4.2.8 Description of the FILTER-SET Object

Below is the object template for the filter-set object. It lists all possible attributes that are allowed in this object type. Required attributes are shown as ‘optional*'.

Attribute Name  Presence   Repeat     Indexed
filter-set: mandatory single primary/lookup key
descr: mandatory multiple
filter: optional single
mp-filter: optional single
remarks: optional multiple
org: optional multiple inverse key
tech-c: mandatory multiple inverse key
admin-c: mandatory multiple inverse key
notify: optional multiple inverse key
mnt-by: mandatory multiple inverse key
mnt-lower: optional multiple inverse key
changed: optional multiple
created: generated single
last-modified: generated single
source: mandatory single

To specify routing policies, it is often useful to define sets of objects. A filter-set object defines a set of routes that match the criteria that you specify in your 'filter' – in other words, it filters out the routes that you do not want to see. The policy filter can match routes using any BGP path attribute, such as the destination address prefix, AS-path, or community attributes. Although the “filter:” and “mp-filter:” attributes are ‘single', they can be composite by using the operators AND, OR, and NOT.

Sets can be built with hierarchical names. Unlike other set objects the filter-set object does not include the “members:” or "mbrs-by-ref:" attributes.

4.2.7.1 Description of Attributes Specific to the FILTER-SET Object

  • “filter-set:” – This attribute defines the name of the set which must start with ‘fltr-‘. It can be a hierarchical name with components separated by a colon (:). At least one component must be a filter-set name. The others can be more set names or AS Numbers. All the set name components of a hierarchical name must be filter-set names. For more details, see the section about sets.
  • “descr:” – A short description related to the object.
  • “filter:” – This attribute defines the policy filter of the set. This is a logical expression which, when applied to a set of routes, returns a subset of these routes. These are the ones that you want to filter in or filter out. A filter-set object is required by business rules to include either a “filter:” or an “mp-filter:” attribute. One of these must exist, but you cannot include both attributes.
  • “mp-filter:” – This attribute extends the "filter:" attribute to allow you to specify IPv4 or IPv6 prefixes and prefix ranges. A filter-set object is required by business rules to include either a “filter:” or an “mp-filter:” attribute. One of these must exist, but you cannot include both attributes.
  • “mnt-lower:” – When creating hierarchical sets, more specific object creations can be authorised using the “mnt-lower:”, if present, otherwise they can be authorised by “mnt-by:” mntner objects. For more details see the section about sets.