draft-ietf-grow-collection-communities-08.txt		rfc4384.txt
	GROW WG D. Meyer		Network Working Group D. Meyer
			Request for Comments: 4384 February 2006
	Expires: February 23, 2006		BCP: 114
			Category: Best Current Practice
	BGP Communities for Data Collection		BGP Communities for Data Collection
	draft-ietf-grow-collection-communities-08
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	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2005).		Copyright (C) The Internet Society (2006).
	Abstract		Abstract
	BGP communities (RFC 1997) are used by service providers for many		BGP communities (RFC 1997) are used by service providers for many
	purposes, including tagging of customer, peer, and geographically		purposes, including tagging of customer, peer, and geographically
	originated routes. Such tagging is typically used to control the		originated routes. Such tagging is typically used to control the
	scope of redistribution of routes within a provider's network, and to		scope of redistribution of routes within a provider's network and to
	its peers and customers. With the advent of large scale BGP data		its peers and customers. With the advent of large-scale BGP data
	collection (and associated research), it has become clear that the		collection (and associated research), it has become clear that the
	information carried in such communities is essential for a deeper		information carried in such communities is essential for a deeper
	understanding of the global routing system. This memo defines		understanding of the global routing system. This memo defines
	standard (outbound) communities and their encodings for export to BGP		standard (outbound) communities and their encodings for export to BGP
	route collectors.		route collectors.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction ....................................................2
	2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Definitions .....................................................3
	2.1. Peers and Peering . . . . . . . . . . . . . . . . . . . . 3		2.1. Peers and Peering ..........................................3
	2.2. Customer Routes . . . . . . . . . . . . . . . . . . . . . 4		2.2. Customer Routes ............................................3
	2.3. Peer Routes . . . . . . . . . . . . . . . . . . . . . . . 4		2.3. Peer Routes ................................................3
	2.4. Internal Routes . . . . . . . . . . . . . . . . . . . . . 4		2.4. Internal Routes ............................................4
	2.5. Internal More Specific Routes . . . . . . . . . . . . . . 4		2.5. Internal More Specific Routes ..............................4
	2.6. Special Purpose Routes . . . . . . . . . . . . . . . . . . 4		2.6. Special Purpose Routes .....................................4
	2.7. Upstream Routes . . . . . . . . . . . . . . . . . . . . . 4		2.7. Upstream Routes ............................................4
	2.8. National Routes . . . . . . . . . . . . . . . . . . . . . 5		2.8. National Routes ............................................4
	2.9. Regional Routes . . . . . . . . . . . . . . . . . . . . . 5		2.9. Regional Routes ............................................4
	3. RFC 1997 Community Encoding and Values . . . . . . . . . . . . 5		3. RFC 1997 Community Encoding and Values ..........................5
	4. Community Values for BGP Data Collection . . . . . . . . . . . 5		4. Community Values for BGP Data Collection ........................5
	4.1. Extended Communities . . . . . . . . . . . . . . . . . . . 7		4.1. Extended Communities .......................................7
	4.2. Four-octet AS specific extended communities . . . . . . . 8		4.2. Four-Octet AS Specific Extended Communities ................9
	5. Note on BGP UPDATE Packing . . . . . . . . . . . . . . . . . . 9		5. Note on BGP UPDATE Packing ......................................9
	6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9		6. Acknowledgements ................................................9
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 9		7. Security Considerations ........................................10
	7.1. Total Path Attribute Length . . . . . . . . . . . . . . . 9		7.1. Total Path Attribute Length ...............................10
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10		8. IANA Considerations ............................................10
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10		9. References .....................................................11
	9.1. Normative References . . . . . . . . . . . . . . . . . . . 10		9.1. Normative References ......................................11
	9.2. Informative References . . . . . . . . . . . . . . . . . . 11		9.2. Informative References ....................................11
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 12
	Intellectual Property and Copyright Statements . . . . . . . . . . 13
	1. Introduction		1. Introduction
	BGP communities [RFC1997] are used by service providers for many		BGP communities [RFC1997] are used by service providers for many
	purposes, including tagging of customer, peer, and geographically		purposes, including tagging of customer, peer, and geographically
	originated routes. Such tagging is typically used to control the		originated routes. Such tagging is typically used to control the
	scope of redistribution of routes within a providers network, and to		scope of redistribution of routes within a provider's network and to
	its customers and peers. Communities are also used for a wide		its customers and peers. Communities are also used for a wide
	variety of other applications, such as allowing customers to set		variety of other applications, such as allowing customers to set
	attributes such as LOCAL_PREF [RFC1771] by sending appropriate		attributes such as LOCAL_PREF [RFC1771] by sending appropriate
	communities to their service provider. Other applications include		communities to their service provider. Other applications include
	signaling various types of VPNs (e.g., VPLS [I-D.ietf-ppvpn-vpls-		signaling various types of Virtual Private Networks (VPNs) (e.g.,
	requirements]), and carrying link bandwidth for traffic engineering		Virtual Private LAN Service (VPLS) [VPLS]), and carrying link
	applications [I-D.ietf-idr-bgp-ext-communities].		bandwidth for traffic engineering applications [RFC4360].
