Project
IEEE 802.21 Media Independent Handover Services
<http://www.ieee802.org/21/>
Title
Information Service (IS) Reference Model, Use Case Scenario and higher Layer
requirements for 802.21 Information Service (IS)
Date
Submitted
October, 2005
Source(s)
Re:
21-05-0348-02-0000-Higher_layer_Requirements_Information_Service
Abstract
This contribution has IS reference model, Use case scenario and initial set of higher layer
requirements for 802.21 Information Service
Purpose
To generate higher layer requirements for Information Service
Notice
Release
Patent
Policy
This document has been prepared to assist the IEEE 802.21 Working Group. It is offered as a basis for
discussion and is not binding on the contributing individual(s) or organization(s). The material in this
document is subject to change in form and content after further study. The contributor(s) reserve(s) the right
to add, amend or withdraw material contained herein.
The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this
contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in
the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution;
and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE
Standards publication. The contributor also acknowledges and accepts that this contribution may be made
public by IEEE 802.21.
The contributor is familiar with IEEE patent policy, as outlined in Section 6.3 of the IEEE-SA Standards
Board Operations Manual <http://standards.ieee.org/guides/opman/sect6.html#6.3> and in Understanding
Patent Issues During IEEE Standards Development <http://standards.ieee.org/board/pat/guide.html>.
1
1 Introduction
The purpose of this document is to identify the requirements to support 802.21
Information Service (IS) via higher layers (L3 and above in terms of OSI layering
model). These requirements are derived from the high level IS reference model and use
case scenarios. At first we discuss the model and use cases and then specify the initial
set of requirements.
2 Information Service (IS) Reference Model
Single hop Model
Network IS Provider (NISP)
UE
802.21
IS Function
(Client)
802.21
IS Function
(Server)
Ia
Information
Database
Ix
Multi hop Model
UE
Network IS Provider (NISP)
Proxy NISP
802.21
IS Function
(Proxy)
802.21
IS Function
(Client)
Ia
802.21
IS Function
(Server)
Ia`
Information
Database
Ix
Ia : Interface between UE and Network IS provider
Ix: Interface between IS function and Information Database
Ia`: Interface between two Network IS providers
Figure 2.1: Information Service Reference Model
Figure 2.1 describes both single hop and multi-hop IS models. UE refers to a user
entity that contains 802.21 Information Service function. NISP refers to a Network
Information Service Provider that provides necessary information to the UE via query
2
and response mechanisms. NISP has two logical components: i) 802.21 IS Server
function and ii) Information Database. UE communicates with the NISP via interface ‘Ia’
in a single-hop model. In multi-hop model a proxy is introduced that helps routing the
information query and response to the appropriate NISP and UE respectively [Note: In
such a scenario, proxy does not have information database]. UE communicates with
the proxy NISP via interface “Ia” while proxy communicates with the NISP via interface
“Ia’ ”. Interface “Ix” represents the communication between an Information Server and
Information Database. However, interface “Ix” is out of scope in current 802.21 PAR.
Regarding interfaces “Ia” and “Ia’”, the communication between UE and NISP over L3
and higher layers is our focus here.
3 Use Cases
3.1 Case I: Information Service co-located with Information Database
3.1.1 Client-Server model
Network IS Provider
802.21 IS
Function/
Information
Database
(Server)
UE
802.21 IS
Function
Ia
(Client)
Ia
IEEE 802.21/
IETF Scope
802.21 IS
Function/
Information
Database
(Server)
NISP
Ia : Interface between UE and Network IS Provider
Ia`: Interface between two Network IS Providers
Figure 3.1.1 : Use Case Scenario I (Client-Server Model)
3
Figure 3.1.1 presents a client-server use case model whereby Information Service
(Server) is co-located with the Information Database.
In this scenario UE
communicates with the individual NISP via interface “Ia”.
3.1.2 Client-Proxy-Server model
Network IS Provider
802.21 IS Function/
Information Database
(Proxy/Server)
UE
802.21 IS
Function
(Client)
Ia
Ia`
802.21 IS Function/
Information
Database
(Server)
IEEE 802.21/
IETF Scope
IEEE 802.21
/IETF Scope
Server-to-server
communication
is out of scope
NISP
Ia : Interface between UE and Network IS Provider
Ia`: Interface between two Network IS Providers
Figure 3.1.2: Use Case Scenario II (Client-Proxy-Server Model)
Figure 3.1.2 presents a Client-Proxy-Server use case model whereby Information
Service (Server) is co-located with the Information Database. In this scenario, UE
communicates with an NISP via interface “Ia” and if the NISP does not have the
required information, it contacts another NISP via interface “Ia’” and the former NISP
acts as a proxy to the latter NISP. [Note: Interface “Ia’” however does not support the
Server-to-Server communication]
3.2 Case 2: Information Service with separate Information Database
4
3.2.1 Client-Server Model
Network IS Provider
802.21 IS
Function
(Server)
UE
802.21 IS
Function
(Client)
Ix
Ia
Ia
IEEE 802.21
/IETF Scope
Information
Database
802.21 IS
Function
(Server)
Information
Database
Ix
Out of Scope
Ia: Interface between UE and Network
Ix : Interface between IS Function and Information Database
Figure 3.2.1: Use Case Scenario III (Client-Server Model)
Figure 3.2.1 presents a Client-Server use case model whereby Information Service
(Server) and Information Database are two separate entities. In this scenario UE
communicates with the individual NISP via interface “Ia” as earlier and interface “Ix” is
out of scope in current 802.21 PAR.
