Lucent Technologies PortMaster 4, Configuration Manual

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Configuring Dial-In Users 5-7
Configuring Network Users
Setting Compression
Compression of TCP/IP headers can increase the performance of interactive TCP sessions
over network hardwired asynchronous lines. Lucent implements Van Jacobson TCP/IP
header compression and Stac LZS data compression. Compression is on by default.
Compression cannot be used with multiline load balancing, but can be used with
Multilink PPP.
Compression must be enabled on both ends of the connection if you are using SLIP.
With SLIP, TCP packets are not passed if only one side of the connection has
compression enabled. For PPP connections, the PortMaster supports both bidirectional
and unidirectional compression. Refer to RFC 1144 for more information about header
compression.
The PortMaster supports Stac LZS data compression only for PPP connections with
bidirectional compression. Stac LZS data compression cannot be used for SLIP
connections.
To set header compression for a network user, use the following command:
Command> set user Username compression on|off
Table 5-2 describes the results of using each keyword.
To find out what type of compression was negotiated for the user, enter the following
command:
Command> show S0
Setting Filters
Input and output packet filters can be applied to each network user. If an input filter is
applied to a user, when the user dials in and establishes a connection, all packets
received from the user are evaluated against the rule set for the applied filter. Only
packets allowed by the filter can pass through the PortMaster. If an output filter is
applied to a user, packets going to the user are evaluated against the rule set for the
applied filter. Only packets allowed by the filter are sent out of the PortMaster to the
user.
If either filter is changed while a user is logged on, the change does not take effect until
the user disconnects and logs in again.
Note – You must define a filter in the filter table before you can apply it. For more
information about filters, see Chapter 8, “Configuring Filters.”
Table 5-2 Keywords for Configuring Compression
Keyword Description
on Enables compression. The PortMaster tries to negotiate both
Van Jacobson and Stac LZS compression. This is the default.
off Disables compression.
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