--- 1/draft-ietf-manet-dlep-lid-extension-03.txt 2018-08-23 10:13:16.414057944 -0700 +++ 2/draft-ietf-manet-dlep-lid-extension-04.txt 2018-08-23 10:13:16.434058428 -0700 @@ -1,36 +1,38 @@ Mobile Ad hoc Networks Working Group R. Taylor Internet-Draft Airbus Defence & Space Intended status: Standards Track S. Ratliff -Expires: February 21, 2019 VT iDirect - August 20, 2018 +Expires: February 24, 2019 VT iDirect + August 23, 2018 DLEP Link Identifier Extension - draft-ietf-manet-dlep-lid-extension-03 + draft-ietf-manet-dlep-lid-extension-04 Abstract - There exists a class of modems that wish to support the Dynamic Link - Exchange Protocol (DLEP) [RFC8175] but do not present a single Layer - 2 network domain as required by DLEP. Such devices may be: + There exists a class of modems that would benefit from supporting the + Dynamic Link Exchange Protocol (DLEP) [RFC8175] but do not present a + single Layer 2 network domain as required by DLEP. Such devices may + be: o Modems that maintain a varying link to some upstream backbone network infrastructure, where the ability to announce link state and DLEP metrics is desired, but the concept of a DLEP destination router for the backbone does not apply. Examples of such devices can include LTE modems, IEEE 802.11 stations not in ad-hoc mode, and some satellite terminals. o Modems that provide Layer 3 wide area network connectivity between - devices, where individual DLEP destinations do exist, but are not - directly reachable by MAC address. + devices, where remote DLEP destinations do exist, but are not + directly reachable by MAC address, such as modems that contain + embedded routing functionality. This document introduces an optional extension to the core DLEP specification, allowing DLEP to be used between routers and modems that operate in this way. Note: o This document is intended as an extension to the core DLEP specification, and readers are expected to be fully conversant with the operation of core DLEP. @@ -43,21 +45,21 @@ 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 February 21, 2019. + This Internet-Draft will expire on February 24, 2019. 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 (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -66,26 +68,26 @@ 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 . . . . . . . . . . . . . . . . . . . . . . 3 2. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Identifier Restrictions . . . . . . . . . . . . . . . . . 4 - 2.2. Negotiation . . . . . . . . . . . . . . . . . . . . . . . 4 + 2.2. Negotiation . . . . . . . . . . . . . . . . . . . . . . . 5 3. New Data Items . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Link Identifier Length Data Item . . . . . . . . . . . . 5 3.2. Link Identifier Data Item . . . . . . . . . . . . . . . . 6 4. Security Considerations . . . . . . . . . . . . . . . . . . . 6 - 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 + 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. Normative References . . . . . . . . . . . . . . . . . . 7 6.2. Informative References . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction The Dynamic Link Exchange Protocol (DLEP) [RFC8175] describes a protocol for modems to advertise the status of wireless links between reachable destinations to attached routers. The core specification @@ -147,47 +149,59 @@ 3 information. In the case of modems that provide Layer 3 wide area network connectivity between devices, this means one or more IPv4 or IPv6 Address Data Items providing the Layer 3 address of the destination. When referring to some upstream backbone network infrastructure, this means one or more IPv4 or IPv6 Attached Subnet Data Items, for example: '0.0.0.0/0' or '::/0'. This allows the DLEP peer router to understand the properties of the link to those routes. When the DLEP peer router wishes to forward packets to the Layer 3 destination or subnet, the MAC address associated with the link MUST - be used as the Layer 2 destination of the packet. + be used as the Layer 2 destination of the packet if it wishes to use + the modem network to forward the packet. + + As most mainstream routers expect to populate their routing + information base with the IP address of the next router towards a + destination, implementations supporting this extension SHOULD + announce one or more valid IPv4 or IPv6 addresses of the last + reachable Layer 2 device, i.e. the device with the corresponding MAC + Address. + + If the last reachable Layer 2 device is not the DLEP peer modem, then + the modem SHOULD announce a DLEP Destination with the required MAC + Address without including a Link Identifier Data Item. 2.1. Identifier Restrictions - A link identifier is by default 4 octets in length. If a modem - wishes to use an identifier of a different length, it MUST be + A Link Identifier is by default 4 octets in length. If a modem + wishes to use a Link Identifier of a different length, it MUST be announced using the Link Identifier Length Data Item (Section 3.1) contained in the DLEP Session Initialization Response message sent by the modem to the router. - During the