draft-ietf-opsawg-ipfix-bgp-community-07.txt   draft-ietf-opsawg-ipfix-bgp-community-08.txt 
opsawg Z. Li opsawg Z. Li
Internet-Draft R. Gu Internet-Draft R. Gu
Intended status: Standards Track China Mobile Intended status: Standards Track China Mobile
Expires: November 13, 2018 J. Dong Expires: March 24, 2019 J. Dong
Huawei Technologies Huawei Technologies
May 12, 2018 September 20, 2018
Export BGP community information in IP Flow Information Export (IPFIX) Export BGP community information in IP Flow Information Export (IPFIX)
draft-ietf-opsawg-ipfix-bgp-community-07 draft-ietf-opsawg-ipfix-bgp-community-08
Abstract Abstract
By introducing new Information Elements (IEs), this draft extends the By introducing new Information Elements (IEs), this draft extends the
existing BGP related IEs to enable IPFIX [RFC7011] to export the BGP existing BGP related IEs to enable IPFIX [RFC7011] to export the BGP
community information, including the information of BGP standard community information, including the information of BGP standard
community [RFC1997], BGP extended community [RFC4360], and BGP large community [RFC1997], BGP extended community [RFC4360], and BGP large
community [RFC8092]. Network traffic information can then be community [RFC8092]. Network traffic information can then be
accumulated and analysed at the BGP community granularity, which accumulated and analysed at the BGP community granularity, which
represents the traffic of different kinds of customers, services, or represents the traffic of different kinds of customers, services, or
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 13, 2018. This Internet-Draft will expire on March 24, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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BGP community is a BGP path attribute defined in IDR (Inter Domain BGP community is a BGP path attribute defined in IDR (Inter Domain
Routing) working group. The already defined BGP community attribute Routing) working group. The already defined BGP community attribute
includes the standard community defined in [RFC1997], the extended includes the standard community defined in [RFC1997], the extended
community defined in [RFC4360], and the large community defined in community defined in [RFC4360], and the large community defined in
[RFC8092]. BGP community attribute has a variety of use cases, one [RFC8092]. BGP community attribute has a variety of use cases, one
practice of which is to use BGP community with planned specific practice of which is to use BGP community with planned specific
values to represent the groups of customers, services, geographical values to represent the groups of customers, services, geographical
and topological regions, which is used by a lot of operators in their and topological regions, which is used by a lot of operators in their
field networks. Please refer to [RFC4384], [RFC8195] and Section 3 field networks. Please refer to [RFC4384], [RFC8195] and Section 3
of this document for the detailed examples. To know the traffic of this document for the detailed examples. To know the traffic
generated by differnt kinds of customers, from differnt geographical generated by different kinds of customers, from differnt geographical
or topological regions, by differnt kinds of customers in differnt or topological regions, by differnt kinds of customers in differnt
regions, we need the corresponding community information related to regions, we need the corresponding community information related to
the traffic flow exported by IPFIX. Netwok traffic statistic at the the traffic flow exported by IPFIX. Network traffic statistics at
BGP community granularity is useful not only for the traffic the BGP community granularity is useful not only for the traffic
analyzing, but also can then be used by other applications, such as analyzing, but also can then be used by other applications, such as
the traffic optimization applications located in IPFIX collector, SDN the traffic optimization applications located in IPFIX collector, SDN
controller or PCE. [Community-TE] also states analyzing network controller or PCE. [Community-TE] also states analyzing network
traffic information at the BGP community granularity is prefered for traffic information at the BGP community granularity is prefered for
inbound traffic engineering. However, there is no IE defined for BGP inbound traffic engineering. However, there is no IE defined for BGP
community attribute in [IANA-IPFIX] yet. community attribute in [IANA-IPFIX] yet.
