Mobile Ad hoc Networks Working I. Chakeres Group Motorola Internet-Draft April 11, 2008 Intended status: Standards Track Expires: October 13, 2008 A Default Route for DYMO draft-chakeres-manet-dymo-default-01 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on October 13, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract This document describes how to distribute, create, and update a default route in DYMO. Chakeres Expires October 13, 2008 [Page 1] Internet-Draft DYMO April 2008 Table of Contents 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Applicability Statement . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Distributing and Installing a Default Route . . . . . . . . . . 4 5. Performing Route Discovery in the Presence of a Default Route . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6. Forwarding Data Packets . . . . . . . . . . . . . . . . . . . . 4 7. Learning about Locally Reachable Destinations . . . . . . . . 4 8. Informing DYMO Routers about Locally Reachable Destinations . . . . . . . . . . . . . . . . . . . . . . . . . 5 9. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 5 10. Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 5 11. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 13.1. Normative References . . . . . . . . . . . . . . . . . . . 6 13.2. Informative References . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 Intellectual Property and Copyright Statements . . . . . . . . . . 7 Chakeres Expires October 13, 2008 [Page 2] Internet-Draft DYMO April 2008 1. Overview This document describes how to distribute, create, and update a default route in DYMO [I-D.ietf-manet-dymo]. A default route can be very effective in reducing the number of route discoveries, particularly for destinations not reachable inside a MANET. The mechanisms proposed in this document reuse DYMO's existing RM processing and forwarding logic. Similarly, this specification ensures that DYMO remains reactive for known locally reachable destinations. 2. Applicability Statement This specification allows one DYMO router within a MANET, called a DYMO Default Router (DDR), to advertise a default route (DROUTE). In the simplest operational mode, we assume that all DYMO routers in the MANET know the locally reachable destination addresses. Reversing this logic, we assume that all DYMO routers know which destination addresses are not locally reachable, and that should be forwarded via the DDR. Correspondingly, the set of reachable/ unreachable destinations is known by all DYMO routers in the MANET. In a more complex mode of operation, we describe how the DDR can inform other DYMO routers that a particular address or set of addresses is directly reachable in the MANET (Section 8). Note that, the DDR may or may not know all the reachable destination addresses. 3. Terminology 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 [RFC2119]. Default Route (DROUTE) A default route is represented by 0.0.0.0 or ::/0 [RFC5156]. REACHABLE_ADDRESSES The list of addresses known/assumed to be reachable with the MANET. Route discoveries are performed for these destinations. Chakeres Expires October 13, 2008 [Page 3] Internet-Draft DYMO April 2008 REACHABLE_ADDRESS_TIMEOUT The amount of time to wait before removing a dynamically added REACHABLE_ADDRESS entry. 4. Distributing and Installing a Default Route The DDR MAY reactively or proactively distribute DROUTE information. The DDR may advertise a default route by attaching the DROUTE address to a RM (RREQ or RREP) as described in DYMO Section 5.3.5 "Adding Additional Routing Information to a RM". The prefix length is set to zero (0). Alternatively, the DDR may advertise a default route by inserting the DROUTE address as the OrigNode and TargetNode in a RREQ. The prefix length is set to zero (0). DYMO routers conforming to this specification process the DDR routing information as if it were a unicast address. 5. Performing Route Discovery in the Presence of a Default Route If a default route exists, DYMO routers MUST still perform route discovery for those destination addresses reachable within the MANET. Each DYMO router SHOULD maintain this list of addresses, and their prefixes. We will refer to this list as REACHABLE_ADDRESSES. 6. Forwarding Data Packets When a DYMO router receives a data packet for forwarding with a destination addresses not reachable within the MANET, the default route SHOULD be used for forwarding. 7. Learning about Locally Reachable Destinations When a DYMO router processes a RM, it SHOULD add the OrigNode.Address and prefix to its REACHABLE_ADDRESSES. These entries SHOULD be removed after REACHABLE_ADDRESS_TIMEOUT seconds. The DDR MAY also learn about locally reachable destinations, by examining the source address in data packets it receives from the MANET for forwarding. These sources SHOULD be added to the DDR's REACHABLE_ADDRESSES. These entries SHOULD be removed after REACHABLE_ADDRESS_TIMEOUT seconds. Chakeres Expires October 13, 2008 [Page 4] Internet-Draft DYMO April 2008 8. Informing DYMO Routers about Locally Reachable Destinations When the DDR receives a data packet for a locally reachable destination, it SHOULD inform the source's DYMO router that this particular destination exists in the local MANET by issuing a Destination Reachable DYMO control message. The Destination Reachable (DR) DYMO control message is unicast hop- by-hop to the DYMO router responsible for the source of the data packet. Note: the exact format of this message will be flushed out in later drafts. DYMO routers processing this DR message SHOULD add the reachable destination(s) to their REACHABLE_DESTINATIONS list. These entries SHOULD be removed after REACHABLE_ADDRESS_TIMEOUT seconds. 9. Backward Compatibility The DYMO specification [I-D.ietf-manet-dymo] defines unicast routing for valid unicast IP destination addresses. Therefore, if a DYMO router does not follow the directions describe in this document, it will not process or forward DROUTE routing information. 10. Parameters REACHABLE_ADDRESS_TIMEOUT should be larger than ROUTE_DELETE_TIMEOUT. Logically, it would also be correct for REACHABLE_ADDRESS_TIMEOUT to be less than ROUTE_AGE_MAX_TIMEOUT. 11. Security Considerations TBD 12. Acknowledgments DYMO is a descendant of the design of previous MANET reactive protocols, especially AODV [RFC3561]. Some of the concepts contained in the document come from AODV, AODV-bis, and early DYMO I-Ds. 13. References Chakeres Expires October 13, 2008 [Page 5] Internet-Draft DYMO April 2008 13.1. Normative References [I-D.ietf-manet-dymo] Chakeres, I. and C. Perkins, "Dynamic MANET On-demand (DYMO) Routing", draft-ietf-manet-dymo-12 (work in progress), February 2008. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 13.2. Informative References [RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On- Demand Distance Vector (AODV) Routing", RFC 3561, July 2003. [RFC5156] Blanchet, M., "Special-Use IPv6 Addresses", RFC 5156, April 2008. Author's Address Ian D Chakeres Motorola Bangalore India Email: ian.chakeres@gmail.com URI: http://www.ianchak.com/ Chakeres Expires October 13, 2008 [Page 6] Internet-Draft DYMO April 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Chakeres Expires October 13, 2008 [Page 7]