	With the advent of large scale BGP data collection [RV][RIS] (and		With the advent of large-scale BGP data collection [RV] [RIS] (and
	associated research), it has become clear that the geographical and		associated research), it has become clear that the geographical and
	topological information, as well as the relationship the provider has		topological information, as well as the relationship the provider has
	to the source of a route (e.g., transit, peer, or customer), carried		to the source of a route (e.g., transit, peer, or customer), carried
	in such communities is essential for a deeper understanding of the		in such communities is essential for a deeper understanding of the
	global routing system. This memo defines standard communities for		global routing system. This memo defines standard communities for
	export to BGP route collectors. These communities represent a		export to BGP route collectors. These communities represent a
	significant part of information carried by service providers as of		significant part of information carried by service providers as of
	this writing, and as such could be useful for internal use by service		this writing, and as such could be useful for internal use by service
	providers. However, such use is beyond the scope of this memo.		providers. However, such use is beyond the scope of this memo.
	Finally, those involved in BGP data analysis are encouraged to verify		Finally, those involved in BGP data analysis are encouraged to verify
	with their data sources as to which peers implement this scheme (as		with their data sources as to which peers implement this scheme (as
	there is a large amount of existing data as well as many legacy		there is a large amount of existing data as well as many legacy
	peerings).		peerings).
	The remainder of this memo is organized as follows. Section 2		The remainder of this memo is organized as follows. Section 2
	provides both the definition of terms used as well as the semantics		provides the definition of terms used as well as the semantics of the
	of the communities used for BGP data collection, and section 3		communities used for BGP data collection, and Section 3 defines the
	defines the corresponding encodings for RFC 1997 [RFC1997]		corresponding encodings for RFC 1997 [RFC1997] communities. Finally,
	communities. Finally, section 4 defines the encodings for use with		Section 4 defines the encodings for use with extended communities
	extended communities [I-D.ietf-idr-bgp-ext-communities].		[RFC4360].
	2. Definitions		2. Definitions
	In this section, we define the terms used and the categories of		In this section, we define the terms used and the categories of
	routes that may be tagged with communities. This tagging is often		routes that may be tagged with communities. This tagging is often
	refered to as coloring, and we refer to a route's "color" as its		referred to as coloring, and we refer to a route's "color" as its
	community value. The categories defined here are loosely modeled on		community value. The categories defined here are loosely modeled on
	those described in [WANG] and [HUSTON].		those described in [WANG] and [HUSTON].
	2.1. Peers and Peering		2.1. Peers and Peering
	Consider two network service providers, A and B. Service providers A		Consider two network service providers, A and B. Service providers A
	and B are defined to be peers when (i). A and B exchange routes via		and B are defined to be peers when (i) A and B exchange routes via
	BGP, and (ii). traffic exchange between A and B is settlement-free.		BGP, and (ii) traffic exchange between A and B is settlement-free.
	This arrangement is also typically known as "peering". Peers		This arrangement is also typically known as "peering". Peers
	typically exchange only their respective customer routes (see		typically exchange only their respective customer routes (see
	"Customer Routes" below), and hence exchange only their respective		"Customer Routes" below), and hence exchange only their respective
	customer traffic. See [HUSTON] for a more in-depth discussion of the		customer traffic. See [HUSTON] for a more in-depth discussion of the
	business models surrounding peers and peering.		business models surrounding peers and peering.
	2.2. Customer Routes		2.2. Customer Routes
	Customer routes are those routes which are heard from a customer via		Customer routes are those routes that are heard from a customer via
	BGP and are propagated to peers and other customers. Note that a		BGP and are propagated to peers and other customers. Note that a
	customer can be an enterprise or another network service provider.		customer can be an enterprise or another network service provider.
