DIME Working Group Internet-Draft Vishnu Ram Expires: February, 2007 Satendra Gera September, 2006 Diameter base loop avoidance Extension draft-vishnu-diameter-loop-avoidance-ext-00.txt 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 February 2007. Copyright Notice Copyright (C) The Internet Society (2006). Abstract The Diameter base protocol which is intended to provide Authentication, Authorization and Accounting (AAA) framework for applications (such as network access) is specified in [RFC 3588]. [RFC 3588] specifies a loop detection mechanism which handles looped messages at the intermediate diameter agent nodes. Vishnu et al., Expires - March 2007 [Page 1] Internet-Draft Diameter predictive loop avoidance ext September 2006 This draft discusses a possible loop avoidance mechanism for diameter request messages. Conventions used in this document 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]. Vishnu et al., Expires - March 2007 [Page 2] Internet-Draft Diameter predictive loop avoidance ext September 2006 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Problem statement. . . . . . . . . . . . . . . . . . . . . . . 3 3. Diameter loop avoidance . . . . . . . . . . . . . . . . . . . 4 5. Backward compatibility . . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. Security Considerations . . . . . . . . . . . . . . . . . . . 5 8. Normative References . . . . . . . . . . . . . . . . . . . . . 6 9. Informative References . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . . . . 8 Disclaimer of Validity . . . . . . . . . . . . . . . . . . . . . . 8 Copyright Statement . . . . . . . . . . . . . . . . . . . . . . . 8 Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Vishnu et al., Expires - March 2007 [Page 3] Internet-Draft Diameter predictive loop avoidance ext September 2006 1. Introduction Section 6.1.3 of [RFC3588], specifies a loop detection mechanism which can detect looped messages at the intermediate diameter nodes. This draft discusses a loop avoidance mechanism for Diameter request messages which shall be used in addition to the loop detection mechanism. 2. Problem statement Loop detection mechanism specified in Section 6.1.3 of [RFC3588] has the following drawbacks: i. It does not provide loop avoidance mechanism. In the absence of agents which corrects the error and retries, potential successful routes to the destination might not be tried even if one exists. ii. No recovery mechanism is specified, [RFC 3588] seems to suggest only a manual or administrative correction. 3. Diameter loop avoidance Before forwarding or routing a request, Diameter agents, in addition to processing in 6.1.3 of [RFC 3588], SHOULD check for the presence of candidate peer's identity in any of the Route-Record AVPs. In an event of the agent detecting the presence of a candidate peer's identity in a Route-Record AVP, the agent MUST ignore such a candidate peer for routing the Diameter request message. In case all the candidate peers are eliminated by the above criteria the agent SHOULD return DIAMETER_UNABLE_TO_DELIVER message. The following figures describe a scenario where Diameter loop avoidance may help. Vishnu et al., Expires - March 2007 [Page 4] Internet-Draft Diameter predictive loop avoidance ext September 2006 ___________ |Destination| | | |___________| ^ ______________ | | Relay 1 | | | | | |______________| | ^ ^ ^ | | | | | | | | | __________v | _v_________ | | Relay 2 | | | Origin | _________v | | | | | | Relay 4 | |___________| | |___________| | | ^ | |__________|<------- | | | | | | | | | v______v___ --> | Relay 3 | | | |___________| Figure 1 Deployment (Arrow show Diameter connections) ---------x---------------x--------------x------------x----------- ___________ |Destination| | | |___________| ______________ | Relay 1 | | | |______________| Msg1| ^(Loop- ^ ( RR- Origin)| | ed) |Msg1 __________v | ___|_______ | Relay 2 | | | Origin | __________ | | | | | | Relay 4 | |___________| | |___________| | | Msg1| |Msg1 |__________| (RR- Origin)| |(RR- Origin) (RR- Relay1)| |(RR- Relay1) | |(RR- Relay2) __v__|_____ | Relay 3 | | | |___________| Figure 2 Possible message path without loop avoidance ------------x------------x----------------x------------x------------- Vishnu et al., Expires - March 2007 [Page 5] Internet-Draft Diameter predictive loop avoidance ext September 2006 ___________ |Destination| | | |___________| Msg1^ ______________ (RR- Origin)| | Relay 1 | (RR- Relay1)| | | (RR- Relay2)| |______________| (RR- Relay3)| Msg1 | ^ | ( RR- Origin)| |Msg1 | __________v __|________ | | Relay 2 | | Origin | _____|____ | | | | | Relay 4 | |___________| |___________| | |<-- Msg1| |__________| | (RR- Origin)| | (RR- Relay1)| | | | ___v_______ ---------| Relay 3 | Msg1| | (RR- Origin)|___________| (RR- Relay1) (RR- Relay2) Figure 3 Message path with loop avoidance ------------x------------x----------------x------------x------------- Explained mechanism will result in: i. Better probability of delivery for diameter request messages as the message will be delivered if there exists at least one path to the destination which does not include a loop. ii. Saving the round-trip to peers which detect loop. 5. Backward compatibility This drafts describes a loop avoidance mechanism which is in addition to the loop detection mechanism described in [RFC 3588]. If a deployment has a node which doesn't support preventive loop avoidance ,the node may end up passing a request message to an already traversed node and the scenario will fall back to the one described in [RFC 3588]. 6. IANA Considerations None 7. Security Considerations This document does not contain a security protocol; it describes Vishnu et al., Expires - March 2007 [Page 6] Internet-Draft Diameter predictive loop avoidance ext September 2006 extensions to the existing Diameter protocol. All security issues of DIAMETER protocol must be considered in implementing this specification. This extension does not add any unique concerns. 8. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko, "Diameter Base Protocol", RFC 3588, September 2003. [IANA] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [IANAADFAM] IANA; "Address Family Numbers", http://www.iana.org/assignments/address-family-numbers [IANAWEB] IANA, "Number assignment", http://www.iana.org 9. Informative References [AAAREQ] Aboba, B., Calhoun, P., Glass, S., Hiller, T., McCann, P., Shiino, H., Zorn, G., Dommety, G., Perkins, C., Patil, B., Mitton, D., Manning, S., Beadles, M., Walsh, P., Chen, X., Sivalingham, S., Hameed, A., Munson, M., Jacobs, S., Lim, B., Hirschman, B., Hsu, R., Xu, Y., Campbell, E., Baba, S. and E. Jaques, "Criteria for Evaluating AAA Protocols for Network Access", RFC 2989, November 2000. [AAATRANS] Aboba, B. and J. Wood, "Authentication, Authorization and Accounting (AAA) Transport Profile", RFC 3539, June 2003. Vishnu et al., Expires - March 2007 [Page 7] Internet-Draft Diameter predictive loop avoidance ext September 2006 Authors' Addresses Vishnu Ram Motorola 66/1, Bagmane Tech Park, C V Raman Nagar, Bangalore, 560093 vishnu@motorola.com Satendra Gera Motorola 66/1, Bagmane Tech Park, C V Raman Nagar, Bangalore, 560093 in1236c@motorola.com Vishnu et al., Expires - March 2007 [Page 8] Internet-Draft Diameter predictive loop avoidance ext September 2006 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. 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. Disclaimer of Validity 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 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. Copyright Statement Copyright (C) The Internet Society (2006). 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. Acknowledgment A significant contribution to this draft was made by Liyaqatali G. Nadaf. Vishnu et al., Expires - March 2007 [Page 9]