U.S. patent application number 11/181635 was filed with the patent office on 2005-11-10 for system and method for inter-domain mobility management.
Invention is credited to Roy, Radhika R..
Application Number | 20050250491 11/181635 |
Document ID | / |
Family ID | 22744865 |
Filed Date | 2005-11-10 |
United States Patent
Application |
20050250491 |
Kind Code |
A1 |
Roy, Radhika R. |
November 10, 2005 |
System and method for inter-domain mobility management
Abstract
The present invention relates to a method and apparatus for
inter-domain mobility management for a telephony network. The
present invention also relates generally to the H.323 standard for
transmitting audio and video data streams, and more particularly to
extending the H.323 standard to support mobility in a multimedia
communication system with services over packet-based networks.
Inventors: |
Roy, Radhika R.; (Howell,
NJ) |
Correspondence
Address: |
AT&T CORP.
P.O. BOX 4110
MIDDLETOWN
NJ
07748
US
|
Family ID: |
22744865 |
Appl. No.: |
11/181635 |
Filed: |
July 14, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11181635 |
Jul 14, 2005 |
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09847915 |
May 2, 2001 |
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60201195 |
May 2, 2000 |
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Current U.S.
Class: |
455/428 |
Current CPC
Class: |
H04L 29/06 20130101;
H04L 65/1043 20130101; H04L 65/1009 20130101; H04W 80/10 20130101;
H04L 29/06027 20130101; H04M 3/42272 20130101; H04M 7/006
20130101 |
Class at
Publication: |
455/428 |
International
Class: |
H04Q 007/20 |
Claims
1-62. (canceled)
63. A method for use at a mobile node for real-time mobile
multimedia communications and conferencing over an H.323-based
packet network, said Mobile Node having an associated Home
Gatekeeper in a first domain and said network comprising a
plurality of Visiting Gatekeepers that support H.323 mobility
services in a second domain, said method comprising the steps of:
if a Mobility Gatekeeper Advertisement is received, obtaining via
said Mobility Gatekeeper Advertisement notification of the
availability of an H.323 mobility service; if no Mobility
Gatekeeper Advertisement is received, sending a message to said
Home Gatekeeper, said message initiating notification from said
Home Gatekeeper to said Visiting Gatekeeper of the desirability for
said H.323 mobility service; registering said Mobile Node with said
Visiting Gatekeeper; and receiving an H.323 mobility service
communication from said Visiting Gatekeeper.
64. The method of claim 63 wherein the step of registering said
Mobile Node with said Visiting Gatekeeper includes sending
registration information to said Visiting Gatekeeper via a wireless
Base Station.
65. The method of claim 63 wherein the step of registering said
Mobile Node with said Visiting Gatekeeper includes sending
registration information to said Visiting Gatekeeper via a Local
Area Network.
66. The method of claim 63 wherein the step of registering said
Mobile Node with said Visiting Gatekeeper includes the steps of:
transmitting a registration request message to said Home
Gatekeeper; and in response to said registration request message,
receiving a registration confirmation message or registration
rejection message.
67. The method of claim 63 wherein the step of registering said
Mobile Node with said Visiting Gatekeeper includes the steps of:
determining that a network point of attachment has changed;
broadcasting a registration request message to said Visiting
Gatekeeper; and receiving a binding update confirmation or binding
update rejection message from said Visiting Gatekeeper.
68. The method of claim 63 wherein said step of registering said
Mobile Node with said Visiting Gatekeeper includes: if said Mobile
Node has already visited a zone regulated by a Visited Gatekeeper
within the first domain, then: broadcasting a registration request
message to said Visiting Gatekeeper; and receiving a provisional
registration confirmation from said Visiting Gatekeeper.
69. The method of claim 63 wherein said communication utilizes an
Internet Protocol.
70. A computer readable medium at a Mobile Node, said computer
readable medium comprising computer program instructions defining
computer-executable steps for real-time mobile multimedia
communications and conferencing over an H.323-based packet network,
said Mobile Node having an associated Home Gatekeeper in a first
domain and said network comprising a plurality of Visiting
Gatekeepers that support H.323 mobility services in a second
domain, said compute-executable steps comprising the steps of: if a
Mobility Gatekeeper Advertisement is received, obtaining via said
Mobility Gatekeeper Advertisement notification of the availability
of a H.323 mobility service; if no Mobility Gatekeeper
Advertisement is received, sending a message to said Home
Gatekeeper, said message initiating notification from said Home
Gatekeeper to said Visiting Gatekeeper of the desirability for said
H.323 mobility service; registering said Mobile Node with said
Visiting Gatekeeper; and receiving said H.323 mobility service
communication from said Visiting Gatekeeper.
71. The computer readable medium of claim 70 wherein the computer
program instructions defining the step of registering said Mobile
Node with said Visiting Gatekeeper further include computer program
instructions defining the step of sending registration information
to said Visiting Gatekeeper via a wireless Base Station.
72. The computer readable medium of claim 70 wherein the computer
program instructions defining the step of registering with said
Visiting Gatekeeper further include computer program instructions
defining the step of sending registration information to said
Visiting Gatekeeper via a Local Area Network.
73. The computer readable medium of claim 70 wherein the computer
program instructions defining the step of registering further
include computer program instructions defining the steps of:
transmitting a registration request message to said Home
Gatekeeper; and in response to said registration request message,
receiving a registration confirmation message or registration
rejection message.
74. The computer readable medium of claim 70 wherein the computer
program instructions defining the step of registering further
include computer program instructions defining the steps of:
determining that a network point of attachment has changed;
broadcasting a registration request message to said one Visiting
Gatekeeper; and receiving a binding update confirmation or binding
update rejection message from said one Visiting Gatekeeper.
75. The computer readable medium of claim 70 wherein the computer
program instructions defining the step of registering further
include computer program instructions defining the steps of: if the
Mobile Node has already visited a zone regulated by a Visited
Gatekeeper within the first domain, then: broadcasting a
registration request message to said Visiting Gatekeeper; and
receiving a provisional registration confirmation from said
Visiting Gatekeeper.
76. The computer readable medium of claim 70 wherein said
communication utilizes an Internet Protocol.
77. A method for use at Visiting Gateway in an H.323-based packet
network for real-time mobile multimedia communications and
conferencing, said network comprising a plurality of Visiting
Gatekeepers that support H.323 mobility services in a corresponding
plurality of zones in a second domain, said method comprising one
of the steps of: a) notifying a Mobile Node of the availability of
at least a first H.323 mobility service via said Mobility
Gatekeeper Advertisement; and b) receiving notification from a Home
Gatekeeper in a first domain associated with said Mobile Node of
the need at said Mobile Node for said at least a first H.323
mobility service; and the steps of: registering said Mobile Node
with said Visiting Gatekeeper; and transmitting an H.323 mobility
service communication to said Mobile Node.
78. The method of claim 77 wherein the step of registering said
Mobile Node with said Visiting Gatekeeper includes receiving
registration information for said Mobile Node via a wireless Base
Station.
79. The method of claim 77 wherein the step of registering said
Mobile Node with said Visiting Gatekeeper includes receiving
registration information for said Mobile Node via a Local Area
Network.
80. The method of claim 77 wherein the step of registering said
Mobile Node with said Visiting Gatekeeper includes the steps of:
receiving a registration request message from said Mobile Node;
transmitting a binding update message to said Home Gatekeeper;
receiving a binding update confirmation message or a binding update
rejection message from said Home Gatekeeper; and transmitting said
binding update confirmation message or said binding update
rejection message to said Mobile Node.
