Creating and using virtual bandwidth buckets

About bandwidth allocation buckets

Bandwidth buckets define the virtual "space" that is to be set aside for a particular type of traffic. When you create a new bandwidth bucket, you specify the bandwidth, admission control, and dynamic creation properties of the bucket. Dynamic bucket properties enable you to write masking schemes that use properties in the IP packet to determine whether a bandwidth bucket should be created.

Creating new bandwidth buckets

To create new bandwidth buckets, use the New Bucket button in the Buckets tab on the Network Bandwidth Allocation page (Setup tab > Bandwidth Allocation > Buckets tab).

Viewing existing bandwidth buckets

If you have existing bandwidth buckets, you can view them in the Current Bandwidth Allocation Buckets table (Setup tab > Bandwidth Allocation > Buckets tab).

Dynamic buckets defined

Dynamic buckets are unique bandwidth allocation buckets that are created at the time they are required. By masking the bits in the IP header field, you can create multiple, unique bandwidth buckets that share a single bucket definition.

The appliance examines the rules set for the bucket and the properties specified in the Dynamic Bucket Properties field on the New Bandwidth Bucket page (Setup tab > Network > Bandwidth Allocation > Buckets tab) to determine if a new bandwidth bucket must be created.

How dynamic buckets are generated

The bandwidth management feature uses the IP header masking scheme to help identify packets that should be sent to a dynamic bucket. The bitmask indicates the number of bits that should be set to one. For example:

mask dst-ip 0xffffffff

In the preceding example, all 32 bits of the destination IP address are set to one. Packets with the same identifier after masking fall into the same queue.

Masking schemes for dynamic buckets

As shown in the following table, you can use several different masking schemes to classify packets for redirection to dynamic buckets.

Mask	Used to identify packets based on	Example
`proto`	Protocol	`mask proto`
`dst-ip`	Destination IP address	`mask dst-ip 0xfffffff`
`src-ip`	Source IP address	`mask src-ip 0xfffffff`
`dst-port`	Destination port	`mask dst-port 0xffff`
`src-port`	Source port	`mask src-port 0xffff`
`all`	All identifiers: `proto, dst-ip, src-ip,dst-port, src-port`	`mask all` (All bits in all fields are used to identify packets.)

You can specify multiple masking properties for the bucket. For example:

mask dst-ip 0xffffffff dst-port 0xffff

The preceding masking properties classify packets based on their destination IP address and port number. For more examples of dynamic bucket masking, see Example 5: Limiting inbound and outbound connections and Example 6: Limiting client-side connections.