Network Working Group E. Osborne Internet-Draft Cisco Intended status: Experimental February 13, 2013 Expires: August 17, 2013 Extended Administrative Groups in MPLS-TE draft-osborne-mpls-extended-admin-groups-00 Abstract This document provides additional administrative groups (sometimes referred to as "link colors") to the IGP extensions for MPLS-TE. Requirements Language 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 2119 [RFC2119]. 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 August 17, 2013. Copyright Notice Copyright (c) 2013 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 Osborne Expires August 17, 2013 [Page 1] Internet-Draft extended-admin-groups February 2013 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Extended Administrative Groups sub-TLV . . . . . . . . . . . . 3 2.1. Packet Format . . . . . . . . . . . . . . . . . . . . . . . 3 2.2. Admin group numbering . . . . . . . . . . . . . . . . . . . 4 2.3. Backward compatability . . . . . . . . . . . . . . . . . . 4 2.3.1. AG and EAG coexistence . . . . . . . . . . . . . . . . 4 2.3.2. Desire for unadvertised EAG bits . . . . . . . . . . . 4 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 6. Normative References . . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 5 Osborne Expires August 17, 2013 [Page 2] Internet-Draft extended-admin-groups February 2013 1. Introduction MPLS-TE advertises 32 administrative groups (commonly referred to as "colors" or "link colors") using the Administrative Group sub-TLV of the Link TLV. This is defined for OSPF [RFC3630]and ISIS [RFC5305]. This document adds a sub-TLV to the IGP TE extensions, "Extended Administrative Group". It 2. Extended Administrative Groups sub-TLV The Extended Administrative Groups sub-TLV is used in addition to the Administrative Groups when a device wishes to advertise more than 32 colors for a link. The EAG sub-TLV is optional. This document uses the term 'colors' as a shorthand to refer to particular bits with an AG or EAG. The examples in this document use 'red' to represent the least significant bit in the AG (red == 0x1), 'blue' to represent the second bit (blue == 0x2). To say that a link has a given color or that the specified color is set on the link is to say that the corresponding bit or bits in the link's AG are set to 1. 2.1. Packet Format The format of the Extended Administrative Groups sub-TLV is: 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: Extended Admin Group | Length: Variable | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Value: Extended Admin Group Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ........... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Value: Extend Admin Group Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Length is the size of the Extended Admin Group (EAG) value in octets. The EAG may be of any length, but must be a multiple of 4 octets. Osborne Expires August 17, 2013 [Page 3] Internet-Draft extended-admin-groups February 2013 2.2. Admin group numbering By convention, the existing Administrative Group TLVs are numbered 0 (LSB) to 31 (MSB). The EAG values pick up where this numbering scheme leaves off. The LSB in the EAG is 32. If the EAG is 4 bytes in length, the MSB is 63. If the EAG is 8 bytes in length, the MSB is 95. 2.3. Backward compatability There are two things to consider for backward compatibility with existing AG implementations - how do AG and EAG coexist, and what happens if a node has matching criteria for unadvertised EAG bits? 2.3.1. AG and EAG coexistence If a node advertises the EAG sub-TLV it MUST also advertise the existing Administrative Group (AG) sub-TLV defined in RFCs 3630 and 5305. This ensures that the first bit of the EAG sub-TLV is always bit 32, and ensures maximum interoperability with legacy implementations. 2.3.2. Desire for unadvertised EAG bits The existing AG bits are optional; thus a node may be configured with a preference to include red or exclude blue, and be faced with a link that is not advertising a value for either blue or red. What does an implementation do in this case? It shouldn't assume that red is set, but it is also arguably incorrect to assume that red is NOT set, as a bit must first exist before it can be set to 0. Practically speaking this has not been an issue for deployments, as many implementations always advertise the AG bits, often with a default value of 0x00000000. However, this issue may be of more concern once EAGs are added to the network. EAGs may exist on some nodes but not others, and the EAG length may be longer for some links than for others. Each implementation is free to choose its own method for handling this question. However, to encourage maximum interoperability an implementation SHOULD treat specified but unadvertised EAG bits as if they are set to 0. A node MAY provide other (configurable) strategies for handling this case. 3. Security Considerations This extension adds no new security considerations. Osborne Expires August 17, 2013 [Page 4] Internet-Draft extended-admin-groups February 2013 4. IANA Considerations This document requests a sub-TLV allocation in both OSPF and ISIS. 5. Acknowledgements Thanks to Santiago Alvarez and Rohit Gupta for their review and comments. 6. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, September 2003. [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, October 2008. Author's Address Eric Osborne Cisco Osborne Expires August 17, 2013 [Page 5]