | 898 +-----------------+------------------+ 899 | 900 +-----------------+------------------+ 901 | RLC (Existing) | 902 +-----------------+------------------+ 903 | 904 +-----------------+------------------+ 905 | MAC Layer (Existing) | 906 +-----------------+------------------+ 907 | 908 +-----------------+------------------+ 909 | Physical L1 (Existing) | 910 +------------------------------------+ 912 Fig. 7. Dual stack ICN protocol interactions 914 1. Existing application layer can be modified to provide options 915 for new ICN based application and existing IP based 916 applications. UE can continue to support existing IP based 917 applications or host new applications developed either to 918 support native ICN as transport, ICNoIP or IPoICN based 919 transport. Application layer has the option of selecting either 920 ICN or IP transport layer as well as radio interface to send 921 and receive data traffic. 923 Our proposal is to provide a common Application Programming 924 Interface (API) to the application developers such that there 925 is no impact on the application development when they choose 926 either ICN or IP transport for exchanging the traffic with the 927 network. As mentioned in section 4.2, the transport convergence 928 layer (TCL) function handles the interaction of application 929 with the multiple transport options. 931 2. The transport convergence layer helps determine what type of 932 transport (e.g. ICN or IP) as well as type of radio interface 933 (e.g. LTE or WiFi or both), is used to send and receive the 934 traffic. Application layer can make the decision to select a 935 specific transport based on preference e.g. content location, 936 content type, content publisher, congestion, cost, quality of 937 service etc. There can be an Application Programming Interface 938 (API) to exchange parameters required for transport selection. 939 The southbound interactions of Transport Convergence Layer 940 (TCL) will be either to IP or ICN at the network layer. 942 3. ICN function (forwarder) is introduced in parallel to the 943 existing IP layer. ICN forwarder contains functional 944 capabilities to forward ICN packets, e.g. Interest packet to 945 eNodeB or response "data packet" from eNodeB to the 946 application. 948 4. For dual stack scenario, when UE is not supporting ICN at 949 transport layer, we use IP underlay to transport ICN packets. 950 ICN function will use IP interface to send Interest and Data 951 packets for fetching or sending data using ICN protocol 952 function. This interface will use ICN overlay over IP using any 953 overlay tunneling mechanism. 955 5. To support ICN at network layer in UE, PDCP layer has to be 956 aware of ICN capabilities and parameters. PDCP is located in 957 the Radio Protocol Stack in the LTE Air interface, between IP 958 (Network layer) and Radio Link Control Layer (RLC). PDCP 959 performs following functions [TS36.323]: 961 a) Data transport by listening to upper layer, formatting and 962 pushing down to Radio Link Layer (RLC) 964 b) Header compression and decompression using ROHC (Robust 965 Header Compression) 967 c) Security protections such as ciphering, deciphering and 968 integrity protection 970 d) Radio layer messages associated with sequencing, packet drop 971 detection and re-transmission etc. 973 6. No changes are required for lower layer such as RLC, MAC and 974 Physical (L1) because they are not IP aware. 976 One key point to understand in this scenario is that ICN is deployed 977 as an overlay on top of IP. 979 4.4.2 Native ICN Deployments in UE 981 We propose to implement ICN natively in UE by modifying PDCP layer in 982 3GPP protocols. Figure 8 provides a high-level protocol stack 983 description where ICN is used at two different layers: 985 1. at user plane communication 987 2. at transport layer 989 User plane communication takes place between PDCP and application 990 layer, whereas transport layer is a substitute of GTP protocol. 