	These routes are sometimes called client routes [HUSTON].		These routes are sometimes called client routes [HUSTON].
	2.3. Peer Routes		2.3. Peer Routes
	Peer routes are those routes heard from peers via BGP, and not		Peer routes are those routes heard from peers via BGP, and not
	propagated to other peers. In particular, these routes are only		propagated to other peers. In particular, these routes are only
	propagated to the service provider's customers.		propagated to the service provider's customers.
	2.4. Internal Routes		2.4. Internal Routes
	Internal routes are those routes that a service provider originates		Internal routes are those routes that a service provider originates
	and passes to its peers and customers. These routes are frequently		and passes to its peers and customers. These routes are frequently
	taken out of the address space allocated to a provider.		taken out of the address space allocated to a provider.
	2.5. Internal More Specific Routes		2.5. Internal More Specific Routes
	Internal more-specific routes are those routes which are frequently		Internal more specific routes are those routes that are frequently
	used for circuit load balancing purposes, IGP route reduction, and		used for circuit load balancing purposes and Interior Gateway
	also may correspond to customer services which are not visible		Protocol (IGP) route reduction. They also may correspond to customer
	outside the service provider's network. Internal more specific		services that are not visible outside the service provider's network.
	routes are not exported to any external peer.		Internal more specific routes are not exported to any external peer.
	2.6. Special Purpose Routes		2.6. Special Purpose Routes
	Special purpose routes are those routes which do not fall into any of		Special purpose routes are those routes that do not fall into any of
	the other classes described here. In those cases in which such		the other classes described here. In those cases in which such
	routes need to be distinguished, a service provider may color such		routes need to be distinguished, a service provider may color such
	routes with a unique value. Examples of special purpose routes		routes with a unique value. Examples of special purpose routes
	include anycast routes, and routes for overlay networks.		include anycast routes and routes for overlay networks.
	2.7. Upstream Routes		2.7. Upstream Routes
	Upstream routes are typically learned from upstream service provider		Upstream routes are typically learned from an upstream service
	as part of a transit service contract executed with the upstream		provider as part of a transit service contract executed with the
	provider.		upstream provider.
	2.8. National Routes		2.8. National Routes
	These are route sets that are sourced from and/or received within a		These are route sets that are sourced from and/or received within a
	particular country.		particular country.
	2.9. Regional Routes		2.9. Regional Routes
	Several global backbones implement regional policy based on their		Several global backbones implement regional policy based on their
	deployed footprint, and on strategic and business imperatives.		deployed footprint and on strategic and business imperatives.
	Service providers often have settlement-free interconnections with an		Service providers often have settlement-free interconnections with an
	AS in one region, and that same AS is a customer in another region.		Autonomous System (AS) in one region, and that same AS is a customer
	This mandates use of regional routing, including community attributes		in another region. This mandates use of regional routing, including
	set by the network in question to allow easy discrimination among		community attributes set by the network in question to allow easy
	regional routes. For example, service providers may treat a route		discrimination among regional routes. For example, service providers
	set received from another service provider in Europe differently than		may treat a route set received from another service provider in
	the same route set received in North America, as it is common		Europe differently than the same route set received in North America,
	practice to sell transit in one region while peering in the other.		as it is common practice to sell transit in one region while peering
			in the other.
	3. RFC 1997 Community Encoding and Values		3. RFC 1997 Community Encoding and Values
	In this section we provide RFC 1997 [RFC1997] community values for		In this section, we provide RFC 1997 [RFC1997] community values for
	the categories described above. RFC 1997 communities are encoded as		the categories described above. RFC 1997 communities are encoded as
	BGP Type Code 8, and are treated as 32 bit values ranging from		BGP Type Code 8, and are treated as 32-bit values ranging from
	0x0000000 through 0xFFFFFFF. The values 0x0000000 through 0x0000FFFF		0x0000000 through 0xFFFFFFF. The values 0x0000000 through 0x0000FFFF
	and 0xFFFF0000 through 0xFFFFFFFF are reserved.		and 0xFFFF0000 through 0xFFFFFFFF are reserved.
