TEAS Working Group A.Wang Internet Draft China Telecom Intended status: Standard Track February 12, 2018 Expires: August 11, 2018 Redistribute Route Originator Extend TLV for BGP-LS draft-wang-idr-redistribute-route-originator-00.txt Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. 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 August 11, 2018. Copyright Notice Copyright (c) 2018 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 (http://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. Abstract This document describes one TLV extended for BGP-LS to transfer the originator of redistributed routes in order to let the SDN controller to deduce the network topology automatically under the multi-domain environments. This extension can expand the usage of BGP-LS protocol to multi- domain; enable the network operator to collect the connection relationship between different domains and then calculate the overall network topology automatically based on the information provided by BGP-LS protocol. Expires August 11, 2018 [Page 1] Internet-Draft Redistribute Route Originator Extend TLV for BGP-LS February 12, 2018 Table of Contents 1. Introduction ................................................ 2 2. Conventions used in this document............................ 2 3. Multi-Domain Scenarios....................................... 2 3.1. Proposed Solution....................................... 3 3.2. Redistributed Routes Originator TLV .................... 3 3.3. Topology Reconstruction................................. 4 4. Security Considerations...................................... 4 5. IANA Considerations ......................................... 4 6. Conclusions ................................................. 4 7. References .................................................. 5 7.1. Normative References.................................... 5 7.2. Informative References.................................. 5 8. Acknowledgments ............................................. 5 1. Introduction BGP-LS [RFC 7752] describes the methodology that using BGP protocol to transfer the Link-State information. Such method can enable SDN controller to collect the underlay network topology automatically, but it can only get the information within one IGP domain. If the operator has more than one IGP domain, and these domains interconnect each other, there is no suitable TLV within current BGP-LS to transfer the interconnect information. This draft introduces one new TLV to extend the BGP-LS protocol to transfer the key information related to the interconnect topology. After that, the SDN controller can then deduce the multi-domain topology automatically based on the information from BGP-LS protocol. 2. Conventions used in this document 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 RFC 2119 [RFC2119]. 3. Multi-Domain Scenarios. Fig.1 illustrates the multi-domain scenarios that this draft discussed. Normally, SDN Controller can get the topology of IGP A and IGP B individually via the BGP-LS protocol, but it can't get the topology connection information between these two IGP domains because there is normally no IGP protocol run on the connected links. Expires April 15, 2018 [Page 2] Internet-Draft Redistribute Route Originator Extend TLV for BGP-LS February 12, 2018 +--------------+ ---|SDN Controller---- | +--------------+ | | | BGP-LS BGP-LS | | | | ------ --- ///- -\\\ //-- --\\ / \ / \ | R3-------R1--|------|-T1-------T3 | | | | | | IGP A | | IGP B | | | | | | R4 ------R2--|------|-T2-------T4 | \ / \ / \\\- -/// \\-- --// ----- --- Fig.1 Multi-Domain Scenarios 3.1. Proposed Solution. To get the topology information between these two domains, we can use the redistribute method to redistribute the connected links into the IGP domain respectively. The prefix of the redistributed links will then be gotten via the BGP-LS border router within each domain. Although these border routers know where these redistributed prefixes coming from, but they do not advertise such information to the BGP-LS information collector. 3.2. Redistributed Routes Originator TLV This draft proposes to define one new TLV to transfer such key information; we call it "Redistributed Routes Originator" TLV. The format of this TLV is illustrated below: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Expires April 15, 2018 [Page 3] Internet-Draft Redistribute Route Originator Extend TLV for BGP-LS February 12, 2018 // Redistributed Routes Originator // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: should be allocated by IANA. Length: 4 Bytes. Redistributed Routes Originator: Router ID of the redistributed routes. This TLV should be coincided with the IGP Route Tag TLV or OSPF Route Type TLV, because these two TLVs indicate the associated prefixes redistributed via other protocols. 3.3. Topology Reconstruction. When SDN Controller gets such information from BGP-LS protocol, it should compares the proximity of the redistributed prefixes. If they are under the same scope, then it should find the corresponding associated "redistributed route originator" TLV, build the link between these two originators. After iterating the above procedures for all of the redistributed prefixes, the SDN controller can then draw the connection topology between different domains automatically. 4. Security Considerations TBD 5. IANA Considerations TBD 6. Conclusions TBD Expires April 15, 2018 [Page 4] Internet-Draft Redistribute Route Originator Extend TLV for BGP-LS February 12, 2018 7. References 7.1. Normative References [RFC7752] H. Gredler, Ed., J. Medved, S. Previdi, A. Farrel, S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP ", RFC7752, March 2016, https://tools.ietf.org/html/rfc7752 7.2. Informative References 8. Acknowledgments TBD. Authors' Addresses Aijun Wang China Telecom Beiqijia Town, Changping District Beijing,China Email: wangaj.bri@chinatelecom.cn Expires April 15, 2018 [Page 5]