3Com 3CRWDR300A-73, Руководство пользователя

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Internet Settings 87
6 If your ISP uses DHCP to automatically assign IP addresses, check the
DHCP Client checkbox.
7 Check the Add Default Route checkbox to set this PVC as the default
route, this is used when you configure more than one PVC for the Router.
8 Enter the VPI/VCI values. Or you can click Auto Search to automatically
find out this information.
9 Select the Encapsulation, VC MUX or LLC . This information should be
provided to you by your ISP.
10 QoS Class: select CBR , UBR or VBR .
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CBR (constant bit rate): the CBR service class is intended for
real-time applications, for example, those requiring tightly
constrained delay and delay variation, such as voice and video
applications. The consistent availability of a fixed quantity of
bandwidth is considered appropriate for CBR service.
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VBR (variable bit rate): QoS class defined by the ATM Forum for
ATM networks. VBR is subdivided into a real time (RT) class and
non-real time (NRT) class. VBR (RT) is used for connections in which
there is a fixed timing relationship between samples. VBR (NRT) is
used for connections in which there is no fixed timing relationship
between samples, but that still need a guaranteed QoS. Compare
with ABR, CBR, and UBR.
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UBR (unspecified bit rate): the UBR service class is intended for
delay-tolerant or non-real-time applications, for example, those
which do not require tightly constrained delay and delay variation,
such as traditional computer communications applications. The
UBR service may be considered as “best effort service”.
11 PCR/SCR/MBS: PCR (Peak Cell Rate), SCR (Sustainable Cell Rate) and MBS
(Maximum Burst Size) are configurable.
12 Click Apply .