3com 520 User Manual

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IP Host on the Same IP Network
 
If your organization operates a TCP/IP network and 
 
needs to extend the IP network over geographically 
 
remote sites, it is possible to bridge the network 
 
using the OfficeConnect Remote. It is only possible to 
 
bridge where both sites have the same network 
 
address and the devices are on the same subnet. In a 
 
class C IP address, the network address is the first 
 
three groups of numbers. For example:
192.000.000.xxx
 
where 
xxx
 
 represents the host ID of the individual 
 
devices on the subnet. See 
 
 
 in 
 
 
 for more information about addresses.
 
Typically IP bridging would be used to connect a 
 
back office or home office into a main site. 
 
Any 
 
further network connections would be carried out 
 
from the main site. An example of such a network is 
 
 
 
.
 
During configuration, you enter the ISDN number and 
 
the IP addresses of any hosts to which you want to 
 
connect. In the example in 
 
 
 
of the host 191.000.000.100 is used and only when data 
 
destined for this device is received by the OfficeConnect 
 
Remote, is a call made to the remote site.
 
Figure 1-17   
 
IP Bridged Network
 
There are some issues about which you should be 
 
aware when implementing an IP bridging solution.
 
Although calls to the remote site are only generated 
 
when data is addressed to a specific IP host or hosts 
 
(in our example, 191.000.000.100), any data that 
 
cannot
 
 be identified as local is also passed over the 
 
link while it is open. This can prevent the link from 
 
closing after the intended data has been transferred.
 
Some devices and applications (for example 
 
autodiscovery programs on SNMP managers) poll all 
 
devices on a subnet at regular intervals and this 
 
could lead to frequent ISDN calls if you have entered 
Rc.bk : RC01.FRM  Page 34  Thursday, July 10, 1997  9:53 AM