IPWAVE Working Group K. Sun
Internet-Draft Y. Kim
Intended status: Informational Soongsil University
Expires: September 12, 2019 March 11, 2019
Considerations for ID/Location Separation Protocols in IP-based
Vehicular Networks
draft-kjsun-ipwave-id-loc-separation-00
Abstract
ID/Location separation protocols are proposed for scalable routing,
enhancing mobility and privacy in IP based internet infrastructure.
When we consider IP based vehicular networks, ID/Location separation
architecture is expected to offer benefits. In this draft, we
analyze whether ID/Location separation protocols can adjust into IP
based vehicular networks and solve requirements.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Use Cases for ID/Location Separation Protocols . . . . . . . 3
3.1. LISP . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. ILNP . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Gap Analysis . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 6
4.2. Mobility Management . . . . . . . . . . . . . . . . . . . 6
4.3. Security and Privacy . . . . . . . . . . . . . . . . . . 7
5. Informative References . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
For vehicular networks, it is required to provide connection to the
Intelligent Transport System (ITS) for the driver's safety, efficient
driving and entertaining with fast mobility management. Other
scenarios besides V2I communication, like V2V and V2X communication
are also considered. Link layer protocols such as IEEE 802.11 OCB
are already defined for low-latency and alternative networks, and it
is designed for enabling IPv6 as a network layer protocol.
Nevertheless, for using IPv6 in the vehicular network, there are some
requirements for optimization as described in
[ietf-ipwave-vehicular-networking]. These issues are classified into
neighbor/service discovery, mobility management, security and
privacy.
In IETF, there are several ID/Location separation protocols such as
LISP [RFC6830] and ILNP [RFC6740] for scalable routing, enhancing
privacy and mobility management. Currently ID/Location separation
concept is useful not only for decomposing ID/Location from an IP
address, but also for control/data plane separation which is a major
evolution of the internet infrastructure. For the vehicular network,
ID/Location separation protocols can be expected to meet requirements
and solve problem statements discussed in IPWAVE WG. In this draft,
we describe use cases for applying ID/Location separation
architecture into IP-based vehicular network, and analyze whether
such protocols can meet requirements for IPv6 in vehicular networks.
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2. 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]. This
document uses the terminology described in
[ietf-ipwave-vehicular-networking], [RFC6830], [RFC6740].
3. Use Cases for ID/Location Separation Protocols
3.1. LISP
Traffic Control Center in Vehicular Cloud
*-----------------------------------------*
* *
* +----------------+ *
* | Mapping System | *
* +----------------+ *
* ^ *
* MS/MR | *
*--------------------v--------------------*
^ ^ ^
| | |
| | |
RLOC1 v v RLOC2 v RLOC3
+--------+ Ethernet +--------+ Tunneling +--------+
| RSU1 |<---------->| RSU2 |<---------->| RSU3 |
| (xTR) | | (xTR) | | (xTR) |
+--------+ +--------+ +--------+
^ ^ ^
+----:------------------:---------+ +--------:---------+
| : V2I V2I : | | V2I : |
| v v | | v |
+--------+ | +--------+ +--------+ | | +--------+ |
|Vehicle1|===> |Vehicle2|===> |Vehicle3|===>| | |Vehicle4|===>|
| (EID) |<....>| (EID) |<....>| (EID) | | | | (EID) | |
+--------+ V2V +--------+ V2V +--------+ | | +--------+ |
| | | |
+---------------------------------+ +------------------+
LISP Site-1 LISP Site-2
<----> Wired Link <....> Wireless Link ===> Moving Direction
Figure 1: LISP Use Case Scenario in IP-based Vehicular Network
Architecture
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Figure 1 describes a vehicular network architecture with the LISP
protocol. A single LISP site can have multiple RSUs with xTR
function to communicate with other LISP sites. In the figure, we
assume that Vehicle 1, 2 and 3 belong to LISP site 1 and Vehicle 4 to
LISP site 2. IPv6 addresses for wireless interfaces of each vehicle
are mapped to unique EIDs, which can communicate with other EIDs in
the same LISP site same as a legacy IPv6 operation. That is,
vehicles are able to communicate with RSU as V2I communication at the
same time with other vehicles in the same LISP site as V2V
communication.
