BIER WG Fangwei. Hu Internet-Draft Ran. Chen Intended status: Standards Track ZTE Corporation Expires: May 7, 2016 November 4, 2015 BIER Multicast Group Information draft-hu-bier-multicast-group-information-00.txt Abstract This draft proposes to solve the multicast group address announcement. The multicast group address information is encapsulated as the BIER data payload. A new TLV is defined in this document to carry the multicast group address information. 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 May 7, 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 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. Hu & Chen Expires May 7, 2016 [Page 1] Internet-Draft BIER multicast group November 2015 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Multicast Group Address Announcement Mechanism . . . . . . . 2 3. BIER-GROUP-ADDRESS LV . . . . . . . . . . . . . . . . . . . . 3 4. ISIS Extension . . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 8. Normative References . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction Bit Index Explicit Replication (BIER)[I-D.ietf-bier-architecture] proposes an architecture that provides optimal multicast forwarding through a "BIER domain" without requiring intermediate routers to maintain any multicast related per-flow state. BIER also does not require any explicit tree-building protocol for its operation. BIER accomplishes this by addressing each of the targeted egress router in a bit mask in the BIER header. A multicast data packet enters a BIER domain at a "Bit-Forwarding Ingress Router" (BFIR), and leaves the BIER domain at one or more "Bit-Forwarding Egress Routers" (BFERs) . The BIER header is encapsulated in the BFIR and decapsulated in the BFER. Each BIER Forwarding Router (BFR) is assigned and uniquely identified by a BFR-prefix which is a routable ipv4 or ipv6 address. Each BIER egress (BFER) router needs a BFR-Identifier (1..65535) in addition to BFR-prefix. To accomplish forwarding in a BIER network, ingress router needs to know the list of egress routers to which the flow is supposed be multicasted. This document proposes a method to solve the issue. The ISIS or OSPF protocol is extended for a BFER to announce its supported multicast group address. A new TLV (BIER-GROUP-ADDRESS TLV) is defined to carry the multicast group address for a BFER and encapsulated as the BIER data payload. When BFER receives a new multicast group through IGMP/MLD protocol, it sends the BIER data payload with the new multicast group address information to all the other edge BFRs to announce this new multicast group information in the BIER domain. 2. Multicast Group Address Announcement Mechanism In order to improve the IGP (ISIS or OSPF protocol) stability, the multicast group address information is encapsulated and carried as the BIER data payload rather than IGP protocol directly. The protocol field in in the MPLS BIER header encapsulation[I-D.ietf-bier-mpls-encapsulation] is coded (7, to be assigned by IANA) to indicated that the payload is the multicast Hu & Chen Expires May 7, 2016 [Page 2] Internet-Draft BIER multicast group November 2015 group address information. The structure is as following (take the MPLS encapsulation as the example): +-----------+-----------+-----------------------------------+ |MPLS header|BIER header|Multicast group address information| +-----------+-----------+-----------------------------------+ Figure 1 Mutlicast Group Address Information Encapsulation The multicast group address information is formatted as TLV (section 3) and filled in LSP or LSA in the BFER. The BFER sends the BIER data payload with the multicast group address information to all the other edge BFRs in the BIER domain. When the BFIR receives the multicast group address information, it keeps and maintains the multicast group and BFR-prefix entries in the local, which is to guide the multicast flow forwarding. 3. BIER-GROUP-ADDRESS LV The format of BIER-GROUP-ADDRESS TLV is specified in figure 2. +--------------+ | Type | +--------------+--------------+ | Length | +-----------------------------+-------------------------------------+ |Res|mutlicast group address type|Number of multicast Group address | +-------------------------------------------------------------------+ | Multicast Group address (1) | +-------------------------------------------------------------------+ | ... | +-------------------------------------------------------------------+ | Multicast Group address (i) | +-------------------------------------------------------------------+ | Multicast Group address (n) | +-------------------------------------------------------------------+ Figure 2 BIER-GROUP-ADDRESS TLV The description for each field is as following: Type: 8 bits. Length: 16 bits, the whole length for this tlv. Res: 8 bits, it is reserved for future use. Hu & Chen Expires May 7, 2016 [Page 3] Internet-Draft BIER multicast group November 2015 Multicast Group address type: 8 bits, it indicates the type for the multicast group address. If it is 1, the multicast group address is IPv4 address, while if 2, the multicast group address is IPv6 address. Number of multicast group address: 16 bits, the number for the multicast group address. Multicast Group address[i]: the multicast group addresses for the BFER to be announced. 4. ISIS Extension If the IGP is ISIS protocol in the BIER domain, the detailed format of Mutlicast Group Address Information is as figure 3. The label is MPLS-BIER label, and the S filed is 1(the end of the MPLS stack) in the MPLS header. All the Bitstring fields in the BEIR header is All-Edge-BFRs (0xFFFF). The protocol fields is 7(to be assigned by IANA) to indicate that that the payload of BIER is the multicast group information payload. The multicast group information payload is formatted as ISIS protocol. The multicast group information TLV is filled in the ISIS LSP. We named this ISIS LSP as MGAA-LSP (Multicast Group Address Announcement) to difference with the common ISIS LSP. While the flooding and synchronization mechanism is similar with the common ISIS LSP. Hu & Chen Expires May 7, 2016 [Page 4] Internet-Draft BIER multicast group November 2015 MPLS header +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label | Cos |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ BIER header 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 0 1| Ver | Len | Entropy | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BitString (first 32 bits) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ BitString (last 32 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |OAM| Reserved |Proto=7| BFIR-id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Multicast Group address payload(Formated as ISIS) +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IS-IS Common Header, IS-IS PDU Specific Fields, IS-IS TLVs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 Multicast Group Address Format All the transit BFR forward MGAA packet as if they were ordinary BIER data packet. All the edge BFRs (BFERs and BFIRs) supporting multicast group address announcement are full mesh logically. 5. Security Considerations TBD. 6. Acknowledgements TBD. 7. IANA Considerations TBD. 8. Normative References Hu & Chen Expires May 7, 2016 [Page 5] Internet-Draft BIER multicast group November 2015 [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-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. Authors' Addresses Fangwei Hu ZTE Corporation No.889 Bibo Rd Shanghai 201203 China Phone: +86 21 68896273 Email: hu.fangwei@zte.com.cn Ran Chen ZTE Corporation No.50 Software Avenue,Yuhuatai District Nanjing, Jiangsu Province 210012 China Phone: +86 025 88014636 Email: chen.ran@zte.com.cn Hu & Chen Expires May 7, 2016 [Page 6]