FI105138B - Use node groups as location information - Google Patents

Description

1 105138

Scope of the Invention

The invention relates to communication systems and in particular to a communicative packet network comprising hierarchically arranged node groups in which the members of the node group know the communication parameters relevant to the routing of members of at least the same node group and the network comprising at least one home database for mobile terminals or subscribers.

Background of the Invention

The telecommunications industry is moving towards new, high-quality services that require high bit rates. As network systems evolve and expand, optimal control of communication between networks has become increasingly important.

15 Some of the solutions of interest are broadband networks, where bit rates typically exceed 2Mbit / s. The transmission technology of these B-ISDN networks (Broadband Integrated Services Digital Network) has been selected as Asynchronous Transfer Mode (ATM). ATM transmission technology is a switching and multiplexing solution 20 specifically associated with a data link layer (OSI Layer 2), which enables B-ISDN networks. . . implements a Connection Oriented packet network.

The present invention is applicable to a plurality of connection network networks to which wireless terminals may be added. * Lightweight routers (such as TCP / IP). The invention will be illustrated by · 25 in the following, utilizing the ATM transmission technology elements and terms of the invention; but not limited to these.

In ATM communication, end-user data traffic is transported from source to destination via virtual links. The information is transmitted over the network via switches in standard size 53 byte packets, r.) T called ATM cells. The structure of ATM cells is illustrated in Figure 1. One cell comprises a 5 byte header and a 48 byte actual payload information field. The physical layer may comprise a plurality of virtual paths that are multiplexed within the ATM layer. Routes are identified by a Virtual Path Identifier (VPI).

2 105138 The User-to-Network Interface (UNI) has an 8-bit VPI and the Network-Node-Interface (NNI) has a 12-bit VPI. Each virtual path may comprise a plurality of virtual channels identified by a 16-bit Virtual Channel Identifier (VCI).

The main purpose of the header is to identify the connection number for the sequence of cells that is transmitted through the virtual channel associated with the connection. In addition to the above, the header includes other fields such as Header Error Control (HEC), Generic Flow 10 Control (GFC), Cell Loss Priority (CLP), and Payload Type (PT). . The ATM cell indirectly contains information about the recipient's address, so that each cell is an independent data transport unit. The number of cells per time unit is proportional to the user's bandwidth requirements.

15 ATM is a connection based communication technology, but since there is no connection before it is established, the connection request must be routed from the source through the ATM network to the destination in much the same way as packets are routed on packet switched networks. After the connection is established, the packets pass through the same virtual channel during the connection. The ATM Forum proposes the implementation of 20 routing PNNI (Private NNI) protocols, the features of which are described in more detail in, for example, ATM Forum, 1996, PNNI Specification, Version 1.0, ATM Forum document af-PNNI-0055,000.

"The PNNI protocol operates on ATMs connected to PNNI links: relay systems such as single switches or entire network

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· 25 yrs. The PNNI link can be a physical link or a virtual link. PNNI link ·: ··: can be, for example, a virtual route that connects two nodes. The nodes are logically parallel to the PNNI protocol.

PNNI basically consists of two components: the PNNI signaling protocol and the virtual circuit routing protocol. The PNNI signaling protocol ..... 30 collets are used to transmit ATM connection set-up messages between the source · · I ”of the network and the destination user-network interface UNI. UNI signaling • · **: · * is converted to NNI signaling at the source switch and NNI signaling is converted to • • UNI signaling at the destination switch. The virtual circuit routing protocol is used to "" route the signaling request through the ATM network. This idea is illustrated in FIG. 2, which illustrates a signaling for establishing a connection between two fixed terminals FT1 and FT2.

• · 3 105138 PNNI consists essentially of two components: the PNNI Signaling Protocol and the Virtual Circuit Routing Protocol. The PNNI signaling protocol is used to transmit ATM connection messages in the network between the source and the destination user-network interface UNI. UNI signaling 5 is converted to NNI signaling at the source switch and NNI signaling is converted to UNI signaling at the destination switch. A virtual circuit routing protocol is used to route a signaling request through an ATM network.

