Filter parameters

The following table shows which parameters are supported by which filter, and whether they are optional ($\circ$) or required ($\bullet$):

Parameter	fw	route	rsvp	tcindex
fall_through	.	.	.	$\circ$
hash	.	.	.	$\circ$
mask	.	.	.	$\circ$
pass_on	.	.	.	$\circ$
protocol	$\circ$	$\circ$	$\circ$	$\circ$
shift	.	.	.	$\circ$

Units and meaning of the parameters are described below:

Parameter	Unit	Description
fall_through	flag	If no match, calculate index
hash	integer	Hash table size
mask	integer	DS field value mask
pass_on	flag	Negation of fall_through
protocol	Ether protocol	Network layer protocol
shift	integer	Number of bits to right-shift DS field

The unit ``Ether protocol'' is special: the value can either be an integer, or a string containing one of the names ip, ipv4, or ipv6.

In addition to the parameters described in this section, filters also allow default values for filter element parameters to be specified at the filter. They are listed in the next section.