	The best current practice among service providers is to use the high		The best current practice among service providers is to use the
	order two octets to represent the provider's AS number, and the low		high-order two octets to represent the provider's AS number, and the
	order two octets to represent the classification of the route, as		low-order two octets to represent the classification of the route, as
	depicted below:		depicted below:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| <AS> | <Value> |		| <AS> | <Value> |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	where <AS> is the 16 bit AS number. For example, the encoding		where <AS> is the 16-bit AS number. For example, the encoding
	0x2A7C029A would represent the AS 10876 with value 666.		0x2A7C029A would represent the AS 10876 with value 666.
	4. Community Values for BGP Data Collection		4. Community Values for BGP Data Collection
	In this section we define the RFC 1997 community encoding for the		In this section, we define the RFC 1997 community encoding for the
	route types described above for use in BGP data collection. It is		route types described above for use in BGP data collection. It is
	anticipated that a service provider's internal community values will		anticipated that a service provider's internal community values will
	be converted to these standard values for output to a route		be converted to these standard values for output to a route
	collector.		collector.
	This memo follows the best current practice of using the basic format		This memo follows the best current practice of using the basic format
	<AS>:<Value>. The values for the route categories are described in		<AS>:<Value>. The values for the route categories are described in
	the following table:		the following table:
	Category Value		Category Value
	skipping to change at page 6, line 44		skipping to change at page 7, line 4
	and <R> takes the values:		and <R> takes the values:
	Africa (AF) 00001		Africa (AF) 00001
	Oceania (OC) 00010		Oceania (OC) 00010
	Asia (AS) 00011		Asia (AS) 00011
	Antarctica (AQ) 00100		Antarctica (AQ) 00100
	Europe (EU) 00101		Europe (EU) 00101
	Latin America/Caribbean Islands (LAC) 00110		Latin America/Caribbean Islands (LAC) 00110
	North America (NA) 00111		North America (NA) 00111
	Reserved 01000-11111		Reserved 01000-11111
	Figure 2: Initially Assigned Community Values
	That is:		That is:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| <AS> | <R> |X| <CC> |		| <AS> | <R> |X| <CC> |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	For example, the encoding for a national route over a terrestrial		For example, the encoding for a national route over a terrestrial
	link in AS 10876 from the Fiji Islands would be:		link in AS 10876 from the Fiji Islands would be:
	<AS> = 10876 = 0x2A7C		<AS> = 10876 = 0x2A7C
	<R> = 00010		<R> = 00010
	<X> = 0		<X> = 0
	<CC> = Fiji Islands Country Code = 242 = 0011110010		<CC> = Fiji Islands Country Code = 242 = 0011110010
	In this case, the low order 16 bits are 0001000011110010 = 0x10F2		In this case, the low-order 16 bits are 0001000011110010 = 0x10F2.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| 0x2A7C | 0x10F2 |		| 0x2A7C | 0x10F2 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Note that a configuration language might allow the specification of		Note that a configuration language might allow the specification of
	this community as 10876:4338 (0x10F2 == 4338 decimal).		this community as 10876:4338 (0x10F2 == 4338 decimal).
	Finally, note that these categories are not intended to be mutually		Finally, note that these categories are not intended to be mutually
	exclusive, and multiple communities can be attached where		exclusive, and multiple communities can be attached where
	appropriate.		appropriate.
	4.1. Extended Communities		4.1. Extended Communities
	In some cases, the values and their encodings described in Section 4		In some cases, the values and their encoding described in Section 4
	may clash with a service provider's existing community assignments.		may clash with a service provider's existing community assignments.
	Extended communities [I-D.ietf-idr-bgp-ext-communities] provide a		Extended communities [RFC4360] provide a convenient mechanism that
	convenient mechanism that can be used to avoid such clashes.		can be used to avoid such clashes.