The PNNI protocol has been developed primarily with two goals in mind: 10 extensions based on flexible scalability and quality of service. The PNNI protocol routes the connection mainly on the basis of quality of service (QoS), traffic parameters, and available resources on the network. The connection request is set with the desired quality of service, which is then maintained throughout the connection. This is based on the Connection Admission Control (CAC) control performed by the ATM switches, which in a simplified manner, when the switch receives a request for establishing a connection, checks whether it can establish a connection without interfering with existing connections. The switch only accepts the connection if no interference is expected, otherwise the connection is routed through another switch.

20 Flexible extensibility in the PNNI protocol is implemented by a hierarchical network organization involving the exchange of aggregated availability information between different hierarchical levels. The PNNI hierarchy is illustrated in Figure 3. Each level of the PNNI hierarchy follows the same recursive mesh: so that basically the same mechanisms are used at each level of <<: 25. Each hierarchy level consists of groups called *: * ·: nodes. A node group is essentially a set of groups, all of which have access to an identical topological database and which exchange information about the state of a link. For a higher-level node group in the hierarchy, each lower-level node group appears as a logical group node, ···, which, like a normal node, swaps the state of links and nodes with other nodes in the same level.

*. ** Each node group has a node that acts as a Peer »♦ ♦: V Group Leader (PGL), performing the functions of a logical group node. The status information of upper-level node groups is aggregated between hierarchical levels, so members of the same-35 node group know exactly the status information of their own group and the upper level "". level data with lower accuracy, according to the difference in group hierarchy levels.

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It is proposed to transfer state information of network elements in PNNI over Topology state packets (PTSP). The packets comprise a large number of link and node status parameters that indicate the traffic conditions within the network. Status communication can be triggered by 5 specific events, and the PNNI protocol is also designed to tune to the desired resolution at regular intervals throughout the network. Thanks to this flooding function, updated status information is available at the selected level throughout the network, and members of the same node group in particular know exactly what their node group is.

10 Members of the same node group are connected by horizontal links.

Edge nodes are nodes in a node group that have links to other node groups, including external networks, that do not implement the PNNI protocol. The edge nodes of different node groups of the same hierarchy level define each other as an uplink link to the corresponding node group and also provide usability information for this link within their own node group.

One interesting trend in recent times has been to bring wireless data and mobility to connectivity data networks.

This means that the network is extended over the air interface to wireless terminals. Existing standards do not as such support the additional features required by wireless communication, but various solutions for implementing mobility management, for example, in the context of ATM, have already been presented. The aim has been to add wireless data transmission and mobility to an ATM network without significant changes to existing ATM networks and standards.

[AF96-1699] Potter, Gilmurray (ORL), 1996, "Tunneling 25 Signaling for Support of Mobile ATM, ATM Forum Contribution 96-" "1699" describes an excellent PNNI protocol-based method for routing communications on ATM wireless. It is proposed that the mobility of ATMs be accomplished by tunneled signaling supported by a location update service The solution presented provides the terminal with a flame address (MHA) to be stored in a permanent memory, which is used to connect to · · · The MHA addresses are proposed to be allocated - *: * 'as such that the number directly identifies whether or not the number V ro is associated with the mobile terminal. When a mobile terminal registers to a roaming network, it is assigned a visit number (MFA). The home network of the mobile terminal stores information about the home address of the terminal and p Whenever a mobile terminal registers under a new switch, the information about the new 5 105138 MFA is updated to the home network of the terminal. When the call setup message arrives at the switch that detects the destination address of the connection message is associated with the mobile terminal, the original destination address of the message is encapsulated within the message and the MFA from the home network is used as the routing address. When the message arrives at the switch indicated by the visit address, the encapsulation is decrypted and the message is routed to the mobile terminal.

Through encapsulation, the connection set-up message to the mobile terminal can be transparently routed through the network using PNNI protocol 10. In this solution, as in other disclosed publications, the encapsulated message is typically directed to an anchor switch associated with a base station under which the terminal is registered. However, from a mobility management point of view, providing position tracking with switch accuracy is not the most cost-effective option. By configuring the routing of the wireless terminal to pass through certain switches, the advantage of a hierarchical network structure is not exploited, which allows routing to be optimally routed to the terminal according to selected traffic-related parameters, for example, along the shortest route and avoiding congested links. Forcing traffic on certain switches weakens routing, which is reflected in degraded quality of service, such as increased latency or increased number of lost cells. In addition, the connections may be congested to the anchor switch, which will quickly deplete the switch buffers and available bandwidth.