991 Removal of GTP protocol stack is significant change in mobile 992 architecture because GTP is used not just for routing but for 993 mobility management functions such as billing, mediation, policy 994 enforcement etc. 996 If we implement ICN natively in UE, communication between UE and 997 eNodeB will change. Also, this will avoid tunneling the user plane 998 traffic from eNodeB to mobile packet core (SGW, PGW) using GTP 999 tunnel. 1001 For native ICN deployment, an application will be configured to use 1002 ICN forwarder so there is no need for Transport Convergence. Also to 1003 support ICN at network layer in UE, we need to modify existing PDCP 1004 layer. PDCP layer has to be aware of ICN capabilities and parameters. 1006 Native implementation will also provide opportunities to develop new 1007 use cases leveraging ICN capabilities such as seamless mobility, UE 1008 to UE content delivery using radio network without traversing the 1009 mobile gateways, etc. 1011 +--------+ +--------+ 1012 | App | | CDN | 1013 +--------+ +--------+ 1014 |Transp. | | | | | |Transp. | 1015 |Converge|.|..............|..............|..............|.|Converge| 1016 +--------+ | | | | +--------+ 1017 | |.|..............|..............|..............|.| | 1018 | ICN/IP | | | | | | | 1019 | | | | | | | | 1020 +--------+ | +----+-----+ | +----------+ | +----------+ | | ICN/IP | 1021 | |.|.| | | | | | | | | | | | 1022 | PDCP | | |PDCP| ICN |.|.| ICN |.|.| ICN |.|.| | 1023 +--------+ | +----+ | | | | | | | | | | 1024 | RLC |.|.|RLC | | | | | | | | | | | 1025 +--------+ | +----------+ | +----------+ | +----------+ | +--------+ 1026 | MAC |.|.| MAC| L2 |.|.| L2 |.|.| L2 |.|.| L2 | 1027 +--------+ | +----------+ | +----------+ | +----------+ | +--------+ 1028 | L1 |.|.| L1 | L1 |.|.| L1 |.|.| L1 |.|.| L1 | 1029 +--------+ | +----+-----+ | +----------+ | +----------+ | +--------+ 1030 UE | BS(enodeB) | SGW | PGW | 1031 Uu S1u S5/S8 SGi 1033 Fig. 8. Native ICN Deployment in UE 1035 4.5 ICN Deployment in eNodeB 1037 eNodeB is physical point of attachment for UE, where radio protocols 1038 are converted into IP transport protocol as depicted in figure 7 and 1039 figure 8 for dual stack/overlay and native ICN respectively. When UE 1040 performs attach procedures, it is assigned an identity either as IP, 1041 dual stack (IP and ICN), or ICN. UE can initiate data traffic using 1042 any of three different options: 1044 1. Native IP (IPv4 or IPv6) 1046 2. Native ICN 1048 3. Dual stack IP (IPv4/IPv6) or ICN 1050 UE encapsulates user data transport request into PDCP layer and sends 1051 the information on air interface to eNodeB. eNodeB receives the 1052 information and using PDCP [TS36.323], de-encapsulates air-interface 1053 messages and converts them to forward to core mobile gateways (SGW, 1054 PGW). As shown in figure 9, in order to support ICN natively in 1055 eNodeB, it is proposed to provide transport convergence layer (TCL) 1056 capabilities in eNodeB (similar to as provided in UE), which provides 1057 following functions: 1059 1. It decides the forwarding strategy for user data request coming 1060 from UE. The strategy can make decision based on preference 1061 indicated by the application such as congestion, cost, quality 1062 of service, etc. 1064 2. eNodeB to provide open Application Programming Interface (API) 1065 to external management systems, to provide capability to eNodeB 1066 to program the forwarding strategies. 