81. The method of claim 77 wherein said step of registering said
Mobile Node with said Visiting Gatekeeper includes: if the Mobile
Node has already visited another zone in said second domain, said
another zone regulated by a Visited Gatekeeper, then: receiving a
registration request message from said Mobile Node; transmitting a
mobility unbinding update message to said Visited Gatekeeper;
receiving a mobility unbinding confirmation message or a mobility
unbinding rejection message from said Visited Gatekeeper;
transmitting a provisional registration confirmation to said Mobile
Node; transmitting a binding update message to the Home Gatekeeper;
and receiving a binding update confirmation message or a binding
update rejection message from said Home Gatekeeper.
82. The method of claim 77 wherein said Visiting Gatekeeper
utilizes a combined Home/Visitor Location Database.
83. The method of claim 77 wherein said plurality of Visiting
Gatekeepers each utilize an individual Visitor Location Database
and share a Home Location Database.
84. The method of claim 77 wherein said communication utilizes an
Internet Protocol.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/201,195, entitled "Framework for H.323
inter-domain mobility management", filed May 2, 2000, and is also
related to "H.323 Mobility Architecture for Terminal User and
Service Mobility", U.S. patent application Ser. No. 09/642,279,
filed Aug. 18, 2000, "Intelligent Signaling Scheme for
Computer-Readable Medium for H.323 Mobility Architecture", U.S.
patent application Ser. No. 09/642,298, filed Aug. 18, 2000, and
"H.323 Mobility Protocol for Terminal User and Service Mobility",
U.S. patent application Ser. No. 09/642,142, filed Aug. 18, 2000,
all assigned to the assignee of the instant application, and the
disclosure of each is hereby entirely incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates to a method and apparatus for
inter-domain mobility management for a telephony network. The
present invention also relates generally to the H.323 standard for
transmitting audio and video data streams, and more particularly to
extending the H.323 standard to support mobility in a multimedia
communication system with services over packet-based networks.
BACKGROUND OF THE INVENTION
[0003] A framework on how the inter-domain communications need to
be done in H.323 for mobility management has been provided in the
context of the existing H.225.0 Annex G standard, as disclosed in
ITU-T Recommendation H.225.0 Annex G (1999), "Communications
Between Administrative Domains". The communication flows for
mobility management considering the BE (Border Elements),
Gatekeepers (GKs), Home location function (HLFs), and domains where
each entity can be arranged in any logical architectural
relationship: Centralized, Distributed, and/or Hybrid Architecture.
ITU-T Recommendation H.323 describes terminals and other entities
that provide multimedia communications services over packet based
networks (PBN) which may not provide a guaranteed Quality of
Service. H.323 entities may provide real-time audio, video and/or
data communications. Support for audio is mandatory, while data and
video are optional, but if supported, the ability to use a
specified common mode of operation is required, so that all
terminals supporting that media type can interwork.
[0004] The inter-domain mobility management of this invention needs
to be independent of the underlying architectural configurations
and is not "hard-wired" for any particular configuration of any
architectural or functional entity as done in the prior art.
[0005] The new messages for mobility management within a domain has
been proposed for H.225.0 RAS (Intra-domain communication)
messages. Similarly, for inter-domain mobility management we need
to extend H.225.0 Annex G, as disclosed in ITU-T Recommendation
H.225.0 Annex G (1999), "Communications Between Administrative
Domains." The new messages, such as, disclosed in R. R. Roy,
AT&T, "H.323 Mobility Architecture and Protocol for Terminal,
User, and Service Mobility," D-354, ITU-T SG 16 Q.13/16, WP2,
Geneva, Switzerland, Feb. 7-18, 2000, the disclosure of which is
entirely incorporated herein by reference, required for mobility
binding and updating will also be applicable for inter-domain
communication with additional parameters like hopcounts and others
in the header as required per H.225.0 Annex G.
[0006] In addition, the existing H.225.0 RAS messages like LRQ
(Location Request) such as, disclosed in R. R. Roy, AT&T,
"H.323 Mobility Management Services, Scenarios, and Information
Flows in an Administrative Domain," MD012, Ad Hoc Mobility
Conference Call, February-May 2000, have been extended to manage
mobility for intra-domain communications. Similarly, the messages
like accessRequest and others of H.225.0 Annex G are also need to
be extended for inter-domain mobility management as described in
this embodiment. However, the mobility related parameters that
specify the information related to the mobile entity used in the
LRQ and call signaling messages of H.225.0 RAS/Q.931 also need to
be passed to the accessRequest and other messages of H.225.0 Annex
G while the mobile entity is visiting a foreign domain.
[0007] It is also the critical need for a mobile entity to have an
option whether it will let others to know its present location in a
foreign domain because of security or other reasons while it is
away from its home domain. If the mobile entity does not want to
make its address public while it is visiting in a foreign domain,
the communications need to be done via mobile entity's home network
address that it may want make to public.
[0008] Originally, the International Telecommunications Union (ITU)
developed H.323 as an adaptation of H.320, which addresses
videoconferencing over ISDN and other circuit-switched networks and
services. ITU-T Recommendation H.320 describes terminals and other
entities that provide multimedia communications services over
circuit-switched networks which provide a guaranteed Quality of
Service. H.320 entities may provide real-time audio, video and/or
data communications. H.320 was ratified in 1990, and corporations
expanded their networks to include Local Area Networks (LANs) and
LAN gateways to the Wide Area Network (WAN). Then, H.323 was
expanded beyond being an extension of H.320 so that H.323 now
covers the corporate intranets and packet-switched networks in
general. The ITU published a set of standards for multimedia
communication over packet-based networks (PBNs) under the H.323
designation, which includes standards for data channels, monitoring
channels, and control channels. It includes provision of real-time
audio, video and/or data communications. The H.323 components
defined by the standard include: terminals, gateways, gatekeepers
and multipoint control units (MCUs). The terminals provide
real-time communications, must support audio/voice communications
and optionally support data and video. The most common H.323
terminals are the applications that run on a personal computer
(PC). H.323 gateways provide services to H.323 clients and allow
communication with non-H.323 entities, such as communication
between H.323 terminals and telephone in a circuit-switched
network. Gatekeepers provide call control services for H.323
endpoints, e.g., address translation and bandwidth management.
Gatekeepers are optional in the H.323 standard, but, if they are
present, the endpoints must use the services of the gatekeepers.
The H.323 standard specifies certain mandatory services that
gatekeepers, if utilized, must provide. The multipoint control
units provide support for conferences of three or more endpoints by
managing conference resources, manage negotiations between the
endpoints to specify which audio or video code(s) to use and may
manage the media stream. The H.323 standard defines how audio and
video conferencing systems communicate over packet-switched
networks defines call control and management practices for
point-to-point and broadcast/multicast/unicast multipoint
conferences, addresses QoS issues with a centralized gatekeeper
that LAN administrators use to manage media traffic, bandwidth and
user participation, and describes functionality that allows calls
to connect from the LAN to the Public Switched Telephone Network
(PST) as well as to other H.32x standards-based terminals.
[0009] In version 2 of the H.323 standard, video and audio data
streams are compressed and packetized in accordance with a
real-time transport protocol (RTP/RTCP) standard from the Internet
Engineering Task Force (IETF) and are used to support video
conferencing and other communications over the Internet. Packets
include data and header information which facilitates detection of
packet loss, detection of packet status and synchronization of the
packets. The video data streams may use H.261, H.262, or H.263
protocols. Audio data streams may use G.711, G.722, G.723.1 G.728
or G.729 protocols. Generally, the H.323 standard supports
teleconferencing in networks that utilize TCP/IP, such as, for
example, the Internet.
