Dell Force10 E600i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 231

Configure IP community lists Within FTOS, 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 FTOS, 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. FTOS also supports BGP Extended Communities as described in RFC 4360-BGP Extended Communities Attribute. Use these commands in the following sequence, starting in the CONFIGURATION mode to configure an IP community list. Step Command Syntax Command Mode Purpose 1 ip community-list CONFIGURATION community-list-name Create a Community list and enter the COMMUNITY-LIST mode. 2 {deny | permit} CONFIG-COMMUNITY-LIST Configure a Community list by denying or {community-number permitting specific community numbers or types of | local-AS | community no-advertise | • community-number: use AA:NN format where no-export | quote-regexp AA is the AS number (2 or 4 Bytes) and NN is a value specific to that autonomous system. regular-expression-li st | regexp regular-expression} • local-AS: routes with the COMMUNITY attribute of NO_EXPORT_SUBCONFED. • no-advertise: routes with the COMMUNITY attribute of NO_ADVERTISE. • no-export: routes with the COMMUNITY attribute of NO_EXPORT. • quote-regexp: followed by any number of regular expressions. The software applies all regular expressions in the list. • regexp: followed by a regular expression. Border Gateway Protocol IPv4 (BGPv4) | 231