--- 1/draft-ietf-opsawg-ipfix-bgp-community-03.txt 2017-12-05 00:13:30.921530684 -0800 +++ 2/draft-ietf-opsawg-ipfix-bgp-community-04.txt 2017-12-05 00:13:30.961531625 -0800 @@ -1,20 +1,20 @@ opsawg Z. Li Internet-Draft R. Gu Updates: 7012 (if approved) China Mobile Intended status: Standards Track J. Dong -Expires: April 20, 2018 Huawei Technologies - October 17, 2017 +Expires: June 7, 2018 Huawei Technologies + December 4, 2017 Export BGP community information in IP Flow Information Export (IPFIX) - draft-ietf-opsawg-ipfix-bgp-community-03 + draft-ietf-opsawg-ipfix-bgp-community-04 Abstract This draft updates RFC7012 IPFIX information model by introducing several information elements to enable IPFIX to export the BGP community information, including BGP standard community defined in RFC1997, BGP extended community defined in RFC4360, and BGP large community defined in RFC8092. Network traffic flow information can then be accumulated and analysed at the granularity specified by the BGP communities, which is suitable for and needed by some traffic @@ -29,64 +29,65 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on April 20, 2018. + This Internet-Draft will expire on June 7, 2018. Copyright Notice Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 3. IEs for BGP Standard Community . . . . . . . . . . . . . . . 4 - 3.1. bgpCommunity . . . . . . . . . . . . . . . . . . . . . . 4 - 3.2. bgpSourceCommunityList . . . . . . . . . . . . . . . . . 4 - 3.3. bgpDestinationCommunityList . . . . . . . . . . . . . . . 5 - 4. IEs for BGP Extended Community . . . . . . . . . . . . . . . 5 - 4.1. bgpExtendedCommunity . . . . . . . . . . . . . . . . . . 6 - 4.2. bgpSourceExtendedCommunityList . . . . . . . . . . . . . 6 - 4.3. bgpDestinationExtendedCommunityList . . . . . . . . . . . 7 - 5. IEs for BGP Large Community . . . . . . . . . . . . . . . . . 7 - 5.1. bgpLargeCommunity . . . . . . . . . . . . . . . . . . . . 8 - 5.2. bgpSourceLargeCommunityList . . . . . . . . . . . . . . . 8 - 5.3. bgpDestinationLargeCommunityList . . . . . . . . . . . . 9 - 6. Operational Considerations . . . . . . . . . . . . . . . . . 9 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 - 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 - 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 - 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 10.1. Normative References . . . . . . . . . . . . . . . . . . 12 - 10.2. Informative References . . . . . . . . . . . . . . . . . 13 - Appendix A. Application Example . . . . . . . . . . . . . . . . 14 - A.1. Template Record . . . . . . . . . . . . . . . . . . . . . 14 - A.2. Data Set . . . . . . . . . . . . . . . . . . . . . . . . 15 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 + 3. BGP Community based Traffic Collection . . . . . . . . . . . 4 + 4. IEs for BGP Standard Community . . . . . . . . . . . . . . . 5 + 4.1. bgpCommunity . . . . . . . . . . . . . . . . . . . . . . 6 + 4.2. bgpSourceCommunityList . . . . . . . . . . . . . . . . . 6 + 4.3. bgpDestinationCommunityList . . . . . . . . . . . . . . . 6 + 5. IEs for BGP Extended Community . . . . . . . . . . . . . . . 7 + 5.1. bgpExtendedCommunity . . . . . . . . . . . . . . . . . . 7 + 5.2. bgpSourceExtendedCommunityList . . . . . . . . . . . . . 8 + 5.3. bgpDestinationExtendedCommunityList . . . . . . . . . . . 8 + 6. IEs for BGP Large Community . . . . . . . . . . . . . . . . . 9 + 6.1. bgpLargeCommunity . . . . . . . . . . . . . . . . . . . . 9 + 6.2. bgpSourceLargeCommunityList . . . . . . . . . . . . . . . 10 + 6.3. bgpDestinationLargeCommunityList . . . . . . . . . . . . 10 + 7. Operational Considerations . . . . . . . . . . . . . . . . . 11 + 8. Security Considerations . . . . . . . . . . . . . . . . . . . 12 + 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 + 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 + 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 + 11.1. Normative References . . . . . . . . . . . . . . . . . . 14 + 11.2. Informative References . . . . . . . . . . . . . . . . . 15 + Appendix A. Encoding Example . . . . . . . . . . . . . . . . . . 16 + A.1. Template Record . . . . . . . . . . . . . . . . . . . . . 16 + A.2. Data Set . . . . . . . . . . . . . . . . . . . . . . . . 17 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 1. Introduction IP Flow Information Export (IPFIX) [RFC7011] provides network administrators with traffic flow information using the information elements (IEs) defined in [IANA-IPFIX] registries. Based on the traffic flow information, network administrators know the amount and direction of the traffic in their network, then they can optimize their network when needed. For example, they can shift some flows from the congested links to the low utilized links through a SDN @@ -134,258 +135,318 @@ octetDeltaCount [RFC7012] etc, can then be accumulated and analysed by the collector or other applications, such as SDN controller or PCE [RFC4655], at the granularity specified by BGP community , which is useful for traffic engineering or traffic optimization applications, especially in the backbone network. The IEs introduced in this document are applicable for both IPv4 and IPv6 traffic. Both exporter and mediator can use these IEs to export BGP community information in IPFIX. + Please