	The Extended Communities Attribute is a transitive optional BGP		The Extended Communities attribute is a transitive optional BGP
	attribute with the Type Code 16, and consists of a set of extended		attribute with the Type Code 16 and consists of a set of extended
	communities of the following format:		communities of the following format:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Type high | Type low(*) | |		| Type high | Type low(*) | |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Value |		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Value |
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	For purposes of BGP data collection, we encode the communities		For purposes of BGP data collection, we encode the communities
	described in Section 4 using the two-octet AS specific extended		described in Section 4 using the two-octet AS specific extended
	community type, which has the following format:		community type, which has the following format:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| 0x00 | Sub-Type | Global Administrator |		| 0x00 | Sub-Type | Global Administrator |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Local Administrator |		| Local Administrator |
	skipping to change at page 8, line 17		skipping to change at page 8, line 26
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| 0x00 | Sub-Type | Global Administrator |		| 0x00 | Sub-Type | Global Administrator |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Local Administrator |		| Local Administrator |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	The two-octet AS specific extended community attribute encodes the		The two-octet AS specific extended community attribute encodes the
	service provider's two octet Autonomous System number (as assigned by		service provider's two-octet Autonomous System number (as assigned by
	a Regional Internet Registry, or RIR) in the Global Administrator		a Regional Internet Registry, or RIR) in the Global Administrator
	field, and the Local Administrator field may encode any information.		field, and the Local Administrator field may encode any information.
	This memo assigns Sub-Type 0x0008 for BGP data collection, and		This memo assigns Sub-Type 0x0008 for BGP data collection, and
	specifies that the <Value> field, as defined in section 3.1, is		specifies that the <Value> field, as defined in Section 3.1, is
	carried in the low order octets of the Local Administrator field.		carried in the low-order octets of the Local Administrator field.
	The two high order octets of the Local Administrator field are		The two high-order octets of the Local Administrator field are
	reserved, and are set to 0x00 when sending and ignored upon receipt.		reserved, and are set to 0x00 when sending and ignored upon receipt.
	For example, the extended community encoding for 10876:4338		For example, the extended community encoding for 10876:4338
	(representing a terrestrial national route in AS 10876 from the Fiji		(representing a terrestrial national route in AS 10876 from the Fiji
	Islands) would be:		Islands) would be:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| 0x00 | 0x0008 | 0x2A7C |		| 0x00 | 0x0008 | 0x2A7C |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| 0x00 | 0x00 | 0x10F2 |		| 0x00 | 0x00 | 0x10F2 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	4.2. Four-octet AS specific extended communities		4.2. Four-Octet AS Specific Extended Communities
	The four-octet AS specific extended community is encoded as follows:		The four-octet AS specific extended community is encoded as follows:
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| 0x02 | 0x0008 | Global Administrator |		| 0x02 | 0x0008 | Global Administrator |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Global Administrator (cont.) | 0x10F2 |		| Global Administrator (cont.) | 0x10F2 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	In this case, the 4 octet Global Administrator sub-field contains a		In this case, the four-octet Global Administrator sub-field contains
	4-octets Autonomous System number assigned by the IANA.		a four-octet Autonomous System number assigned by the IANA.
	5. Note on BGP UPDATE Packing		5. Note on BGP UPDATE Packing
	Note that data collection communities have the potential of making		Note that data collection communities have the potential of making
	the attribute set of a specific route more unique than it would be		the attribute set of a specific route more unique than it would be
	otherwise (since each route collects data that is specific to it's		otherwise (since each route collects data that is specific to its
	path inside one or more ASes). This, in turn, can affect whether		path inside one or more ASes). This, in turn, can affect whether
	multiple routes can be grouped in the same BGP update message, and		multiple routes can be grouped in the same BGP update message, and it
	may lead to increased use of bandwidth, router CPU cycles, and		may lead to increased use of bandwidth, router CPU cycles, and
	memory.		memory.
	6. Acknowledgments		6. Acknowledgements
	The community encoding described in this memo germinated from an		The community encoding described in this memo germinated from an
	interesting suggestion from Akira Kato at WIDE. In particular, the		interesting suggestion from Akira Kato at WIDE. In particular, the
	idea would be to use the collection community values to select paths		idea would be to use the collection community values to select paths
	that would result in (hopefully) more efficient access to various		that would result in (hopefully) more efficient access to various
	services. For example, in the case of RFC 3258 [RFC3258] based DNS		services. For example, in the case of RFC 3258 [RFC3258] based DNS
	anycast service, BGP routers may see multiple paths to the same		anycast service, BGP routers may see multiple paths to the same
	prefix, and others might be coming from the same origin with		prefix, and others might be coming from the same origin with
	different paths, but others might be from different region/country		different paths, but others might be from different region/country
	(with the same origin AS).		(with the same origin AS).
