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Each of the following is key to the success of NetWare Mobile IPXTM configuration:
When selecting your driver for the mobile client, verify with the vendor that the driver is written specifically with mobile operations in mind and that it supports the following:
Planning ahead and knowing the appropriate ways to use NetWare Mobile IPX will help you to use your mobile client efficiently. We recommend that you do the following:
This section helps you choose the best location on your network to configure the Home Router software. It also explains why more than one Home Router can provide more efficient network operation in certain environments.
A Home Router forwards every packet destined for the mobile clients it serves. If the Home Router is located far from both the file server and the mobile client, and if the mobile client is close to the file server, a packet destined for the mobile client travels more hops than necessary before arriving at the destination, as shown in Figure 7.
Figure 7
Inferior Home Router Placement
The request from the mobile client takes the shortest route to the server. The response from the server is first forwarded to the Home Router, because the destination address is the internal network configured for the server on which the Home Router resides. The router then patches the response with the mobile client's actual address and forwards the packet to the mobile client. In this topology, the response takes an inferior path to the mobile client because of the extra hops taken.
In general, you should install the Home Router in the middle of the network so that most clients are only a few hops away, as shown in Figure 8. The Home Router should be located somewhere on the path between the file server and the mobile clients.
Figure 8
Better Home Router Positioning
The best place to install the NetWare Mobile IPX Home Router software is on the file server that the mobile clients use most, as shown in Figure 9. In this way, when mobile clients access the file server, the responses from the file server are patched with the mobile client's actual location before they ever leave the server. Therefore, the responses do not travel an extra hop before reaching the client.
Figure 9
Best Home Router Positioning
HINT: We recommend having a Home Router in each operating area. For example, in a large corporation, you should have a Home Router in marketing, finance, manufacturing, and so on. This enables mobile client users to connect to a preferred Home Router.
If the server and mobile clients are located on one side of a WAN link and the Home Router is on the other side of the link, costly WAN bandwidth is used unnecessarily. If both networks on each side of a WAN link require NetWare Mobile IPX, you should have two Home Routers---one on each side of the WAN link. Mobile clients use the closest Home Router, as shown in Figure 10.
Figure 10
Home Router Positioning over WAN Links
IMPORTANT: When a mobile client is transferred between the two sites over the WAN and not restarted, the client still uses the original Home Router for communications---crossing the WAN if necessary---until the mobile client is restarted.
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