Internet2 BGP communities

    The following represents Internet2's understanding of its own community settings and how Internet2, STAR TAP, and CA*net set and receive communities of peer networks with respect to each other.
    Internet2, CA*net, and STAR TAP set BGP communities to indicate prefixes' status and exchange prefixes with each other as described in the ITN program description set forth athttp://international.internet2.edu/intl_connect/index.html#itn www.ucaid.edu/abilene/html/itnservice.html . Internet2 advertises to STAR TAP and CA*net3 all of its ITN-peerprefixes; CA*net and STAR TAP advertise to Internet2 only those ITN-peerprefixes from networks which have MoUs with Internet2.
    Internet2 community values are set (additively) for agiven prefix. See "show ip bgp <prefix>" in the Internet2 routerproxy for real-world examples.
    Internet2-connected Gigapops and connectors with heterogeneous participants (i.e. not all are universities) may need to use these communities to help them pass prefixes appropriately to their participants. For example, connectors can pass all prefixes on to their university participants,but should not pass commercial or US Fednet prefixes to their commercialor Fednet participants.
    Beginning in February 2002, Internet2 allows its peers to use communities to influence Internet2's preference-setting for prefixes. See Table 2 below for details.

community value	community name	description	prefixes passed to non-ITN peer nets	prefixes passed to ITN peer nets	prefixes passed to connectors	prefixes passed to commercial participants
11537:40/160	FED/ITN pref (see below)	Influence local-pref	as usual	as usual	as usual	as usual
11537:140/260	Connector-pref (see below)	Influence local-pref	as usual	as usual	as usual	as usual
11537:600	IPv6 special (see below)	V6 prefixes learned via tunnels	YES	YES	YES	YES
11537:902	SPONSORED	non-UCAID R&E sites sponsored for connection by members	YES	YES	YES	YES
11537:910	Abilene SEGP	sponsored educational groups (primarily state networks)	YES	YES	YES	YES
11537:911	Black Hole (see below)	Traffic to these prefixes will be discarded	no	no	no	no
11537:950	Abilene_DC	all Abilene connected participants	YES	YES	YES	YES
11537:2000	COMMERCIAL	commercial research-lab participant	YES	YES	YES	no
11537:2001	COMMERCIAL- PEER	This prefix from a peer network, not a regular Abilene participant, is commercial. Examples may be AUP-free prefixes accepted for ipv6 or multicast peering.
11537:2002	BLOCK-TO- COMMERCIAL	Connectors may set this community for prefixes they pass to Abilene. Abilene will not advertise prefixes with this community to commercial peers.	YES	YES	YES	no
11537:2500	nonTRANSIT	non-ITN (and non-US) peer network	no	no	YES	YES
11537:2501	TRANSIT	ITN(non-US) peer network	no	YES	YES	YES
11537:3000	FEDNET	US federal peer network	no	no	YES	YES
11537:3500	CONNECTOR- ONLY	Abilene uses this to mark prefixes sent to connectors but not peers	no	no	YES

Using BGP communities to influence Internet2's local-preference setting: (these settings may be used for ipv4 or ipv6) Beginning February 2002, Internet2's BGP peers may set BGP communities to influence Internet2's setting of its local-preference for the prefixes we receive from you. The community may cause the preference to be lower or higher than the default preferences, and may be useful in cases where we peer with you in more than one place and you want to influence our choice of pathsto you. Refer to the table below for the community to use and its result. For example, if you are an Internet2 connector, the default local-pref for the prefixes we receive from you is set to 200. If you set a community 11537:260 for some prefixes, Internet2 will set the local-pref for that path tothose prefixes at 260. Note: only the communities specifiedbelow are supported.
	Default	High	Low
Abilene CONNECTORS set community to: ... and Abilene's local-pref for the associated prefixes will be:	(none) 200	11537:260 260	11537:140 140
Abilene ITN/nonITN/FEDNET peers set community to: ... and Abilene's local-pref for the associated prefixes will be:	(none) 100	11537:160 160	11537:40 40

IPv6 special community: beginning November2002, Internet2 began setting a new community, 11537:600, to indicatethat prefixes with this community come to Internet2 through a tunneled interface.

"Black Hole” community: beginning November 2004, connectors may set a community to communicate to Internet2 that traffic to designated prefixes should be blackholed within Internet2. This is to allow some protection in DoS attacks. Connectors may only set this for their own prefixes.

Internet2 BGP communities

Using BGP communities to influence Internet2's local-preference setting:

IPv6 special community: beginning November2002, Internet2 began setting a new community, 11537:600, to indicatethat prefixes with this community come to Internet2 through a tunneled interface.

"Black Hole” community: beginning November 2004, connectors may set a community to communicate to Internet2 that traffic to designated prefixes should be blackholed within Internet2. This is to allow some protection in DoS attacks. Connectors may only set this for their own prefixes.