[0010] The H.323 system supports interoperability and assumes that
users, terminals, and services are fixed. If an H.323 terminal is
moved form one network to another, its point of attachment or
network address changes. In this situation, the address of the
mobile terminal needs to be resolved to set up a new call or
continue a same call. Thus, there is a need for an H.323 mobility
architecture that provides for terminal, user and service mobility
for inter-domain mobility management.
SUMMARY OF THE INVENTION
[0011] The present invention provides an H.323-based mobility
protocol for real-time inter-domain mobility management for a
telephony network between the administrative domains.
[0012] Therefore, in one aspect the invention is an inter-domain
mobility management method, comprising:
[0013] (a) a mobile H.323 entity communicating information related
to the mobile entity with a first gatekeeper in a first
administrative domain;
[0014] (b) said first gatekeeper being unable to verify information
on said mobile H.323 entity and sending information to a first
border element within said first administrative domain;
[0015] (c) said first border element communicating information with
a second border element in a second administrative domain to
resolve said information related to the mobile entity;
[0016] (d) said second border element communicates back with said
first border element with information to resolve said information
related to the mobile entity;
[0017] (e) said second border element accepting said resolved
information related to the mobile entity and communicates said
information with said mobile H.323 entity via said first
gatekeeper.
[0018] In another aspect the invention is an inter-domain mobility
management method, comprising:
[0019] (a) a mobile H.323 entity communicating information related
to the mobile entity with a first gatekeeper in a first
administrative domain having a first backend services;
[0020] (b) said first gatekeeper being unable to verify information
on said mobile H.323 entity and sending information to a first
border element within said first administrative domain;
[0021] (c) said first border element communicating information with
a second border element in a second administrative domain to
resolve said information related to the mobile entity;
[0022] (d) said second border element obtains information from a
second backend services in said second administrative domain and
communicates back with said first border element with information
to resolve said information related to the mobile entity;
[0023] (e) said second border element accepting said resolved
information related to the mobile entity and communicates said
information with said mobile H.323 entity via said first
gatekeeper.
[0024] In yet another aspect the invention is an inter-domain
mobility management method, comprising:
[0025] (a) a mobile H.323 entity communicating information related
to the mobile entity with a first gatekeeper in a first
administrative domain having a first backend services;
[0026] (b) said first gatekeeper being unable to verify information
on said mobile H.323 entity and sending information to a first
border element within said first administrative domain;
[0027] (c) said first border element communicating information with
a first backend services to resolve said information related to the
mobile entity, wherein said first backend services is shared with
both said first administrative domain and a second administrative
domain;
[0028] (d) said second border element obtains information from said
first backend services in said first and said second administrative
domain and communicates it back to said first border element with
information to resolve said information related to the mobile
entity;
[0029] (e) said second border element accepting said resolved
information to related to the mobile entity and communicates said
information with said mobile H.323 entity via said first
gatekeeper.
[0030] In still another aspect the invention is an inter-domain
mobility management method, comprising:
[0031] (a) a mobile H.323 entity communicating information related
to the is mobile entity with a first gatekeeper in a first
administrative domain having a first backend services;
[0032] (b) said first gatekeeper being unable to verify information
on said mobile H.323 entity and sending information to a first
border element within said first administrative domain;
[0033] (c) said first border element communicating information with
a second border element in a second administrative domain to
resolve said information related to the mobile entity;
[0034] (d) said second border element obtains information from a
second backend services in said second administrative domain via at
least one gatekeeper in said second administrative domain and
communicates back with said first border element with information
to resolve said information related to the mobile entity;
[0035] (e) said second border element accepting said resolved
information related to the mobile entity and communicates said
information with said mobile H.323 entity via said first
gatekeeper.
[0036] In still yet another aspect the invention is an inter-domain
mobility management method, comprising:
[0037] (a) a mobile H.323 entity communicating information related
to the mobile entity with a first gatekeeper in a first
administrative domain having a first home location function;
[0038] (b) said first gatekeeper being unable to verify information
on said mobile H.323 entity and sending information to a first
border element within said first administrative domain;
[0039] (c) said first border element communicating information with
a second border element in a second administrative domain to
resolve said information related to the mobile entity;
[0040] (d) said second border element obtains information from a
second home location function in said second administrative domain
and communicates back with said first border element with
information to resolve said information related to the mobile
entity;
[0041] (e) said second border element accepting said resolved
information related to the mobile entity and communicates said
information with said mobile H.323 entity via said first
gatekeeper.
[0042] In yet another aspect the invention is an inter-domain
mobility management method, comprising:
[0043] (a) a mobile H.323 entity communicating information related
to the mobile entity with a first gatekeeper in a first
administrative domain having a first home location function;
[0044] (b) said first gatekeeper being unable to verify information
on said mobile H.323 entity and sending information to a first
border element within said first administrative domain;
[0045] (c) said first border element communicating information with
a second border element in a second administrative domain to
resolve said information related to the mobile entity;
[0046] (d) said second border element obtains information from a
second home location function in said second administrative domain
via at least one gatekeeper in said second administrative domain
and communicates back with said first border element with
information to resolve said information related to the mobile
entity;
[0047] (e) said second border element accepting said resolved
information related to the mobile entity and communicates said
information with said mobile H.323 entity via said first
gatekeeper.
[0048] In still another aspect this invention is an H.323-based
mobility protocol for real-time mobile multimedia communications
and conferencing over packet-based networks by a Mobile
Terminal/Node/Entity having a Home Gatekeeper/Home Database,
comprising the steps of:
[0049] upon becoming mobile and initiating an H.323 communication
that includes at least one of: audio, video and data, by the Mobile
Terminal/Node/Entity, with respect to notification, one of:
[0050] providing, by at least one of a plurality of available H.323
Visiting/Foreign Gatekeepers in a first administrative domain,
notification of H.323 mobility services availability by
periodically broadcasting/multicasting/unicasting a Mobility
Gatekeeper Advertisement; and
[0051] where the Mobile Terminal/Node/Entity lacks notification of
H.323 mobility services availability,
broadcasting/multicasting/unicasting/send- ing, by the Mobile
Terminal/Node/Entity, a message to the Home Gatekeeper/Home
Location Database in a second administrative domain, which notifies
H.323 Visiting/Foreign Gatekeepers that the Mobile
Terminal/Node/Entity needs H.323 mobility services and notifying,
by the H.323 Visiting/Foreign Gatekeepers, to the Mobile
Terminal/Node/Entity of available H.323 Visiting/Foreign
Gatekeepers within the first administrative domain;
[0052] registering, by the Mobile Terminal/Node/Entity, with a
H.323 Visiting/Foreign Gatekeeper of the available H.323
Visiting/Foreign Gatekeepers that support H.323 mobility services;
and
[0053] providing, for the Mobile Terminal/Node/Entity by the H.323
Visiting/Foreign Gatekeeper with which the Mobile
Terminal/Node/Entity is registered, support for the H.323
communication that includes at least one of: audio, video and
data.