1068 +---------------+ | 1069 | UE request | | ICN +---------+ 1070 +---> | content using |--+--- transport -->| | 1071 | |ICN protocol | | | | 1072 | +---------------+ | | | 1073 | | | | 1074 | +---------------+ | | | 1075 +-+ | | UE request | | IP |To mobile| 1076 | |---+---> | content using |--+--- transport -->| GW | 1077 +-+ | | IP protocol | | |(SGW,PGW)| 1078 UE | +---------------+ | | | 1079 | | | | 1080 | +---------------+ | | | 1081 | | UE request | | Dual stack | | 1082 +---> | content using |--+--- IP+ICN -->| | 1083 |IP/ICN protocol| | transport +---------+ 1084 +---------------+ | 1085 eNodeB S1u 1087 Fig. 9. Native ICN Deployment in eNodeB 1089 3. eNodeB shall be upgraded to support three different types of 1090 transport: IP, ICN, and dual stack IP+ICN towards mobile 1091 gateways, as depicted in figure 9. It is also recommended to 1092 deploy IP and/or ICN forwarding capabilities into eNodeB for 1093 efficient transfer of data between eNodeB and mobile gateways. 1094 There can be four choices for forwarding data request towards 1095 mobile gateways: 1097 a) Assuming eNodeB is IP-enabled and UE requests IP transfer, 1098 eNodeB forwards data over IP. 1100 b) Assuming eNodeB is ICN-enabled and UE requests ICN transfer, 1101 eNodeB forwards data over ICN. 1103 c) Assuming eNodeB is IP-enabled and UE requests ICN, eNodeB 1104 overlays ICN on IP and forwards the user plane traffic over 1105 IP. 1107 d) Assuming eNodeB is ICN-enabled and UE requests IP, eNodeB 1108 overlays IP on ICN and forwards the user plane traffic over 1109 ICN [IPoICN]. 1111 4.6 ICN Deployment in Packet Core (SGW, PGW) Gateways 1113 Mobile gateways a.k.a. Evolved Packet Core (EPC) include SGW, PGW, 1114 which perform session management for UE from the initial attach to 1115 disconnection. When UE is powered on, it performs NAS signaling and 1116 after successful authentication it attaches to PGW. PGW is an 1117 anchoring point for UE and responsible for service creations, 1118 authorization, maintenance etc. Entire functionality is managed using 1119 IP address(es) for UE. 1121 In order to implement ICN in EPC, the following functions are needed. 1123 1. Insert ICN function at session management layer as additional 1124 functionality with IP stack. Session management layer is used 1125 for performing attach procedures and assigning logical identity 1126 to user. After successful authentication by HSS, MME sends 1127 create session request (CSR) to SGW and SGW to PGW. 1129 2. When MME sends Create Session Request message (step 12 in 1130 [TS23.401]) to SGW or PGW, it contains Protocol Configuration 1131 Option Information Element (PCO IE) containing UE capabilities. 1132 We can use PCO IE to carry ICN related capabilities information 1133 from UE to PGW. This information is received from UE during the 1134 initial attach request in MME. Details of available TLV, which 1135 can be used for ICN are given in subsequent sections. UE can 1136 support either native IP, or ICN+IP, or native ICN. IP is 1137 referred to as both IPv4 and IPv6 protocols. 1139 3. For ICN+IP capable UE, PGW assigns the UE both IP address and 1140 ICN identity. UE selects either of the identities during the 1141 initial attach procedures and registers with network for 1142 session management. For ICN-capable UE it will provide only ICN 1143 attachment. For native IP-capable UE there is no change. 1145 4. In order to support ICN-capable attach procedures and use ICN 1146 for user plane traffic, PGW needs to have full ICN protocol 1147 stack functionalities. Typical ICN capabilities include 1148 functions such as content store (CS), Pending Interest Table 1149 (PIT), Forwarding Information Base (FIB) capabilities etc. If 1150 UE requests ICN in PCO IE, then PGW registers UE with ICN 1151 names. For ICN forwarding, PGW caches content locally using CS 1152 functionality. 