Owner's Manual

Chapter 26. BGP | 699
NETGEAR 8800 User Manual
• Next_hop—The IP address of the next hop BGP router to reach the destination listed in
the NLRI field.
• Multi_Exit_Discriminator—Used to select a particular border router in another AS when
multiple border routers exist.
• Local_Preference—Used to advertise this router’s degree of preference to other routers
within the AS.
• Atomic_aggregate—Indicates that the sending border router has used a route aggregate
prefix in the route update.
• Aggregator—Identifies the BGP router AS number and router ID for the router that
performed route aggregation.
• AS4_Aggregator: This attribute is used by 4-byte peers when sending updates to 2-byte
peers. This attribute carries AS-number information that can be represented only in
4-bytes.
• Community—Identifies a group of destinations that share one or more common
attributes.
• Cluster_ID—Specifies a 4-byte field used by a route reflector to recognize updates from
other route reflectors in the same cluster.
• Originator_ID—Specifies the router ID of the originator of the route in the local AS.
• Extended Community—Provides a mechanism for labeling BGP-4 update messages that
carry information
• Multiprotocol reachable NLRI—Used to advertise a feasible BGP route for the non
IPv4-unicast address family
• Multiprotocol unreachable NLRI—This attribute is used to withdraw multiple unfeasible
routes from service
BGP Community Attributes
A BGP community is a group of BGP destinations that require common handling. XCM8800
supports the following well-known BGP community attributes:
• no-export
• no-advertise
• no-export-subconfed
Extended Community Attributes
The extended community attribute provides a mechanism to label BGP routes. It provides
two important enhancements over the standard community attribute:
• An expanded range. Extended communities are 8-bytes wide, whereas regular
communities were only 4-bytes wide. So, this ensures that extended communities can be
assigned for a plethora of uses, without the fear of overlap.
• The addition of 'Type' field provides structure for the extended community