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Published byBelinda Wells Modified over 8 years ago
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Extended Attributes RADEXT - Interim Alan DeKok FreeRADIUS
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RADEXT - Interim Requirements More RADIUS Attribute Types 256 is too limited Standard support for “long” attributes > 253 octets Better grouping RFC 2868 tags are inadequate
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RADEXT - Interim Un-Requirements Systems which were discussed and rejected too complex too limited which can’t be applied to existing RFCs
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RADEXT - Interim Current Attributes Type 1 octet Length 1 octet Value … 1..253 octets
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RADEXT - Interim Extended Attributes Type 1 octet Length 1 octet Ext-Type 1 octet Value … 1..252 octets
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RADEXT - Interim That’s pretty much it. “Steal” one octet of “value” for extended types Allocate 4 attributes of this format 241, 242, 243, 244 Solves the “need more attributes” problem Allows for ~1K new attributes
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RADEXT - Interim Naming We need to name the new attributes types. Use SNMP / IP Address style “dotted number” 241.{1-255} 241.1 “This-Is-A-New-attr” Versus 1 “User-Name” Naming applies only for the IANA registry
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RADEXT - Interim Grouping Better grouping by defining a TLV data type Already in WiMAX, 3GPP2, and other SDOs / vendors.
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RADEXT - Interim TLV Data Type TLV-Type 1 octet TLV-Length 1 octet Value … 1..253 octets
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RADEXT - Interim TLV in Ext-Attribute Type 1 octet Length 1 octet = 9 Ext-Type 1 octet TLV-Type 1 octet TLV-Length 1 octet Value … 4 octets
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RADEXT - Interim TLVs in Ext-Attribute Type 1 octet Length 1 octet = 29 Ext-Type 1 octet TLV-Type 1 octet TLV-Length 1 octet Value … 4 octets TLV-Type’ 1 octet TLV-Length’ 1 octet Value’ … 18 octets
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RADEXT - Interim TLV Properties Can carry any existing or future data type Including TLVs. Multiple TLVs can be on in one Ext-Attr Nested or concatenated Nesting is limited only by TLV-Length field 253 / 3 =~ 80 Practicalities show a depth of 5 is sufficient
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RADEXT - Interim TLV Naming Leverage the same “dotted number” notation! 241.1.2 RADIUS Attr 241, of type “ext-attr” Extended Attr 1, data type “tlv” TLV 2, data type “integer” Allows for ~250 fields in a struct Extends type space past 1K attributes
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RADEXT - Interim “Long” Attributes Leverage the Ext-Type format Allocate 2 attributes of this type 245, 246 Add another field: “flags” Standard way to say “more than 253 octets of data”
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RADEXT - Interim Long Ext Attributes Type 1 octet Length 1 octet Ext-Type 1 octet Flags 1 octet Value … 1..251 octets
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RADEXT - Interim Flags 1 bit of “M” for More (or continuation) Same meaning as existing ext-attrs / WiMAX 7 bits of “reserved” We have no idea what to do with these It’s likely that these will never be used
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RADEXT - Interim Additional notes 24{1-6}.26 are VSAs Allows for many more VSAs 24{1-6}.{241-255} are reserved No “experimental” or “implementation- specific” They have not been useful Detail instructions for IANA are included
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RADEXT - Interim Motivation RADEXT discussions have been long We need a solution soon (i.e. within 2-3 years) All other solutions are more complex Attribute audit shows the needs to be simple
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Attribute Audit CountData Type 2257 integer 1762 text 273 IPv4 Address 235 string 96 other data types 35 IPv6 Address 18 date 4 Interface Id 3 IPv6 Prefix 4683 Total Public dictionaries ~100 vendors 55% or more are “short” (<20 bytes) ~20 “long” attributes
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RADEXT - Interim Summary > 1K of new attribute space With TLVs, potentially 10’s of 1000’s Grouping via TLVs Proven to work in SDO VSAs Standard way to have “long” attrs No more “ad hoc method”
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RADEXT - Interim Implementations In FreeRADIUS “stable” branch http://git.freeradius.org Implements TLVs, basic type No support for “long attrs”
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RADEXT - Interim Questions?
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