ZyXEL Communications unified security gateway 用户手册
Chapter 28 Bandwidth Management
ZyWALL USG 20/20W User’s Guide
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Maximize Bandwidth Usage Effect
With maximize bandwidth usage enabled, after each server gets its configured
rate, the rest of the available bandwidth is divided equally between the two. So
server A gets its configured rate of 300 kbps and server B gets its configured rate
of 200 kbps. Then the ZyWALL divides the remaining bandwidth (1000 - 500 =
500) equally between the two (500 / 2 = 250 kbps for each). The priority has no
effect on how much of the unused bandwidth each server gets.
rate, the rest of the available bandwidth is divided equally between the two. So
server A gets its configured rate of 300 kbps and server B gets its configured rate
of 200 kbps. Then the ZyWALL divides the remaining bandwidth (1000 - 500 =
500) equally between the two (500 / 2 = 250 kbps for each). The priority has no
effect on how much of the unused bandwidth each server gets.
So server A gets its configured rate of 300 kbps plus 250 kbps for a total of 550
kbps. Server B gets its configured rate of 200 kbps plus 250 kbps for a total of
450 kbps.
kbps. Server B gets its configured rate of 200 kbps plus 250 kbps for a total of
450 kbps.
Priority and Over Allotment of Bandwidth Effect
Server A has a configured rate that equals the total amount of available
bandwidth and a higher priority. You should regard extreme over allotment of
traffic with different priorities (as shown here) as a configuration error. Even
though the ZyWALL still attempts to let all traffic get through and not be lost,
regardless of its priority, server B gets almost no bandwidth with this
configuration.
bandwidth and a higher priority. You should regard extreme over allotment of
traffic with different priorities (as shown here) as a configuration error. Even
though the ZyWALL still attempts to let all traffic get through and not be lost,
regardless of its priority, server B gets almost no bandwidth with this
configuration.
Finding Out More
• See
policies with bandwidth restrictions.
• See
for a description of DSCP
marking.
28.1.3 Bandwidth Management Examples
Bandwidth management is very useful when applications are competing for limited
bandwidth. For example, say you have a WAN zone interface connected to an
ADSL device with a 8 Mbps downstream and 1 Mbps upstream ADSL connection.
bandwidth. For example, say you have a WAN zone interface connected to an
ADSL device with a 8 Mbps downstream and 1 Mbps upstream ADSL connection.
Table 129 Maximize Bandwidth Usage Effect
POLICY
CONFIGURED RATE
MAX. B. U.
PRIORITY ACTUAL RATE
A
300 kbps
Yes
1
550 kbps
B
200 kbps
Yes
2
450 kbps
Table 130 Priority and Over Allotment of Bandwidth Effect
POLICY
CONFIGURED RATE
MAX. B. U.
PRIORITY
ACTUAL RATE
A
1000 kbps
Yes
1
999 kbps
B
1000 kbps
Yes
2
1 kbps