refer Appendix A for the encoding example and Section 3 for a + detailed use case. + 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. -3. IEs for BGP Standard Community +3. BGP Community based Traffic Collection + + [RFC4384] introduces the mechanism of using BGP standard communities + and extended communities to collect the geographical and topological + related information in BGP routing system. The traffic flow + information corresponding to BGP standard communities and extended + communities are also useful for service providers to analyze and + optimize the network traffic between different regions in the + network. This section gives a use case in which network operator + uses the BGP community based traffic information to adjust the + network paths for different traffic flows. + + Considering the following scenario, AS C provides transit connection + between AS A and B, the routes of AS A and B are categorized into + several groups respectively, which are tagged using different BGP + communities, for example community A:X and A:Y are used in routes + originated from different regions of AS A, and community B:M and B:N + are used with routes originated from different regions of AS B . By + default, all traffic originated from AS A and destinated to AS B (we + call it 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 all the traffic A-B from Path-1 to Path C1-C4-C3 (call it Path- + 2), which will cause congestion in Path-2. + + +----------+ + | PCE/SDN | + +-------|Controller|-------+ + | +----------+ | + | | + | AS C | + | | +----------+ | | + | | +---|Router C2 |---+ | | + | | | +----------+ | | | + AS A | | |100 50| | | AS B + +--------+ | +---------+ +---------+ | +--------+ + |Router A|--|--|Router C1| |Router C3|--|--|Router B| + +--------+ | +---------+ +---------+ | +--------+ + Community: | |100 100| | Community: + A:X | | +----------+ | | B:M + A:Y | +---|Router C4 |---+ | B:N + +----------+ + + Figure 1: BGP Community based Traffic Collection + + If the network operator can obtain the traffic statistics at BGP + community granularity, based on this traffic statistics information + and the utilization of different paths, the PCE/SDN controller can + steer some traffic related to some BGP communities, or some BGP + community pairs from Path-1 to Path-2. The BGP community pairs are + used when both the source and destination of the traffic are taken + into consideration. Consider both the source and the destination of + the traffic from AS A to AS B, the traffic can be categorized into 4 + groups as indicated by 4 BGP community pairs, (A:X, B:M), (A:X, + B:N),(A:Y, B:M), (A:Y, B:N). IPFIX can be used to export the traffic + information of particular BGP community, or BGP community pairs to + the collector. Then the accumulated traffic information at BGP + community granularity can be used by the PCE/SDN controller to steer + a subset of the traffic from AS A to AS B to go through Path-2. + +4. IEs for BGP Standard Community [RFC1997] defines the BGP Communities attribute, called BGP Standard Community in this document, which describes a group of routes sharing some common properties. BGP Standard Communities are treated as 32 bit values as stated in[RFC1997]. In order to export BGP standard community information along with other flow information defined by IPFIX, three new IEs are introduced. One is bgpCommunity, which is used to identify that the value in this IE is a BGP standard community. The other two are bgpSourceCommunityList and bgpDestinationCommunityList, which are both basicList [RFC6313] of bgpCommunity, and are used to export BGP standard community information corresponding to a specific flow's source IP and destination IP respectively. The detailed information of the three new IEs are shown in the following sections. -3.1. bgpCommunity +4.1. bgpCommunity ---------------------------------------------------------------------- | ElementID | to be assigned by IANA | |--------------------------------------------------------------------| | Name | bgpCommunity | |--------------------------------------------------------------------| | Data Type | unsigned32 | |--------------------------------------------------------------------| | Data Type Semantics | identifier | |--------------------------------------------------------------------| | Description | BGP community as defined in [RFC1997] | |--------------------------------------------------------------------| | Units | none | |--------------------------------------------------------------------| - Figure 1: bgpCommunity + Figure 2: bgpCommunity + +4.2. bgpSourceCommunityList -3.2. bgpSourceCommunityList ---------------------------------------------------------------------- | ElementID | to be assigned by IANA | |--------------------------------------------------------------------| | Name | bgpSourceCommunityList | |--------------------------------------------------------------------| | Data Type | basicList, as specified in [RFC6313] | |--------------------------------------------------------------------| | Data Type Semantics | list | |--------------------------------------------------------------------| | Description | zero or more BGP communities corresponding | | | with source IP address of a specific flow | |--------------------------------------------------------------------| | Units | none | |--------------------------------------------------------------------| - Figure 2: bgpSourceCommunityList - -3.3. bgpDestinationCommunityList + Figure 3: bgpSourceCommunityList +4.3. bgpDestinationCommunityList --------------------------------------------------------------------- | ElementID | to be assigned by IANA | |--------------------------------------------------------------------| | Name | bgpDestinationCommunityList | |--------------------------------------------------------------------| | Data Type | basicList, as specified in [RFC6313] | |--------------------------------------------------------------------| | Data Type Semantics | list | |--------------------------------------------------------------------| | Description | zero or more BGP communities corresponding | | |with destination IP address of a specific flow| |--------------------------------------------------------------------| | Units | none | |--------------------------------------------------------------------| - Figure 3: bgpDestinationCommunityList + Figure 4: bgpDestinationCommunityList -4. IEs for BGP Extended Community +5. IEs for BGP Extended Community [RFC4360] defines the BGP Extended Communities attribute, which provides a mechanism for labeling the information carried in BGP. Each Extended Community is encoded as an 8-octet quantity with the format defined in [RFC4360]. In order to export BGP Extended Community information together with other flow information by IPFIX, three new IEs are introduced. The first one is bgpExtendedCommunity, which is used to identify that the value in this IE is a BGP Extended Community. The other two are bgpSourceExtendedCommunityList and bgpDestinationExtendedCommunityList, which are both basicList [RFC6313] of bgpExtendedCommunity, and are used to export the BGP Extended Community information corresponding to a specific flow's source IP and destination IP respectively. The detailed information of the three new IEs are shown in the following sections. -4.1. bgpExtendedCommunity - +5.1. bgpExtendedCommunity ---------------------------------------------------------------------- | ElementID | to be assigned by IANA | |--------------------------------------------------------------------| | Name | bgpExtendedCommunity | |--------------------------------------------------------------------| | Data Type | octetArray | |--------------------------------------------------------------------| | Data Type Semantics | default | |--------------------------------------------------------------------| | |BGP Extended Community as defined in [RFC4360]| | Description |The size of this Information Element is 8 | | |octets. | |--------------------------------------------------------------------| | Units | none | |--------------------------------------------------------------------| - Figure 4: bgpExtendedCommunity + Figure 5: bgpExtendedCommunity + +5.2. bgpSourceExtendedCommunityList -4.2. bgpSourceExtendedCommunityList ---------------------------------------------------------------------- | ElementID | to be assigned by IANA | |--------------------------------------------------------------------| | Name | bgpSourceExtendedCommunityList | |--------------------------------------------------------------------| | Data Type | basicList, as specified in [RFC6313] | |--------------------------------------------------------------------| | Data Type Semantics | list | |--------------------------------------------------------------------| | | zero or more BGP Extended Communities | | Description | corresponding with source IP address | | | of a specific flow | |--------------------------------------------------------------------| | Units | none | |--------------------------------------------------------------------| - Figure 5: bgpSourceExtendedCommunityList - -4.3. bgpDestinationExtendedCommunityList + Figure 6: bgpSourceExtendedCommunityList +5.3. bgpDestinationExtendedCommunityList ---------------------------------------------------------------------- | ElementID | to be assigned by IANA | |--------------------------------------------------------------------| | Name | bgpDestinationExtendedCommunityList | |--------------------------------------------------------------------| | Data Type | basicList, as specified in [RFC6313] | |--------------------------------------------------------------------| | Data Type Semantics | list | |--------------------------------------------------------------------| | | zero or more BGP Extended communities | | Description | corresponding with destination IP address | | | of a specific flow | |--------------------------------------------------------------------| | Units | none | |--------------------------------------------------------------------| - Figure 6: bgpDestinationExtendedCommunityList + Figure 7: bgpDestinationExtendedCommunityList -5. IEs for BGP Large Community +6. IEs for BGP Large Community [RFC8092] defines the BGP Large Communities attribute, which is suitable for use with all Autonomous System Numbers (ASNs) including four-octet ASNs. Each BGP Large Community is encoded as a 12-octet quantity with the format defined in [RFC8092]. In order to export BGP Large Community information together with other flow information by IPFIX, three new IEs are introduced. 