Network Working Group A. Lindem Internet-Draft Cisco Systems Intended status: Standards Track K. Patel Expires: September 14, 2017 Arrcus, Inc S. Zandi LinkedIn March 13, 2017 BGP Logical Link Discovery Protocol (LLDP) Peer Discovery draft-acee-idr-lldp-peer-discovery-00.txt Abstract Link Layer Discovery Protocol (LLDP) or IEEE 802.1AB is implemented in networking equipment from many vendors. It is natural for IETF protocols to avail this protocol for simple discovery tasks. This document describes how BGP would use LLDP to discover directly connected and 2-hop peers when peering is based on loopback addresses. 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 September 14, 2017. 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 (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 Lindem, et al. Expires September 14, 2017 [Page 1] Internet-Draft BGP LLDP Peer Discovery March 2017 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 1.1. Requirements Notation . . . . . . . . . . . . . . . . . . 2 2. LLDP Extensions . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. LLDP Organizationally Specific TLV Format . . . . . . . . 3 2.2. Local IP Address OS-TLV Format . . . . . . . . . . . . . 4 2.3. BGP Config OS-TLV Format . . . . . . . . . . . . . . . . 5 2.3.1. BGP Config OS-TLV - Peering Address Sub-TLV . . . . . 6 2.3.2. BGP Config OS-TLV - BGP Local AS Sub-TLV . . . . . . 7 2.3.3. BGP Config OS-TLV - BGP Capabilities Sub-TLV . . . . 8 3. BGP LLDP Peer Discovery Operations . . . . . . . . . . . . . 9 3.1. Advertising BGP Speaker . . . . . . . . . . . . . . . . . 9 3.2. Receiving BGP Speaker . . . . . . . . . . . . . . . . . . 9 4. Security Considerations . . . . . . . . . . . . . . . . . . . 10 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 5.1. IANA Assigned LLDP Subtype . . . . . . . . . . . . . . . 10 5.2. BGP Config LLDP OS-TLV Sub-TLVs . . . . . . . . . . . . . 11 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.1. Normative References . . . . . . . . . . . . . . . . . . 11 6.2. Informative References . . . . . . . . . . . . . . . . . 12 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 1. Introduction Link Layer Discovery Protocol (LLDP) [LLDP] or IEEE 802.1AB is implemented in networking equipment from many vendors. It is natural for IETF protocols to avail this protocol for simple discovery tasks. This document describes how BGP [BGP] would use LLDP to discover directly connected and 2-hop peers when peering is based on loopback addresses. 1.1. Requirements Notation 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-KEYWORDS]. Lindem, et al. Expires September 14, 2017 [Page 2] Internet-Draft BGP LLDP Peer Discovery March 2017 2. LLDP Extensions 2.1. LLDP Organizationally Specific TLV Format The format of the LLDP Basic Organizationally Specific TLV (OS-TLV) is defined in [LLDP]. It is shown below for completeness. 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 (127) | Length | OUI (3 Octets) 00-00-5E | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OUI Continued | Subtype | Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... (Up to 507 Octets) | Type Organizationally Specific TLV type value, 127. Length The length of the remainder of the TLV. OUI Organizationally unique identifier for the organization's OUI. For the IANA, this is value is 00-00-5E as specified in [RFC7042]. Subtype IETF specific subtype Value Value for organizationally specific TLV. The Length of the value is 4 octets less than the TLV length. LLDP Organizationally Specific TLV The OUI for the IANA was allocated in section 1.4 of [IEEE-802-IANA]. This document requests creation of a registry for IETF specific sub- types for LLDP Organizationally Specific TLVs. Lindem, et al. Expires September 14, 2017 [Page 3] Internet-Draft BGP LLDP Peer Discovery March 2017 2.2. Local IP Address OS-TLV Format The Local IP Address Organizationally Specific TLV will be used to advertise IPv4 or IPv6 addresses that are local to the link. A network device can advertise multiple Local IP Address