General description

    According to the classic implementation, the search of an ESR to which a command for data tunnel establishment (data tunnel create) should be sent, is conducted up to the node tree beginning with a node where an AP is located. This logic requires AP and ESR to be located at the same branch of ESR object tree, and ESR to be located at the same node with AP or higher. This solution is not suitable for clients that have a part of access points grouped by clients and another part grouped by regions in its domain structure. It is not also suitable for federal clients that have division into clients (AllClients.Federal.BANK) and then into regions (BANK.Centr.Moskva).
    The proposed solution gives an opportunity to configure the ESR location parameter "Domain of Station ESR" where a node where a search for an ESR (for data tunnel establishment) should be conducted can be specified. Thus, when moving up the tree from an AP to find an ESR for data tunnel establishment, EMS will be able to use this parameter to move from a federal client node to a region node containing the ESR.

The classic scheme of node tree search for data tunnel establishment

    ESR has two options to establish data tunnels for access points:
1) data tunnels configured dynamically (locally) - in this case, all necessary information for data tunnel configuring is contained in ESR configuration, and its interaction with EMS management system is not required (this option is not considered further);
2) data tunnels configured dynamically on RADIUS server commands. In this case, it is necessary to configure interaction with the RADIUS server on ESR and complete the settings in EMS. PCRF server acts as a RADIUS server with which ESR interacts. This way to establish data tunnels will be considered further.
    Establishing data tunnels to ESR is made on the PCRF command initiated by EMS and sent in the following cases:
1) initializing a new AP;
2) reinitializing of an AP;
3) moving an AP to another node;
4) changing SSID parameters linked to a domain where an AP is located;
5) removing/creating a SSID link to an AP domain;
6) changing/assigning/removing a domain shaper or SSID of an AP.
    In all these cases, EMS should define ESR devices to which a command for data tunnel establishment will be sent. To use ESR for data tunnel establishment, it should be added to EMS node tree with "ESR mode" = "Station" in the tab "Access". It should not be phased out.

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If several ESR devices appropriate for data tunnel establishment are found, the command will be sent to all of them.

Problems of defining an ESR for data tunnel establishing in a classic ESR search

    Look at the scheme in Figure 3.1:

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     In the scheme for AP Alfabank-KRS-Achinks10kv_1_a8:f9:4b:12:12:10 given above, a data tunnel should be established from the node "Krasnoyarsk_Achinsk10kv" to the ESR that is located in the node "MRF_Sibir". If the classic scheme is used, the device will not be detected, and the command for data tunnel establishment will not be sent. To solve this problem, the opportunity to define ESR location in node settings has been added to SoftWLC 1.14 and EMS 3.18. ESR search logic for tunnel establishment has been also added.

The scheme of searching ESR for data tunnel establishment by location configuration in a node

    In the scheme of searching ESR for data tunnel establishment by location configuration there is an opportunity to specify a domain to search an ESR in node configuration. The logic is as follows:

1) EMS starts checking an AP node for configuration of a domain appropriate to move to. This rule has the highest priority, and if the domain is found, EMS will move to it regardless of whether there is an ESR suitable for data tunnel establishment. 2) if a transition rule for moving to another node has been found, the node is checked for ESR searches held before:
     2.1) if the search has not been held, the algorithm will move to this node, and start checking for the transition rule (beginning from           paragraph from paragraph 1);
     2.2) if the search has been held, the rule is ignored, and the algorithm moves to paragraph 3.
3) if a transition rule had not been found (or it was ignored due to the reasons described in 2.2), a search to find ESR devices appropriate to establish a data tunnel will be done;
4) if no transition rules and ESR devices for data tunnel establishment had been found, the algorithm moves to a higher-level node, and the search is done again, beginning with paragraph 1.
In Figure 4.1, a block diagram of the algorithm for searching an ESR appropriate for data tunnel establishment is given:

The below Figure 4.2 shows an example of search implementation for the case when a domain node contains a rule of transition to another domain to find ESR for data tunnel establishment:

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step 4: Check the node MRF_Sibir for the transition rule: not found; check the node for ESR devices appropriate for data tunnel establishment: ESR is found!

Configuring ESR location in EMS

In the example in the figure 5.1. an AP is located in the node "Alfabank-KRS-Achinsk10kv.Krasnoyarsk.Sibir.ALFA_BANK.Federal.AllClients.root". ESR devices to which it establishes GRE tunnels according to option 43 parameters assigned during getting the primary address, are located in the node "MRF_Sibir.Local.AllClients.root". Therefore, it will not be found by the AP, if the classic ESR search will be done. It is necessary to define a node on which ESR location will be configured, and from which a transition to a node containing ESR will be made.

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In the example above (Figure 5.1), ESR location could be configured in the node "MRF_Sibir.Local.AllClients.root", but it would not be appropriate, as the rule would work only for access points that are located in this node and in lower-level ones. When new clients will be connected, new nodes will be created for them in neighbouring branches. Thus, it will be necessary to define ESR location for each new client and to configure it for all existing clients in the transition to a scheme with dynamic configuration of data tunnels using RADIUS commands, that can be a very time-consuming task.     But if a rule that will oblige all access points located lower than the domain "Sibir" to establish tunnels to ESR devices located in the node "MRF_Sibir" (and to take it into consideration when assigning a primary address to an AP) is adopted, then ESR location can be configured in the node "Sibir" (of the domain "Sibir.ALFA_BANK.Federal.AllClients.root"), that will allow all access points located lower than the node "Sibir" to find an ESR, to which data tunnels can be established without additional settings.       To configure ESR location, move to the node "Sibir" and open the tab "Access" (Figure 5.2).

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To clear ESR location configuration, move to the node where it is configured, open the tab "Access"and click "Edit". Select a domain in the field "Domain of Station ESR" and click "Clear" (see Figure 5.8 below):

Figure 5.8

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Occupancy monitoring of the node where ESR devices for data tunnel establishment are located

    To monitor occupancy of nodes where ESR devices to which access points can establish tunnels, the new tab "Wireless" accessible for any node has been implemented. All ESR devices having access points that establish tunnels on them are displayed there, starting with the selected node and then down the tree.
    In the example in Figure 6.1, the root node is selected to see all ESR devices:

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In the above figure 6.3, the following parameters are shown:
"Node ID" - object index
"Node name" - the node where an ESR device to which an AP should establish tunnels is located
"Node domain" - the domain in which ESR devices to which an AP should establish tunnels are located
"ESR list" - the list of devices that are located in the node. Several ESR devices can be located in a node, because to provide redundancy, two devices are usually used.

ESR location configuration principles

    When configuring ESR location, the following principles should be adhered to:

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