Flow information based on BGP community may be collected by a Flow information based on BGP community may be collected by a
mediator defined in [RFC6183]. Mediator is responsible for the mediator defined in [RFC6183]. Mediator is responsible for the
correlation between flow information and BGP community. However no correlation between flow information and BGP community. However no
IEs are defined in [RFC6183] for exporting BGP community information IEs are defined in [RFC6183] for exporting BGP community information
in IPFIX. Furthermore, to correlate the BGP community with the flow in IPFIX. Furthermore, to correlate the BGP community with the flow
information, mediator needs to learn BGP routes and perform lookup in information, the mediator needs to learn BGP routes and perform
the BGP routing table to get the matching entry for a specific flow. lookup in the BGP routing table to get the matching entry for a
Neither BGP route learning nor routing table lookup is trivial for a specific flow. Neither BGP route learning nor routing table lookup
mediator. Mediator is mainly introduced to release the performance is trivial for a mediator. The mediator is mainly introduced to
requirement for the exporter [RFC5982]. In fact, to obtain the release the performance requirement for the exporter [RFC5982]. In
information for the already defined BGP related IEs, such as fact, to obtain the information for the already defined BGP related
bgpSourceAsNumber, bgpDestinationAsNumber, and bgpNextHopIPv4Address, IEs, such as bgpSourceAsNumber, bgpDestinationAsNumber, and
etc, the exporter has to hold the up-to-date BGP routing table and bgpNextHopIPv4Address, etc, the exporter has to hold the up-to-date
perform lookup in the BGP routing table. The exporter can obtain the BGP routing table and perform lookup in the BGP routing table. The
BGP community information in the same procedure, thus the additional exporter can obtain the BGP community information in the same
load added by exporting BGP community information is minimal if the procedure, thus the additional load added by exporting BGP community
exporter is already exporting the existing BGP related IEs. It is information is minimal if the exporter is already exporting the
RECOMMENDED that the BGP community information be exported by the existing BGP related IEs. It is RECOMMENDED that the BGP community
exporter directly using IPFIX. information be exported by the exporter directly using IPFIX.
Through running BGP [RFC4271] or BMP [RFC7854] and performing lookup Through running BGP [RFC4271] or BMP [RFC7854] and performing lookup
in the BGP routing table to get the matching entry for a specific in the BGP routing table to get the matching entry for a specific
flow (we call it correlation), IPFIX collectors and other flow (we call it correlation), IPFIX collectors and other
applications, such as SDN controller or PCE, can figure up the applications, such as SDN controller or PCE, can determine the
network traffic at the BGP community granularity. However, neither network traffic at the BGP community granularity. However, neither
running BGP or BMP protocol nor routing table lookup is trivial for running BGP or BMP protocol nor routing table lookup is trivial for
the IPFIX collectors and other applications. Moreover correlation the IPFIX collectors and other applications. Moreover correlation
between IPFIX flow information and the BGP RIB on the exporter (such between IPFIX flow information and the BGP RIB on the exporter (such
as router) is more accurate, compared to the correlation on a as router) is more accurate, compared to the correlation on a
collector, since the BGP routing table may be updated when the IPFIX collector, since the BGP routing table may be updated when the IPFIX
collectors and other applications reveive the IPFIX flow information. collectors and other applications reveive the IPFIX flow information.
And as stated above, the exporter can obtain the BGP community And as stated above, the exporter can obtain the BGP community
information in the same procedure when it obtains other BGP related information in the same procedure when it obtains other BGP related
informaiton. So exporting the BGP community information directly by informaiton. So exporting the BGP community information directly by
the exporter to the collector is the efficient and accurate way. If the exporter to the collector is the efficient and accurate way. If
the IPFIX collectors and other applications only want to figure up the IPFIX collectors and other applications only want to figure up
the network traffic at the BGP community granularity, they do not the network traffic at the BGP community granularity, they do not
need to run the heavy BGP or BMP protocol when the BGP community need to run the heavy BGP or BMP protocol when the BGP community
information can be obtained by IPFIX. However, we have to clarify, information can be obtained by IPFIX. However, we have to clarify,
the BMP protocol has its own application scenario, the mechanisum the BMP protocol has its own application scenario, the mechanism
introduced in this document has no purpose to replace it. introduced in this document has no purpose to replace it.
By introducing new IEs, this draft extends the existing BGP related By introducing new IEs, this draft extends the existing BGP related
IEs to enable IPFIX [RFC7011] to export the BGP community IEs to enable IPFIX [RFC7011] to export the BGP community
information, including BGP standard community defined in [RFC1997], information, including BGP standard community defined in [RFC1997],
BGP extended community defined in [RFC4360], and BGP large community BGP extended community defined in [RFC4360], and BGP large community
defined in [RFC8092]. Flow information, including packetDeltaCount, defined in [RFC8092]. Flow information, including packetDeltaCount,
octetDeltaCount [RFC7012] etc, can then be accumulated and analysed octetDeltaCount [RFC7012] etc, can then be accumulated and analysed
by the collector or other applications, such as SDN controller or PCE by the collector or other applications, such as SDN controller or PCE
[RFC4655], at the BGP community granularity, which is useful for [RFC4655], at the BGP community granularity, which is useful for
knowing the traffic generted by different kinds of customers, from knowing the traffic generated by different kinds of customers, from
differnt geographical or topological regions according to the differnt geographical or topological regions according to the
operator's BGP community plan, and can then be used by the traffic operator's BGP community plan, and can then be used by the traffic
engineering or traffic optimization applications, especially in the engineering or traffic optimization applications, especially in the
backbone network. backbone network.
