Methods and Devices for Handling an Extended Proxy Informa ^¬ tion Item

The invention relates to methods and devices for handling an extended proxy information item, whereby the devices are based on nodes and or proxy mesh gates of a wireless mesh network .

In recent years the standard IEEE 802.11s (IEEE - Institute of Electrical and Electronics Engineers) was developed that defines a usage of a mesh network topology with nodes / mesh stations in the mesh network serving as relay for propagation of messages. In order to connect such a mesh network to ex ^¬ ternal station located outside the mesh network proxy mesh gates are implemented at the border of the mesh network that forward messages from outside to inside the mesh network and vice versa. The mesh proxy gate may change the message con- tent such as address translation or protocol translation.

A draft D11.0 of the IEEE 802.11s standard defines for WLAN mesh networks (WLAN - Wireless Local Area Network) a proxy information and so-called proxy update PXU and proxy update confirmation PXUC elements. Proxy information consists of a proxy MAC address of the proxy mesh gate and an external MAC address of the external station, together with an optional lifetime of this proxy information. By using the proxy update PXU and proxy update confirmation PXUC elements the proxy in- formation is made available to other nodes in the mesh net ^¬ work, whereby the other nodes are informed which external ad ^¬ dresses can be reached through which (proxy) mesh gate.

The proxy mesh gate Gl that proxies an external MAC address El can send a corresponding proxy update element. However some other mesh station Ml in the wireless mesh network might send this proxy information about the external MAC address of the external station and the proxy MAC address of the proxy mesh gate Gl too, see Figure 1. Dashed lines show communica ^¬ tion connection, such as WLAN mesh links.

However a mesh station Ml might not have received a proxy up- date element from the mesh proxy gate Gl that changed the proxy information about the mesh proxy gate Gl and external MAC address El (for instance, the deletion of the proxy in ^¬ formation) , so the mesh station might send a proxy update element with outdated proxy information on the mesh proxy gate Gl and external MAC address El. A recipient of both proxy update elements cannot recognize the wrong chronologi ^¬ cal order and will reestablish the proxy information, which is not correct. In the current draft a specification of the proxy update ele ^¬ ment defines a field called PXU Sequence Number (8 bit long) . However, it is used only as a proxy update identifier, which identifies the received proxy update element in a proxy in ^¬ formation confirmation (PXUC) element that is sent in order to acknowledge the receipt of the proxy update element.

The messages of the path selection protocol HWMP (HWMP - Hybrid Wireless Mesh protocol) of IEEE 802.11s can also contain proxy information. It always contains a HWMP sequence number, but this sequence number is only used as sequence number for the forwarding information, not for the proxy information.

Hence it is an object to provide methods and devices that prevent wrong setting of proxy information in a mesh network.

This objective is solved by the independent claims. Specific solutions of the invention are solved by the dependent claims . The invention relates to a method for generating an extended proxy information item in a mesh network,

- the mesh network with nodes formed as a proxy mesh gate and/or a mesh station, - for signaling an external MAC address of an external sta ^¬ tion located outside the mesh network via a proxy MAC ad ^¬ dress of the proxy mesh gate (Gl),

- for a specific MAC address pair defined by the proxy ad- dress and by the external MAC address,

comprising :

- Detecting a change in a connection of the external station with the proxy mesh gate;

- Generating, if the change is detected, a proxy information sequence number either (i) by incrementing an existing proxy information sequence number for the specific MAC ad ^¬ dress pair by at least one, or (ii) by using a sequence number of a message or an element coded by the standard Hy ^¬ brid Wireless Mesh Protocol, whereby this sequence number is higher than a sequence number of a previously generated message or element coded by the standard Hybrid Wireless Mesh Protocol;

- Generating the extended proxy information item by:

- a first field (Fl) indicating an addition or deletion of the connection, a presence of a third field (F3) and a presence of a fifth field (F5) ,

- a second field (F2) covering the external MAC address (EMACA) ;

- a third field (F3) covering the proxy MAC address

(PMACA), the presence of the third field (F3) is indi ^¬ cated by the first field (Fl);

- a fourth field (F4) covering the proxy information sequence number (PISN) ;

- a fifth field (F5) covering a proxy information lifetime (PILIFE), the presence of the fifth field (F5) is indi ^¬ cated by the first field (Fl) .

In the context of this description a term proxy information, as known from a standard IEEE 802.11s, is called proxy infor- mation item. Furthermore an extended proxy information is called extended proxy information item. The term MAC is used in the description as an abbreviation of Media Access Control, as specified e.g. by IEEE 802.3-2002 section 4.1.4 (IEEE - Institute of Electrical and Electronics Engineers) e.g. to be used in Ethernet protocol as MAC address.

