| The Apple Talk Protocol suite
includes the following protocols: |
| |
| AARP |
AppleTalk
Address Resolution Protocol |
| DDP |
Datagram Delivery Protocol |
| RTMP |
Routing Table Maintenance Protocol |
| AEP |
AppleTalk Echo Protocol |
| ATP |
AppleTalk Transaction Protocol |
| NBP |
Name-Binding Protocol |
| ZIP |
Zone Information Protocol |
| ASP |
AppleTalk Session Protocol |
| PAP |
Printer Access Protocol |
| ADSP |
AppleTalk Data Stream Protocol |
| AFP |
AppleTalk Filing Protocol |
Apple Computer developed the AppleTalk protocol
suite to implement file transfer, printer sharing, and mail
service among Apple systems using the LocalTalk interface built
into Apple hardware. AppleTalk ports to other network media
such as Ethernet by the use of LocalTalk to Ethernet bridges
or by Ethernet add-in boards for Apple machines.
AppleTalk is a multi-layered protocol providing
internetwork routing, transaction and data stream service, naming
service, and comprehensive file and print sharing. In addition,
many third-party applications exist for the AppleTalk protocols.
To extend the addressing capability of AppleTalk
networks and provide compliance with the IEEE 802 standard,
Apple Computer introduced AppleTalk Phase 2 in 1989. AppleTalk
Phase 2 differs primarily in the range of available network
layer addresses and the use of the IEEE 802.2 Logical Link Control
(LLC) protocol at the Data Link Layer.
The AppleTalk protocol suite is illustrated
here in relation to the OSI model:
Click the protocols on the map to see more
details.
AARP
AARP (AppleTalk Address Resolution Protocol)
maps between any two sets of addresses at any level of one or
more protocol stacks. Specifically, it is used to map between
AppleTalk node addresses used by the Datagram Delivery Protocol
(DDP), as well as higher-level AppleTalk protocols, and the
addresses of the underlying data link that is providing AppleTalk
connectivity. AARP makes it possible for AppleTalk systems to
run on any data link.
The AARP packet structure is shown below:
8
|
16
bits |
Data-link header |
Hardware type |
Protocol type |
Hardware address length |
Protocol address length |
Function |
AARP
packet structure |
Hardware type
Identifier for the data-link type.
Protocol type
Identifier for the protocol family.
Hardware address length
Length in bytes of the hardware address field.
Protocol address length
Length in bytes of the protocol address field.
Function
Indicates the packet function (1=AARP request, 2=AARP response
and 3-AARP probe).
Following the header are the hardware and
protocol addresses according to the values of the function field.
Interested
in more details about testing this protocol?
DDP
The Datagram Delivery Protocol (DDP) provides
a datagram delivery and routing service to higher layer protocols.
DDP frame headers can use the long or short format. Short format
DDP headers carry only the source and destination service socket
numbers, while long format DDP headers also carry the source
and destination network and node addresses needed for routing
capability. Because AppleTalk Phase 2 does not use LLAP to identify
source and destination nodes, it supports only the long format
DDP header for Phase 2.
Short Format Frames
The following fields are present for short
format DDP frames:
Destination socket
Destination service socket address used by the frame.
Source socket
Source service socket address used by the frame.
Length
Total length of the datagram.
DDP typeCode used to indicate the higher layer protocol used.
Long Format Frames
The following additional fields are present
for long format DDP frames:
DestinationDestination network/node/socket. Destination network number,
node address, and socket address used by the frame, displayed
in the following format: NNNN.nn (ss), where NNNN is the network
number, nn is the node address and ss is the socket address.
Source
Source network/node/socket. Source network number, node
address, and socket address used by the frame, in the same format
as D.
Checksum
Checksum of the entire datagram beginning after the checksum
field. A checksum of zero implies that the checksum is not in
use.
Hop count
Number of routers encountered by the frame. After 16 hops,
the protocol discards the frame.
Interested
in more details about testing this protocol?
