draft-ietf-grow-collection-communities-06.txt   draft-ietf-grow-collection-communities-07.txt 
INTERNET-DRAFT D. Meyer GROW WG D. Meyer
draft-ietf-grow-collection-communities-06.txt
Category Best Current Practice
Expires: March 2005 September 2004
BGP Communities for Data Collection Expires: February 18, 2006
<draft-ietf-grow-collection-communities-06.txt>
Status of this Memo BGP Communities for Data Collection
draft-ietf-grow-collection-communities-07
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
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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 . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Peers and Peering . . . . . . . . . . . . . . . . . . . . . 5 2.1. Peers and Peering . . . . . . . . . . . . . . . . . . . . 3
2.2. Customer Routes . . . . . . . . . . . . . . . . . . . . . . 5 2.2. Customer Routes . . . . . . . . . . . . . . . . . . . . . 4
2.3. Peer Routes . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3. Peer Routes . . . . . . . . . . . . . . . . . . . . . . . 4
2.4. Internal Routes . . . . . . . . . . . . . . . . . . . . . . 5 2.4. Internal Routes . . . . . . . . . . . . . . . . . . . . . 4
2.5. Internal More Specific Routes . . . . . . . . . . . . . . . 5 2.5. Internal More Specific Routes . . . . . . . . . . . . . . 4
2.6. Special Purpose Routes. . . . . . . . . . . . . . . . . . . 6 2.6. Special Purpose Routes . . . . . . . . . . . . . . . . . . 4
2.7. Upstream Routes . . . . . . . . . . . . . . . . . . . . . . 6 2.7. Upstream Routes . . . . . . . . . . . . . . . . . . . . . 4
2.8. National Routes . . . . . . . . . . . . . . . . . . . . . . 6 2.8. National Routes . . . . . . . . . . . . . . . . . . . . . 5
2.9. Regional Routes . . . . . . . . . . . . . . . . . . . . . . 6 2.9. Regional Routes . . . . . . . . . . . . . . . . . . . . . 5
3. RFC 1997 Community Encoding and Values . . . . . . . . . . . . 7 3. RFC 1997 Community Encoding and Values . . . . . . . . . . . . 5
3.1. Community Values for BGP Data Collection. . . . . . . . . . 7 4. Community Values for BGP Data Collection . . . . . . . . . . . 5
4. Extended Communities . . . . . . . . . . . . . . . . . . . . . 9 4.1. Extended Communities . . . . . . . . . . . . . . . . . . . 7
4.1. Four-octet AS specific extended communities . . . . . . . . 11 4.2. Four-octet AS specific extended communities . . . . . . . 8
5. Note on BGP Update Packing . . . . . . . . . . . . . . . . . . 11 5. Note on BGP UPDATE Packing . . . . . . . . . . . . . . . . . . 9
6. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 11 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
7. Security Considerations. . . . . . . . . . . . . . . . . . . . 13 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7.1. Total Path Attribute Length . . . . . . . . . . . . . . . . 13 7.1. Total Path Attribute Length . . . . . . . . . . . . . . . 9
8. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 13 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1. Normative References. . . . . . . . . . . . . . . . . . . . 14 9.1. Normative References . . . . . . . . . . . . . . . . . . . 10
9.2. Informative References. . . . . . . . . . . . . . . . . . . 14 9.2. Informative References . . . . . . . . . . . . . . . . . . 11
10. Author's Addresses. . . . . . . . . . . . . . . . . . . . . . 15 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 providers network, and to
its customers and peers. Communities are also used for a wide variety its customers and peers. Communities are also used for a wide
of other applications, such as allowing customers to set attributes variety of other applications, such as allowing customers to set
such as LOCAL_PREF [RFC1771] by sending appropriate communities to attributes such as LOCAL_PREF [RFC1771] by sending appropriate
their service provider. Other applications include signaling various communities to their service provider. Other applications include
types of VPNs (e.g., VPLS [VPLS]), and carrying link bandwidth for signaling various types of VPNs (e.g., VPLS [I-D.ietf-ppvpn-vpls-
traffic engineering applications [EXTCOMM]. requirements]), and carrying link bandwidth for traffic engineering
applications [I-D.ietf-idr-bgp-ext-communities].