It is an advantage of this method that misinterpretation of messages covering the outdated proxy information item can be avoided. This means that a reliability of proxy information item available at nodes in the mesh network can be enhanced as a forwarding of frames to a wrong proxy mesh gate due to outdated proxy information item is prevented.

The proxy information sequence number is incremented for a generation of PXU elements (PXU - proxy update) with proxy information, e.g. for the IEEE 802.11s standard, especially if a lifetime of the proxy information item is included. An- other case that leads to an increment of the proxy informa ^¬ tion sequence number relates to PXUs that related to proxy information to be deleted by the respective nodes of the mesh network. In the case the proxy information sequence number is determined for a specific MAC address pair for the first time, the proxy information sequence number can be set to a pre-defined or arbitrary number.

When using a dedicated fourth field in the enhanced proxy in ^¬ formation item the proxy information sequence number is gen- erated by incrementing an existing proxy information sequence number. In the case that the sequence number of the element of message of the standard Hybrid Wireless Mesh Protocol HWMP is used no dedicated fourth field is generated in the ex ^¬ tended proxy information item but the sequence number is used as the proxy information sequence number. Also in this case when a new element or message coded by HWMP is sent the se ^¬ quence number of the new element or message is incremented compared with a sequence number of a previously sent HWMP element or message. This means that the extended proxy infor- mation item can be distinguished from previously generated extended proxy information items due to the higher proxy in ^¬ formation sequence number. The invention further relates to a method for receiving and executing information of an extended proxy information item in a mesh network,

- the mesh network) with nodes formed as a proxy mesh gate and/or a mesh station,

- for signaling an external MAC address of an external sta ^¬ tion located outside the mesh network via a proxy MAC ad ^¬ dress of the proxy mesh gate (Gl),

- for a specific MAC address pair defined by the proxy ad- dress and by the external MAC address,

comprising :

Receiving the extended proxy information item;

Executing an addition or deletion of a connection of the external station with the proxy mesh gate, indicated by the ex- tended proxy information item, by the node, if a proxy infor ^¬ mation sequence number of the extended proxy information item is larger than an existing proxy information sequence number of the specific MAC address pair. It is an advantage of this method that misinterpretation of messages covering outdated proxy information item can be avoided. This means that a reliability of proxy information item available to nodes in the mesh network can be enhanced as a forwarding of frames to wrong proxy mesh gates due to outdated proxy information is prevented. According to the previous description the proxy information sequence number is extracted either from the fourth field of the proxy informa ^¬ tion item or from the sequence number of the message or ele ^¬ ment coded by the HWMP standard. A proxy information sequence number that was received by a previous element or previous message coded by HWMP or as a fourth field of a previous proxy information element is set and used as the existing proxy information sequence number. In an optional enhancement of the described methods it is beneficial to transmit or receive the extended proxy informa ^¬ tion item as part of an element or message coded by a stan ^¬ dard Hybrid Wireless Mesh Protocol. By using the standard Hy- brid Wireless Mesh Protocol a cost and resource-effective im ^¬ plementation and execution of the invention can be provided.

The invention further relates to a proxy mesh gate for gener- ating an extended proxy information item in a mesh network (MNET) ,

- the mesh network with nodes formed as a proxy mesh gate and/or a mesh station,

- for signaling an external MAC address of an external sta- tion located outside the mesh network via a proxy MAC ad ^¬ dress of the proxy mesh gate,

- for a specific MAC address pair defined by the proxy ad ^¬ dress and by the external MAC address,

comprising :

- First unit for detecting a change in a connection of the external station with the proxy mesh gate;

- Second unit for generating, if the change is detected, a proxy information sequence number is generated either (i) by incrementing an existing proxy information sequence num- ber for the specific MAC address pair or (ii) by using a sequence number of a message or an element coded by the standard Hybrid Wireless Mesh Protocol, whereby this se ^¬ quence number is higher than a sequence number of a previously generated message or element coded by the standard Hybrid Wireless Mesh Protocol;

- Third unit for generating the extended proxy information item by:

- a first field indicating an addition or deletion of the connection, a presence of a third field and a presence of a fifth field,

- a second field covering the external MAC address;

- a third field covering the proxy MAC address, the pres ^¬ ence of the third field is indicated by the first field;

- a fourth field covering the proxy information sequence number;

