HPE FlexNetwork HSR6800 Configuration Manual page 197

•
ORIGIN
The ORIGIN attribute identifies the origin of routing information (how a route became a BGP
route). This attribute has the following types:
IGP—Has the highest priority. Routes generated in the local AS have the IGP attribute.
EGP—Has the second highest priority. Routes obtained through EGP have the EGP attribute.
INCOMPLETE—Has the lowest priority. The source of routes with this attribute is unknown. The routes
redistributed from other routing protocols have the INCOMPLETE attribute.
•
AS_PATH
The AS_PATH attribute identifies the ASs through which a route has passed. Before
advertising a route to another AS, BGP adds the local AS number into the AS_PATH attribute,
so the receiver can determine ASs to route the message back.
The AS_PATH attribute has the following two types:
AS_SEQUENCE—Arranges AS numbers in sequence. As shown in
closest to the receiver's AS is the first one listed in the AS_PATH.
AS_SET—Arranges AS numbers randomly.
Figure 59 AS_PATH attribute
BGP uses the AS_PATH attribute to implement the following functions:
Avoid routing loops—A BGP router does not receive routes containing the local AS number to avoid
routing loops.
Affect route selection—BGP gives priority to the route with the shortest AS_PATH length if other factors
are the same. As shown in
sending data to the destination 8.0.0.0. In some applications, you can apply a routing policy to control BGP
route selection by modifying the AS_PATH length.
Filter routes—By configuring an AS path filtering list, you can filter routes based on AS numbers
contained in the AS_PATH attribute. For more information about routing policies and AS path filtering lists, see
"Configuring routing policies."
•
NEXT_HOP
The NEXT_HOP attribute is not necessarily the IP address of a directly-connected router. Its
value is determined as follows:
Figure 59, the BGP router in AS 50 gives priority to the route passing AS 40 for
Figure
185
59, the number of the AS