[0054] In yet another aspect this invention is a computer-readable
medium having computer-executable steps for implementing, by a
Mobile Terminal/Node/Entity, an H.323-based mobility protocol for
real-time mobile multimedia communications and conferencing over
packet-based networks wherein a plurality of H.323 gatekeepers
provide notification of H.323 mobility services availability by
periodically broadcasting/multicasting/unicasting a Mobility
Gatekeeper Advertisement, comprising the computer-executable steps
of:
[0055] where the Mobile Terminal/Node/Entity becomes mobile and
initiates an H.323 communication that includes at least one of:
audio, video and data, by the Mobile Terminal/Node/Entity, with
respect to notification, one of:
[0056] providing, by at least one of a plurality of available H.323
Visiting/Foreign Gatekeepers within a first administrative domain,
notification of H.323 mobility services availability by
periodically broadcasting/multicasting/unicasting/sending a
Mobility Gatekeeper Advertisement; and
[0057] where the Mobile Terminal/Node/Entity lacks notification of
H.323 mobility services availability,
broadcasting/multicasting/unicasting/send- ing, by the Mobile
Terminal/Node/Entity, a message to the Home Gatekeeper/Home
Location Database in a second administrative domain, which notifies
H.323 Visiting/Foreign Gatekeepers that the Mobile
Terminal/Node/Entity needs H.323 mobility services and notifying,
by the H.323 Visiting/Foreign Gatekeepers, to the Mobile
Terminal/Node/Entity of available H.323 Visiting/Foreign
Gatekeepers within the first administrative domain;
[0058] registering, by the Mobile Terminal/Node/Entity, with a
H.323 Visiting/Foreign Gatekeeper of the available H.323
Visiting/Foreign Gatekeepers that support H.323 mobility services;
and
[0059] providing, for the Mobile Terminal/Node/Entity by the H.323
Visiting/Foreign Gatekeeper with which the Mobile
Terminal/Node/Entity is registered, support for the H.323
communication that includes at least one of: audio, video and
data.
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] The features of the invention believed to be novel and the
elements characteristic of the invention are set forth with
particularity in the appended claims. The drawings are for
illustration purposes only and are not drawn to scale. Furthermore,
like numbers represent like features in the drawings. The invention
itself, however, both as to organization and method of operation,
may best be understood by reference to the detailed description
which follows taken in conjunction with the accompanying drawings
in which:
[0061] FIG. 1 illustrates an embodiment of the Inter-Domain
Mobility Management system of this invention which illustrates
communications between two administrative domains.
[0062] FIG. 2 illustrates another embodiment of the Inter-Domain
Mobility Management system of this invention with backend
services.
[0063] FIG. 3 illustrates yet another embodiment of the
Inter-Domain Mobility Management system of this invention where
requests are resolved by the backend server shared among multiple
administrative domains.
[0064] FIG. 4 illustrates still another embodiment of the
Inter-Domain Mobility Management system of this invention where
requests are resolved by the backend server not shared among
multiple administrative domains.
[0065] FIG. 5 illustrates yet another embodiment of the
Inter-Domain Mobility Management system of this invention using
centralized home location function servers/databases.
[0066] FIG. 6 illustrates still another embodiment of the
Inter-Domain Mobility Management system of this invention using
distributed home location function servers/databases.
DETAILED DESCRIPTION
[0067] The present invention provides for extending the H.323
standard to support mobility in a multimedia communication system
with services over packet-based networks. The present H.323
standard is known to those skilled in the art and is hereby
incorporated by reference. The invention supports extending H.323
to support mobility in a transport independent way, create new
H.323 messages and/or message elements that needed to support
mobility, and facilitate interoperability for implementation of
H.323 mobility over specific networking environments such as
wireless/PSTN-IP-LAN. The invention provides for extension to
existing H.225.0 (H.323) messages to accommodate mobility. Messages
are provided to facilitate mobility binding as the mobile entity
moves form one place to another. H.323 mobility service varies from
traditional services such as cellular wireless/PSTN, and mobile IP,
mobility services in that the IETF=s mobile protocol may be
modified to include an interworking function (IWF) to provide
interoperability between the mobile H.323 system and the
wireless-PSTN mobile network.
[0068] When a mobile unit implementing H.323 uses a packet-based
network, e.g., the IP subnet, together with an H.323-based point of
attachment (e.g., network point of attachment, zone, domain), the
mobility information is managed via a gatekeeper. There may be a
gatekeeper at the transmitting end and at the receiving end also.
If necessary, the gatekeeper can also perform bandwidth management,
address translation, maps LAN aliases to IP addresses, and sets up
a real-time transport control protocol (RTCP) for exchanging status
information between the transmitting end and the receiving end. A
H.245 control channel is set up to provide control functions such
as, for example, opening and closing data channels.
[0069] The functional requirements of H.323 mobility are primarily
described at the H.323 application level as:
[0070] Terminal Mobility: the ability for a terminal to changes
location, network point of attachment, and H.323 point of
attachment and still be able to communicate. A fixed or mobile
H.323 terminal must be able to reach an H.323 mobile user and vice
versa. Conversations are provided even when the mobile terminal
moves from one place to another with a different point of
attachment or network address. Where desired, communications are
also provided among the H.323 mobile users. Intra-zone, inter-zone
(intra-domain) and/or inter-domain handoff is supported. Handoff
between intra-zone, inter-zone (intra-domain) and or inter-domain
users is supported.
[0071] User Mobility: the ability for a user to maintain the same
user identity on different terminals or terminal types. An H.323
user maintains the same identity and may receive the same or, where
desired, different services even when the user moves. Service
providers may be switched with the user maintaining the same
identity.
[0072] Mobility Management: The H.323 mobility management is
supported to provide registration, call establishment, roaming and
handoff.
[0073] QoS Support: QoS service is maintained during intra-zone,
inter-zone (intra-domain) and/or inter-domain roaming for the H.323
user.
[0074] Authentication and Security: Authentication and security
mechanisms are provided in support of H.323 mobility.
[0075] Typically, a gatekeeper (GK) manages a zone. A zone is
generally a collection of H.323 entities such as terminals,
gateways (GWs) or interworking functions (IWFs) and multi-point
controllers (MCs). Each H.323 entity has a unique network point of
attachment or address, and each zone may contain many network
points of attachment, subnets, or addresses under the management of
a GK. For example, a zone many have multiple networks in the case
of an IP, ATM, or other network. If a user or terminal moves within
a zone, its network attachment or subnetwork address may also
change.
[0076] A domain may consist of a single or of multiple zones. Thus,
H.323 mobility is addressed in terms of zones and domains as well.
If an H.323 user, entity or terminal crosses a zone boundary, such
a change may be termed as a change of H.323 point of attachment
because an H.323 gatekeeper manages the registration of all H.323
entities in a given zone. In addition, H.323 services are ensured
during the call and between calls while users or terminals move
from place to place.
[0077] Other terminology used herein is:
[0078] Discrete terminal mobility or roaming: the ability for a
terminal to make discrete changes of physical location, i.e., to
change location while no media streams are active to Continuous
terminal mobility or handover: the ability for a terminal to change
location while media streams are active. Such a change may be
seamless, i.e., without loss of data, or alternatively, may not be
seamless, i.e., wherein some media stream data is lost.
[0079] Service mobility: the ability for a user to obtain a
particular service independent of user and terminal mobility, i.e.,
wherein a foreign network has the means to obtain the parameters
required for the service.
[0080] Network Point of Attachment: the attachment or address,
e.g., an IP address, of an H.323 entity, e.g., terminals, MCUs,
MCs, and/or GWs, to a network. Similarly, the network point of
attachment for ATM and other network can also be defined. Each
H.323 entity has at least one network address which uniquely
identifies the H.323 entity on the network. The address is specific
to the network environment in which the endpoint is located.
Different network environments may have different network address
formats. H.323 permits an endpoint to use different network
addresses for different channels within the same call.
[0081] H.323 Point of Attachment: the gatekeeper with which an
H.323 terminal, GW (IWF), MC, or MCU is Databased.
[0082] Mobile Entity: the H.323 entity that changes its point of
attachment (network and/or H.323 point of attachment) from one
attachment to another. A mobile entity can continue to communicate
with other H.323 entities at any location as it moves from place to
place.
