Specifications

UDM Hub Control Protocol
109
UDM-0404 4x4 Multi-Format Distribution Hub
Handshaking
Although UDP is not deterministic (there is no guarantee that a UDP packet will be delivered), using UDP
greatly simplifies the stack processing in the hubs. To accommodate UDP, this protocol requires that the hubs
send a completion reply on receipt (and completion) of any command. This is not a great restriction since some
commands may not complete (selection of a disabled input for example) and status must be returned and
decoded anyway.
To facilitate decoding, returned status messages duplicate the command and add a status return value.
Returned status replies can therefore be matched with commands, even if delivered out of order. If a reply is
not received, the sender must retry. Since all commands are stateless, such a simple scheme is adequate.
The command format allows for a number of user-defined bytes to be sent with the command, which will be
returned in the status. These may be used, for example, for sequence numbering or decoding.
Command Set
In each of the following descriptions, only the contents of the UDP data packet are specified.
Authentication
Before any SLIP (ethernet UDP commands do not require authentication) commands can be executed the user
must be authenticated - this uses the same password mechanism as authentication from the console command
line or from a web browser.
Authenticate (Login)
Provides authentication information for this UDP session - the password is the same as for web browser and
console sessions (default is admin). If the password is correct, further UDP commands will be accepted.
Currently, the password is unencrypted.
Return Status:
The status value returned is as follows:
If the session is not logged (hasn't been correctly authenticated) then any command will return a status value of
70.
Logout
Logs the UDP session out - further communications will require a login command to be sent:
Return Status:
The status value returned is as follows:
This authentication process may be disabled using a Setup web page option.
Byte # 0 1 2 3..n
Byte value 98 User defined Password length Password string
Byte # 0 1 2 3 4 5
Byte value 98 Status Undefined Undefined Undefined Undefined
Status value Description
1 Command completed successfully
70 Unable to authenticate (password incorrect)
Byte #012345
Byte value 97 User Defined User Defined User Defined User Defined User Defined
Byte # 0 1 2 3 4 5
Byte value 97 Status Undefined Undefined Undefined Undefined
Status Value Description
1 Command completed successfully
70 System is already logged out