lifetime of a DLEP session, the length of link identifiers + During the lifetime of a DLEP session, the length of Link Identifiers MUST remain constant, i.e. the Length field of the Link Identifier Data Item MUST NOT differ between destinations. - The method for generating identifiers is a modem implementation + The method for generating Link Identifiers is a modem implementation matter and out of scope of this document. Routers MUST NOT make any - assumptions about the meaning of identifiers, or how identifiers are - generated. + assumptions about the meaning of Link Identifiers, or how Link + Identifiers are generated. - Within a single DLEP session, all link identifiers MUST be unique per + Within a single DLEP session, all Link Identifiers MUST be unique per MAC Address. This means that a Layer 3 DLEP Destination is uniquely - identified by the pair: {MAC Address,Link Id}. + identified by the pair: {MAC Address,Link Identifier}. - Identifiers MUST NOT be reused, i.e. a {MAC Address,Link Id} pair - that has been used to refer to one destination MUST NOT be recycled - to refer to a different destination within the lifetime of a single - DLEP session. + Link Identifiers MUST NOT be reused, i.e. a {MAC Address,Link + Identifier} pair that has been used to refer to one DLEP Destination + MUST NOT be recycled to refer to a different destination within the + lifetime of a single DLEP session. 2.2. Negotiation To use this extension, as with all DLEP extensions, the extension MUST be announced during DLEP session initialization. A router advertises support by including the value 'Link Identifiers' (TBD1), Section 5, in the Extension Data Item within the Session Initialization Message. A modem advertises support by including the value 'Link Identifiers' (TBD1) in the Extension Data Item within the Session Initialization Response Message. If both DLEP peers @@ -210,39 +224,41 @@ 3. New Data Items This extension introduces two new DLEP Data Items: the Link Identifier Data Item (Section 3.2) used to identify a Layer 3 link at or beyond a destination, and the Link Identifier Length Data Item (Section 3.1) used to announce the length of Link Identifiers at session initialization. 3.1. Link Identifier Length Data Item - The Link Identifier Length Data Item MUST be used by a DLEP modem - implementation to define the length of Link Identifier Data Items if - it does not with to use the default value of 4 octets. + The Link Identifier Length Data Item is used by a DLEP modem + implementation to specify the length of Link Identifier Data Items. + It MUST be used if the specified length is not the default value of 4 + octets. The Link Identifier Length Data Item MAY be used during Session Initialization, contained in a Session Initialization Response Message. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Data Item Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Identifier Length | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Data Item Type: TBD2, Section 5 Length: 2 + Link Identifier Length: The length, in octets, of Link Identifiers used by the DLEP modem for this session. 3.2. Link Identifier Data Item The Link Identifier Data Item MAY be used wherever a MAC Address Data Item is defined as usable in core DLEP. 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 @@ -252,46 +268,45 @@ | Link Identifier... : +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Data Item Type: TBD3, Section 5 Length: The length of the Data Item, by default 4, but may be different if a Link Identifier Length Data Item (Section 3.1) has been announced during session initialization. Link Identifier: The unique identifier of the Layer 3 destination. - This identifier has no implicit meaning and is only used to + This Link Identifier has no implicit meaning and is only used to discriminate between multiple links. 4. Security Considerations As an extension to the core DLEP protocol, the security considerations of that protocol apply to this extension. This extension adds no additional security mechanisms or features. None of the features introduced by this extension require extra consideration by an implementation. 5. IANA Considerations Upon approval of this document, IANA is requested to: - o Assign a new value (TBD1) from the Specification Required section - of the DLEP Extensions Registry, named "Link Identifiers". + o Assign a new DLEP Extensions Registry value (TBD1) from the + Specification Required section, named "Link Identifiers". - o Assign a new value (TBD2) from the Specification Required section - of the DLEP Data Item Type Values Registry, named "Link Identifier + o Assign a new DLEP Data Item Type Values Registry value (TBD2) from + the Specification Required section, named "Link Identifier Length". - o Assign a new value (TBD3) from the Specification Required section - of the DLEP Data Item Type Values Registry, named "Link - Identifier". + o Assign a new DLEP Data Item Type Values Registry value (TBD3) from + the Specification Required section, named "Link Identifier". 6. References 6.1. 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, .