Reference Guide

Border Gateway Protocol IPv4 (BGPv4) | 217
Configure IP community lists
Within Dell Networking OS, you have multiple methods of manipulating routing attributes. One attribute
you can manipulate is the COMMUNITY attribute. This attribute is an optional attribute that is defined for
a group of destinations. In Dell Networking OS, you can assign a COMMUNITY attribute to BGP routers
by using an IP Community list. After you create an IP Community list, you can apply routing decisions to
all routers meeting the criteria in the IP Community list.
IETF RFC 1997 defines the COMMUNITY attribute and the pre-defined communities of INTERNET,
NO_EXPORT_SUBCONFED, NO_ADVERTISE, and NO_EXPORT. All BGP routes belong to the
INTERNET community. In the RFC, the other communities are defined as follows:
• All routes with the NO_EXPORT_SUBCONFED (0xFFFFFF03) community attribute are not sent to
CONFED-EBGP or EBGP peers, but are sent to IBGP peers within CONFED-SUB-AS
• All routes with the NO_ADVERTISE (0xFFFFFF02) community attribute must not be advertised
• All routes with the NO_EXPORT (0xFFFFFF01) community attribute must not be advertised outside a
BGP confederation boundary, but are sent to CONFED-EBGP and IBGP peers
Dell Networking OS also supports BGP Extended Communities as described in RFC 4360—BGP
Extended Communities Attribute.
2
neighbor add-path
CONFIG-ROUTER-BGP Allow the specified neighbor/peer group to send/
receive multiple path advertisements.
3
max-path number
CONFIG-ROUTER-BGP Configure the maximum number of parallel
routes (multipath support) BGP supports. Range:
2-64
Step Command Syntax Command Mode Purpose