Traffic control center in the vehicular cloud is appropriate to
deploy a mapping system, since it is a point accessible from all
RSUs. When vehicles enter each LISP site and attach to the RSU, RSU
sends Map-Register message to the mapping system including vehicle's
EID and RLOC of attached RSU. After registration, the vehicle can be
provided reachability from other LISP sites or non-LISP sites. In
the figure, for communication between vehicle 4 and vehicle 3, RSU 3
which is the attachment point of vehicle 4 should request for the
RLOC of vehicle 3 from the mapping system by sending Map-Requests
message. After receiving mapping information of vehicle 3's EID and
its RLOC in Map-Reply message, RLOC 3 can forward packets via the IP
tunnel between xTR (e.g. RSU 2 in this figure) assigned to vehicle
3. Note that several data plane protocols (e.g. SRv6, etc.) can be
used with LISP control plane functions.
3.2. ILNP
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Traffic Control Center in Vehicular Cloud
*-----------------------------------------*
* *
* +-----------------+ *
* | DNS Server | *
* +-----------------+ *
* ^ *
* | *
*--------------------v--------------------*
^ ^ ^
| | |
+---------------------+ |
| SBR | |
+---------------------+ |
| | |
v v v
+--------+ Ethernet +--------+ +--------+
| RSU1 |<----------->| RSU2 |<------->|RSU3/SBR|
+--------+ +--------+ +--------+
^ ^ ^
+----:------------------:---------+ +--------:---------+
| : V2I V2I : | | V2I : |
| v v | | v |
+--------+ | +--------+ +--------+ | | +--------+ |
|Vehicle1|===> |Vehicle2|===> |Vehicle3|===>| | |Vehicle4|===>|
| (I-LV) |<....>| (I-LV) |<....>| (I-LV) | | | | (I-LV) | |
+--------+ V2V +--------+ V2V +--------+ | | +--------+ |
| | | |
+---------------------------------+ +------------------+
Subnet-1 Subnet-2
<----> Wired Link <....> Wireless Link ===> Moving Direction
Figure 2: ILNP Use Case Scenario in IP-based Vehicular Network
Architecture
In the ILNPv6, IPv6 address is replaced with an I-LV value. The I-LV
has a 128-bit length allowing it to be applied to the current IPv6
header without modification. [RFC6740] describes in detail how I-LV
value can replace an IPv6 address at the same time how can it works
in current IPv6 based infrastructure. In [RFC6741], the details of
the ILNPv6 packet header, locator subnetting and new DNS resource
record type for mapping I-LV values are defined.
Vehicular network architecture design for supporting ILNP is shown in
Figure 2. Most of the components are similar with architecture
described in [ietf-ipwave-vehicular-networking]. Every vehicle can
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have more than one NID to connect to a network, and the IPv6 address
for communication is represented as a combination of NID and Locator.
Site Border Router (SBR) can be implemented in the RSU or border of
ILNP subnet site, which should have a routing table mapped with I-LV
values for forwarding packets. A DNS server can be deployed in the
vehicular cloud which is accessible from both in ILNP site and
external internet.
4. Gap Analysis
4.1. Neighbor Discovery
In both cases of LISP and ILNP, usage of existing neighbor discovery
message defined in [RFC4861] is possible without modification. In
LISP, vehicles and RSUs in the same LISP site can exchange ND/NA
messages for routing via EID configured as IPv6 format. Also, ILNP
can operate Neighbor Discovery for configuration of I-LV value as the
I-LV for ILNPv6 occupies the same bits as the IPv6 address in the
IPv6 header[RFC6740]. Thus, for vehicular networking, we expect that
the same solutions already mentioned in
[ietf-ipwave-vehicular-networking] (e.g. new ND option
[ID-Vehicular-ND]) also can be applicable in ID/Location separation
architecture.
4.2. Mobility Management
One of the advantages for using LISP is that mobility management can
be provided efficiently, when a device is roaming across different
LISP sites while maintaining its EID. Existing IP mobilty management
schemes such as MIP or PMIP required an anchor function(e.g. Home
Agent, Local Mobility Anchor) to maintain the IP address of mobile
node when the mobile node moves so that it occurs non-optimized
forwarding path between anchor and current attachment point of mobile
node. In LISP, however, forwarding path can be optimized by updating
EID-RLOC mapping information and establishing IP tunnel between xTR
of coresponding node and xTR of current mobile node's attachement
point. This provides advantages for easly optimizing forwarding path
especially in the vehicular network where connection point of the
mobile node can be fastly moved away from its initial attachment
point. In the vehicular network, EID will roam much faster and it
means that the mapped RLOC will be changed more frequently. For
faster RLOC assignment, a predictive RLOC algorithm for roaming-EID
is proposed in LISP WG [draft-ietf-lisp-predictive-rlocs]. Using
this algorithm, it predicts moving direction of roaming-EID,
registers predictive RLOCs as a list to the mapping system, and
replicates packets to each RLOC in the list. It can minimize packet
loss while maintaining transport session continuity.
