1. IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-07-0xxx-00-0000 Title: Proposal about multiple IS domains Date Submitted: May 8, 2007 Presented at IEEE 802.21 session in Montreal, Canada Authors or Source(s): Junxiang Guo Abstract: This contribution proposes a deployment example for multiple IS domains.

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3. Background According to the IS model in current draft D05, if a MN wants to query an information which is not stored in its serving IS server, the serving MIH PoS will forward the query message to another MIH PoS (PoS21), PoS21 gets the required information from its IS server, the query path is as below figure show: Figure 1

4. Background If the said MIH PoS21 still cannot get the information from its IS server, PoS21 will forward this query message to next-hop MIH PoS, this process will repeat until the query message reaches the destination IS server where the information is stored. Obviously, the query path is so long and wastes too many processing and transporting resources of all traversed PoSs. Figure 2

5. Proposal In practical deployment scenarios, it is much possible that multiple IS servers can be used for storing IS information. The previous multi-hop IS operation is unavoidable. We propose a more efficient way to retrieve information in the case of multiple IS servers deployed.

6. Proposal Multiple IS servers deployment model Figure 3

7. Proposal Description of the model: In practice, there may be multiple IS servers deployed in the core networks. In such circumstances, the IS servers can be categorized as different IS domains, each IS server forms a IS domain and stores the IS information in a certain region. A IS server can be used as a IS Proxy Gateway for inter IS domain information retrieval. That is to say, when any IS server cannot provide the information required by MNs, the IS server will send a information request message to interrogate the Proxy Gateway to get the information, the Proxy Gateway will then route the request to the appropriate target IS server, the target IS server obtain the information from its database and respond the required information to the Proxy Gateway via response message, the Proxy Gateway forward the response to the source IS server which send the information request. The detailed inter IS domain information retrieval flow is as figure 3.

8. Proposal Benefits of the model: Wherever the remote target IS server is, the source IS server needs only to interrogate the IS Proxy Gateway to get the required information. That is to say, only two hops at most. Each IS server does not need to maintain the topology of the IS servers distribution. Only IS Proxy Gateway needs to know the topology and maintain the route relationship. As per this model, the topology is easily to be extended and maintained. Eliminated the aforementioned long path drawback.

9. Suggestion Suggest to put the following text in Annex M: Annex M Multiple IS servers deployment model and information retrieval method In practice, there may be multiple IS servers deployed in the core networks. In such circumstances, the IS servers can be categorized as different IS domains, each IS server forms a IS domain and stores the IS information in a certain region. A IS server can be used as a IS Proxy Gateway for inter IS domain information retrieval. That is to say, when any IS server cannot provide the information required by MNs, the IS server will send a information request message to interrogate the Proxy Gateway to get the information, the Proxy Gateway will then route the request to the appropriate target IS server, the target IS server obtain the information from its database and respond the required information to the Proxy Gateway via response message, the Proxy Gateway forward the response to the source IS server which send the information request. The detailed inter IS domain information retrieval flow is as following Figure M-1.

10. Suggestion Figure M-1 (Continued)

11. Thank you!