- a fifth field covering a proxy information lifetime, the presence of the fifth field is indicated by the first field . It is an advantage of this proxy mesh gate that misinterpre ^¬ tation of messages covering outdated proxy information can be avoided. This means that a reliability of proxy information available to nodes in the mesh network can be enhanced as a forwarding of frames to wrong proxy mesh gates due to out ^¬ dated proxy information is prevented. Further advantages are described by the corresponding method. The proxy information sequence number is incremented for a generation of PXU elements (PXU - proxy update) with proxy information item, e.g. for the IEEE 802.11s standard, espe ^¬ cially if a lifetime of the proxy information item is in ^¬ cluded. Another case that leads to an increment of the proxy information sequence number relates to PXUs that relate to proxy information item to be deleted by the respective nodes of the mesh network. In the case the proxy information sequence number is determined for a specific MAC address pair for the first time, the proxy information sequence number can be set to a pre-defined or arbitrary number. The same applies for using the sequence number of the HWMP as the proxy infor ^¬ mation sequence number.

The proxy mesh gate can further be enhanced by a fourth unit for transmitting the extended proxy information item as part of an element or message coded by a standard Hybrid Wireless Mesh Protocol. By using the standard Hybrid Wireless Mesh Protocol a cost and resource-effective implementation and execution of the invention can be provided.

Finally a part of the invention is a node for receiving and executing information of an extended proxy information item in a mesh network,

- the mesh network with nodes formed as a proxy mesh gate and/or a mesh station,

- for signaling an external MAC address of an external sta ^¬ tion located outside the mesh network via a proxy MAC ad ^¬ dress of the proxy mesh gate, - for a specific MAC address pair defined by the proxy ad ^¬ dress and by the external MAC address,

comprising :

First unit for receiving the extended proxy information item; Second unit for executing an addition or deletion of a connection of the external station with the proxy mesh gate, in ^¬ dicated by the extended proxy information item, if a proxy information sequence number of the extended proxy information item is larger than an existing proxy information sequence number of the specific MAC address pair.

It is an advantage of the node that a misinterpretation of messages covering outdated proxy information can be avoided. This means that a reliability of proxy information items available to nodes in the mesh network can be enhanced as a forwarding of frames to wrong proxy mesh gates due to out ^¬ dated proxy information items is prevented.

The node may further be enhanced by a third unit for receiv- ing the extended proxy information item as part of an element coded by a standard Hybrid Wireless Mesh Protocol. By using the standard Hybrid Wireless Mesh Protocol a cost and re ^¬ source-effective implementation and execution of the invention can be provided.

The invention is described by the aid of the following fig ^¬ ures :

Fig. 1 Proxy information exchanged in a mesh network ac- cording to the present state of the art;

Fig. 2 Proxy information exchanged according to an example of the invention; Fig. 3 Setup of an extended proxy information element;

Fig. 4 Proxy mesh gate according to the present invention; Fig. 5 Node in a mesh network according to the present invention .

Elements with the same functionality are labeled by identical reference signs.

In the context of this description a term proxy information, as known from a standard IEEE 802.11s, is called proxy infor ^¬ mation item. Furthermore an extended proxy information is called extended proxy information item. The term MAC is used in the description as an abbreviation of Media Access Control, as specified e.g. by IEEE 802.3-2002 section 4.1.4 (IEEE - Institute of Electrical and Electronics Engineers) e.g. to be used in Ethernet protocol as MAC address.

Figure 2 shows a first example of the invention. A mesh net ^¬ work MNET covers three proxy mesh gates Gl, G2, G3 that transmit messages from outside the mesh network to the inside and vice versa. Furthermore the mesh network covers a mesh station STA that may represent a laptop of a user within the mesh network. The second and third proxy mesh gate G2, G3 and the mesh station STA are also known as other mesh stations Ml . In general the proxy mesh gates and the mesh station are also known as nodes of the mesh network.

At a point in time the first proxy mesh gate Gl recognizes an external station El that can be used to send messages to or from. In order to allow the other mesh stations Ml to send messages to the external station El the first proxy mesh gate Gl informs at least one of the other mesh stations Ml about the external station. Hence the first proxy gate Gl forms an extended proxy information item EPI based on the following fields Fl, F5, see also Fig. 3: Field Description

Fl Flags, see description below; F2 External MAC (media access control) address EMACA of the external station El, e.g. a 48bit MAC ad ^¬ dress;

F3 Proxy MAC address PMACA of the first proxy gate Gl, e.g. a 48-bit MAC address;

F4 Proxy information sequence number PISN, e.g. an unsigned integer value;

F5 Proxy information lifetime, e.g. unsigned integer value; it is set to the time for which the other mesh station STA, Ml receiving the extended proxy information item considers this proxy information to be valid; the proxy information lifetime is measured in TUs (TU - Time Units) ; The field Fl defines specific flags indicating specific func ^¬ tionalities of the extended proxy information item EPI :

Bit Description

Position

0 It is set to 1 if the proxy information is to be deleted, and set to 0 otherwise. This bit is also known as "Delete subfield".