[0083] Home GK: a gatekeeper in the mobile entity's home zone which
performs the necessary management functions for departed mobile
entities and maintains current location information for each. Any
H.323 GK that provides the support for H.323 mobile entities can
act as a home GK.
[0084] Home Network: the network in the mobile entity's home
network and the network which has been declared by the mobile
entity as its home network, e.g., an IP subnetwork in the home zone
declared as a home network by a mobile entity.
[0085] Home Network Address: the address of the network point of
attachment in the home network of a mobile entity, e.g., IP address
(RAS transport address) in a home IP subnetwork. If the transport
address contains the network address in addition to the TSAP, the
home transport address will also contain the home network
address.
[0086] Foreign GK: a gatekeeper on a mobile entity's visited- or
visiting-zone which cooperates with the home GK to have the
information related to the mobile entity while it is away from its
home zone. Any H.323 GK that provides the support for H.323 mobile
entities can act as a foreign GK.
[0087] Foreign Network: the network in the mobile entity's foreign
zone where the said network has been declared by the mobile entity
as its foreign network, e.g., an IP subnetwork in a foreign zone of
a mobile entity.
[0088] Care-of Network Address: the address of the network point of
attachment in a foreign network of a mobile entity, e.g., IP
address (RAS transport address) in a foreign IP subnetwork. If the
transport address contains the network address in addition to the
TSAP, the care-of transport address will also contain the care-of
network address.
[0089] Visiting GK: a foreign GK that the mobile entity is
presently visiting, i.e., the mobile entity is currently residing
within a foreign zone that is managed by a foreign GK.
[0090] Visited GK: the foreign GK that had been visited by the
mobile entity previously.
[0091] Target GK: the foreign GK that the mobile entity intends to
visit.
[0092] Target Network: the target network that the mobile entity
intends to visit.
[0093] Mobile GK: either a home GK or a foreign GK.
[0094] Home Zone: a zone that is managed by a home GK of a mobile
entity.
[0095] Foreign Zone: a zone managed by a foreign GK.
[0096] Visiting Zone: a zone other than a mobile entity's home zone
in which the mobile entity is currently residing, i.e., a foreign
zone in which the mobile entity is presently visiting.
[0097] Visited Zone: a zone other than a mobile entity's home zone
that the mobile entity has visited previously, i.e., the foreign
zone which had been visited by the mobile entity previously.
[0098] Target Zone: a zone other than a mobile entity's home zone
that the mobile entity intends to visit.
[0099] Visiting Entity: a mobile entity that is residing in a
visiting zone managed by a visiting GK.
[0100] Visiting Terminal: a mobile H.323 terminal that is residing
in a visiting zone managed by a visiting GK. Visiting User: a
mobile H.323 terminal that is residing in a visiting zone managed
by a visiting GK.
[0101] Visitor List: the list of mobile entities currently visitng
a foreign zone.
[0102] GK Advertisement for Mobility Services: foreign gatekeepers
advertise their presence by using a special message to provide
services for mobile entities.
[0103] Care-of Address: the terminal address of the point of
attachment, e.g., care-of network address of mobile entity or
care-of address of a foreign GK where a mobile entity is
residing.
[0104] There are two different types of care-of address: a foreign
GK care-of address with which a mobile entity is Databased; a
care-of network address which the mobile entity has associated with
one of its own network interfaces, e.g., a temporary IP address of
the visitor may be acquired dynamically using the Dynamic Host
Configuration Protocol (DHCP).
[0105] Location Area: a location area may constitute a cell or a
certain group of cells in a given geographical area that resides
within a zone.
[0106] Administrative Domain: An administrative domain is a
collection of H.323 entities administered by one administrative
entity and may contain one or more gatekeepers (that is, one or
more zones). It may also contain one or more border elements for
communications between the domains. Like zone, an administrative
domain can also be termed as home or foreign (visited, visiting, or
target) domain.
[0107] Mobile H.323 (Mobile H.323 Protocol): the extended and
existing H.323/H.225.0/H.245 messages that are used to support
mobility in H.323 are termed as mobile H.323 protocol or simply as
mobile H.323.
[0108] Clearly, H.323 mobility provides two kinds of changes in
point of attachment: changing Network Point of Attachment in H.323
to H.323 calls (it can also be termed as a part of change in H.323
point of attachment), and changing H.323 Point of Attachment (e.g.,
change in zone or domain). Broadly speaking, both kinds of change
in attachment can be termed as change in H.323 point of attachment.
The change of attachment can also occur during calls, i.e.,
handover, and between calls, e.g., roaming. A change in point of
attachment, e.g., a change in IP address or a change in zone/domain
boundary, may result in handover during the call.
[0109] FIG. 1 illustrates an embodiment of the Inter-Domain
Mobility Management system of this invention which illustrates
communications between two administrative domains. Administrative
domain 10 has a GK/BE.sub.1b 12, a GK.sub.1a 14 and a GK.sub.1c 16.
Administrative domain 20 has a GK/BE.sub.2b 22, a GK.sub.2a 24 and
a GK.sub.2c 26. A mobile H.323 entity 28 contacts the GK.sub.2c 26
after moving from administrative domain 10 to administrative domain
20. Basically, the mobile entity 28 will discover the gatekeeper
(GK) and then communicate with the gatekeeper (GK) for registration
using the procedures as described in ITU-T Recommendation H.323,
such as, GK.sub.2c 26 of the administrative domain 20 of a given
administrative domain. The Gate-keeper (GK) 26, will find from the
registration request message that the mobile user has moved from
another administrative domain and needs to communicate with the
other administrative domain. As result, GK.sub.2c 26 of the
administrative domain 20 will then communicate with a border
element (BE) 22 of that administrative domain 20 as appropriate
depending on the needs dictated by the optimal routing so that
minimal resources are used. The border element (BE) 22 will then
communicate with another border element (BE) 12 of administrative
domain 10 for resolving the information (e.g., address,
registration, verification, authentication, etc.).
[0110] Gatekeeper discovery is the process an endpoint uses to
determine which Gatekeeper to register with. This may be done
manually or automatically. Manual discovery relies on methods
outside the scope of this recommendation to determine which
Gatekeeper an endpoint is associated with. The endpoint may
multicast (or use other methods as described in Appendix
IV/H.225.0) a Gatekeeper Request (GRQ) message, asking "Who is my
Gatekeeper?". This is sent to the Gatekeeper's well-known Discovery
Multicast Address. One or more Gatekeepers may respond with the
Gatekeeper Confirmation (GCF) message indicating "I can be your
Gatekeeper.", and return the Transport Address of the Gatekeeper's
RAS Channel. If a Gatekeeper does not want the endpoint to register
to it, it shall return Gatekeeper Reject (GRJ).
[0111] It should be appreciated that FIG. 1 shows the logical
communications model between the two administrative domains where
no backend services (BES) are considered. BES provide additional
value-added services, such as, for example, permanent and/or
temporary address resolution/allocation services, authentication,
and others using the database/server not defined in H.323 and also
not shown in FIG. 1.
