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
Copyright (C) The Internet Society (2006).
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.
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.
Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
skipping to change at page 13, line 29 skipping to change at page 12, line 45
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
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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
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ietf-ipr@ietf.org. ietf-ipr@ietf.org.
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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