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 bgpSourceLargeCommunityList and bgpDestinationLargeCommunityList, which are both basicList [RFC6313] of bgpLargeCommunity, and are used to export the BGP Large Community information corresponding to a specific flow's source IP and destination IP respectively. The detailed information of the three new IEs are shown in the following sections. -5.1. bgpLargeCommunity - +6.1. bgpLargeCommunity ---------------------------------------------------------------------- | ElementID | to be assigned by IANA | |--------------------------------------------------------------------| | Name | bgpLargeCommunity | |--------------------------------------------------------------------| | Data Type | octetArray | |--------------------------------------------------------------------| | Data Type Semantics | default | |--------------------------------------------------------------------| | | BGP Large Community as defined in [RFC8092] | | Description | The size of this Information Element is 12 | | | octets. | |--------------------------------------------------------------------| | Units | none | |--------------------------------------------------------------------- - Figure 7: bgpLargeCommunity + Figure 8: bgpLargeCommunity + +6.2. bgpSourceLargeCommunityList -5.2. bgpSourceLargeCommunityList ---------------------------------------------------------------------- | ElementID | to be assigned by IANA | |--------------------------------------------------------------------| | Name | bgpSourceLargeCommunityList | |--------------------------------------------------------------------| | Data Type | basicList, as specified in [RFC6313] | |--------------------------------------------------------------------| | Data Type Semantics | list | |--------------------------------------------------------------------| | | zero or more BGP Large Communities | | Description | corresponding with source IP address | | | of a specific flow | |--------------------------------------------------------------------| | Units | none | |--------------------------------------------------------------------| - Figure 8: bgpSourceLargeCommunityList - -5.3. bgpDestinationLargeCommunityList + Figure 9: bgpSourceLargeCommunityList +6.3. bgpDestinationLargeCommunityList ---------------------------------------------------------------------- | ElementID | to be assigned by IANA | |--------------------------------------------------------------------| | Name | bgpDestinationLargeCommunityList | |--------------------------------------------------------------------| | Data Type | basicList, as specified in [RFC6313] | |--------------------------------------------------------------------| | Data Type Semantics | list | |--------------------------------------------------------------------| | Description | zero or more BGP Large communities | | | corresponding with destination IP address | | | of a specific flow | |--------------------------------------------------------------------| | Units | none | |--------------------------------------------------------------------| - Figure 9: bgpDestinationLargeCommunityList + Figure 10: bgpDestinationLargeCommunityList -6. Operational Considerations +7. Operational Considerations The maximum length of an IPFIX message is 65535 bytes as per [RFC7011] , and the maximum length of a normal BGP message is 4096 bytes as per [RFC4271]. Since BGP communities, including standard, extended, and large communities , are BGP path attributes carried in 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 message with maximum length of 65535 bytes has enough space to fit all the communities related to a specific flow, both the source IP and the destination IP related. @@ -404,31 +465,31 @@ communities may be truncated due to limited message space. In this case, it is RECOMMENDED to configure export policy of BGP communities on the exporter to limit the BGP communities to be exported, so as to only export some specific communities,or not to export some specific communities. If needed, we may consider to extend the message length of IPFIX [RFC7011] from 16 bits to 32 bits to solve this problem completely. The detailed mechanism is out of the scope of this document. -7. Security Considerations +8. Security Considerations This document only defines three new IEs for IPFIX. This document itself does not directly introduce security issues. The same security considerations as for the IPFIX Protocol Specification [RFC7011] and Information Model [RFC7012] apply. As the BGP community information is deducible by other means, there are no increased privacy concerns, neither. -8. IANA Considerations +9. IANA Considerations This draft specifies the following IPFIX IEs to export BGP community information along with other flow information. The Element IDs for these IEs are solicited to be assigned by IANA. The following table is for IANA's reference to put in each field in the registry. ---------------------------------------------------------------------- |ElementID| Name | Data Type|Data Type Semantics| @@ -504,34 +564,34 @@ |--------------------------------------------------------------------| | TBA6 | |RFC6313,RFC4360|this draft | 0 | | |--------------------------------------------------------------------| | TBA7 | | RFC8092 |this draft | 0 | | |--------------------------------------------------------------------| | TBA8 | |RFC6313,RFC8092|this draft | 0 | | |--------------------------------------------------------------------| | TBA9 | |RFC6313,RFC8092|this draft | 0 | | |--------------------------------------------------------------------| - Figure 10: IANA Considerations + Figure 11: IANA Considerations -9. Acknowledgements +10. Acknowledgements The authors would like to thank Benoit Claise and Paul Aitken for their comments and suggestions to promote this document. Appreciations are given to Tianran Zhou, Warren Kumari, Jeffrey Haas, Ignas Bagdonas, Stewart Bryant, Paolo Lucente, Job Snijders, Jared Mauch, Rudiger Volk, etc, for their discussion, comments and suggestions in the face to face meetings and in the mail list. -10. References +11. References -10.1. Normative References +11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC6313] Claise, B., Dhandapani, G., Aitken, P., and S. Yates, "Export of Structured Data in IP Flow Information Export (IPFIX)", RFC 6313, DOI 10.17487/RFC6313, July 2011, . @@ -540,32 +600,32 @@ "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of Flow Information", STD 77, RFC 7011, DOI 10.17487/RFC7011, September 2013, . [RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model for IP Flow Information Export (IPFIX)", RFC 7012, DOI 10.17487/RFC7012, September 2013, . -10.2. Informative References +11.2. Informative References [Community-TE] Shao, W., Devienne, F., Iannone, L., and JL. Rougier, "On the use of BGP communities for fine-grained inbound traffic engineering", Computer Science 27392(1):476-487, November 2015. [I-D.ietf-idr-bgp-extended-messages] Bush, R., Patel, K., and D. Ward, "Extended Message - support for BGP", draft-ietf-idr-bgp-extended-messages-22 - (work in progress), August 2017. + support for BGP", draft-ietf-idr-bgp-extended-messages-24 + (work in progress), November 2017. [IANA-IPFIX] "IP Flow Information Export (IPFIX) Entities", . [RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, . [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A @@ -594,40 +654,41 @@ [RFC6183] Kobayashi, A., Claise, B., Muenz, G., and K. Ishibashi, "IP Flow Information Export (IPFIX) Mediation: Framework", RFC 6183, DOI 10.17487/RFC6183, April 2011, . [RFC8092] Heitz, J., Ed., Snijders, J., Ed., Patel, K., Bagdonas, I., and N. Hilliard, "BGP Large Communities Attribute", RFC 8092, DOI 10.17487/RFC8092, February 2017, . -Appendix A. Application Example +Appendix A. Encoding Example In this section, we give an example to show the encoding format for - the three new introduced IEs. + the new introduced IEs. Flow information including BGP communities is shown in the below table. Suppose we want all the fields to be reported by IPFIX. ----------------------------------------------------------------------- |Source ip|Destination ip |Source BGP community| Destination BGP | | | | | community | ----------------------------------------------------------------------- | 1.1.1.1 | 2.2.2.2 |1:1001,1:1002,8:1001| 2:1002,8:1001 | ----------------------------------------------------------------------- | 3.3.3.3 | 4.4.4.4 |3:1001,3:1002,8:1001| 4:1001,8:1001 | ----------------------------------------------------------------------- - Figure 11: Flow information including BGP communities + Figure 12: Flow information including BGP communities A.1. Template Record + 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SET ID = 2 | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 256 | Field Count = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| SourceIPv4Address = 8 | Field length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| DestinationIPv4Address = 12 | Field length = 4 | @@ -631,21 +692,21 @@ |0| SourceIPv4Address = 8 | Field length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| DestinationIPv4Address = 12 | Field length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| bgpSourceCommunityList = 459| Field length = 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| bgpDestinationCommunityList | Field length = 0xFFFF | | | = 460 | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - Figure 12: Template Record Encoding Format + Figure 13: Template Record Encoding Format In this example, the Template ID is 256, which will be used in the data record. The field length for bgpSourceCommunityList and bgpDestinationCommunityList is 0xFFFF, which means the length of this IE is variable, the actual length of this IE is indicated by the list length field in the basic list format as per [RFC6313]. A.2. Data Set The data set is represented as follows: @@ -693,21 +754,21 @@ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | List length = 13 |semantic =allof| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | bgpCommunity = 458 | Field Len = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BGP Destination Community Value 1 = 4:1001 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BGP Destination Community Value 2 = 8:1001 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - Figure 13: Data Set Encoding Format + Figure 14: Data Set Encoding Format Authors' Addresses Zhenqiang Li China Mobile 32 Xuanwumen West Ave, Xicheng District Beijing 100053 China Email: li_zhenqiang@hotmail.com