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In ILNP, mobility management is classified into host mobility and
network(site) mobility. For a vehicular network, host mobility
scenario is suitable[RFC6740]. When the vehicle moves to its network
attachment point and locator, it is changed to belong to new site, it
may send Locator Update (LU) message to the Corresponding Node (CN)
and also send a request to the DNS server to change its entry. Even
though LU procedure is necessary, it causes delay and packet loss
during handover, and it may become a more critical issue in the
vehicular network which changes locator of vehicle faster and more
frequently. Therefore, ILNP needs to minimize LU process including
DNS updates for seamless mobility management in vehicular networks.
For example, [ILNP-Sol-Wireless-Net] may be one possible solution
that defines a geological information server, which gives information
of attachment points nearby to devices to prepare handover, deliver
its predictive locator to the CN so that it reduces packet loss and
latency for updating DNS.
4.3. Security and Privacy
ID/Location separation architecture can enhance privacy. It is
difficult to track a device using single RLOC or locator value since
its locator changes with movement across sites. Nevertheless, since
EID or identifier is defined as permanent, additional methodologies
may be considered for enhancing access security of device identifier
information. For example, [draft-ietf-lisp-eid-anonymity] defines
Ephemeral-EID which is frequently changed by the device. For ILNP,
identity privacy supports using IPv6 privacy extensions for stateless
address autoconfiguration[RFC4941] and Locator Rewriting Relay (LRR)
component for locator privacy[RFC6748], can be solutions for
enhancing privacy in vehicular network.
5. Informative References
[draft-ietf-lisp-eid-anonymity]
Farinacci, D., Pillay-Esnault, P., and W. Haddad, "LISP
EID Anonymity", draft-ietf-lisp-eid-anonymity-04(working
on progress) (work in progress), October 2018.
[draft-ietf-lisp-predictive-rlocs]
Farinacci, D. and P. Pillay-Esnault, "LISP Predictive
RLOCs", draft-ietf-lisp-predictive-rlocs-03(working on
progress) (work in progress), November 2018.
[ID-Vehicular-ND]
Xiang, Z., Jeong, J., and Y. Shen, "IPv6 Neighbor
Discovery for IP-Based Vehicular Networks", draft-xiang-
ipwave-vehicular-neighbor-discovery-00(working on
progress) (work in progress), November 2018.
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[ietf-ipwave-vehicular-networking]
Jeong, J., "IP Wireless Access in Vehicular Environments
(IPWAVE): Problem Statement and Use Cases", draft-ietf-
ipwave-vehicular-networking-07(working on progress) (work
in progress), July 2017.
[ILNP-Sol-Wireless-Net]
Isah, M. and CJ. Edwards, "An ILNP-based solution for
future heterogeneous wireless networks", PGNET
2013: Proceedings of the 14th Annual Postgraduate
Symposium on the Convergence of Telecommunications,
Networking and Broadcasting, June 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007.
[RFC6740] Atkinson, RJ., Bhatti, SN., and U. St Andrews,
"Identifier-Locator Network Protocol (ILNP) Architectural
Description", RFC 6740, November 2012.
[RFC6741] Atkinson, RJ., Bhatti, SN., and U. St Andrews,
"Identifier-Locator Network Protocol (ILNP) Engineering
Considerations", RFC 6741, November 2012.
[RFC6748] Atkinson, RJ., Bhatti, SN., and U. St Andrews, "Optional
Advanced Deployment Scenarios for the Identifier-Locator
Network Protocol (ILNP)", RFC 6748, November 2012.
[RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
Locator/ID Separation Protocol (LISP)", RFC 6830, January
2013.
Authors' Addresses
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Kyoungjae Sun
School of Electronic Engineering
Soongsil University
369, Sangdo-ro, Dongjak-gu
Seoul, Seoul 06978
Republic of Korea
Phone: +82 10 3643 5627
EMail: gomjae@dcn.ssu.ac.kr
Younghan Kim
School of Electronic Engineering
Soongsil University
369, Sangdo-ro, Dongjak-gu
Seoul, Seoul 06978
Republic of Korea
Phone: +82 10 2691 0904
EMail: younghak@ssu.ac.kr
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