BIER WG Z. Zhang Internet-Draft Fangwei. Hu Intended status: Standards Track ZTE Corporation Expires: June 23, 2016 December 21, 2015 CONFORMANCE OF ACROSSING NON-BIER NODES draft-zhang-bier-across-non-bier-nodes-00.txt Abstract Bit Index Explicit Replication (BIER) is an architecture that provides optimal multicast forwarding through a "multicast domain", without requiring intermediate routers to maintain any per-flow state or to engage in an explicit tree-building protocol. There may be some routers which could not support BIER technology (We name them as non-BIER node in this document) in the BIER domain when deployed. This document specifies a solution for the BIER packet transiting the non-BIER nodes. 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 http://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 June 23, 2016. Copyright Notice Copyright (c) 2015 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. Code Components extracted from this document must Zhang & Hu Expires June 23, 2016 [Page 1] Internet-Draft CONFORMANCE OF ACROSSING NON-BIER NODES December 2015 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Encapsulation Negotiation of the BIER nodes . . . . . . . . . . 3 2.1. Extension of OSPF protocol . . . . . . . . . . . . . . . . 3 2.2. Extension of IS-IS protocol . . . . . . . . . . . . . . . . 4 3. The Protocol Treatment . . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 6. Normative References . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Zhang & Hu Expires June 23, 2016 [Page 2] Internet-Draft CONFORMANCE OF ACROSSING NON-BIER NODES December 2015 1. Introduction Every node in the BIER domain may support different tunnel technology to encapsulate BIER packets. For example, There are some non-BIER nodes between BFR2 and BFR5. If BIER packets should forward to BFR5 via BFR2, suppose that BFR2 encapsulate the BIER packets by GRE header. When the BIER packets reachs BFR5, BFR5 support only mpls encapsulation, and can not recognize the encapsulation of GRE. Then BFR5 will discard the packets. BFIR1-- BFR2 -- non-BFR3 -- non-BFR4 -- BFR5 -- BFER6 Figure 1: An example of packets forwarding BFR2 and BFR5 negotiate the encapsulation function in advance. BFR2 will choose the right function that can support by BFR5 to encapsulate BIER packets. BFR5 can recognize the BIER packets and forward correctly. 2. Encapsulation Negotiation of the BIER nodes Network nodes who support BIER use IGP extension to exchange BIER information. In this document, we define IGP extension to exchange BIER encapsulation function, include OSPF and IS-IS protocols. 2.1. Extension of OSPF protocol We define new OSPF Router Information (RI) TLV to indicate the encapsulation function that supported by BIER nodes. 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Value // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: format of OSPF extension o Type : The value is TBD. The Type indicate that it is a non-bier- tunnel-type sub-tlv. o Length: The length of this field is 6 bits. o Value: The length of this field is 16 bits, is used to indicate every encapsulation type. We define the bit from rightmost bit. Zhang & Hu Expires June 23, 2016 [Page 3] Internet-Draft CONFORMANCE OF ACROSSING NON-BIER NODES December 2015 Now we define three types of encapsulation for BIER packets. 00000001 : MPLS 00000010 : GRE 00000100 : UDP 2.2. Extension of IS-IS protocol We define new IS-IS Router capability TLV (TLV 242) to indicate the encapsulation function that supported by BIER nodes. 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Value // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: format of IS-IS extension o Type : The value is TBD. The Type indicate it's OSPF-BIER-Encap- Func sub-tlv. o Length: The length of this tlv is 6 bits. o The value of this tlv is 2 octets, 16bits is used to indicate every encapsulation function. We define the bit from rightmost bit. Now we define three function of encapsulation of BIER packets. 00000001 : mpls 00000010 : GRE 00000100 : UDP 3. The Protocol Treatment At a given BFR, in above example, BFR2 starts with a copy of the IGP- computed shortest path tree from BFR2 to each router in the domain. BFIR1 BFR2 non-BFR3 non-BFR4 BFR5 BFER6 | | | | | | | | | | | | IP IP IP GRE GRE GRE BIER BIER BIER BIER BIER Figure 4: example of packets forwarding of GRE encapsulation After IGP computed, BFR2 notice that there are non-BIER nodes between BFR2 and BFR5. After BFR2 check the IGP BIER-encapsulation tlvs. BFR2 notices that BFR5 support GRE encapsulation function, and the non-BIER nodes also support IP encapsulation function. BFR2 will encapsulate the BIER packets to GRE header and forward the packets to Zhang & Hu Expires June 23, 2016 [Page 4] Internet-Draft CONFORMANCE OF ACROSSING NON-BIER NODES December 2015 non-BIER nodes names non-BIER3. and the destination of packets is the IP address of BFR5. After the packets reach BFR5, BFR5 will discover that there are BIER packets after the IP header and GRE header. BFR5 then forward the packets by use BIER forwarding function defined in draft-ietf-bier-architecture. BFIR1 BFR2 non-BFR3 non-BFR4 BFR5 BFER6 | | | | | | | | | | | | label label label BIER BIER BIER BIER BIER Figure 5: example of packets forwarding of mpls encapsulation After IGP computed, BFR2 notice that there are non-BIER nodes between BFR2 and BFR5. And all the nodes in domain support MPLS. After BFR2 check the IGP BIER-encapsulation tlvs. BFR2 will encapsulate the BIER mpls label from the messages advertised by BFR2, and BFR2 will encapsulate the IP mpls label to BFR5 in front of the packets. Non- BIER nodes forward packets to BFR5. When the packets reach BFR5, BFR5 will discover that there are BIER packets after the BIER mpls label. BFR5 then forward the packets by use BIER forwarding function defined in draft-ietf-bier-mpls-encapsulation. 4. Security Considerations For general BIER Security Considerations. 5. IANA Considerations IANA is requested to allocate the OSPF and IS-IS extension for the function in this document. 6. Normative References [I-D.ietf-bier-architecture] Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and S. Aldrin, "Multicast using Bit Index Explicit Replication", draft-ietf-bier-architecture-02 (work in progress), July 2015. [I-D.ietf-bier-isis-extensions] Ginsberg, L., Przygienda, T., Aldrin, S., and J. Zhang, "BIER support via ISIS", draft-ietf-bier-isis-extensions-01 (work in progress), October 2015. Zhang & Hu Expires June 23, 2016 [Page 5] Internet-Draft CONFORMANCE OF ACROSSING NON-BIER NODES December 2015 [I-D.ietf-bier-mpls-encapsulation] Wijnands, I., Rosen, E., Dolganow, A., Tantsura, J., and S. Aldrin, "Encapsulation for Bit Index Explicit Replication in MPLS Networks", draft-ietf-bier-mpls-encapsulation-02 (work in progress), August 2015. [I-D.ietf-bier-ospf-bier-extensions] Psenak, P., Kumar, N., Wijnands, I., Dolganow, A., Przygienda, T., Zhang, J., and S. Aldrin, "OSPF Extensions For BIER", draft-ietf-bier-ospf-bier-extensions-01 (work in progress), October 2015. Authors' Addresses Zheng(Sandy) Zhang ZTE Corporation No. 50 Software Ave, Yuhuatai Distinct Nanjing, 210000 China Email: zhang.zheng@zte.com.cn Fangwei Hu ZTE Corporation No.889 Bibo Rd Shanghai, 201203 China Email: hu.fangwei@zte.com.cn Zhang & Hu Expires June 23, 2016 [Page 6]