RTMP
The Routing Table Maintenance Protocol (RTMP)
manages routing information for AppleTalk networks. RTMP communicates
known network numbers and data concerning accessibility between
networks. AppleTalk Phase 2 allows for split horizon routing
where the protocol transfers only routing data about directly
connected networks in an effort to reduce the traffic overhead
imposed by routing updates.
Frames
RTMP frames may be one of the following types:
| [request] |
Requests network
number and local router ID. |
| [reply] |
Supplies network
number and local router ID. |
| [data] |
Carries the
current routing table data. |
| [RDR split]
|
Requests immediate
routing data using split horizon (only Phase 2). |
| [RDR full] |
Requests full
table of routing data (only Phase 2). |
Frame Parameters
The following parameters are present in Apple
RTMP frames:
Source network/node
ID
Network number and address of the system sending the RTMP
[reply] or [data] frame. The network/node ID is displayed in
the following format: NNNN.nn, where NNNN is the network number
and nn is the node address.
Routing Table
List of known network nodes and accessibility number representing
the relative routing cost to the network. The routing table
displays items in the following format: NNNN(cc), where NNNN
is the network number and cc is the routing cost. AppleTalk
Phase 2 RTMP frames can specify a range of network numbers and
a protocol version number for the first term, as follows:
NNNN-NNNN(cc) [V=x], where NNNN is the network number, cc is
the routing cost in hops and x is the protocol version (2 for
Phase 2).
Interested
in more details about testing this protocol?
AEP
The AppleTalk Echo Protocol (AEP) provides
an echo service to AppleTalk hosts. It can specify up to 585
bytes of data for an echo transaction.
AEP frames may be one of the following types:
| [echo reqst]
|
Request to
echo the specified data. |
| [echo reply]
|
Echo response
containing echo data. |
Interested
in more details about testing this protocol?
ATP
The AppleTalk Transaction Protocol (ATP)
provides reliable delivery service for transaction-oriented
operations. ATP uses a bitmap token to handle acknowledgement
and flow control and a sequence of reserved bytes for use by
higher level protocols.
Frames
ATP frames may be of the following types:
| [request] |
Requests data specified by the
bitmap. |
| [reply] |
Returns requested data. |
| [release] |
Indicates end of transaction.
|
Frame Parameters
ATP frames contain the following parameters:
Transaction IDReference code used to match
ATP requests with ATP replies.
Transaction bitmap
Bitmap requests a specific data frame
and provides acknowledgment for received data. 1 in the bitmap
indicates an outstanding request for a data segment; 0 indicates
that the system satisfied the request. The bitmap position corresponds
to the data segment position. The bit on the far right represents
the first data segment with successive segments indicated to
the left. The bitmap is 8 bits wide, permitting ATP to send
up to 8 data segments per transaction request.
Sequence number corresponding
to the data segment of the current response frame.
User bytesFour bytes reserved for use by
higher level protocols.
Control FlagsThe following control flags
display in upper-case when set and in lower-case when inactive:
| x,X |
When set, exactly-once mode is set, ensuring
that the current transaction is performed only once. |
| e, E |
When set, the frame is the end of a data response. |
| s, S |
When set, the bitmap status requests reuse
of buffers already acknowledged. |
Interested
in more details about testing this protocol?
NBP
The AppleTalk Name Binding Protocol (NBP)
manages the use of names on AppleTalk networks. NBP maintains
a names directory that includes names registered by hosts and
bound to socket addresses. After a name is registered, the AppleTalk
host can perform a name lookup to find the socket address associated
with the name. When the host issues a name lookup on the Internet,
NBP sends a broadcast lookup to a router that generates name
lookup requests to each network within the zone specified in
the name.
Frames
NBP frames may be one of the following types:
| [brdcast lookup]
|
Broadcast search
for the specified name. |
| [name lookup]
|
Local search
for the specified name. |
| [lookup reply]
|
Reply to a
name lookup. |
Frame Parameters
NBP frames have the following parameters:
Number of names
Number of socket/name pairs contained in the message.
Transaction ID
Reference code used to match NBP replies with NBP requests.
Interested
in more details about testing this protocol?
ZIP
The AppleTalk Zone Information Protocol (ZIP)
manages the relationship between network numbers and zone names.