With the advent of large scale BGP data collection [RIS,ROUTEVIEWS] With the advent of large scale BGP data collection [RV][RIS] (and
(and associated research), it has become clear that the geographical associated research), it has become clear that the geographical and
and topological information, as well as the relationship the provider topological information, as well as the relationship the provider has
has to the source of a route (e.g., transit, peer, or customer), to the source of a route (e.g., transit, peer, or customer), carried
carried in such communities is essential for a deeper understanding in such communities is essential for a deeper understanding of the
of the global routing system. This memo defines standard communities global routing system. This memo defines standard communities for
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 both the definition of terms used as well as the semantics
of the communities used for BGP data collection, and section 3 of the communities used for BGP data collection, and section 3
defines the corresponding encodings for RFC 1997 [RFC1997] defines the corresponding encodings for RFC 1997 [RFC1997]
communities. Finally, section 4 defines the encodings for use with communities. Finally, section 4 defines the encodings for use with
extended communities [EXTCOMM]. extended communities [I-D.ietf-idr-bgp-ext-communities].
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 refered 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
skipping to change at page 6, line 4 skipping to change at page 4, line 36
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 which are frequently
used for circuit load balancing purposes, IGP route reduction, and used for circuit load balancing purposes, IGP route reduction, and
also may correspond to customer services which are not visible also may correspond to customer services which are not visible
outside the service provider's network. Internal more specific routes outside the service provider's network. Internal more specific
are not exported to any external peer. 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 which do not fall into any of
the other classes described here. In those cases in which such routes the other classes described here. In those cases in which such
need to be distinguished, a service provider may color such routes routes need to be distinguished, a service provider may color such
with a unique value. Examples of special purpose routes include routes with a unique value. Examples of special purpose routes
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 upstream service provider
as part of a transit service contract executed with the upstream as part of a transit service contract executed with the upstream
provider. 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. AS in one region, and that same AS is a customer in another region.
This mandates use of regional routing, including community attributes This mandates use of regional routing, including community attributes
set by the network in question to allow easy discrimination among set by the network in question to allow easy discrimination among
regional routes. For example, service providers may treat a route set regional routes. For example, service providers may treat a route
received from another service provider in Europe differently than the set received from another service provider in Europe differently than
same route set received in North America, as it is common practice to the same route set received in North America, as it is common
sell transit in one region while peering in the other. 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 high
skipping to change at page 7, line 27 skipping to change at page 5, line 45
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.
3.1. 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:
skipping to change at page 8, line 21 skipping to change at page 6, line 26
Internal More Specific Routes <AS>:0000000000000100 Internal More Specific Routes <AS>:0000000000000100
Special Purpose Routes <AS>:0000000000000101 Special Purpose Routes <AS>:0000000000000101
Upstream Routes <AS>:0000000000000110 Upstream Routes <AS>:0000000000000110
Reserved <AS>:0000000000000111- Reserved <AS>:0000000000000111-
<AS>:0000011111111111 <AS>:0000011111111111
National and Regional Routes <AS>:0000100000000000- National and Regional Routes <AS>:0000100000000000-
<AS>:1111111111111111 <AS>:1111111111111111
Encoded as <AS>:<R><X><CC> Encoded as <AS>:<R><X><CC>
Reserved National and Regional values <AS>:0100000000000000- Reserved National and Regional values <AS>:0100000000000000-
<AS>:1111111111111111 <AS>:1111111111111111
Where Where
<AS> is the 16-bit AS <AS> is the 16-bit AS
<R> is the 5-bit Region Identifier <R> is the 5-bit Region Identifier
<X> is the 1-bit satellite link indication <X> is the 1-bit satellite link indication
X = 1 for satellite links, 0 otherwise X = 1 for satellite links, 0 otherwise
<CC> is the 10-bit ISO-3166-2 country code <CC> is the 10-bit ISO-3166-2 country code [ISO3166]
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:
skipping to change at page 9, line 35 skipping to change at page 7, line 34
| 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. Extended Communities 4.1. Extended Communities
In some cases, the encoding described in section 3.1 may clash with a In some cases, the values and their encodings described in Section 4
service provider's existing community assignments. Extended may clash with a service provider's existing community assignments.
communities [EXTCOMM] provide a convenient mechanism that can be used Extended communities [I-D.ietf-idr-bgp-ext-communities] provide a
to avoid such clashes. convenient mechanism that 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 |
skipping to change at page 10, line 12 skipping to change at page 8, line 4
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 3.1 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 0x05 for BGP data collection, and This memo assigns Sub-Type 0x0006 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. The carried in the low order octets of the Local Administrator field.