[0112] FIG. 2 illustrates another embodiment of the Inter-Domain
Mobility Management system of this invention which basically
describes the communications flow when the backend services (BES)
(e.g., home location functions (HLFs)) are considered. Like FIG. 1,
it is assumed that mobile entity 28 has moved from administrative
domain 30 to administrative domain 40 and performs the GK discovery
and registers with the GK.sub.2c 26 using H.323 procedures as
described earlier. The relationships for communications between
border elements (BEs) and backend services (BES) (e.g., home
location function (HLFs)) and gate keepers (GKs) needs to be done
in accordance with H.323 standards. The backend services (BES) of a
given administrative domain can equally be accessed by both the
gatekeeper (GK) and the border element (BE). However, a user can
send the request for any services via the gatekeeper (GK). Upon
receipt of a request for backend services the GK will examine the
request and will determine that the user has moved from another
administrative domain and that the related service information
needs to be known from the earlier BES that is not located in this
domain 40. Then the gatekeeper (GK) decides how the backend
services (BES) can be accessed to another administrative domain
using the Border elements (BEs). Depending on the configuration
between the administrative domains optimal routing will be provided
to optimize the resource utilization. Normally the Border element
(BE) is accessed if the services information needs to be resolved
from another administrative domain. In this context FIG. 2 shows
that the backend services (BES) are being accessed from another
administrative domain via the border elements (BEs). As described
earlier, a user or mobile H.323 entity 28 needs to send the service
request to the GK where the user or H.323 mobile entity has
registered. As a result, when the user 28 enters administrative
domain 40, the communication is sent to a gatekeeper 26, which
routes it to the border element 22. The communication is then sent
to border element 12 in administrative domain 30 and then routed to
backend services 32. The request that is sent from the mobile user
or H.323 mobile entity 28 located in administrative domain 40 to
the BES.sub.1b 32 via GK 26, BE 22, and BE 12, is resolved in BES
32 of administrative domain 30 and, a reply is sent back by the BES
32 to the mobile entity 28 via BE 12, BE 22, and GK 26.
Administrative domain 30 will have a plurality of gatekeepers 14,
16 and backend services 34 (BES.sub.1a), 36 (BES.sub.1c).
Similarly, the Administrative domain 40 will have a plurality of
gatekeepers 24, 26 and backend services 42 (BES.sub.2b), 44
(BES.sub.2a), 46(BES.sub.2c). In the same token, there can be a
plurality of border elements (BEs) in each administrative domain
and has not been shown for simplicity. However, FIG. 2 also shows
that the backend services (BES) (e.g., home location functions
(HLFs)) information resolution is provided from another
administrative domain for an H.323 mobile entity if the information
is not available in a given administrative domain.
[0113] FIG. 3 illustrates yet another embodiment of the
Inter-Domain Mobility Management system of this invention where the
backend services (BES) (e.g., home location function (HLFs))
overlap or are common to both the administrative domains, and where
requests are resolved by the backend server shared among multiple
administrative domains. FIG. 3 shows a configuration 50 where a
given back end services (BES) server 55 is being shared or is
common between the two administrative domains, namely,
administrative domain 30 and administrative domain 40. It should
also be noted that there may be other back end services (BES)
servers in those domains whose services are not being shared. As a
result, the services from the non-sharing back end services (BES)
server has to be accessed using the normal procedure of the H.323
protocol via gatekeepers (GKs) and/or border elements (BEs). Also
shown is a mobile H.323 entity 38 in the administrative domain that
would also be sharing the back end services (BES) server 55, and
getting similar information whether it is within the home domain or
in a foreign domain.
[0114] FIG. 4 illustrates still another embodiment of the
Inter-Domain Mobility Management system of this invention showing
the accessing of a non-sharing back end services (BES) server in
two overlapping administrative domains. The non-shared backend
services (BES) server (e.g., BES.sub.1a 34) needs to be accessed
although a given back end services (BES) server (or servers) may be
shared because of the overlapping administrative domains, and where
requests are resolved by the backend server not shared among
multiple administrative domains. FIG. 4 also illustrates how the
inter-domain communication needs to be done in the context of H.323
communications protocol. The H.323 signaling messages for
inter-domain communications flows from the border element (BEs) 22,
to the border element 12 between the administrative domains 40, 30,
as discussed earlier. However, the backend services (BES) from a
back end services (BES) server that reside behind a gate keeper
(GK) and/or a border element (BE) may be accessed via the gate
keeper (GK) and/or border element (BE) as appropriate. The
non-shared backend services (BES) server BES.sub.1a 34 is then
accessed although the gatekeeper 14. However, it should be
understood that a given back end services (BES) server (or servers)
may be shared because of the overlapping administrative domains,
and where requests are resolved by the backend server and are not
shared among multiple administrative domains. The services from a
back end server (BES) 34 can only be requested by an H.323 endpoint
28, 38 via a gate keeper (GK) 14 (because a border element (BE) is
not directly accessible by an H.323 endpoint (e.g., terminal, GW
(gateway)). Furthermore, the mobile entity 28, 38 moves from one
place to another and may not be aware whether it is attached to its
home network address, home zone, and/or home domain. It is expected
that the MGA (mobile gatekeeper advertisement) message that helps
to discover the gatekeeper (GK) for the mobile entity to receive
services for receiving or sending calls will provide this
information or some other mechanisms will help the mobile H.323
entity to discover that it is in a new administrative domain. When
the mobile entity is in a foreign (visiting) administrative domain,
it may so happen that there is a need to verify mobile entity's
profile for proper identification, authorization, and other
purposes from its home domain. If a mobile entity does not need to
verify its profile from its home domain, there is almost no need
for any new standard work in H.323 for mobility because
re-registration mechanisms that exits in H.323 may be sufficient
for this purpose.
[0115] Inter-zone communications and the inter-domain
communications will also need the following: (a) Gate-keeper (GK)
discovery and identification whether it is in its home domain or in
foreign domain, (b) Registration with the gate keeper (GK), (c)
Location updates, (d) Smooth location updates, (e) Call
establishment.
[0116] Communications between the administrative domains are done
via border elements (BEs) and gate-keepers (GKs) when there are
back end services (BES) servers as discussed earlier. The back end
services (BES) server resides behind the gate-keepers (GKs) and
border elements (BEs). The home location function (HLF) and visitor
location function (VLF) are also considered as back end services
(BES) servers that are used for storage of information related to
mobility. The relationship between the border elements (BEs), home
location function (HLFs), visitor location function (VLFs), and
gate keepers (GKs) for H.323 communications protocol is the same as
described in the context of Back end services (BES) servers.
[0117] FIG. 5 illustrates yet another embodiment of the
Inter-Domain Mobility Management system of this invention using a
centralized home location function (HLF) server/database. FIG. 5
also shows the communications flows when a mobile entity moves from
one administrative domain to another where each domain has only one
home location function (HLF) configured in a centralized
architecture. In this embodiment the mobile entity discovers the
gatekeeper (GK.sub.2c) and finds that its is in a foreign
(visiting) domain. Then the mobile entity proceeds with
registration with the gatekeeper (GK) (GK.sub.2c). The gatekeeper
(GK.sub.2c) finds that mobile H.323 entity 28 is a visitor and
keeps the information in the visitor location function (VLF) (not
shown in FIG. 5 for simplicity). There can be some communications
between the visitor location function (VLF), GK2c, and HLF2b to
find out if mobile H.323 entity 28 is a visitor from another domain
(similar one described in R. R. Roy, AT&T, "H.323 Inter-Zone
Mobility Management," MD018, Ad Hoc Mobility Conference Call,
February-May 2000, the disclosure of which is entirely incorporated
herein by reference, in the context of inter-zone mobility
management), and the communication flow between gatekeeper and
gatekeeper from or within one domain has not been shown in FIG. 5
for simplicity. Then, GK2c 26 contacts the border element (GK/BE2b)
22 to contact the administrative domain 75 for verifying the
visitor's profile. The border element (GK/BE2b) 22 of the foreign
domain 75 being unable to provide the information related to the
mobile H.323 entity 28 then contacts the border element (GK/BE1b)
12 of mobile entity's home domain 70. There is only one home
location function (HLF) 72 in the home administrative domain 70
because of the centralized configuration, and GK/BE1b 12
communicates with HLF1b 72 directly to verify the profile of the
mobile entity 28 that is currently residing in administrative
domain 75. The information is then sent back from the home domain
70 to the foreign (visiting) administrative domain 75 after
verifying the profile of the mobile entity 28. (These information
flows are not shown in FIG. 5 for simplicity.) Administrative
domain 75 may have additional home location functions HLF2b (78)
that may be available for additional information.