OS-TLVs in its LLDP PDU and is only constrained by the length of the PDU. Normally a network device would only advertise its own local address but advertising addresses local to the link for another networking device is not specifically disallowed. The format is shown 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 (127) | 8 or 20 | OUI (3 Octets) 00-00-5E | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OUI Continued | 1 | Address Family| IPv4/IPv6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4/IPv6 Address | IPv6 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Length The length will be 8 for IPv4 addresses or 20 for IPv6 addresses. Subtype IETF specific subtype for a Local IP address for the link. The value shall be 1. Address IANA Address family (1 for IPv4 or 2 for IPv6) Family Value Local IPv4 or IPv6 Address. Lindem, et al. Expires September 14, 2017 [Page 4] Internet-Draft BGP LLDP Peer Discovery March 2017 2.3. BGP Config OS-TLV Format The BGP Config Organizationally Specific TLV (OS-TLV) will be used to advertise BGP configuration information. The configuration information will be composed of Sub-TLVs. Since the length is limited to 507 octets, multiple BGP Config OS-TLVs could be included in a single LLDP advertisement. 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 (127) | Length | OUI (3 Octets) 00-00-5E | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |OUI Continued | 2 | BGP Config Sub-TLVs ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... (Up to 507 Octets) | Length The length of the BGP TLV. Subtype IETF specific subtype for BGP Config OS-TLV. The value shall be 2. Value BGP Config Sub-TLVs each with a 1 byte Type and Length. The Length will include solely the value portion of the TLV and not the Type and Length fields themselves. Lindem, et al. Expires September 14, 2017 [Page 5] Internet-Draft BGP LLDP Peer Discovery March 2017 2.3.1. BGP Config OS-TLV - Peering Address Sub-TLV The BGP OS-TLV Peering Address Sub-TLV will be used to advertise the local IP address used for BGP sessions and the associated address families. The format of the BGP Peering Address Sub-TLV is shown 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 (1) | Length | Address Family| IPv4/IPv6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ IPv4/IPv6 Peering Address ... ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AFI | SAFI | o o o +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type The Sub-TLV Type value shall be 1. Length The Sub-TLV length in octets will be 4 for IPv4 or 16 for IPv6 plus 3 times the number of AFI/SAFI pairs. Address IANA Address family (1 for IPv4 or 2 for IPv6) Family Peering An IPv4 address (4 octets) or an IPv6 address (16 Address octet) peering address. AFI/SAFI One or more AFI/SAFI pairs for BGP session using this Pairs peering address. Lindem, et al. Expires September 14, 2017 [Page 6] Internet-Draft BGP LLDP Peer Discovery March 2017 2.3.2. BGP Config OS-TLV - BGP Local AS Sub-TLV The BGP Config OS-TLV Local AS Sub-TLV will be used to advertise the 4-octet local Autonomous System (AS) number. The format of the BGP Local AS Sub-TLV is shown 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 (2) | Length (4) | Local AS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Local AS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type The Sub-TLV Type value shall be 2. Length The Sub-TLV Length will be 4 octets. Local AS Local Autonomous System (AS) Lindem, et al. Expires September 14, 2017 [Page 7] Internet-Draft BGP LLDP Peer Discovery March 2017 2.3.3. BGP Config OS-TLV - BGP Capabilities Sub-TLV The BGP Config OS-TLV Capabilities Sub-TLV will be used to advertise an 8-octet Capabilities field. The capabilities are represented as bit flags identifying the supported BGP capabilities. The format of the BGP Capabilities Sub-TLV is shown 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 (3) | Length (8) | Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type The Sub-TLV Type value shall be 3. Length The Sub-TLV Length