1 This so called "Originator Is Proxy" subfield indi ^¬ cates that the originator of the extended proxy in- formation item EPI is the proxy mesh gate of this proxy information when set to 1. In this example a value of 1 signals the first proxy mesh gate Gl . If it is set to 1 the extended proxy information item EPI does not contain field F3. If this subfield is 0 than the proxy MAC address is present.

2 This bit indicates whether the extended proxy in ^¬ formation item EPI contains lifetime information of the proxy information, when set to 1.

3-7 Reserved.

In the present example the fields are set as follows: Fl = 0000.0110 (binary form) (delete flag not set, extended proxy information item is added; the first mesh proxy gate is the originator, field F3 not used; lifetime field F5 used)

F2 = OxOFFFAlOOAAOOBA (field F2 is a 48 bit MAC address)

F3 - not present

F4 = 376 (coded as unsigned integer)

F5 = 5000 When the proxy information sequence number PISN is set for the first time any arbitrary number can be used, e.g. 376.

Then the extended proxy information item EPI is sent to the mesh station STA and the second proxy mesh gate G2. These other mesh stations perform the following steps: if it does not have proxy information for the proxy mesh gate-external MAC address pair that is called specific MAC address pair SMACAP, it creates this proxy information and sets the proxy mesh gate, the external MAC address, the proxy information sequence number, and the proxy informa ^¬ tion lifetime to the values as received in the extended proxy information item EPI with this proxy information if it does have proxy information for the specific set, it updates this proxy information only if the proxy informa ^¬ tion sequence number of the received proxy information is larger than the proxy information sequence number of the stored proxy information. The stored proxy information is also known as existing proxy information EPISN.

Now the respective other mesh station knows that the external station can be reached under a certain external MAC address and via the first proxy mesh gate Gl . Next a second extended proxy information item EPI2 is gener ^¬ ated by the first proxy mesh gate, because the external sta ^¬ tion is no longer present, e.g. it was a mobile device that moved away from the mesh network. The second extended proxy information item EPI2 is generated as follows:

Fl = 0000.0011 (binary form) (delete flag set; the first mesh proxy gate is the originator, field F3 not used; no lifetime information flag set, field F5 not used)

F2 = OxOFFFAlOOAAOOBA (field F2 is a 48 bit MAC address)

F3 - not present

F4 = 377 (coded as unsigned integer)

F5 - not present

In order to discover the latest extended proxy information the proxy information sequence number PISN is incremented e.g. by one or any arbitrary positive value compared to a ex- isting proxy information sequence number that was used in the previous extended proxy information item. Hence PSNI = 376 + 1 = 377.

This second extended proxy information item EPI2 for the spe- cific MAC address pair is transmitted to the second and third proxy mesh gates and the mesh station.

When the second extended proxy information item EPI2 is re ^¬ ceived by the other mesh stations and the recipient has a valid proxy information for the specific MAC address pair stored, it compares the existing proxy information sequence number with the proxy information sequence number received. If the proxy information sequence number received is higher than the existing proxy information sequence number it will delete the proxy information for the specific MAC address pair. Otherwise no deletion will be performed.

If one of the other mesh stations Ml receives an proxy infor ^¬ mation element with extended proxy information item to be de- leted, it may or has still to record the deleted proxy infor ^¬ mation so that it is able to compare the proxy information sequence number with other received extended proxy informa ^¬ tion items for this proxy mesh gate-external MAC address pair in order to determine whether the received proxy information is newer or older than the deletion.

This can be best achieved by extending the stored extended proxy information item with a Delete flag indicating whether the extended proxy information item is valid (added) or inva ^¬ lid (deleted) . It is set according to the Delete flag for the extended proxy information item in the received proxy update element PXU.