AppleTalk networks primarily implement ZIP in routers that gather
network number information by monitoring RTMP frames.
Frames
ZIP frames may be one of the following types:
| [zonename query]
|
Requests zone
name for a network number. |
| [zonename reply]
|
Supplies zone
name for network number. |
| [zonelist query]
|
Requests the
complete list of known zones. |
| [zonelist reply]
|
Supplies the
complete zone list. |
| [get zone reqst]
|
Requests the
local zone ID. |
| [get zone reply]
|
Supplies the
local zone ID. |
| [takedown zone]
|
Removes a zone
from the zone list. |
| [bring up zone]
|
Adds a zone
to the zone list. |
| [local zone
req] |
Requests local
zones on extended networks. |
| [ext name reply]
|
Zone name replies
too long for one frame. |
| [change notify
] |
Alerts nodes
of a zone name change. |
| [net info reqst]
|
Requests network
information for a zone name. |
| [net info reply]
|
Supplies network
range and multicast address for zones on extended nets.
|
Frame Parameters
Apple ZIP frames contain the following parameters:
Number
Number of networks for the request or zone information reply.
Start index
The starting zone for the zone list request.
Zone name
The name associated with the specified zone.
Multicast
Multicast address assigned to the specified zone.
Default zone
The local zone name.
Old zone name
The previously used name for the specified zone.
New zone name
New zone name for the specified zone.
Network range
The range of network numbers associated with the specified
zone display in the format: SSSS-EEEE where SSSS is the starting
network number and EEEE is the ending network number.
Network/zone list
List of networks and zone names represented as follows:
NNNN = zonename, where NNNN is the network number and zonename
is the zone name.
Messages
Apple ZIP [net info reply] and [change notify]
frames can contain the following messages:
| {invalid zone}
|
Specified zone
name does not exist. |
| {one zone}
|
Specified zone
is the only zone. |
| {use broadcast}
|
Local network
does not support multicasting, use broadcasting. |
The AppleTalk Session Protocol (ASP) manages
sessions for higher layer protocols such as AFP. ASP issues
a unique session identifier for each logical connection and
continuously monitors the status of each connection. It maintains
idle sessions by periodically exchanging keep alive frames in
order to verify the session status.
Frames
ASP frames can be one of the following types:
| [open session
reqst] |
Requests to
open an ASP session. |
| [close session
reqst] |
Requests to
close an ASP session. |
| [command call
reqst] |
Calls to higher
level protocol. |
| [status request] |
Requests server
status. |
| [session keep
alive] |
Maintains
idle connections. |
| [session write
reqst] |
Requests to
perform a write operation. |
| [write continue
req] |
Begins the
transfer of write data. |
| [attention
request] |
Send urgent
data. |
| [close session
reply] |
Acknowledges
session close. |
| [command call
reply] |
Reply from
higher level protocol. |
| [server status
reply] |
Reply containing
server information. |
| [open session
reply] |
Reply to open
session request. |
| [session write
reply] |
Reply to session
write request. |
| [write continue
rply] |
Session write
data. |
| [attention
reply] |
Acknowledges
receipt of attention request. |
Frame Parameters
Apple ASP frames can contain the following
parameters:
Session
ID
A reference code used to identify the session.
Sequence
number
Used by command, write, and write
continue frames to maintain data order.
Server
session socket
The socket number in use by the server end of the
connection.
Workstation
session socket
Workstation session socket. The socket number in
use by the workstation end of the connection.
Version
number
ASP version number currently in
use.
Buffer
size
Buffer size available for receiving command blocks.
Messages
Apple ASP reply frames can contain the following
messages:
| {OK} |
Command completed
successfully. |
| {xxxx bytes
written} |
Number of
bytes written for [write continue rply] frames. |
| {bad version
number} |
ASP version
not supported. |
| {buffer too
small} |
Request buffer
too small for command block. |
| {no more sessions} |
Server cannot
open any more sessions. |
| {no servers} |
Server not
responding. |
| {parameter
error} |
ASP parameter
values invalid. |
| {server is
busy} |
Server too
busy to open another session. |
| {session closed} |
Referenced
session has been closed. |
| {size error} |
Command block
larger than maximum. |
| {too many
clients} |
Client number
limit exceeded. |
| {no acknowledgement} |
Workstation
did not acknowledge. |
| {unknown error} |
Unknown error
condition. |
Interested
in more details about testing this protocol?