will be 8 octets. Capabilities Bit fields identify BGP capabilities The BGP Capabilities is an 8-octet bit field. The most significant bit is the first bit (Bit 1) of the Capabilities. The following bits are defined: Bit 1: This bit indicates that support for TCP MD5 authentication [TCP-MD5]. Bit 2: This bit indicates support for TCP-AO authentication [TCP-AO]. Bit 3: This bit indicates support for Generalized TTL Security Mechanism (GTSM) [GTSM] with a configured TTL range of 254-255. TCP MD5 authentication is described in [TCP-MD5]. The TCP Authentication Option (TCP-AO) is described in [TCP-AO]. The Generalized TTL Security Mechanism (GTSM) is described in [GTSM]. If both TCP MD5 authentication and TCP-AO authentication are specified and TCP-AO is supported, it will take precedence. Lindem, et al. Expires September 14, 2017 [Page 8] Internet-Draft BGP LLDP Peer Discovery March 2017 3. BGP LLDP Peer Discovery Operations The simple use case is to just use the peer address advertised in the LLDP Packet Data Unit (PDU) to establish a 1-hop BGP peer session. This can be used in data centers using BGP as described in [BGP-DC]. The more complex use case is when a loopback address in advertised as the peering address in the LLDP PDU. 3.1. Advertising BGP Speaker A BGP speaker MAY advertise its BGP peering address in an LLDP PDU for a link using the BGP Local Address Sub-TLV of BGP-OS TLV Format. This can be an IPv4 or IPv6 address local to the link for 1-hop peering or a loopback address for 2-hop peering. Additionally, a BGP speaker MAY advertise one or more local addresses IPv4 and IPv6 addresses. In the case of 2-hop peering, a local address on the link can be used as a next-hop for the peering address. In this manner both the peering address and reachability can be discovered. A BGP speaker MAY advertise its local AS number using BGP AS Sub-TLV of BGP-OS TLV format. It may also announce relevant capabilities using BGP Capabilities Sub-TLV of BGP-OS TLV format. 3.2. Receiving BGP Speaker A BGP speaker configured for LLDP peer discovery will attempt to establish peers using the address in the BGP Local Address Sub-TLV of BGP-OS TLV format. If the peering address is directly accessible over the link on which the LLDP PDU was received, the BGP speaker will attempt to establish a 1-hop BGP session with the peer. If the received BGP Peering Address is not directly accessible over the link, the BGP speaker may add a route to the access the BGP peer. The next-hop for the route MAY be one of the addresses the BGP speaker has advertised in the Local IP Address OS-TLV. If the BGP speaker receives the same BGP peering address in LLDP PDU on multiple links, it will not establish multiple sessions. Rather a single 2-hop session will be established. Optionally, ECMP routes are added to the BGP peering session over each link on which an LLDP PDU containing the same Peering Address is received. A BGP speaker MAY receive remote neighbor's local AS number in LLDP in BGP AS Sub-TLV of the BGP-OS TLV. A BGP speaker MAY use the received local AS number to perform validation check of AS received in the OPEN message. Furthermore, A BGP speaker MAY receive remote neighbor's capabilities in LLDP in BGP Capabilities Sub-TLV of the Lindem, et al. Expires September 14, 2017 [Page 9] Internet-Draft BGP LLDP Peer Discovery March 2017 BGP-OS TLV. A BGP speaker MAY use the received capabilities to ensure appropriate neighbor based configuration is done locally so as to facilitate the session establishment. 4. Security Considerations This security considerations for BGP [BGP] apply equally to this extension. Additionally, BGP peering address discovery should only be done on trusted links (e.g., in a data center network) since LLDP packets are not authenticated or encrypted [LLDP]. 