	Joe Abley, Randy Bush, Sean Donelan, Xenofontas Dimitropoulos, Vijay		Joe Abley, Randy Bush, Sean Donelan, Xenofontas Dimitropoulos, Vijay
	Gill, John Heasley, Geoff Huston, Steve Huter, Michael Patton,		Gill, John Heasley, Geoff Huston, Steve Huter, Michael Patton,
	Olivier Marce, Ryan McDowell, Rob Rockell, Rob Thomas, Pekka Savola,		Olivier Marce, Ryan McDowell, Rob Rockell, Rob Thomas, Pekka Savola,
	Patrick Verkaik and Alex Zinin all made many insightful comments on		Patrick Verkaik, and Alex Zinin all made many insightful comments on
	early versions of this draft. Henk Uijterwaal suggested the use of		early versions of this document. Henk Uijterwaal suggested the use
	the ISO-3166-2 country codes.		of the ISO-3166-2 country codes.
	7. Security Considerations		7. Security Considerations
	While this memo introduces no additional security considerations into		While this memo introduces no additional security considerations into
	the BGP protocol, the information contained in the communities		the BGP protocol, the information contained in the communities
	defined in this memo may in some cases reveal network structure that		defined in this memo may in some cases reveal network structure that
	was not previously visible outside the provider's network. As a		was not previously visible outside the provider's network. As a
	result, care should be taken when exporting such communities to route		result, care should be taken when exporting such communities to route
	collectors. Finally, routes exported to a route collector should		collectors. Finally, routes exported to a route collector should
	also be tagged with the NO_EXPORT community (0xFFFFFF01).		also be tagged with the NO_EXPORT community (0xFFFFFF01).
	7.1. Total Path Attribute Length		7.1. Total Path Attribute Length
	The communities described in this memo are intended for use on egress		The communities described in this memo are intended for use on egress
	to a route collector. Hence an operator may choose to overwrite its		to a route collector. Hence an operator may choose to overwrite its
	internal communities with the values specified in this memo when		internal communities with the values specified in this memo when
	exporting routes to a route collector. However, operators should in		exporting routes to a route collector. However, operators should in
	general ensure that the behavior of their BGP implementation is well-		general ensure that the behavior of their BGP implementation is
	defined when the addition of an attribute causes a PDU to exceed 4096		well-defined when the addition of an attribute causes a PDU to exceed
	octets. For example, since it is common practice to use community		4096 octets. For example, since it is common practice to use
	attributes to implement policy (among other functionality such as		community attributes to implement policy (among other functionality
	allowing customers to set attributes such as LOCAL_PREF), the		such as allowing customers to set attributes such as LOCAL_PREF), the
	behavior of an implementation when the attribute space overflows is		behavior of an implementation when the attribute space overflows is
	crucial. Among other behaviors, an implementation might usurp the		crucial. Among other behaviors, an implementation might usurp the
	intended attribute data or otherwise cause indeterminate failures.		intended attribute data or otherwise cause indeterminate failures.
	These behaviors can result in unanticipated community attribute sets,		These behaviors can result in unanticipated community attribute sets,
	and hence result in unintended policy implications.		and hence result in unintended policy implications.
	8. IANA Considerations		8. IANA Considerations
	This memo assigns a new Sub-Type for the AS specific extended		This memo assigns a new Sub-Type for the AS specific extended
	community type in the First Come First Served extended transitive		community type in the First Come First Served extended transitive
	category. In particular, the IANA should assign Sub-type 0x0008 as		category. The IANA has assigned Sub-Type 0x0008 as defined in
	defined in Section 4.1.		Section 4.1.
	In addition, this memo instructs the IANA to create two registries		In addition, the IANA has created two registries for BGP Data
	for BGP Data Collection Communities, one for standard communities and		Collection Communities, one for standard communities and one for
	one for extended communities. Both of these registries should		extended communities. Both of these registries will initially be
	initially be populated by the values described in Section 4. IETF		populated by the values described in Section 4. IETF Consensus, as
	Consensus, usually through the Global Routing Operations Working		described in [RFC2434], usually through the Global Routing Operations
	Group (grow) is required for the assignment of new values in these		Working Group (grow), is required for the assignment of new values in
	registries (in particular, for <Value> or <R>), as described in		these registries (in particular, for <Value> or <R> in the table of
	Figure 2 [RFC2434].		values for the route categories in Section 4).
	9. References		9. References
	9.1. Normative References		9.1. Normative References
	[RFC1771] Rekhter, Y. and T. Li, "A Border Gateway Protocol 4		[ISO3166] "ISO 3166 Maintenance agency (ISO 3166/MA)", Web
	(BGP-4)", RFC 1771, March 1995.		Page: http://www.iso.org/iso/en/prods-services/
			iso3166ma/index.html, 2004.