; .v Moving a subscriber from one service area of the anchor switch to another <<:.; 25 always guarantees the new registration and the associated location update to the subscriber *: ··: home network. If the switch has a small service area and the subscribers move a lot, the network, and especially the switch used as the destination address for encapsulation, will be burdened with the additional signaling required for mobility management. If the subscriber visits a network far away from the home network, ···, 30 update messages will have to be transported remotely, and the signaling volume should be minimized. Similarly, if the service area of the anchor switch is enlarged, there is a risk that the switch will be congested.

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BRIEF SUMMARY OF THE INVENTION It is an object of the present invention to provide a solution by which the service set-up message and the subsequent connection-related traffic packets can be routed through the network so that the above problems can be resolved without significant changes to existing networks.

The object of the invention is achieved by the connection packet network according to claim 1. Said network is characterized in that the status-5 location information in the home database comprises the address of the node group with which the mobile terminal or subscriber was last registered, and that said parameters relevant for routing contain information for intra-node group routing.

The invention also relates to a mobile terminal for a packet communication network according to claim 8, the network comprising hierarchically arranged node groups, wherein the members of the node group know the traffic parameters relevant to the routing of other members of the same node, in the form of a temporary address 15. The terminal is characterized in that said temporary address comprises the address of the node group to which the mobile terminal or subscriber was last registered, and that the terminal is adapted to update the location information in the home database when moving from one node group to another.

The invention also relates to a method for routing a message in a communication packet network according to claim 9, comprising hierarchically arranged node groups, wherein the members of each node group know the communication parameters relevant to the routing of other members of the same node group. terminal management, the connection set-up message containing the call - *: *: permanent address of the mobile terminal or subscriber is sent from the first network node to the home database of the called mobile terminal or subscriber which stores the location information of the mobile terminals or subscribers; is given to the first network node in response to a called mobile · · !!! a temporary address of the terminal or subscriber, routing the connection establishment from the first network node forward from the switch, using said temporary address to the destination of the connection:, [[:. The method is characterized in that the address of the node group to which the mobile terminal or subscriber was last registered is stored in said home register as a temporary address, using the relevant traffic parameters 5 for routing.

Preferred embodiments of the invention are claimed in the dependent claims.

The invention is based on the fact that instead of a single network node or switch, the location of the mobile terminal / subscriber is tracked in the home database with the accuracy of 10 nodal groups. The location of the subscriber with node accuracy is known at least within the node group. The location update to the home network is performed mainly when the terminal / subscriber moves from one node group to another. A switch routing a connection message that performs a location query from a database containing location information routes the message to a received temporary address 15, which is a node group address. The message moves according to the protocol towards said node group. When the message arrives at a node edge node, the node recognizes the message as a message addressed to the mobile terminal or subscriber and either routes the message to the mobile terminal or, if the edge node does not contain sufficient functionality to perform routing, sends the message to another node node. Intra-node routing utilizes internal node data management, which allows: 'Each member is aware of the information of other members of the same node group. traffic parameters relevant to routing. According to the invention 25, the information includes the identity or address of the base station serving the wireless terminal. Flooding known as PNNI can be used to disseminate this information within a cell group. Essentially, the edge node already knows how the message is to be routed within the node group.

. ···. The solution according to the invention makes it possible to improve routing by taking advantage of the advantages of a hierarchical network structure and protocol also in implementing wireless connections, while avoiding the problems described above. Due to the invention, the location update signaling does not affect the size of the anchor switch service area because the location information is in the home database. 35 only needs to be updated when the terminal or subscriber changes the node group. The method is easy to implement and does not cause significant ': changes to existing networks or protocols. Reducing signaling associated with Mobility Management 8 105138 also facilitates the implementation of distributed database functions.

List of figures

Figure 1 illustrates the structure of ATM cells, Figure 2 illustrates the nodes in the PNNI protocol, Figure 3 illustrates the hierarchical structure of the PNNI protocol and the concept of a node block diagram 10, the prior art call setup message routing utilizing tunneling, the block and signaling diagram of Figure 5 illustrates the advantage of the solution of the invention in the example shown.