The IEs introduced in this document are applicable for both IPv4 and The IEs introduced in this document are applicable for both IPv4 and
IPv6 traffic. Both the exporter and the mediator can use these IEs IPv6 traffic. Both the exporter and the mediator can use these IEs
to export BGP community information in IPFIX. When needed, the to export BGP community information in IPFIX. When needed, the
mediator or collector can use these IEs to report the BGP community mediator or collector can use these IEs to report the BGP community
related traffic flow information it gets either from exporters or related traffic flow information it gets either from exporters or
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To clarify, no new BGP community attribute is defined in this To clarify, no new BGP community attribute is defined in this
document, IDR (Inter Domain Routing) working group is the right place document, IDR (Inter Domain Routing) working group is the right place
to define new community attributes for the BGP protocol. to define new community attributes for the BGP protocol.
Note that this document does not update the IPFIX specification Note that this document does not update the IPFIX specification
[RFC7011] and the Information Model [RFC7012] because IANA's IPFIX [RFC7011] and the Information Model [RFC7012] because IANA's IPFIX
registry [IANA-IPFIX] is the ultimate Information Element reference, registry [IANA-IPFIX] is the ultimate Information Element reference,
per Section 1 of [RFC7012]. per Section 1 of [RFC7012].
Please refer [IANA-IPFIX] for the whole list of the already defined Please refer to[IANA-IPFIX] for the whole list of the already defined
BGP related IEs. BGP related IEs.
Please refer Appendix A for the encoding example and Section 3 for a Please refer Appendix A for the encoding example and Section 3 for a
detailed use case. detailed use case.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
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information to adjust the network paths for different traffic flows. information to adjust the network paths for different traffic flows.
Considering the following scenario, AS C provides transit connection Considering the following scenario, AS C provides transit connection
between AS A and B. By tagging with different BGP communities, the between AS A and B. By tagging with different BGP communities, the
routes of AS A and B are categorized into several groups respectively routes of AS A and B are categorized into several groups respectively
with the operator's plan. For example community A:X and A:Y are used with the operator's plan. For example community A:X and A:Y are used
for the routes originated from different geographical regions in AS for the routes originated from different geographical regions in AS
A, and community B:M and B:N are used for the routes representing the A, and community B:M and B:N are used for the routes representing the
different kinds of customers in AS B, such as B:M is for the mobile different kinds of customers in AS B, such as B:M is for the mobile
customers and B:N is for the fixed line customers. By default, all customers and B:N is for the fixed line customers. By default, all
traffic originated from AS A and destinated to AS B (we call it traffic originating from AS A and destined to AS B (we call it
traffic A-B) goes through path C1-C2-C3 (call it Path-1) in AS C. traffic A-B) goes through path C1-C2-C3 (call it Path-1) in AS C.
When the link between C1 and C2 is congested, we cannot simply steer When the link between C1 and C2 is congested, we cannot simply steer
all the traffic A-B from Path-1 to Path C1-C4-C3 (call it Path-2), all the traffic A-B from Path-1 to Path C1-C4-C3 (call it Path-2),
becuse it will cause the congestion in Path-2. becuse it will cause congestion in Path-2.
+----------+ +----------+
| PCE/SDN | | PCE/SDN |
+-------|Controller|-------+ +-------|Controller|-------+
| +----------+ | | +----------+ |
| | | |
| AS C | | AS C |
| | +----------+ | | | | +----------+ | |
| | +---|Router C2 |---+ | | | | +---|Router C2 |---+ | |
| | | +----------+ | | | | | | +----------+ | | |
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If the PCE/SDN controller in AS C can obtain the network traffic If the PCE/SDN controller in AS C can obtain the network traffic
information at the BGP community granularity, it can steer some information at the BGP community granularity, it can steer some
traffic related to some BGP communities (when we consider only the traffic related to some BGP communities (when we consider only the
source or destination of the traffic), or some BGP community pairs source or destination of the traffic), or some BGP community pairs
(when we consider both the source and the destination of the traffic) (when we consider both the source and the destination of the traffic)
from Path-1 to Path-2 according to the utilization of different from Path-1 to Path-2 according to the utilization of different
paths. For instance, steer the traffic generated by community A:X paths. For instance, steer the traffic generated by community A:X
from Path-1 to Path-2 by deploying route policy at Router C1, or from Path-1 to Path-2 by deploying route policy at Router C1, or
steer the traffic from community A:Y to community B:M from Path-1 to steer the traffic from community A:Y to community B:M from Path-1 to
Path-2. Using the IEs defined in this document, IPFIX can export the Path-2. Using the IEs defined in this document, IPFIX can export the
BGP community information related to a specific traffic flow togecher BGP community information related to a specific traffic flow together
with other flow information. The traffic information can then be with other flow information. The traffic information can then be
accumulated at the BGP community granularity and used by the PCE/SDN accumulated at the BGP community granularity and used by the PCE/SDN
controller to steer the appropriate traffic from Path-1 to Path-2. controller to steer the appropriate traffic from Path-1 to Path-2.
