Chapter 27 Application Patrol

27.4.5.4 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 111 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

 

 

 

 

 

27.5 Application Patrol 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. The following sections give some simplified examples of using application patrol policies to manage applications competing for that 1 Mbps of upstream bandwidth.

Here is an overview of what the rules need to accomplish. See the following sections for more details.

•SIP traffic from VIP users must get through with the least possible delay regardless of if it is an outgoing call or an incoming call. The VIP users must be able to make and receive SIP calls no matter which interface they are connected to.

•HTTP traffic needs to be given priority over FTP traffic.

•FTP traffic from the WAN to the DMZ must be limited so it does not interfere with SIP and HTTP traffic.

•FTP traffic from the LAN to the DMZ can use more bandwidth since the interfaces support up to 1 Gbps connections, but it must be the lowest priority and limited so it does not interfere with SIP and HTTP traffic.

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ZyWALL USG 1000 User’s Guide