1154 5. Protocol configuration options information elements described 1155 in [TS24.008] (see Figure 10.5.136 on page 598) and [TS24.008] 1156 (see Table 10.5.154 on page 599) provide details for different 1157 fields. 1159 - Octet 3 (configuration protocols defines PDN types) which 1160 contains details about IPv4, IPv6, both or ICN. 1162 - Any combination of Octet 4 to Z can be used to provide 1163 additional information related to ICN capability. It is most 1164 important that PCO IE parameters are matched between UE and 1165 mobile gateways (SGW, PGW) so that they can be interpreted 1166 properly and UE can attach successfully. 1168 6. Deployment of ICN functionalities in SGW and PGW should be 1169 matched with UE and eNodeB because they will exchange ICN 1170 protocols and parameters. 1172 7. Mobile gateways SGW, PGW will also need ICN forwarding and 1173 caching capability. 1175 8. The transport between PGW and CDN provider can be either IP or 1176 ICN. When UE is attached to PGW with ICN identity and 1177 communicates with an ICN-enabled CDN provider, it will use ICN 1178 primitives to fetch the data. On other hand, for an UE attached 1179 with an ICN identity, if PGW has to communicate with an IP- 1180 enabled CDN provider, it will have to use an ICN-IP 1181 interworking gateway to perform conversion between ICN and IP 1182 primitives for data retrieval. Further study is required to 1183 understand how this ICN to IP (and vice versa) interworking 1184 gateway would function. 1186 5. Security Considerations 1188 To ensure only authenticated UEs are connected to the network, LTE 1189 mobile network implements various security mechanisms. From 1190 perspective of ICN deployment in user plane, it needs to take care of 1191 the following security aspects: 1193 1. UE authentication and authorization 1195 2. Radio or air interface security 1197 3. Denial of service attacks on mobile gateway, services 1199 4. Content positioning either in transport or servers 1201 5. Content cache pollution attacks 1202 6. Secure naming, routing, and forwarding 1204 7. Application security 1206 Security over the LTE air interface is provided through cryptographic 1207 technique. When UE is powered up, it performs key exchange between 1208 UE's USIM and HSS/Authentication Center using NAS messages including 1209 ciphering and integrity protections between UE and MME. Details of 1210 secure UE authentication, key exchange, ciphering and integrity 1211 protections messages are given in 3GPP call flow [TS23.401]. 1213 LTE is an all-IP network and uses IP transport in its mobile backhaul 1214 (e.g. between eNodeB and core network). In case of provider owned 1215 backhaul, it may not implement security mechanisms; however, they are 1216 necessary in case it uses shared or a leased network. The native IP 1217 transport continues to leverage security mechanism such as Internet 1218 key exchange (IKE) and the IP security protocol (IPsec). More details 1219 of mobile backhaul security are provided in 3GPP network security 1220 [TS33.310] and [TS33.320]. When mobile backhaul is upgraded to 1221 support dual stack (IP+ICN) or native ICN, it is required to 1222 implement security techniques which are deployed in mobile backhaul. 1223 When ICN forwarding is enabled on mobile transport routers, we need 1224 to deploy security practices based on [RFC7476] and [RFC7927]. 1226 Some of the key functions supported by LTE mobile gateway (SGW, PGW) 1227 are content based billing, deep packet inspection (DPI), and lawful 1228 intercept (LI). For ICN-based user plane traffic, it is required to 1229 integrate ICN security for session between UE and gateway; however, 1230 in ICN network, since only consumers who are in possession of 1231 decryption keys can access the content, some of the services provided 1232 by mobile gateways mentioned above may not work. Further research in 1233 this area is needed. 