4. IEs for BGP Standard Community 4. IEs for BGP Standard Community
[RFC1997] defines the BGP Communities attribute, called BGP Standard [RFC1997] defines the BGP Communities attribute, called BGP Standard
Community in this document, which describes a group of routes sharing Community in this document, which describes a group of routes sharing
some common properties. BGP Standard Communities are treated as 32 some common properties. BGP Standard Communities are treated as 32
bit values as stated in[RFC1997]. bit values as stated in[RFC1997].
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four-octet ASNs. Each BGP Large Community is encoded as a 12-octet four-octet ASNs. Each BGP Large Community is encoded as a 12-octet
quantity with the format defined in [RFC8092]. quantity with the format defined in [RFC8092].
In order to export BGP Large Community information together with In order to export BGP Large Community information together with
other flow information by IPFIX, three new IEs are introduced. The other flow information by IPFIX, three new IEs are introduced. The
first one is bgpLargeCommunity, which is used to identify that the first one is bgpLargeCommunity, which is used to identify that the
value in this IE is a BGP Large Community. The other two are value in this IE is a BGP Large Community. The other two are
bgpSourceLargeCommunityList and bgpDestinationLargeCommunityList, bgpSourceLargeCommunityList and bgpDestinationLargeCommunityList,
which are both basicList [RFC6313] of bgpLargeCommunity, and are used which are both basicList [RFC6313] of bgpLargeCommunity, and are used
to export the BGP Large Community information corresponding to a to export the BGP Large Community information corresponding to a
specific flow's source IP and destination IP respectively. specific flow's source and destination IP address respectively.
The detailed information of the three new IEs are shown in the The detailed information of the three new IEs are shown in the
following sections. following sections.
6.1. bgpLargeCommunity 6.1. bgpLargeCommunity
---------------------------------------------------------------------- ----------------------------------------------------------------------
| ElementID | to be assigned by IANA | | ElementID | to be assigned by IANA |
|--------------------------------------------------------------------| |--------------------------------------------------------------------|
| Name | bgpLargeCommunity | | Name | bgpLargeCommunity |
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7. Operational Considerations 7. Operational Considerations
The maximum length of an IPFIX message is 65535 bytes as per The maximum length of an IPFIX message is 65535 bytes as per
[RFC7011] , and the maximum length of a normal BGP message is 4096 [RFC7011] , and the maximum length of a normal BGP message is 4096
bytes as per [RFC4271]. Since BGP communities, including standard, bytes as per [RFC4271]. Since BGP communities, including standard,
extended, and large communities , are BGP path attributes carried in extended, and large communities , are BGP path attributes carried in
BGP Update messages, the total length of these attributes can not BGP Update messages, the total length of these attributes can not
exceed the length of a BGP message, i.e. 4096 bytes. So one IPFIX exceed the length of a BGP message, i.e. 4096 bytes. So one IPFIX
message with maximum length of 65535 bytes has enough space to fit message with maximum length of 65535 bytes has enough space to fit
all the communities related to a specific flow, both the source IP all the communities related to a specific flow, relating to both the
and the destination IP related. source and destination IP addresses.