	[RFC1997] Chandrasekeran, R., Traina, P., and T. Li, "BGP
	Communities Attribute", RFC 1997, August 1996.
	[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an		[RFC1771] Rekhter, Y. and T. Li (Editors), "A Border Gateway
	IANA Considerations Section in RFCs", BCP 26, RFC 2434,		Protocol (BGP-4)", RFC 1771, March 1995.
	October 1998.
	[I-D.ietf-idr-bgp-ext-communities]		[RFC1997] Chandra, R. and P. Traina, "BGP Communities
	Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended		Attribute", RFC 1997, August 1996.
	Communities Attribute",
	draft-ietf-idr-bgp-ext-communities-07 (work in progress),
	March 2004.
	[ISO3166] "ISO 3166 Maintenance agency (ISO 3166/MA)", Web Page:		[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
	http://www.iso.org/iso/en/prods-services/iso3166ma/		Communities Attribute", RFC 4360, January 2006.
	index.html, 2004.
	9.2. Informative References		9.2. Informative References
	[I-D.ietf-ppvpn-vpls-requirements]		[HUSTON] Huston, G., "Interconnection, Peering, and
	Augustyn, W., "Requirements for Virtual Private LAN		Settlements",
	Services (VPLS)", draft-ietf-ppvpn-vpls-requirements-00		http://www.isoc.org/inet99/proceedings/1e/1e_1.htm
	(work in progress), March 2002.
	[RIS] "The RIPE Routing Information Service", Web		[RFC2434] Narten, T., and H. Alvestrand, "Guidelines for
	Page: http://www.ripe.net/ris, 2004.		Writing an IANA Considerations Section in RFCs", BCP
			26, RFC 2434, October 1998.
	[RV] Meyer, D., "The Routeviews Project", Web		[RFC3258] Hardie, T., "Distributing Authoritative Name Servers
	Page: http://www.routeviews.org, 2002.		via Shared Unicast Addresses", RFC 3258, April 2002.
			[RIS] "The RIPE Routing Information Service", Web Page:
			http://www.ripe.net/ris, 2004.
			[RV] Meyer, D., "The Routeviews Project", Web Page:
			http://www.routeviews.org, 2002.
			[VPLS] Kompella, K., et al., "Virtual Private LAN Service",
			Work in Progress, April 2005.
	[WANG] Wang, F. and L. Gao, "Inferring and Characterizing		[WANG] Wang, F. and L. Gao, "Inferring and Characterizing
	Internet Routing Policies", ACM SIGCOMM Internet		Internet Routing Policies", ACM SIGCOMM Internet
	Measurement Conference, 2003.		Measurement Conference 2003.
	[HUSTON] Huston, G., "Interconnection, Peering, and Settlements",
	Web
	Page: http://www.isoc.org/inet99/proceedings/1e/1e_1.htm,
	2003.
	Author's Address		Author's Address
	David Meyer		David Meyer
	Email: dmm@1-4-5.net		EMail: dmm@1-4-5.net
	Intellectual Property Statement		Full Copyright Statement
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			This document is subject to the rights, licenses and restrictions
			contained in BCP 78, and except as set forth therein, the authors
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			This document and the information contained herein are provided on an
			"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
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			ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
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	http://www.ietf.org/ipr.		http://www.ietf.org/ipr.
	The IETF invites any interested party to bring to its attention any		The IETF invites any interested party to bring to its attention any
	copyrights, patents or patent applications, or other proprietary		copyrights, patents or patent applications, or other proprietary
	rights that may cover technology that may be required to implement		rights that may cover technology that may be required to implement
	this standard. Please address the information to the IETF at		this standard. Please address the information to the IETF at
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	Disclaimer of Validity		Acknowledgement
	This document and the information contained herein are provided on an
	"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
	OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
	ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
	INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
	INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
	WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	Copyright Statement
	Copyright (C) The Internet Society (2005). This document is subject
	to the rights, licenses and restrictions contained in BCP 78, and
	except as set forth therein, the authors retain all their rights.
	Acknowledgment
	Funding for the RFC Editor function is currently provided by the		Funding for the RFC Editor function is provided by the IETF
	Internet Society.		Administrative Support Activity (IASA).
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