HP-UX TCP/IP Performance White Paper, March 2008

udp_largest_anon_port:

Largest port number to use for anonymous bind requests.

[1024,65535] Default: 65535

This is analogous to the tcp_largest_anon_port tunable.

udp_status:

Obtain UDP information report similar to "netstat -an".

Requests for this report through concurrent execution of

ndd instances are serialized through semaphore. Hence udp_status

report invocation through ndd may appear to hang incase there is

an ndd instance generating tcp_status/udp_status report already

running on the system.

udp_recv_hiwater_max:

Limits the receive buffer size for TCP and UDP sockets or

communication endpoints specified in a SO_RCVBUF option of a

setsockopt() call or XTI_RCVBUF option in a t_optmgmt() call.

A setsockopt() call with a SO_RCVBUF option that exceeds the

corresponding kernel parameter value will fail and return the

errno value EINVAL.

A t_optmgmt() call with an XTI_RCVBUF option that exceeds the

corresponding kernel parameter value will fail and return the

t_errno value TBADOPT.

A socket() call to create a UDP socket will fail and return

the errno value EINVAL if the value of the ndd parameter

socket_udp_rcvbuf_default exceeds the value of udp_recv_hiwater_max

[1024-2147483647] Default: 2147483647 bytes

This tunable can be used to limit the maximum value for udp_recv_hiwater_max and for the value

passed-in via setsockopt() for SO_RCVBUF (similarly XTI_RCVBUF for t_optmgt). In doing so, the

administrator can make sure that no one application can monopolize the memory of the system by asking

for a very large socket buffer and then filling it.

The default and maximum value for this parameter is 2147483647 (2

) bytes.