Cabletron Systems SmartSwitch Router, Руководство пользователя

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Chapter 22: WAN Configuration Guide
320 SmartSwitch Router User Reference Manual
The following command line displays an example for PPP:
Packet Encryption
Packet encryption allows data to travel through unsecured networks. You can enable
packet encryption for PPP ports, however, both ends of a link must be configured to use
packet encryption.
The following command line displays an example:
WAN Quality of Service
Increasing concentrations of audio, video, and data traffic are now presenting the
networking industry with the significant challenge of employing the most effective use of
WAN Quality-of-Service (QoS) as possible to ensure reliable end-to-end communication.
For example, critical and time-sensitive traffic such as audio should have higher levels of
bandwidth allocated than less time-sensitive traffic such as file transfers or e-mail. Simply
adding more and more bandwidth to a network is not a viable solution to the problem.
WAN access is extremely expensive, and there is a limited (albeit huge) supply. Therefore,
making the most effective use of existing bandwidth is now a more critical issue than ever
before.
The fact that IP communications to the desktop are clearly the most prevalent used today
has made it the protocol of choice for end-to-end audio, video, and data applications. This
means that the challenge for network administrators and developers has been to construct
their networks to support these IP-based audio, video, and data applications along with
their tried-and-true circuit-based applications over a WAN.
In addition, these audio, video, and data traffic transmissions hardly ever flow at a steady
rate. Some periods will see relatively low levels of traffic, and others will temporarily
surpass a firm’s contracted Committed Information Rate (CIR). Carrier-based packet-
switched networks such as Frame Relay and ATM are designed to handle these temporary
peaks in traffic, but it is more cost- and resource- efficient to employ effective QoS
configuration(s), thus relaxing the potential need to up your firm’s CIR. By applying some
of the following sorts of attributes to interfaces on your network, you can begin to shape
your network’s QoS configuration to use existing bandwidth more effectively.
ppp set payload-compress port se.4.2
ppp set payload-encrypt transmit-key 0x123456789abcdef receive-key
0xfedcba987654321 port se.4.2, mp.1