SNMP over AppleTalk
RFC 1419
Network Working Group G. Minshall
Request for Comments: 1419 Novell, Inc.
M. Ritter
Apple Computer, Inc.
March 1993
SNMP over AppleTalk
Status of this Memo
This RFC specifies an IAB standards track protocol for the Internet
community, and requests discussion and suggestions for improvements.
Please refer to the current edition of the "IAB Official Protocol
Standards" for the standardization state and status of this protocol.
Distribution of this memo is unlimited.
Introduction
This memo describes the method by which the Simple Network Management
Protocol (SNMP) as specified in [1] can be used over AppleTalk
protocols [2] instead of the Internet UDP/IP protocol stack. This
specification is useful for network elements which have AppleTalk
support but lack TCP/IP support. It should be noted that if a
network element supports multiple protocol stacks, and UDP is
available, it is the preferred network layer to use.
SNMP has been successful in managing Internet capable network
elements which support the protocol stack at least through UDP, the
connectionless Internet transport layer protocol. As originally
designed, SNMP is capable of running over any reasonable transport
mechanism (not necessarily a transport protocol) that supports bi-
directional flow and addressability.
Many non-Internet capable network elements are present in networks.
Some of these elements are equipped with the AppleTalk protocols.
One method of using SNMP to manage these elements is to define a
method of transmitting an SNMP message inside an AppleTalk protocol
data unit.
This RFC is the product of the SNMP over a Multi-protocol Internet
Working Group of the Internet Engineering Task Force (IETF).
1. Background
The AppleTalk equivalent of UDP (and IP) is DDP (Datagram Delivery
Protocol). The header field of a DDP datagram includes (at least
conceptually) source and destination network numbers, source and
Minshall & Ritter [Page 1]
RFC 1419 SNMP over AppleTalk March 1993
destination node numbers, and source and destination socket numbers.
Additionally, DDP datagrams include a "protocol type" in the header
field which may be used to further demultiplex packets. The data
portion of a DDP datagram may contain from zero to 586 octets.
AppleTalk's Name Binding Protocol (NBP) is a distributed name-to-
address mapping protocol. NBP names are logically of the form
"object:type@zone", where "zone" is determined, loosely, by the
network on which the named entity resides; "type" is the kind of
entity being named; and "object" is any string which causes
"object:type@zone" to be unique in the AppleTalk internet.
Generally, "object" also helps an end-user determine which instance
of a specific type of service is being accessed. NBP names are not
case sensitive. Each field of the NBP name ("object", "type", and
"zone") is limited to 32 octets. The octets usually consist of
human-readable ascii characters.
2. Specification
SNMP REQUESTS encapsulated according to this standard will be sent to
DDP socket number 8; they will contain a DDP protocol type of 8. The
data octets of the DDP datagram will be a standard SNMP message as
defined in [1].
SNMP RESPONSES encapsulated according to this standard will be sent
to the DDP socket number which originated the corresponding SNMP
request; they will contain a DDP protocol type of 8. The data octets
of the DDP datagram will be a standard SNMP message as defined in
[1]. (Note: as stated in [1], section 4.1, the *source* address of
a RESPONSE PDU will be the same as the *destination* address of the
corresponding REQUEST PDU.)
A network element which is capable of responding to SNMP REQUESTS
over AppleTalk must advertise this capability via the AppleTalk Name
Binding Protocol using an NBP type of "SNMP Agent" (hex 53, 4E, 4D,
50, 20, 41, 67, 65, 6E, 74).
A network management station which is capable of receiving an SNMP
TRAP must advertise this capability via the AppleTalk Name Binding
Protocol using an NBP type of "SNMP Trap Handler" (hex 53, 4E, 4D,
50, 20, 54, 72, 61, 70, 20, 48, 61, 6E, 64, 6C, 65, 72).
SNMP TRAPS encapsulated according to this standard will be sent to
DDP socket number 9; they will contain a DDP protocol type of 8. The
data octets of the DDP datagram will be a standard SNMP message as
defined in [1]. The agent-addr field of the Trap-PDU must be filled
with a NetworkAddress of all zeros (the unknown IP address). Thus, to
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