[0118] FIG. 6 illustrates still another embodiment of the
Inter-Domain Mobility Management system of this invention showing
the inter-domain communication flow using distributed home location
function (HLF) servers/databases. FIG. 6 also shows a configuration
for communications between the two administrative domains where the
home location function (HLF) function is distributed in a domain.
The communications scenarios are almost similar as shown in FIG. 5,
but with the difference that a gate-keeper (GK) has the
intelligence to decide which home location function (HLF) is needed
to be accessed for resolving the information. However, how the
decision is made by the gatekeeper (GK) for contacting a particular
gate keeper (GK) and/or home location function (HLF) is not the
subject of standardization. For example, when the border element
(GK/BE2b) 22 of the foreign (visiting) domain 75 communicates with
border element (GK/BE1b) 12 of the home administrative domain 70,
GK/BE1b 12 decides that this particular mobile entity 28 is managed
by GK1a 14 and contacts GK1a 14. The gatekeeper (GK1a) 14 will then
communicate with HLF1a 84 to verify the profile of the mobile
entity 28 that is currently residing in a foreign domain 90. The
information relating to the mobile entity 28 that is obtained is
then routed back from the home administrative domain 80 to the
foreign administrative domain 90. This information relating to the
mobile entity 28 may be temporarily or permanently stored in HLF2b
92 in the foreign administrative domain 90. Both administrative
domains 80 and 90 may have additional home location functions HLF1c
(86), HLF2a (94), HLF2b (92), HLF2c (96) that may be available for
additional information.
[0119] It may be noted that the communications between the visitor
location function (VLF) and home location function (HLF) after
registration of the mobile entity in a visiting (foreign) domain in
view of the distributed Home location function (HLF) will be almost
similar to that described in AT&T's contribution for inter-zone
mobility management, namely, R. R. Roy, AT&T, "H.323 Inter-Zone
Mobility Management," MD018, Ad Hoc Mobility Conference Call,
February-May 2000, the disclosure of which is entirely incorporated
herein by reference.
[0120] In R. R. Roy, AT&T, AH.323 "Mobile Communications
Environments and Intra-Zone Mobility Management," MD017, Ad Hoc
Mobility Conference Call, February-May 2000, and R. R. Roy,
AT&T, "Needs for Creation of New Mobility Binding Messages
Exclusively for H.323 Mobility Management", APC-1769, SG16,
Q.13/16, WP2, Osaka, Japan, May 15-19, 2000, the disclosures of
which are entirely incorporated herein by reference, it has been
explained why there is a need for creation of separate signaling
messages for mobility binding and updating in addition to
extensions of existing messages to support mobility. The
characteristics of the mobility binding and updating messages are
such that the existing H.323 signaling messages do not have the
properties to satisfy those requirements. The new mobility binding
and updating messages proposed in contribution, such as, R. R. Roy,
AT&T, "H.323 Mobility Architecture and Protocol for Terminal,
User, and Service Mobility," D-354, ITU-T SG 16 Q.13/16, WP2,
Geneva, Switzerland, Feb. 7-18, 2000, the disclosure of which is
entirely incorporated herein by reference, can also be used for
inter-domain communications.
[0121] However, the existing accessRequest and other messages of
H.225.0 Annex G, for inter-administrative domain communications
also need to be extended to support mobility. It may be noted that
we still need to create new messages for mobility binding and
updating as suggested in R. R. Roy, AT&T, "H.323 Mobility
Architecture and Protocol for Terminal, User, and Service
Mobility," D-354, ITU-T SG 16 Q.13/16, WP2, Geneva, Switzerland,
February 7-18, 2000, the disclosure of which is entirely
incorporated herein by reference.
[0122] The new messages that support mobility binding and updating
has been proposed in R. R. Roy, AT&T, "H.323 Mobility
Architecture and Protocol for is Terminal, User, and Service
Mobility,". D-354, ITU-T SG 16 Q.13/16, WP2, Geneva, Switzerland,
Feb. 7-18, 2000, the disclosure of which is entirely incorporated
herein by reference. The same messages can be used for both
intra-domain and inter-domain communications. For inter-domain
communications additional message headers like hopcount and others
need to be added.
[0123] Like LRQ (Location Request), we also need to extend the
accessRequest and few other messages to indicate where the RAS
(Registration, Admission, and Status) and call signaling addresses
need to be sent for the mobile entity while the mobile entity will
move from one place to another. Moreover, a mechanism that allows
whether the mobile entity will let others know its actual location
other than its original home network address for a single, multiple
or all media (may be based subscription policy like security or
otherwise) while it is in a foreign domain is also need to be kept
as an option.
[0124] It has clearly been articulated how the inter-domain
communications need to be made to manage mobile entity users that
conforms the existing H.323 standard. In particular, it has been
shown that the relationship and communications flows among the
border elements (BEs), gate keepers (GKs), home location function
(HLFs), and visitor location function (VLFs) considering the
following:
[0125] (a) Border elements (BEs) can be configured as centralized,
distributive, and/or hybrid architecture.
[0126] (b) Gatekeepers (GKs) can have any architectural
relationships: centralized, distributive, and/or hybrid
architecture.
[0127] (c) Home location function (HLFs) that are considered as the
backend servers behind the Border elements (BEs) and Gate keepers
(GKs) can also be arranged in any architectural relationship with
respect to the Border elements (BEs) and Gate keepers (GKs):
centralized, distributive, and/or hybrid architecture.
[0128] (d) The administrative domains can also be arranged
logically among themselves in any form: centralized, distributive,
and/or hybrid architecture.
[0129] (e) The overlapping administrative domains that can have the
shared backend services (e.g., Home location function (HLF)).
[0130] The inter-domain communications protocol for mobility
management needs to be robust enough to satisfy all probable
configurations of all functional entities (e.g., border elements
(BEs), gate keepers (GKs), home location function (HLFs), visitor
location function (VLFs), zones, domains) whether each
architectural element is configured as centralized, distributed,
and/or hybrid manner. However, the back end services (BES) server
(e.g., home location function (HLF)) to back end services (BES)
(e.g., home location function (HLF)) server communications protocol
is not the scope of H.323.
[0131] The invention provides a framework how the inter-domain
communications need to be done in H.323 for mobility management. It
has been shown the communication flows for mobility management
considering the border elements (BEs), gate keepers (GKs), home
location function (HLFs), and domains where each entity can be
arranged in any logical architectural relationship: centralized,
distributed, and/or hybrid architecture.
[0132] In addition, the messages like accessRequest and other are
also need to be extended to let know the RAS and the call signaling
addresses of the mobile entity while it is visiting a foreign
domain. Furthermore, it is the critical need for a mobile entity to
have an option whether it will let others to know its present
location in a foreign domain while it is away from its home domain
because the communications can also be done via its home network
address that it may want make to public.
[0133] This invention also shows various relationships for
communications between border elements (BEs), home location
function (HLFs), visitor location function (VLFs), and gate keepers
(GKs).