DETAILED DESCRIPTION OF THE INVENTION The block and signaling diagram of Figure 4 illustrates a prior art routing of a connection set-up using tunneling. The example illustrates three node groups A, B, and C. A fixed terminal device FT of node group A having address A. 10. transmits a connection request to node group (C.2) terminal MT 4 having address (M.2) (C.2.11). Switches 20 that do not support the management of mobile terminals routing connection; the formation message normally towards the node group C.2 (Steps 1 and 2). When the message arrives at the switch MESI 6 that supports the wireless terminals, it notices from the address that it is a message addressed to the mobile terminal and performs a location query from the MT 4 home network (C.2) 2: ·. 25 (step 3). The home network has a database HLR 7 which contains information about the network

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permanent and temporary addresses of associated terminals. The subscriber database * HLR 7 returns to the switch MESI 6 the temporary address (step 4) of the terminal MT 4, which is the address of the anchor switch MES2 8 associated with its base station AP1 to which the terminal was last registered (B.3.3). The MESI switch 6 • · · 30 changes the destination address of the connection message to a temporary address «* ··; (B.3.3), places the original destination address (C.2.11) in one of

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. ···. field (for example, "called party subaddress"), and in accordance with the PNNI protocol send a message to the visited network (B.3) 3 <<· ··: (steps 5, 6 and 7). When the message arrives at the MES2 switch 8, the switch 35 decrypts the message by reading the original destination address C.2.11 from the rest of the message, replacing it with the temporary destination address B.3.3 and sending the message to the terminal MT (steps 8-9) via AP1.

Figure 4 also shows the second base station AP2 of the network (B.3), which 5 is connected to the same anchor switch as the base station AP1. When the terminal moves in the service area of the anchor switch MES2, e.g.

Figure 5 illustrates a node group (B.3) 3 having several base stations. If the traffic of all base stations were controlled via switch MES2, the switch would be overloaded prematurely. In principle, the situation could be resolved by adding more anchor switches to node group B.3, but still the generic problem of forcing traffic through a single switch would not be exploited and the advantage of the network structure to control routing would not be realized. The quality of service would not be significantly improved and the location update signaling would still be unnecessarily increased as location updating to the home network would have to be performed each time the anchor switch area was moved.

Figure 5 illustrates the advantage of the solution of the invention in the above example. Networks A, (B.3) and, (C.2) are separate PNNI node groups. In the example, the node groups include: “partly to a different hierarchical level, but the mutual hierarchy of the node groups is not essential to the invention. Steps 1-3 occur as in Figure 4. Kek- • «! In the solutions according to the invention, the temporary address of the terminal MT is stored in the subscriber database HLR of the home node group C.2 so that the permanent address of the terminal MT is associated with the address of the node group (B.3) with which the terminal was last registered. This address (B.3) is returned to the MESI switch in response to the location query (step 4). Switch 6 changes the connection setting. ···. The destination address of the 30 message messages is a temporary address, which is the node group address (B.3), places the original destination address (C.2.11) in a field called “party subaddress” and sends, according to the PNNI protocol. · I forward to the visitor network (B.3) (steps 5 and 6).

When the message arrives at the peripheral node of the roaming network (B.3.1), the node 9 of the peripheral 35 recognizes the message as a message addressed to the mobile terminal MT 4. The identification may be based, for example, on the node recognizing the destination address of the word «· 4 '' as a node group rather than a switch address. The identification mechanism may also be other, and as such is not essential to the invention.

If edge switch 9 is not a switch supporting wireless terminals, it will direct the message to a switch supporting wireless terminals in the node group, performing routing according to the PNNI protocol. If the edge node (B.3.1) is a switch supporting 5 wireless terminals, it routes the message to the AP2 according to the PNNI protocol, for example, along route (7a, 8a, 10) or along route (7b, 8b, 9b, 10).

As long as the terminal MT moves within the node group (B.3), the registration to the base stations AP1-AP4 does not cause any changes in the location register HLR 10 7. The information of the base station MT of the terminal MT is available according to the invention. Only if the terminal registers to a new node group, the location information is updated to the home node group C.2.

