ZyXEL P-791R v2 Guia Do Utilizador
P-791R v2 Support Notes
PCR as the maximum value according to the line rate (for example, 2.3 Mbps
line rate will result PCR as 5424 cell/sec.)
line rate will result PCR as 5424 cell/sec.)
12. What do ATM QoS Types (CBR, UBR, VBR-nRT, VBR-RT) mean?
Constant bit rate(CBR): An ATM bandwidth-allocation service that requires
the user to determine a fixed bandwidth requirement at the time the connection
is set up so that the data can be sent in a steady stream. CBR service is often
used when transmitting fixed-rate uncompressed video.
the user to determine a fixed bandwidth requirement at the time the connection
is set up so that the data can be sent in a steady stream. CBR service is often
used when transmitting fixed-rate uncompressed video.
Unspecified bit rate(UBR): An ATM bandwidth-allocation service that does
not guarantee any throughput levels and uses only available bandwidth. UBR
is often used when transmitting data that can tolerate delays, such as e-mail.
not guarantee any throughput levels and uses only available bandwidth. UBR
is often used when transmitting data that can tolerate delays, such as e-mail.
Variable bit rate(VBR): An ATM bandwidth-allocation service that allows
users to specify a throughput capacity (i.e., a peak rate) and a sustained rate
but data is not sent evenly. You can select VBR for bursty traffic and
bandwidth sharing with other applications. It contains two subclasses:
Variable bit rate nonreal time (VBR-nRT) and Variable bit rate real time
(VBR-RT).
13. Why do we perform traffic shaping in the P-791R v2?
users to specify a throughput capacity (i.e., a peak rate) and a sustained rate
but data is not sent evenly. You can select VBR for bursty traffic and
bandwidth sharing with other applications. It contains two subclasses:
Variable bit rate nonreal time (VBR-nRT) and Variable bit rate real time
(VBR-RT).
13. Why do we perform traffic shaping in the P-791R v2?
The P-791R v2 must manage traffic fairly and provide bandwidth allocation for
different sorts of applications, such as voice, video, and data. All applications
have their own natural bit rate. Large data transactions have a fluctuating
natural bit rate. The P-791R v2 is able to support variable traffic among
different virtual connections. Certain traffic may be discarded if the virtual
connection experiences congestion. Traffic shaping defines a set of actions
taken by the P-791R v2 to avoid congestion; traffic shaping takes measures to
adapt to unpredictable fluctuations in traffic flows and other problems among
virtual connections.
different sorts of applications, such as voice, video, and data. All applications
have their own natural bit rate. Large data transactions have a fluctuating
natural bit rate. The P-791R v2 is able to support variable traffic among
different virtual connections. Certain traffic may be discarded if the virtual
connection experiences congestion. Traffic shaping defines a set of actions
taken by the P-791R v2 to avoid congestion; traffic shaping takes measures to
adapt to unpredictable fluctuations in traffic flows and other problems among
virtual connections.
14. The P-791R v2 supports Bridge and Router mode, what's the
difference between them?
When the ISP limits some specific computers to access Internet, which means
only the traffic to/from these computers will be forwarded and the other will be
filtered. In this case, we use bridge mode which works as an DSL modem to
connect to the ISP. The ISP will generally give one Internet account and limit
only one computer to access the Internet.
For most Internet users having multiple computers want to share an Internet
account for Internet access, they have to add another Internet sharing device,
only the traffic to/from these computers will be forwarded and the other will be
filtered. In this case, we use bridge mode which works as an DSL modem to
connect to the ISP. The ISP will generally give one Internet account and limit
only one computer to access the Internet.
For most Internet users having multiple computers want to share an Internet
account for Internet access, they have to add another Internet sharing device,
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