The IP over ATM Mailing List Archive by date

[Carl Marcinik <carlm@fore.com>]

Rick,
    Not sure anyone has answered your question yet. ILMI is based on
SNMPv1 and therefore uses SNMP messages to communicate address
and prefix information between the user-side and network-side ILMI 
entities (UMEs). Both the SNMP messages and the ILMI MIB (which is the
conceptual information store used for both addresses and prefixes) are defined
in ASN.1 syntax and encoded on the "wire" using ASN.1 BER encoding rules.
As such, SNMP messages are not fixed size but vary according to the
number and type of object identifiers (OIDs) carried in a specific SNMP
message. You really need to understand a little bit about SNMP(v1) and
ASN.1 to tackle ILMI (Implementing ILMI really requires full support for
SNMPv1, there is not much you can do about that unless you can convince
the ATM Forum that they've made a mistake ;-).

I would suggest that you start by reading RFC 1157, RFC 1155, and
RFC 1213 in regard to SNMP(v1). ASN.1 syntax is defined in ISO standard 8824
and BER is defined in ISO standard 8825. However, there is a good exposition
of ASN.1 in Marshall Rose's book "The Open Book: A Practical Perspective
on OSI" and a shorter (and not as good) exposition in Rose's "The Simple
Book." "The Simple Book," however, contains a good exposition of SNMP.


Carl Marcinik
FORE Systems

>Question (actually request):
>
>I'm looking for the size and format of the messages used by ILMI to both
>register/acquire complete ATM addresses (ie put the NSAP prefix with the
>ESI) and perform Get and Get next operations.
>
>I have the UNI3.1 specs but I dont really understand the format that the
>instructions are in. If anyone could help me out by explaining them or just
>mailing me the info in a more readable form I would be eternally greatful
>(OK maybe not eternally).
>
>TIA,
>Rick
>
>rtb4328@tntech.edu
>