120 likes | 276 Views
Diameter NASreq (RFC 4005) and RADIUS Compatibility. David Mitton RSA Security Inc. Overview. Diameter designed to be upwards compatible with RADIUS There will be encodings in Diameter that are not expressible in RADIUS
E N D
Diameter NASreq (RFC 4005) and RADIUS Compatibility David MittonRSA Security Inc. IETF 64, Vancouver Canada
Overview • Diameter designed to be upwards compatible with RADIUS • There will be encodings in Diameter that are not expressible in RADIUS • Most RADIUS attributes are supported in RFC 4005, exceptions are noted in Section 9. • Difficulty arises with Vendor Specific Attributes (VSAs) IETF 64, Vancouver Canada
Problems • RADIUS VSA typical practice involves unknown formats for sub-types and lengths. Gateway must know format to translate • RFC 4005 Section 9.6 only works for some RADIUS VSAs • Imposes limitations on Vendor type space • Diameter VS AVPs must be restrained to fit into RADIUS • Diameter AVP type space larger than RADIUS suggested format • Diameter AVP data can be longer • Diameter AVPs have flags IETF 64, Vancouver Canada
RADIUS VSAs vs Diameter Vendor Specific AVPs IETF 64, Vancouver Canada
Goals • Provide a mapping that allows bidirectional communication through a translating gateway system or bilingual server • Minimize special cases and vendor specific knowledge • Allow mix of Diameter and RADIUS speaking equipment and servers that don’t use different AVPs for same information IETF 64, Vancouver Canada
Proposal draft-mitton-diameter-radius-vsas-00.txt • RADIUS VSAs to Diameter AVP #26(not as described in RFC 4005 Sect 9.6) • Diameter VS AVPs to a new RADIUS attribute IETF 64, Vancouver Canada
RADIUS VSAs as Diameter AVP 26 • No transformation of attribute data – avoids vendor specific knowledge for pass-through • Only consumer needs to know inner format • No additional encoding overhead IETF 64, Vancouver Canada
Proposed RADIUS VSA to Diameter AVP 26 IETF 64, Vancouver Canada
Diameter Vendor Specific AVPsin RADIUS • Add a new RADIUS attribute • Provide fields of the proper length • Define fragmentation and aggregation • Similar to EAP message attribute • Use V flag to indicate start of sequenceand suppress redundant VID and VType IETF 64, Vancouver Canada
Proposed RADIUS Attribute for Diameter Vendor Specific AVPs IETF 64, Vancouver Canada
Affects Documents: • Change Diameter Vendor EncapsulationAffects Diameter Base RFC 3588, and Diameter NAS Application RFC 4005 • Specify RADIUS format of Diameter TLVsAffects RADIUS documents ??? IETF 64, Vancouver Canada
Conclusion • If we get rid of the RADIUS VSAs transformation in RFC 4005 Section 9 and add AVP #26 can transit Diameter with no transformational knowledge or loss of data • Add a RADIUS attribute to hold Diameter VS AVPs • The two vendor spaces end up independent, but can be used by either. IETF 64, Vancouver Canada