5. IANA Considerations 5.1. IANA Assigned LLDP Subtype IANA is requested to create a registry for IANA assigned subtypes in the Organizationally Specific TLV assigned to IANA (OUI of 000-00-53 [IEEE-802-IANA]. Assignment is requested for 1 for the Local IP Address OS-TLV. Assignment is also requested for 2 for the BGP Config OS-TLV. +-------------+-----------------------------------+ | Range | Assignment Policy | +-------------+-----------------------------------+ | 0 | Reserved (not to be assigned) | | | | | 1 | Local IP Address | | | | | 2 | BGP Configuration | | | | | 3-127 | Unassigned (IETF Review) | | | | | 128-254 | Reserved (Not to be assigned now) | | | | | 255 | Reserved (not to be assigned) | +-------------+-----------------------------------+ IANA LLDP Organizationally Specific TLV Sub-Types o Types in the range 3-127 are to be assigned subject to IETF Review. New values are assigned only through RFCs that have been shepherded through the IESG as AD-Sponsored or IETF WG Documents [IANA-GUIDE]. o Types in the range 128-254 are reserved and not to be assigned at this time. Before any assignments can be made in this range, Lindem, et al. Expires September 14, 2017 [Page 10] Internet-Draft BGP LLDP Peer Discovery March 2017 there MUST be a Standards Track RFC that specifies IANA Considerations that covers the range being assigned. 5.2. BGP Config LLDP OS-TLV Sub-TLVs IANA is requested to create a registry for Sub-TLVs of the BGP Config LLDP OS-TLV. Assignment is requested for 1 for the BGP Peering Address Sub-TLV. Assignment is also requested for 2 for the Local AS Sub-TLV. Additionally, assignment is requested for 3 for the Capabilities Sub-TLV. +-------------+-----------------------------------+ | Range | Assignment Policy | +-------------+-----------------------------------+ | 0 | Reserved (not to be assigned) | | | | | 1 | Peering Address | | | | | 2 | Local AS | | | | | 3 | Capabilities | | | | | 4-127 | Unassigned (IETF Review) | | | | | 128-254 | Reserved (Not to be assigned now) | | | | | 255 | Reserved (not to be assigned) | +-------------+-----------------------------------+ LLDP BGP Config OS-TLV Types o Types in the range 4-127 are to be assigned subject to IETF Review. New values are assigned only through RFCs that have been shepherded through the IESG as AD-Sponsored or IETF WG Documents [IANA-GUIDE]. o Types in the range 128-254 are reserved and not to be assigned at this time. Before any assignments can be made in this range, there MUST be a Standards Track RFC that specifies IANA Considerations that covers the range being assigned. 6. References 6.1. Normative References [BGP] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. Lindem, et al. Expires September 14, 2017 [Page 11] Internet-Draft BGP LLDP Peer Discovery March 2017 [BGP-DC] Lapukhov, P., Premji, A., and J. Mitchell, "BGP Routing in Data Centers", RFC 7938, August 2016. [LLDP] IEEE, "IEEE Standard for Local and metropolitan area networks-- Station and Media Access Control Connectivity Discovery Corrigendum 2: Technical and Editorial Corrections", IEEE 802.1AB-2009/Cor 2-2015, DOI 10.1109/ ieeestd.2015.7056401, March 2015. [RFC-KEYWORDS] Bradner, S., "Key words for use in RFC's to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 6.2. Informative References [GTSM] Gill, V., Heasley, J., Savola, P., and C. Pignataro, "The Generalized TTL Security Mechanism", RFC 5082, October 2007. [IANA-GUIDE] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 5226, May 2008. [IEEE-802-IANA] Eastlake, D. and J. Abley, "IANA Considerations and IETF Protocol and Documentation Usage for IEEE 802 Parameters", RFC 7042, October 2013. [TCP-AO] Touch, J., Mankin, A., and R. Bonica, "The TCP Authentication Option", RFC 5925, June 2010. [TCP-MD5] Heffernan, A., "TCP MD5 Signature Option", RFC 2385, August 1998. Appendix A. Acknowledgments The RFC text was produced using Marshall Rose's xml2rfc tool. Authors' Addresses Acee Lindem Cisco Systems 301 Midenhall Way Cary, NC 27513 USA Email: acee@cisco.com Lindem, et al. Expires September 14, 2017 [Page 12] Internet-Draft BGP LLDP Peer Discovery March 2017 Keyur Patel Arrcus, Inc Email: keyur@arrcus.com Shawn Zandi LinkedIn 222 2nd Street San Francisco, CA 94105 USA Email: szandi@linkedin.com Lindem, et al. Expires September 14, 2017 [Page 13]