[0134] H.225.0 Annex G provides the communications between the
administrative domains via the border elements (BEs). A domain may
have one or more border elements (BEs) while these border elements
(BEs) may have the logical relationship, such as, (a) centralized,
(b) distributed, or (c) hybrid architecture.
[0135] A Border element (BE) is usually co-located with a
gatekeeper (GK). If they are not co-located, the communications
between the border element (BE) and the gatekeeper (GK) will be
done using the H.225.0 RAS signaling messages (e.g., LRQ/LCF/LRJ)
for the address resolution and location update.
[0136] However, it is felt that it would be more efficient to use
the H.225.0 Annex G messages between the gatekeepers (GKs) as well
as between the gatekeeper (GK) and the border element (BE).
[0137] Furthermore, the administrative domains can also be arranged
among themselves, such as (a) centralized, (b) distributed, or (c)
hybrid architectural relationship from logical communications point
of view.
[0138] There may also be overlapping administrative domains and
more than one administrative domain that may be able to resolve a
given address.
[0139] A border element (BE) element configures itself with all
address information obtaining the address templates in the
following ways (a) static configuration with explicit provisioning
with address templates for all zones for which it is responsible,
(b) receiving descriptors containing the address information from
other border elements (BEs) in response to general requests, and
(c) receiving responses to specific queries.
[0140] It is important to understand that home location function
(HLFs)/visitor location function (visitor location function (VLFs))
can be accessed equally by border elements (BEs) and gatekeepers
(GKs). However, a mobile entity can only communicate with the
gatekeeper (GK) directly (not the border element (BE)).
[0141] The H.323-based mobility registers with the H.323
Visiting/Foreign Gatekeeper including sending registration
information for the Mobile Terminal/Node/Entity using a Base
Station to Base Station Controller to Mobile Switching Center to
H.323 Visiting/Foreign Gatekeeper system. Wherein registering with
the at least one H.323 Visiting/Foreign Gatekeeper includes sending
registration information for the Mobile Terminal/Node/Entity using
a wireless/wire-line Local Area Network to Router/Switch to H.323
Visiting/Foreign Gatekeeper system. Furthermore, the registering
includes the steps of broadcasting/multicasting/unicastin-
g/sending, by the Home Gatekeeper, a Mobility Gatekeeper
Advertisement (MGA) message periodically;
broadcasting/multicasting/unicasting/sending a registration request
message (RRQ) to the Home Gatekeeper by the Mobile
Terminal/Node/Entity; and sending, by the Home Gatekeeper, a
registration confirmation/registration rejection (RCF/RRJ) to the
Mobile Terminal/Node/Entity. The registering steps can also include
the steps of: upon determining, by the Mobile Terminal/Node/Entity,
that a network point of attachment has changed/a foreign zone has
been entered, broadcasting/multicasting/unicasting/sending, by the
Mobile Terminal/Node/Entity, a registration request message (RRQ)
to a Foreign/Visiting Gatekeeper;
broadcasting/multicasting/unicasting/sending- , by the
Foreign/Visiting Gatekeeper, a binding update message (BuRQ) to the
Home Gatekeeper; broadcasting/multicasting/unicasting/sending, by
the Home Gatekeeper, a binding update confirmation/rejection
(BuCF/BuRJ) to the Foreign/Visiting Gatekeeper;
broadcasting/multicasting/unicasting/sen- ding, by the
Foreign/Visiting Gatekeeper, the binding update
confirmation/rejection to the Mobile Terminal/Node/Entity.
[0142] The H.323-based mobility would also include a situation
wherein, where the Mobile Terminal/Node/Entity has already visited
another zone regulated by a Visited Gatekeeper within the first
administrative domain, registering includes:
broadcasting/multicasting/unicasting/sending, by the Home
Gatekeeper, a mobility unbinding message (UbRQ) to the Visited
Gatekeeper; and broadcasting/multicasting/unicasting/sending, by
the Visited Gatekeeper, a mobility unbinding confirmation/rejection
(UbCF/UbRJ) to the Home Gatekeeper. Or, where the H.323-based
Mobile Terminal/Node/Entity has already visited another zone
regulated by a Visited Gatekeeper within the first administrative
domain, registering would include:
broadcasting/multicasting/unicasting/sending, by the Mobile
Terminal/Node/Entity, a registration request message (RRQ) to a
Foreign/Visiting Gatekeeper;
broadcasting/multicasting/unicasting/sending- , by the
Foreign/Visiting Gatekeeper, a mobility unbinding update message
(UbRQ) to the Visited Gatekeeper,
broadcasting/multicasting/unicasting/se- nding, by the Visited
Gatekeeper, a mobility unbinding confirmation/rejection (UbCF/UbRJ)
to the Foreign/Visiting Gatekeeper;
broadcasting/multicasting/unicasting/sending, by the
Foreign/Visiting Gatekeeper, a provisional registration
confirmation to the Mobile Terminal/Node/Terminal and
broadcasting/multicasting/unicasting/sending, by the
Foreign/Visiting Gatekeeper, a binding update message (BuRQ) to the
Home Gatekeeper; and broadcasting/multicasting/unicasting/sending,
by the Home Gatekeeper, a binding update confirmation/rejection
(BuCF/BuRJ) to the Foreign/Visiting Gatekeeper.
[0143] The H.323-based Mobile Terminal/Node/Entity having already
visited another zone regulated by a Visited Gatekeeper within the
first administrative domain, and wherein registration could
include: broadcasting/multicasting/unicasting/sending, by the
Mobile Terminal/Node/Entity, a registration request message (RRQ)
to a Foreign/Visiting Gatekeeper;
broadcasting/multicasting/unicasting/sending- , by the Visited
Gatekeeper, a mobility unbinding confirmation/rejection (UbCF/UbRJ)
to the Foreign/Visiting Gatekeeper; broadcasting/multicasting-
/unicasting/sending, by the Foreign/Visiting Gatekeeper, a
provisional registration confirmation to the Mobile
Terminal/Node/Terminal and
broadcasting/multicasting/unicasting/sending, by the
Foreign/Visiting Gatekeeper, a binding update message (BuRQ) to the
Home Gatekeeper, broadcasting/multicasting/unicasting/sending, by
the Home Gatekeeper, a binding update confirmation/rejection
(BuCF/BuRJ) to the Foreign/Visiting Gatekeeper;
broadcasting/multicasting/unicasting/sending, by the Home
Gatekeeper, a mobility unbinding update message (UbRQ) to the
Visited Gatekeeper; and
broadcasting/multicasting/unicasting/sending, by the Visited
Gatekeeper, a mobility unbinding confirmation/rejection (UbCF/UbRJ)
to the Home Gatekeeper.
[0144] The H.323-based mobility wherein at least one
Visiting/Foreign Gatekeeper utilizes a combined Home/Visitor
Location Database. The H.323-based mobility wherein a plurality of
Visiting/Foreign Gatekeepers each utilize an individual Visitor
Location Database and share a Home Location Database.
[0145] The H.323-based mobility wherein the communication utilizes
an Internet Protocol.
[0146] This invention provides a communication link between a
telephone device and/or another telephone device(s) and/or
server(s). It also allows for programming a telephone device to
accept or reject communications between administrative domains.
This invention also allows a mobile entity unit to be in
communication with a telephone network, especially when a user
moves between different administrative domains.
[0147] While the present invention has been particularly described,
in conjunction with a specific preferred embodiment, it is evident
that many alternatives, modifications and variations will be
apparent to those skilled in the art in light of the foregoing
description. It is therefore contemplated that the appended claims
will embrace any such alternatives, modifications and variations as
falling within the true scope and spirit of the present
invention.
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