PAP
The Printer Access Protocol (PAP) manages
the virtual connection to printers and other servers. PAP is
used to convey connection status and coordinate data transfer.
Frames
PAP frames can be one of the following types:
| [open connection
rqst] |
Request to
open a PAP connection. |
| [open connection
rply] |
Reply to open
connection request. |
| [send data
request] |
Request to
send PAP data. |
| [PAP data
segment] |
Segment of
PAP data transfer. |
| [session keep
alive] |
Verify connection
status. |
| [close connection
req] |
Request to
close a PAP connection. |
| [close connection
rep] |
Reply to close
connection request. |
| [send server
status] |
Request server
status. |
| [server status
reply] |
Reply to server
status request. |
Frame Parameters
PAP frames can contain the following parameters:
Connection
ID
Reference code used to identify the PAP connection.
ATP
responding socket
ATP socket number used for PAP status and data transfers.
Maximum
buffer size
Maximum amount of data in bytes that the protocol can send in
response to each [send data request] (also known as the Flow
Quantum).
Wait
time
Length of time that a workstation waits for a connection.
Sequence
number
Used in send data request frames
to maintain data order.
EOF
End-of-file indicator. Used to
indicate the end of a data transfer.
Result
Result code indicating the outcome
of an [open connection rqst]:
0000 Connect OK.
FFFF Printer busy.
Status
Status message returned by status and open connection
reply frames.
Interested
in more details about testing this protocol?
ADSP
The AppleTalk Data Stream Protocol (ADSP)
provides a data channel for the hosts. It is a connection-oriented
protocol that guarantees in-sequence data delivery with flow
control.
Frames
ADSP frames can be one of the following
types:
| [acknowledge/probe] |
Acknowledges
data or requests acknowledge. |
| [open connect
reqst] |
Requests an
ADSP connection. |
| [open connect
ackn] |
Acknowledges
ADSP connection. |
| [open
request & ackn] |
Acknowledges
inbound connection and requests an outbound connection. |
| [open connect
denial] |
Refuses an
inbound connection. |
| [close connection] |
Requests to
close an ADSP connection. |
| [forward reset] |
Requests to
ignore specific data. |
| [forward reset
ackn] |
Acknowledges
forward reset of data stream. |
| [retransmit
advise] |
Requests to
retransmit data. |
Frame Parameters
ADSP frames can contain the following parameters:
Source
connection ID
Reference code used to identify
the sending side of a connection.
Destination
connection ID
Reference code identifying the
receiving side of a connection.
Send
sequence number
Sequence number used for the outbound
data stream.
Receive
sequence number
Sequence number used for the inbound data stream.
Receive
window size
Amount of unacknowledged data
that the other side of a connection can send.
Interested
in more details about testing this protocol?
AFP
The AppleTalk Filing Protocol (AFP) is the
file sharing protocol of the AppleTalk architecture. It provides
a native mode interface to Apple file system resources.
Apple files are comprised of two data structures
called forks. An Apple file may be accessed by its data fork
or its resource fork. The data fork holds raw file data while
the resource fork contains information used by the operating
system to manage icons and drivers.