1235 6. Summary 1237 In this draft, we have discussed complexities of LTE network and key 1238 dependencies for deploying ICN in user plane data transport. 1239 Different deployment options described cover aspects such as inter- 1240 operability and multi-technology, which is a reality for any service 1241 provider. We are currently evaluating the ICN deployment options, 1242 described in section 4, using LTE gateway software and ICN simulator. 1243 One can deploy ICN for data transport in user plane either as an 1244 overlay, dual stack (IP + ICN) or natively (by integrating ICN with 1245 CDN, eNodeB, SGW, PGW and transport network etc.). It is important to 1246 understand that for above discussed deployment scenarios, additional 1247 study is required for lawful interception, billing/mediation, network 1248 slicing, and provisioning APIs. 1250 Mobile Edge Computing (MEC) [CHENG] provides capabilities to deploy 1251 functionalities such as Content Delivery Network (CDN) caching and 1252 mobile user plane functions (UPF) [TS23.501]. Recent research for 1253 delivering real-time video content using ICN has also been proven to 1254 be efficient [NDNRTC] and can be used towards realizing the benefits 1255 of ICN deployment in eNodeB, MEC, mobile gateways (SGW, PGW) and CDN. 1256 The key aspect for ICN is in its seamless integration in LTE and 5G 1257 networks with tangible benefits so that we can optimize content 1258 delivery using simple and scalable architecture. Authors will 1259 continue to explore how ICN forwarding in MEC could be used in 1260 efficient data delivery from mobile edge. 1262 Based on our study of control plane signaling it is not beneficial to 1263 deploy ICN with existing protocols unless further changes are 1264 introduced in the control protocol stack itself. As mentioned in 1265 [TS23.501], 5G network architecture proposes simplification of 1266 control plane messages and can be a candidate for use of ICN. 1268 As a starting step towards ICN user plane deployment, it is 1269 recommended to incorporate protocol changes in UE, eNodeB, SGW/PGW 1270 for data transport. ICN has inherent capabilities for mobility and 1271 content caching, which can improve the efficiency of data transport 1272 for unicast and multicast delivery. Authors welcome the contributions 1273 and suggestions including those related to further validations of the 1274 principles by implementing prototype and/or proof of concept in the 1275 lab and in production environment. 1277 7 References 1279 7.1 Normative References 1281 [GRAYSON] Grayson M, Shatzkamer K, Wainner S.; Cisco Press book "IP 1282 Design for Mobile Networks" by. page 108-112. 1284 [IPSEC1] Cisco IPSec overhead calculator tool 1285 . 1288 [IPSEC2] IPSec Bandwidth Overhead Using AES 1289 . 1292 [BROWER] Brower, E.; Jeffress, L.; Pezeshki, J.; Jasani, R.; 1293 Ertekin, E. "Integrating Header Compression with IPsec", 1294 Military Communications Conference, 2006. MILCOM 2006. 1295 IEEE, On page(s): 1 - 6. 1297 [TS25.323] 3GPP TS25.323 Rel. 14 (2017-03) Packet Data Convergence 1298 Protocol (PDCP) specification. 1300 [TS23.501] 3GPP TS23.501 Rel. 15 (2017-06) System Architecture for 1301 the 5G System. 1303 [TS23.203] 3GPP TS23.203 Rel. 14 (2017-03) Policy and charging 1304 control and QoS architecture 1306 [TS23.401] 3GPP TS23.401 Rel. 14 (2017-03) E-UTRAN Access procedures 1307 architecture 1309 [TS33.310] 3GPP TS33.310 Rel. 14 (2016-12) LTE Network Domain 1310 Security (NDS); Authentication Framework (AF) 1312 [TS33.320] 3GPP TS33.320 Rel. 14 (2016-12) Security of Home Node B 1313 (HNB) / Home evolved Node B (HeNB) 1315 [TS24.008] 3GPP TS24.008 Rel. 14 (2017-06) Mobile radio interface 1316 Layer 3 specification. 