ZyXEL Communications ZyWall USG 2000 User Manual page 448

Chapter 29 Application Patrol
Priority Effect
Here the configured rates total more than the available bandwidth. Because server
A has higher priority, it gets up to it's configured rate (800 kbps), leaving only 200
kbps for server B.
Table 125 Priority Effect
POLIC
Y
A
B
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.
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.
Table 126 Maximize Bandwidth Usage Effect
POLIC
Y
A
B
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.
Table 127 Priority and Over Allotment of Bandwidth Effect
POLIC
Y
A
B
448
CONFIGURED MAX. B.
RATE U.
800 kbps Yes
1000 kbps Yes
CONFIGURED MAX. B.
RATE U.
300 kbps Yes
200 kbps Yes
CONFIGURED MAX. B.
RATE U.
1000 kbps Yes
1000 kbps Yes
PRIORIT ACTUAL
Y RATE
1 800 kbps
2 200 kbps
PRIORIT ACTUAL
Y RATE
1 550 kbps
2 450 kbps
PRIORIT ACTUAL
Y RATE
1 999 kbps
2 1 kbps
ZyWALL USG 2000 User's Guide