Frames
AFP frames can be one of the following commands:
| [lock/unlock
bytes] |
Locks or unlocks
a specified byte range. |
| [close volume] |
Closes the
specified volume resource. |
| [close directory] |
Closes the
specified directory. |
| [close fork] |
Closes the
specified fork (file). |
| [copy file] |
Copies the
specified file. |
| [create directory] |
Creates the
specified directory. |
| [create file] |
Creates the
specified file. |
| [delete file] |
Deletes the
specified file or directory. |
| [list directory] |
Lists the
specified directory. |
| [flush to
disk] |
Writes data
held in RAM to disk. |
| [flush fork] |
Writes data
to disk for the specified fork. |
| [get fork
params] |
Retrieves
parameters for the specified fork. |
| [get server
info] |
Retrieves
server information. |
| [get server
params] |
Retrieves
server parameters. |
| [get volume
params] |
Retrieves
volume parameters. |
| [consumer
login] |
Begins workstation
log-in. |
| [login continue] |
Continues
workstation log-in. |
| [logout] |
Workstation
log-out. |
| [map user/group
ID] |
Gets ID associated
with user/group name. |
| [map user/grp
name] |
Gets name
associated with user/group ID. |
| [move and
rename] |
Moves and
renames a file. |
| [open volume] |
Opens the
specified volume. |
| [open directory] |
Opens the
specified directory. |
| [open fork] |
Opens the
specified fork (file). |
| [read from
fork] |
Reads from
the specified fork (file). |
| [rename file/dir] |
Renames a
file or directory. |
| [set dir params] |
Sets directory
parameters. |
| [set file
params] |
Sets file
parameters. |
| [set fork
params] |
Sets fork
parameters. |
| [set volume
params] |
Sets volume
parameters. |
| [write to
fork] |
Writes to
the specified fork (file). |
| [get file/dir
pars] |
Gets file
or directory parameters. |
| [set file/dir
pars] |
Sets file
or directory parameters. |
| [change password] |
Changes user
password. |
| [get user
info] |
Retrieves
user information. |
| [open database] |
Opens the
desktop database. |
| [close database] |
Closes the
desktop database. |
| [get icon] |
Retrieves
an icon from the desktop database. |
| [get icon
info] |
Retrieves
icon information. |
| [add APPL
mapping] |
Adds application
information. |
| [remove APPL] |
Removes application
information. |
| [get APPL
mapping] |
Retrieves
application information. |
| [add comment] |
Adds a comment
to a file or directory. |
| [remove comment] |
Removes a
comment from a file or directory. |
| [get comment] |
Retrieves
comment text from a file/directory. |
| [add icon] |
Adds an icon
for an application. |
Frame Parameters
Apple AFP frames can contain the following
parameters:
APPL
index
Index,
beginning with 1, of the first application mapping contained
in the frame.
APPL tag
Tag information
associated with the application mapping contained in the frame.
Attributes
Attributes of
a file or directory are as follows:
Directory attributes:
| Inv |
Invisible to workstation
user. |
| Sys |
System directory. |
| Bk |
Backup is needed (dir modified). |
| RI |
Rename inhibit mode set. |
| DI |
Delete inhibit mode set. |
File attributes:
| Inv |
Invisible to workstation
user. |
| MU |
Multi-user application. |
| RAO |
File resource fork already
open. |
| DAO |
File data fork already
open. |
| RO |
Read only mode set for
both forks. |
| WI |
Cannot write to either
fork. |
| Sys |
File is system file. |
| Bk |
Backup is needed (file
modified). |
| RI |
Rename inhibit mode set. |
| DI |
Delete inhibit mode set. |
| CP |
Copy protect mode set. |
Backup
date
Date of
the last time the system backed-up the volume or directory.
Bitmap
Field containing
bits used to indicate the parameters present in request or
reply.
Request count
Maximum number
of files to return for list directory requests.
Creation
date
Date that the
system created the file or directory.
File
creator
ID string of the
application or device that created a file.
Destination
directory ID
Destination directory
ID for a file copy or move.
Data
fork length
Length of the
file.
Destination volume ID
Destination volume
ID for a file copy or move.
Directory
bitmap
Field with bits
that indicate which directory parameters are present in AFP
frames.
Directory ID
Identifier associated
with the specified directory.
Desktop
database reference number
Reference number
used to access the desktop database.
File
bitmap
Bits that indicate
which file parameters are present in AFP frames.
Free
bytes
Number of bytes
free on the volume.
Open fork reference number
Reference code
used to access the open fork.
Group ID
Group ID used
for authentication.
Group name
Group name used
for authentication.
Icon tag
Tag information
associated with the specified icon.
Icon
size
Size of the specified
icon, in bytes.
Icon type
Type code identifying
the specified icon.
Long name
Long file name
(maximum 31 characters).