1318 [TS23.501] 3GPP TS23.501 Rel. 14 (2017-06) System Architecture for 1319 the 5G System 1321 [TS23.214] 3GPP TS23.214 Rel. 14 (2017-06) Architecture enhancements 1322 for control and user plane separation of EPC nodes 1324 [TS36.323] 3GPP TS36.323 Rel. 14 (2017-06) Evolved Universal 1325 Terrestrial Radio Access (E-UTRA); Packet Data Convergence 1326 Protocol (PDCP) specification 1328 [TS23.714] 3GPP TS23.714 Rel. 14 (2016-06) Technical Specification 1329 Group Services and System Aspects: Study on control and 1330 user plane separation of EPC nodes 1332 [TS29.060] 3GPP TS29.060 Rel. 14 (2017-03) General Packet Radio 1333 Service (GPRS); GPRS Tunnelling Protocol (GTP) across the 1334 Gn and Gp interface 1336 [TS29.274] 3GPP TS29.274 Rel. 14 (2017-09) 3GPP Evolved Packet System 1337 (EPS); Evolved General Packet Radio Service (GPRS) 1338 Tunnelling Protocol for Control plane (GTPv2-C) 1340 [TS29.281] 3GPP TS29.281 Rel. 14 (2017-05) General Packet Radio 1341 System (GPRS) Tunnelling Protocol User Plane (GTPv1-U) 1343 [RFC7476] Information-Centric Networking: Baseline Scenarios 1344 1346 [RFC7927] Information-Centric Networking (ICN) Research Challenges 1347 1349 [RFC6459] IPv6 in 3rd Generation Partnership Project (3GPP) Evolved 1350 Packet System (EPS) 1351 1353 7.2 Informative References 1355 [RFC2119] Key words for use in RFCs to Indicate Requirement Levels 1356 1358 [RFC4594] Configuration Guidelines for DiffServ Service Classes 1359 1361 [H2020] The POINT Project 1363 [MECSPEC] European Telecommunication Standards Institute (ETSI) MEC 1364 specification ETSI-GS-MEC-IEG-001 V1.1.1 (2015-11). 1366 [CCNxTLV] CCNx Messages in TLV Format 1367 1370 [CCNxSem] mmCCNx Semantics 1373 [NDNPUB] Named Data Networking 1376 [CCN] Content Centric Networking and 1377 1379 [5GICN] Enabling ICN in 3GPP's 5G NextGen Core 1380 Architecturehttps://datatracker.ietf.org/doc/draft-ravi- 1381 icnrg-5gc-icn/ 1383 [NDN] Lixia Z., Lan W. et al. SIGCOMM Named Data Networking 1385 [ALM] J. Aug'e, G. Carofiglio et al. "Anchor-less producer 1386 mobility in icn," in Proceedings of the 2Nd ACM Conference 1387 on Information-Centric Networking, ACM-ICN '15, pp. 189- 1388 190, ACM, 2015. 1390 [VNIIDX] Cisco Visual Networking Index (VNI) dated 16 Feb 2016, 1391 . 1394 [NDNRTC] Peter Gusev,Zhehao Wang, Jeff Burke, Lixia Zhang et. All, 1395 IEICE Trans Communication, RealtimeStreaming Data Delivery 1396 over Named Data Networking, Vol E99-B, No.5 May 2016. 1398 [CHENG] Chengchao L., F. Richard Yu, Information-centric network 1399 function virtualization over 5G mobile wireless networks, 1400 IEEE network (Volume:29, Issue:3), page 68-74, 01 June 1401 2015. 1403 [NGMN] Backhaul Provisioning for LTE-Advanced & Small Cells 1404 1407 [IPoICN] IP Over ICN - The Better IP? 1408 1410 [HICN] Cisco Hybrid ICN 1414 [GALIS] Autonomic Slice Networking-Requirements and Reference 1415 Model 1418 [EPCCUPS] Control and User Plane Separation of EPC nodes (CUPS). 1420 1422 [SDN5G] Software-defined networking for low-latency 5G core 1423 network. 1425 [ICNQoS] Quality of Service in an Information-Centric Network 1426 1428 [OFFLOAD] Data Offloading Techniques in Cellular Networks: A Survey 1429 1431 Authors' Addresses 1433 Prakash Suthar 1434 9501 Technology Blvd. 1435 Rosemont, Illinois 60018 1437 EMail: psuthar@cisco.com 1439 Milan Stolic 1440 9501 Technology Blvd. 1441 Rosemont, Illinois 60018 1443 EMail: mistolic@cisco.com 1445 Anil Jangam 1446 3625 Cisco Way 1447 San Jose, CA 95134 1448 USA 1450 Email: anjangam@cisco.com 1452 Dirk Trossen 1453 InterDigital Inc. 1454 64 Great Eastern Street, 1st Floor 1455 London EC2A 3QR 1456 United Kingdom 1458 Email: Dirk.Trossen@InterDigital.com 1459 Ravishankar Ravindran 1460 Huawei Technologies 1461 2330 Central Expressway 1462 Santa Clara, CA 95050 1463 USA 1465 Email: ravi.ravindran@huawei.com