5
3.2.2 Client-Proxy-Server Model
Network IS Provider
802.21 IS
Function
(Proxy/Server)
UE
802.21 IS
Function
(Client)
IEEE 802.21/
IETF Scope
Ia
Ia`
IEEE 802.21/
IETF Scope
802.21 IS
Function
(Server)
Information
Database
Ix
Server-to-Server
Communication
is out of scope
Information
Database
Ix
Out of Scope
Ia: Interface between UE and Network
Ix : Interface between IS Function and Information Database
Figure 3.2.2: Use Case Scenario IV (Client-Proxy-Server Model)
Figure 3.2.2 presents a Client-Proxy-Server use case model whereby Information
Service (Server) and Information Database are two separate entities. In this scenario,
UE communicates with an NISP via interface “Ia” and if the NISP does not have the
required information, it contacts the other NISP via interface “Ia’” and the former NISP
acts as a proxy to the latter NISP. [Note: Interface “Ia’” however does not support the
Server-to-Server communication]. Interface “Ix” is out of scope in current 802.21 PAR.
6
4 Requirements
IEEE 802.21 higher layer information service has several components: i) Information
service elements and abstract representation; ii) information service encoding; iii)
information service exchange; iv) information service discovery; iv) information service
protocol; and v) information service transport. Following sub-sections capture the
requirements of these components.
Note: Attempts were made to capture all possible requirements of higher layer
information service that are required for an IS to be deployed. The purpose of
this exercise would be to clearly identify the requirements that need to be
addressed within IEEE and IETF (by the .21 members).
4.1 Requirements for Information Service Elements and Abstract Representation
4.1.1 The IS specification shall define information elements (IEs) that are media
independent.
4.1.2 The IS specification shall define a basic set of IEs that are mandatory to support
the IS service.
4.1.3 The IS specification shall define an extended set of IEs that are optional to
support the IS service.
4.1.4 The IS specification shall allow the vendors to define their own IEs within the
extended set.
4.1.5 The IS specification shall provide a schema for basic set of IEs in order to define
the relationship with other IEs.
4.1.6 The IS specification shall provide a common method to define such schemas.
4.1.7 ……
7
4.2 Requirements for Information Service Encoding
4.2.1 The IS specification shall provide a common information service encoding to
exchange the IEs.
4.2.2 Information service encoding must be efficient (e.g., minimize un-necessary
overhead)
4.2.3 …….
4.3 Requirements for Information Service Exchange
4.3.1 The IS specification shall define a common semantic query based on schema
definition
4.3.2 The IS service exchange shall provide a common language for the semantic
query
4.3.3 The IS specification shall allow vendors to define specific filters.
4.3.4 The IS specification may allow unsolicited message exchange provided it fulfills
the security requirements.
4.3.5 ….
4.4 Requirements for Information Service Discovery
4.4.1 The IS specification shall support multiple methods of information service
discovery.
4.4.2 The IS discovery mechanism shall support for both IPv4 and IPv6 hosts.
4.4.3 The IS discovery shall be secured and protected from known attacks
4.4.4 The IS discovery should support NAT/firewall traversal
4.4.5 …..
8
4.5 Requirements for Information Service Protocol
4.5.1 The IS specification shall define a common information service protocol between
a client and a server both for IPv4 and IPv6 hosts.
4.5.2 The IS protocol shall allow for both client-server and client-proxy-server models.
4.5.3 The IS protocol shall provide a reliable delivery of information if the underlying
transport does not provide this feature.
4.5.4 The IS protocol shall provide a way to indicate the lifetime of the information
4.5.5 The IS protocol shall provide a congestion control mechanism if underlying
transport does not provide this feature.
4.5.6 The IS protocol may support simultaneous queries per client.
4.5.7 …..
4.6 Requirements for Information Service Transport
4.6.1 The IS specification shall provide a common information service transport
mechanism for both IPv4 and IPv6 networks
4.6.2 The IS specification shall provide transport for both Client-server and clientproxy-server models.
4.6.3 The IS transport shall allow the fragmentation of Information service exchange
4.6.4 The IS transport should support the NAT.
4.6.5 The IS transport shall provide peer authentication.
4.6.6 The IS transport shall provide message authentication and may provide
confidentiality.
4.6.7 The IS transport shall provide replay protection.
4.6.8 The IS transport may provide a congestion control mechanism.
4.6.9 The IS transport may provide a reliable message delivery.
4.6.10 …..
9
10