Nortel BCM 3.7, Manual

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PPTP 763
Programming Operations Guide
3 Click the Save button.
Modifying a Destination Network
1
Click the Destination Network to modify.
2 On the Configuration menu, click Modify Destination Network .
The Destination Networks screen appears.
3 Change the Destination Networks attributes.
4
Click the Save button.
Subnet Mask Allows you to specify the subnet mask for the destination network.
You require Subnet Mask only if you have entered a value in the Destination Network box.
Always use a valid subnet address and mask pair. If you are using a mask that contains more
than 1 host address, then always specify the subnet number that corresponds to that subnet
and not any other address. For example, if you are using a mask of 24 bits, (255.255.255.0)
then use a subnet number of 192.168.100.0 and not something like 192.168.100.11 (where
the last number should have been 0).
Enter the subnet mask in the dotted format.
Preference Level Allows you to specify the preference level for this tunnel.
When there are multiple tunnels assigned to a destination network, the preference level
determines which tunnel is used to connect to the destination network. Business
Communications Manager attempts to use the tunnel with the lowest preference number first.
If the connection fails, Business Communications Manager retries the connection as many
time as is specified in the Connect retries box on the Tunnel Link Parameters screen. After the
specified number of retries fails, Business Communications Manager attempts to use the
tunnel with the next lowest preference level. Business Communications Manager continues to
attempt to establish a tunnel until a connection succeeds or all of the tunnels to the destination
network have failed.
For example, a site may have two connections to the internet to take advantage of varied
capacities and costs. You can maintain a PPTP server at each of these connection points.
When you are specifying PPTP tunnels to reach private networks in this site, you may want to
use the connection that is most cost-effective first and use the other connection only if the
most cost effective connection is not in service. To do this, you create two tunnels to reach the
site. You specify the corresponding PPTP server addresses for each tunnel, but enter the
same destination addresses (unless you want to distinguish between the normal and stand-by
operation). However, for the most desired connection to the site, you specify higher
precedence level for the tunnel by putting a lower value for Preferred Level than for the other
tunnel.
When a packet is received by Business Communications Manager with the destination
address of this site, Business Communications Manager tries to bring up the most desired
tunnel. If the connection succeeds, tunnel is established. If Business Communications
Manager cannot connect to this tunnel after the specified number of retries, it attempts to bring
up the 'less desired' tunnel using its parameters.
This feature is useful for providing redundant links to sites that have multiple connections to
the internet.
Note that this parameter is only used with On Demand tunnels.
Table 224 PPTP Destination Networks attributes (Continued)
Attribute Description