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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:
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Figure 4.1
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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Figure 4.2
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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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