two high order octets of the Local Administrator field are reserved, The two high order octets of the Local Administrator field are
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 | 0x05 | 0x2A7C | | 0x00 | 0x0006 | 0x2A7C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | 0x00 | 0x10F2 | | 0x00 | 0x00 | 0x10F2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.1. 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 | 0x05 | Global Administrator | | 0x02 | 0x0006 | 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 4 octet Global Administrator sub-field contains a
4-octets Autonomous System number assigned by the IANA. 4-octets 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 it's
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
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. Acknowledgments
skipping to change at page 13, line 12 skipping to change at page 9, line 42
early versions of this draft. Henk Uijterwaal suggested the use of early versions of this draft. Henk Uijterwaal suggested the use of
the ISO-3166-2 country codes. 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 also collectors. Finally, routes exported to a route collector should
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 well-
defined when the addition of an attribute causes a PDU to exceed 4096 defined when the addition of an attribute causes a PDU to exceed 4096
octets. For example, since it is common practice to use community octets. For example, since it is common practice to use community
skipping to change at page 13, line 35 skipping to change at page 10, line 20
allowing customers to set attributes such as LOCAL_PREF), the 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 particular, the IANA should assign Sub-type 0x05, community type in the First Come First Served extended transitive
using the "First Come First Served" policy defined in RFC 2434 category. In particular, the IANA should assign Sub-type 0x0006 as
[RFC2434], for the Sub-Type defined in Section 4. This corresponds to defined in Section 4.1.
a Type Field value of 0x0005.
In addition, this memo instructs the IANA to create two registries
for BGP Data Collection Communities, one for standard communities and
one for extended communities. Both of these registries should
initially be populated by the values described in Section 4. IETF
Consensus, usually through the Global Routing Operations Working
Group (grow) is required for the assignment of new values in these
registries (in particular, for <Value> or <R>), as described in
Figure 2 [RFC2434].
9. References 9. References
9.1. Normative References 9.1. Normative References
[EXTCOMM] Sangali, S., D. Tappan and Y. Rekhter, "BGP Extended [RFC1771] Rekhter, Y. and T. Li, "A Border Gateway Protocol 4
Communities Attribute", draft-ietf-idr-bgp-ext-communities-07.txt, (BGP-4)", RFC 1771, March 1995.
Work in progress.
[ISO-3166-2] http://www.iso.org/iso/en/prods-services/iso3166ma/index.html [RFC1997] Chandrasekeran, R., Traina, P., and T. Li, "BGP
Communities Attribute", RFC 1997, August 1996.
[RIS-ISO-3166] ftp://ftp.ripe.net/iso3166-countrycodes.txt [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[RFC1771] Rekhter, Y. and T. Li (Editors), "A Border [I-D.ietf-idr-bgp-ext-communities]
Gateway Protocol (BGP-4)", RFC 1771, March 1995. Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute",
draft-ietf-idr-bgp-ext-communities-07 (work in progress),
March 2004.
[RFC1997] Chandra, R. and P. Traina, "BGP Communities [ISO3166] "ISO 3166 Maintenance agency (ISO 3166/MA)", Web Page:
Attribute", RFC 1997, August 1996. http://www.iso.org/iso/en/prods-services/iso3166ma/
index.html, 2004.
9.2. Informative References 9.2. Informative References
[HUSTON] Huston, G., "Interconnection, Peering, and Settlements", [I-D.ietf-ppvpn-vpls-requirements]
http://www.isoc.org/inet99/proceedings/1e/1e_1.htm Augustyn, W., "Requirements for Virtual Private LAN
Services (VPLS)", draft-ietf-ppvpn-vpls-requirements-00
[RFC2028] Hovey, R. and S. Bradner, "The Organizations (work in progress), March 2002.
Involved in the IETF Standards Process", BCP 11,
RFC 2028, October 1996.
[RFC2434] Narten, T., and H. Alvestrand, "Guidelines for
Writing an IANA Considerations Section in RFCs",
BCP 26, RFC 2434, October 1998.
[RFC3258] Hardie, T., "Distributing Authoritative Name
Servers via Shared Unicast Addresses", RFC 3258,
April 2002.
[RIS] "Routing Information Service", http://www.ripe.net/ris [RIS] "The RIPE Routing Information Service", Web
Page: http://www.ripe.net/ris, 2004.
[ROUTEVIEWS] "The Routeviews Project", http://www.routeviews.org [RV] Meyer, D., "The Routeviews Project", Web
[VPLS] Kompella, K., et al., "Virtual Private LAN Page: http://www.routeviews.org, 2002.
Service", draft-ietf-l2vpn-vpls-bgp-02.txt,
Work in Progress.
[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.
10. Author's Addresses [HUSTON] Huston, G., "Interconnection, Peering, and Settlements",
Web
Page: http://www.isoc.org/inet99/proceedings/1e/1e_1.htm,
2003.
Author's Address
David Meyer David Meyer
EMail: dmm@1-4-5.net
Email: dmm@1-4-5.net
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skipping to change at page 16, line 9 skipping to change at page 13, line 41
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