Optional transitive
Transitive attribute between ASs. A BGP router not supporting this attribute can still receive routes with this
attribute and advertise them to other peers.
Optional non-transitive
If a BGP router does not support this attribute, it will not advertise routes with this attribute.
The category of each BGP path attribute is described in the following table.
Table 39: BGP path attributes
Name
Category
ORIGIN
Well-known mandatory
AS_PATH
Well-known mandatory
NEXT_HOP
Well-known mandatory
LOCAL_PREF
Well-known discretionary
ATOMIC_AGGREGATE
Well-known discretionary
COMMUNITY
Optional transitive
MULTI_EXIT_DISC (MED)
Optional non-transitive
ORIGINATOR_ID
Optional non-transitive
CLUSTER_LIST
Optional non-transitive
Using BGP path attributes
ORIGIN
ORIGIN is a well-known mandatory attribute that defines the origin of routing information, that is, how a route
became a BGP route. There are three types:
IGP
Has the highest priority. Routes added to the BGP routing table using the network command have the IGP
attribute.
EGP
Has the second highest priority. Routes obtained via EGP have the EGP attribute.
Incomplete
Has the lowest priority. The source of routes with this attribute is unknown, which does not mean such routes
are unreachable. The routes that are redistributed from other routing protocols have this attribute.
AS_PATH
AS_PATH is a well-known mandatory attribute. This attribute identifies the autonomous systems through which
routing information carried in the Update message has passed. When a route is advertised from the local AS to
another AS, each passed AS number is added into the AS_PATH attribute, allowing the receiver to determine the
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Aruba 3810 / 5400R Multicast and Routing Guide for ArubaOS-
Switch 16.08