[I-D.ietf-idr-bgp-extended-messages] extends the maximum size of a [I-D.ietf-idr-bgp-extended-messages] extends the maximum size of a
BGP Update message to 65535 bytes. Then theoretically the BGP BGP Update message to 65535 bytes. Then theoretically the BGP
community information related to a specific flow may exceed the community information related to a specific flow may exceed the
length one IPFIX message. However, according to the information length of one IPFIX message. However, according to information about
about the networks in the field, the number of BGP communities in one networks in the field, the number of BGP communities in one BGP route
BGP route is usually no more than 10. Nevertheless, BGP speakers is usually no more than 10. Nevertheless, BGP speakers that support
that support the extended message SHOULD be careful to export the BGP the extended message SHOULD be careful to export the BGP communities
communities in the IPFIX message properly, such as only convey as in the IPFIX message properly, such as only convey as many
many communities as possible in the IPFIX message. The collector communities as possible in the IPFIX message. The collector which
which receives an IPFIX message with maximum length and BGP receives an IPFIX message with maximum length and BGP communities
communities contained in its data set SHOULD be aware that the BGP contained in its data set SHOULD be aware that the BGP communities
communities may be truncated due to limited message space. In this may be truncated due to limited message space. In this case, it is
case, it is RECOMMENDED to configure export policy of BGP communities RECOMMENDED to configure the export policy of BGP communities to
on the exporter to limit the BGP communities to be exported, so as to limit the BGP communities by including or excluding specific
only export some specific communities,or not to export some specific
communities. communities.
If needed, we may consider to extend the message length of IPFIX If needed, we may consider to extend the message length of IPFIX
[RFC7011] from 16 bits to 32 bits to solve this problem completely. [RFC7011] from 16 bits to 32 bits to solve this problem completely.
The detailed mechanism is out of the scope of this document. The details of increasing IPFIX message length is out of scope of
this document.
To align with the size of BGP extended community and large community, To align with the size of BGP extended community and large community,
the size of IE bgpExtendedCommunity and bgpLargeCommunity is 8 octets the size of IE bgpExtendedCommunity and bgpLargeCommunity is 8 octets
and 12 octets respectively. In the event that the and 12 octets respectively. In the event that the
bgpExtendedCommunity or bgpLargeCommunity IE is not of its expected bgpExtendedCommunity or bgpLargeCommunity IE is not of its expected
size, the IPFIX collector SHOULD ignore it. This is intended to size, the IPFIX collector SHOULD ignore it. This is intended to
protect implementations using BGP logic from calling their parsing protect implementations using BGP logic from calling their parsing
routines with invalid lengths. routines with invalid lengths.
For the proper processing of the exporter, when it receives the For the proper processing of the exporter, when it receives the
template requesting to report the BGP community information (refer template requesting to report the BGP community information (refer to
Appendix A for an example), the exporter SHOULD obtain the Appendix A for an example), the exporter SHOULD obtain the
corresponding BGP community information through BGP lookup using the corresponding BGP community information through BGP lookup using the
corresponding source or destination IP of the specific traffic flow. corresponding source or destination IP address of the specific
When exporting the IPFIX information to the collector, the exporter traffic flow. When exporting the IPFIX information to the collector,
SHOULD include the corresponding BGP communities in the IPFIX the exporter SHOULD include the corresponding BGP communities in the
message. IPFIX message.
8. Security Considerations 8. Security Considerations
This document only defines new IEs for IPFIX. This document itself This document only defines new IEs for IPFIX. This document itself
does not directly introduce security issues. The same security does not directly introduce security issues. The same security
considerations as for the IPFIX Protocol Specification [RFC7011] and considerations as for the IPFIX Protocol Specification [RFC7011] and
Information Model [RFC7012] apply. Information Model [RFC7012] apply.
As the BGP community information is deducible by other means, there As the BGP community information is deducible by other means, there
are no increased privacy concerns, neither. are no increased privacy concerns, neither.
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11.2. Informative References 11.2. Informative References
[Community-TE] [Community-TE]
Shao, W., Devienne, F., Iannone, L., and JL. Rougier, "On Shao, W., Devienne, F., Iannone, L., and JL. Rougier, "On
the use of BGP communities for fine-grained inbound the use of BGP communities for fine-grained inbound
traffic engineering", Computer Science 27392(1):476-487, traffic engineering", Computer Science 27392(1):476-487,
November 2015. November 2015.
[I-D.ietf-idr-bgp-extended-messages] [I-D.ietf-idr-bgp-extended-messages]
Bush, R., Patel, K., and D. Ward, "Extended Message Bush, R., Patel, K., and D. Ward, "Extended Message
support for BGP", draft-ietf-idr-bgp-extended-messages-24 support for BGP", draft-ietf-idr-bgp-extended-messages-26
(work in progress), November 2017. (work in progress), June 2018.
[IANA-IPFIX] [IANA-IPFIX]
"IP Flow Information Export (IPFIX) Entities", "IP Flow Information Export (IPFIX) Entities",
<http://www.iana.org/assignments/ipfix/>. <http://www.iana.org/assignments/ipfix/>.
[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities [RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities
Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
<https://www.rfc-editor.org/info/rfc1997>. <https://www.rfc-editor.org/info/rfc1997>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
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