3Com 520, 510, 530 manual IP Host on Another IP Network

Models: 520 530 510

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several IP hosts to generate autocalls to the remote site. When combined with the problem described above, you could find your ISDN line permanently connected.

To avoid this situation you need to be sure that no devices or applications exist on your local site that could make unnecessary and costly calls to your remote site. You can also configure the OfficeConnect Remote units at both ends of the link to implement a Firewall and/or Call Guillotine to reduce the amount of traffic permitted to pass across the link. See the Software Reference guide for more information about these features.

Alternatively, you may wish to configure the OfficeConnect Remote to operate as a router to prevent this problem occurring altogether. This however requires that each site consists of separate subnets. See the next section for more information about IP routing.

Examples of Typical ISDN Networking Applications

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IP Host on Another IP Network

Most organizations using TCP/IP protocols on their network, choose to subnet remote sites or even to have them on different networks. This requires that connections to remote sites are routed rather than bridged. The advantage of routing over bridging is that calls to the remote site are only made when data is specifically addressed to a remote network. Bridging passes any data not known to be for the local network to the remote network whether that is its destination or not.

Because the ISDN number can be associated with a remote network rather than just a specific IP host, any data for the remote network can generate an autocall and be routed over the OfficeConnect Remote. If you need to connect to IP hosts on several networks, you will need to use routing to be able to communicate with the different hosts.

The example shown in Figure 1-18shows the Local Site connected to two Remote sites over ISDN. All sites are connected using OfficeConnect Remote units.

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3Com 520, 510, 530 manual IP Host on Another IP Network