RADEXT WG RADIUS Attribute Guidelines draft-weber-radius-attr-guidelines-01.txt Greg Weber November 8th, 2005 v1 IETF-64, Vancouver

RADIUS Attribute Guidelines WG Charter Item: “RADIUS design guidelines. This document will provide guidelines for design of RADIUS attributes. It will specifically consider how complex data types may be introduced in a robust manner, maintaining backwards compatibility with existing RADIUS RFCs, across all the classes of attributes: Standard, Vendor-Specific and SDO-Specific. In addition, it will review RADIUS data types and associated backwards compatibility issues.” Milestone: Dec ’04 completion IETF-64, Vancouver

RADIUS Attribute Guidelines draft-weber-radius-attr-guidelines-01.txt Have you read the draft? :-) Aimed at charter item Current revision primarily collects data points from early radius-ext threads Strawman recommendations Guidelines (when to do what) largely absent so far IETF-64, Vancouver

RADIUS Attribute Guidelines Data Model Alignment Vendor space somewhat varied :-) Vendor Packet Cable Vendor Vendor 3GPP VSAs Microsoft 3GPP2 Tags Vendor 3GPP2 FRAGMENT ENCRYPT COMPACT SHARED Simple TLV COMPLEX DATA GROUPING IETF-64, Vancouver

RADIUS Attribute Guidelines Recommendations 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 (TBD) | Length |V|E|C| (reserved flags) | | Vendor-Id (opt) | | Type | Length | Value... Standardize existing VSA recommendation Ease vendor to standard transition Accommodate most VSA behavior Plan for increased attribute number space IETF-64, Vancouver

RADIUS Attribute Guidelines 00 to 01 Largely editorial changes Would like to get some confirmation that the problem statement is captured before proceeding much further. Open Issue: 106, Vendor Specific Values Standardize a method for vendors to define custom values for standard attributes? IETF-64, Vancouver

RADIUS Attribute Guidelines Vendor Specific Values VSE (enumerations) described in RFC 2882 embeds vendor ID in value, e.g. val=((vendor-id << 16) | num) Require revision of RFC 3575 (RADIUS IANA policy) and therefore a standards track doc? IETF-64, Vancouver

RADIUS Attribute Guidelines Fragmentation Simpler method than attribute flagging? EAP-Message is a non-AAA endpoint conversation, so opaque assembly makes sense. For AAA endpoint, the less opaque, the more checking that can be performed. DHCP (RFC 3396) Encoding Long Options. Concatenate any adjacent attributes of the same type. Do we need to support long & short attributes of the same type in the same message? How much do we rely on attribute ordering (consecutiveness)? How does this apply to VSAs –which are already the same type? IETF-64, Vancouver

RADIUS Attribute Guidelines Grouping Named vs. unnamed tagging Known contents vs. arbitrary contents Can newly defined groups of data contain previously defined (standard) attributes? IETF-64, Vancouver

RADIUS Attribute Guidelines When to use which format (SHOULD/MUST) When to move from vendor to standard When to define vendor specific values When to use the extended type space How to translate to/from Diameter (see draft-mitton-diameter-radius-vsas-00.txt) IETF-64, Vancouver

RADIUS Attribute Guidelines To think about, get consensus, do... Diameter translation Agree on recommended approach Actual guidelines Address vendor specific values IETF-64, Vancouver

RADIUS Attribute Guidelines Finally, Is this a reasonable starting point for this charter work item? Volunteers for this work? Discussion IETF-64, Vancouver

RADIUS Attribute Guidelines Backup Slides IETF-64, Vancouver

RADIUS Attribute Guidelines Motivation – why do we need guidelines? Divergent data models Attribute space exhaustion Diameter alignment IETF-64, Vancouver

RADIUS Attribute Guidelines Data Model Two attribute spaces: standard & vendor Small number of data types Consistent TLV payload use enables: interoperability, intermediate nodes (proxies) simple implementation: attributes can be added without new parsing code Many exceptions Simple TLV IETF-64, Vancouver

RADIUS Attribute Guidelines Scope Backwards compatibility Intermediate nodes Dictionary based implementations Unaware endpoints Existing VSA usage Transport Impact Non-AAA applications Diameter compatibility IETF-64, Vancouver