How to get the heel of RAS Message.

8 May 2001


      Hi, all:
I have two problems concerning H.323 ASN.1.
1>
H.323 ASN.1 states as follows:
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>>>
H323-UserInformation::=SEQUENCE
{
    h323-uu-pdu  H323-UU-PDU,
    user-data      SEQUENCE
    {
       protocol-discriminator    INTEGER  (0..255),
       user-information            OCTET STRING (SIZE(1..131)),
       .....
    }OPTIONAL,
    ....
}
<<<<<<<<<<
My question is," What's the use of "user-date" field and what its
protocol-discriminator field stand for? " Can anyone present me an example?
2>
The H.323 ASN.1 tells us that following the path
"H323-UserInformation>>h323-uu-pdu>>h323-message-body", we can get and set
UUIE of Q931 messages. But how can we do the same thing with RAS messages?
Or, what are the "ABSOLUTE PATH", the root, of the messages?
Thanks,
-Delphi