Machine type
Type of AFP server
in use.
Maximum reply size
Maximum number
of bytes this protocol returns for list directory requests.
Access mode
Open mode attributes
for a fork, represented as follows:
| R |
Allows everyone read access. |
| W |
Allows everyone write access. |
| Deny-R |
Denies read access if the
file is open. |
| Deny-W |
Denies write access if
the file is open. |
Modification
date
Date the system
last modified the file or directory.
New
line character
Character used
to indicate a new line (CR, LF) for read data.
New
line mask
Value used to
mask data for comparison to the new line character.
Offset
Starting file
offset for write commands.
Offspring count
Number of files
returned for list directory requests.
Owner
ID
ID of the file
or directory.
Volume password
Password required
for access to the volume.
Parent directory ID
ID of the parent
directory.
ProDOS information
ProDOS file type
and Aux type for use by ProDOS workstations.
Resource
fork length
Length of the
file resource fork, in bytes.
Source directory ID
Source directory
ID for a file copy or move.
Short name
Short file name
(maximum 12 characters).
Signature
Identifies the
volume type, as follows:
| 1 |
Flat, no support for directories. |
| 2 |
Fixed directory ID. |
| 3 |
Variable directory ID. |
Source
volume ID
Source
volume ID for a file copy.
Start index
Start index, beginning
with 1, of the requested file list for list directory commands
and replies.
Total bytes
Total number of
bytes on the volume.
User authentication method
Type of user authentication
in effect.
User ID
User ID number
used for authentication.
User name
User name used
for authentication.
Version
Version number
of AFP in use.
Volume bitmap
Field with bits
that indicate which volume parameters are present in AFP frames.
Volume ID
Identifier associated
with the specified volume.
Volumes
Number of volumes
contained on the server.
Messages
AFP [get server params] replies contain
a listing in the format: VolName(P,II), where VolName is a list
of the volume names, P indicates password-protection and II
indicates Apple II configuration information present.
The following status and error messages
may be displayed for AFP replies:
| Status
|
Error
Message |
| {OK} |
Command completed
successfully. |
| {Object locked} |
Specified
object locked. |
| {Volume locked} |
Specified
volume locked. |
| {Icon type
error} |
Icon size
mismatch. |
| {Directory
not found} |
Specified
directory does not exist. |
| {Can't rename} |
Cannot rename
volume or root directory. |
| {Server going
down} |
The server
is no longer active on the network. |
| {Too many
open files} |
Open file
limit exceeded. |
| {Object type
error} |
Specified
object invalid for operation. |
| {Call not
supported} |
AFP call unsupported
by this version. |
| {User not
authorized} |
User has insufficient
access rights. |
| {Session closed} |
Specified
session ID has been closed. |
| {Byte range
overlap} |
Lock conflicts
with existing lock. |
| {Range not
locked} |
Attempt to
unlock an unlocked byte range. |
| {Parameter
error} |
Specified
parameters invalid for operation. |
| {Object not
found} |
Specified
object does not exist. |
| {Object exists} |
Specified
object already exists. |
| {No server} |
AFP server
is not responding. |
| {No more locks} |
Number of
server locks exceeded. |
| {Miscellaneous
error} |
General command
error. |
| {Lock error} |
Byte range
already locked by another user. |
| {Item not
found} |
Specified
item not found. |
| {Flat volume} |
Volume does
not support directories. |
| {File busy} |
Specified
file is currently open. |
| {EOF error} |
End of fork
reached unexpectedly. |
| {Disk full} |
Volume is
out of disk space. |
| {Directory
not empty} |
Attempt to
delete a non-empty directory. |
| {Deny conflict} |
Specified
deny rights conflict. |
| {Cannot move} |
Cannot move
directory to a descendent directory. |
| {Bitmap error} |
Invalid bitmap
specified for object. |
| {Bad version
number} |
Specified
version number is invalid. |
| {Bad User
Authentic} |
User authentication
failed. |
| {Continue
Authentic} |
Authentication
not completed. |
| {Access denied} |
User does
not have permission for operation. |
Interested
in more details about testing this protocol?
|
