DCE Application Programming Guide

Application Design Considerations
HP NonStop DCE Application Programming Guide—429551-003
2-4
Capacity and Limits
The DCE run-time code uses RPCs internally for communication with the endpoint
map service, the directory service, and the security service.
TCP/IP Fault Tolerance
NonStop DCE uses the standard HP NonStop TCP/IP product to provide transport
services for an application; parallel library NonStop TCP/IP is not yet supported. The
failure of the TCP/IP IOP’s primary processor has the following effect:
•
When the ncacn_ip_tcp protocol is used, RPC communication between the
client and the server is interrupted; the client must rebind its sockets to recover.
•
When the ncadg_ip_udp protocol is used, there is no effect; the datagram
protocol tolerates such failures.
Capacity and Limits
NonStop DCE applications are limited in the number of clients and the size of the
thread stack.
Processing Limits
Because the ncacn_ip_tcp protocol sequence currently limits the maximum number
of clients to under 512, a DCE server servicing a large number of clients should
Table 2-2. Protocol Sequence File Opens
Protocol ncacn_ip_tcp (TCP) ncadg_ip_udp (UDP)
Server N + 1 files, where N is the number of active
associations for the protocol.
A server can have as many as
M associations from
a client, where M is the maximum number of
concurrent remote procedure calls from the client.
An association is shut down if it is not used for over
100 seconds, with the exception that at least one
association is maintained with a client that has an
active context handle.
One file
Client One file for each active association.
A client can have as many as
M associations with a
server, where
M is the maximum number of
concurrent remote procedure calls from the client to
the server.
An association is shut down if it is not used for over
five minutes, except that at least one association is
maintained with a server that has an active context
handle.
One file