It will be obvious to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not limited to the examples described above, but may vary within the scope of the claims.

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Claims (14)

11 105138 An interconnected packet network comprising hierarchically arranged node groups (1,2,3), wherein the members of the node group know the traffic parameters relevant to the routing of members of at least the same 5 node groups, the network comprising at least one home database (7) of mobile terminals (4) or subscribers for storing location information in the form of temporary addresses, characterized in that the temporary location information in the home database (7) comprises the address of the node group (3) with which the mobile terminal or subscriber is last registered 10 and said routing relevant parameters include information for internal node grouping. A network according to claim 1, characterized in that the network or terminal is adapted to update the temporary location information in the home database as the terminal moves from one node group to another. The network according to claim 1, characterized in that the network comprises a first node (6) which supports mobile terminal management and is adapted in response to the received connection set-up message to request from said home database (7) a temporary address of the mobile terminal or subscriber the message to said temporary address, the target node peripheral node (9) to which the node group (3) is registered, and in response to the received word-: V: made, recognizes the message addressed to the mobile terminal or subscriber: 25 messages, and proceeds message inside the node group. A network according to claim 3, characterized in that said edge node, upon detection of a message to the mobile terminal, has an address] ·; ·. as a second message, further routing the message to another node in the same node group, ♦ ♦ · supporting mobile terminal management, said second switch being ... 30 matched, in response to the received message, to route the message to the terminal. * ··· * The network of claim 3, characterized in that the mesh; said edge node supports the management of the mobile terminals and, upon detection of a message addressed to the mobile terminal, routes the message to the mobile ·. 35 images for the terminal. «4 · 14 4 · • 4 · 12 105138 A network according to any one of claims 3 to 5, characterized in that the edge node recognizes the message as a message addressed to the mobile terminal, indicating that the destination address of the message is a node group address. Network according to one of Claims 1 to 6, characterized in that said nodes are ATM switches. A mobile terminal for a connection packet network comprising hierarchically arranged node groups (1,2,3), wherein the members of the node group know the traffic parameters relevant to the routing of other members of the same node group, the network comprising mobile terminals of mobile stations of home for storage in the form of a temporary address, characterized in that said temporary address; address Contains the address of the node group (3) to which the mobile terminal or subscriber was last registered, and that the terminal 15 is adapted to update the location information in the home database when moving from one node group to another. A method for routing a message in a communications packet network comprising hierarchically arranged node groups (1,2,3), wherein members of each node group know the traffic parameters relevant to the routing of other members of the same node group, the method comprising receiving at a first network node (6) -; '· Managing picture terminals (4), a connection set-up message containing: V the fixed address of the called mobile terminal or subscriber ,; ; 25, transmitting a routing information request from the first network node (6) to the called mobile terminal or subscriber's home database (7) which stores: ·. locating mobile terminals or subscribers in the form of a temporary address, • · · ** * providing a temporary address of the called mobile terminal or subscriber in response to the first network node (6), · routing the connection establishment from the first network node (6); from the switch using said temporary address as the destination of the connection, · ·. characterized in that: 35 the address of the <: node group (3) to which the mobile terminal or subscriber is last re * t is stored in said home location register (7) as a temporary address. ':: Registered, 105138 13 routing the call establishment based on the address of said node group to said node group (3), further routing the incoming call set up within the node group using the traffic parameters 5 relevant to the routing. A method according to claim 9, characterized by receiving a routed connection setup message based on the node group address to the node edge node, identifying the message 10 received at the node edge node of the target node group as a message addressed to the mobile terminal and forwarding the message within the node group. Method according to claim 9 or 10, characterized in that a message addressed to the mobile terminal is routed from the edge node 15 to another node in the same node group that supports the management of the mobile terminals, the message is routed to the mobile terminal. Method according to claim 9 or 10, characterized in that the message is routed from the edge node directly to the mobile terminal. 13. A method according to any one of claims 9 to 12, characterized in that the message is identified as a message addressed to the mobile terminal that the destination address is a node group address. A method according to any one of claims 9 to 13, characterized in that said connection packet network is an ATM based communication: ·; kenneverkko. • • • · • t t t t t ♦ «« «« · · t t «« «4 105138 14