Next in time the second proxy mesh gate G2 sends the extended proxy information item EPI covering as proxy information sequence number PISN = 376 to the third proxy mesh gate G3. The proxy mesh gate G3 does not update its stored proxy informa- tion for the specific MAC address pair based on the received extended proxy information item, because the received proxy information sequence number 376 is not larger than the stored (existing) = proxy information sequence number 377. Hence the third proxy mesh gate G3 retains the correct proxy informa- tion for the specific MAC address pair and does not accept the wrong proxy information on the specific MAC address pair contained in the recent extended proxy information item from the second proxy mesh gate G2. In another example the proxy information is transmitted using a HWMP of a standard IEEE 802.11 (HWMP - Hybrid Wireless Mesh Protocol; IEEE - Institute of Electrical and Electronics En ^¬ gineers) . When e.g. the mesh station STA receives proxy in ^¬ formation of the extended proxy information items in a HWMP element (address extension is available) , it does the follow ^¬ ing :

if the mesh station does not have proxy information for the proxy mesh gate-external MAC address pair (the proxy mesh gate is for instance the Originator Mesh STA address or the Target Mesh STA address, the external MAC address is for instance the Originator External Address or the Target External Address) , it creates this proxy informa ^¬ tion and sets the proxy mesh gate, the external MAC ad- dress, the proxy information sequence number, and the proxy information lifetime to the corresponding values as received in the HWMP element with this proxy information according to the existing rules. The proxy information se- quence number is set to the HWMP sequence number from the received HWMP element.

if it does have proxy information for the proxy mesh gate- external MAC address pair, it updates this proxy informa ^¬ tion only if the HWMP sequence number of the received HWMP element with the proxy information is larger than the proxy information sequence number of the stored proxy in ^¬ formation .

The method steps described above may be implemented in soft- ware, whereby the software may be stored on a memory device such as a CDROM and may be executed by a processor unit. Data may be received or sent via an 10 unit that is connected to the processor unit. In addition the processor unit may be connected to a memory unit for storing intermediate data and/or instruction of the software.

The invention further covers the proxy mesh gate for generat ^¬ ing an extended proxy information item in the mesh network with the following units as shown in Fig. 4:

- First unit Ul for detecting a change in a connection of the external station El with the proxy mesh gate Gl;

- Second unit U2 for generating, if the change is detected, a proxy information sequence number PISN either (i) by incrementing an existing proxy information sequence number EPISN for the specific MAC address pair SMACAP by at least one or

(ii) by using a sequence number of a message of element coded by the standard Hybrid Wireless Mesh protocol, whereby this sequence number is higher than a sequence num ^¬ ber of a previously generated message or element coded by the standard Hybrid Wireless Mesh Protocol;

- Third unit U3 for generating the extended proxy information item EPI by: - a first field Fl indicating an addition or deletion of the connection, a presence of a third field F3 and a presence of a fifth field F5,

- a second field F2 covering the external MAC address

EMACA;

- a third field F3 covering the proxy MAC address PMACA, the presence of the third field F3 is indicated by the first field Fl;

- a fourth field F4 covering the proxy information sequence number PISN;

- a fifth field F5 covering a proxy information lifetime PILIFE, the presence of the fifth field F5 is indicated by the first field Fl . The proxy mesh gate may cover further a fourth unit U4 for transmitting the extended proxy information item EPI, EPI2 as part of an element coded by a standard Hybrid Wireless Mesh Protocol and/or a fifth unit U5 for setting the proxy information sequence number by a sequence number of the element coded by a standard Hybrid Wireless Mesh Protocol.

The units Ul, U5 may be connected via a bus BUS to ex ^¬ change data among each other and/or with a processor PROZ and memory unit MEM. Furthermore the units, the processor and the memory may receive or transmit data via an 10 module 10.

The other mesh station or node G2, G3, Ml for receiving and executing information of an extended proxy information item EPI, EPI2 in a mesh network MNET may contain the following units:

First unit Zl for receiving the extended proxy information item EPI;

Second unit Z2 for executing an addition or deletion of a connection of the external station El with the proxy mesh gate Gl, indicated by the extended proxy information item

EPI, by the node G2, G3, Ml only, if a proxy information sequence number PISN of the extended proxy information item EPI, EPI2 is larger than an existing proxy information sequence number EPISN of the specific MAC address pair SMACAP.

In addition the mesh station or node may cover a third unit Z3 for transmitting the extended proxy information item EPI, EPI2 as part of an element coded by a standard Hybrid Wire ^¬ less Mesh Protocol. Furthermore the mesh station or node may contain a fourth unit Z4 for executing additional functions of the respective node as described before.

The units Zl, Z4 may be connected via a bus BUS to ex ^¬ change data among each other and/or with a processor PROZ and memory unit MEM. Furthermore the units, the processor and the memory may receive or transmit data via an IO-module 10.