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Community Member

Pack and unpack Radius VSA attributes


As far as I know there are some methods to pack radius VSA attributes. Here are:

  1. As the part of Cisco-AVPair

    • 26 - VSA

    • Length

    • 9  - Vendor ID

    • 1  - Vendor Type (Cisco-AVPair Attribute ID)

    • Attribute Name=Value

  2. In the Vendor Specific attribute ("throught attribute ID")

    • 26  - VSALength

    • 9 - Vendor ID

    • 2 - Vendor Type (Attribute ID)

    • Vendor Length

    • Attribute Name=Value

  3. In the Vendor Specific attribute ("throught attribute ID") 

    • 26 - VSA

    • Length

    • 9 - Vendor ID

    • 2 - Vendor Type (Attribute ID)

    • Value

i.e. with attribute name and witout.
How to understand which attribute needs attribute name in value string?

For example:

  1. 26|Length|9|2|Vendor Length|1|h323-incoming-conf-id=82b5fc8cd6f411dfa3c6080027716a9a
  2. 26|Length|9|2|Vendor Length|35|h323-incoming-conf-id=82b5fc8cd6f411dfa3c6080027716a9a
  3. 26|Length|9|2|Vendor Length|35|82b5fc8cd6f411dfa3c6080027716a9a

which of the methods is right?

Everyone's tags (3)
Cisco Employee

Re: Pack and unpack Radius VSA attributes


For the specific VSA you used in the example (h323-incoming-conf-id), (1) is the correct encoding, since Cisco VSA vendor type 1 (also more commonly referred to as  cisco AV Pair) is always encoded in strings with the format of "attribute=value". This applies to other cisco VSAs that use string encoding as well. For VSA's that don't use string encoding, eg., fax-pages (vendor type 5, encoding integer), it typically doesn't include the value. You should be able to check that against the vendor dictionary to confirm. Please also see:



Community Member

Re: Pack and unpack Radius VSA attributes

Hi Wen,

I have looked at, I found the possible values for atribute “gw-rxd-cgn”, but not the meaning of them.

Cisco-AVPair = "gw-rxd-cgn=ton:0,npi:0,pi:1,si:0,#:391450098"
Cisco-AVPair = "gw-rxd-cgn=ton:0,npi:0,pi:0,si:0,#:391450098"

I think pi:1 means that the calling number is anonymous and pi:0 is present, they can also be 2 or 3. Where can I found information to decode this string and other VSAs strings?

David Costa

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