NS3000/iX NMMGR Screens Reference Manual - Edition 8 (36922-90038)

Chapter 4 59

Network Transport Conﬁguration Screens

Packet Exchange Protocol (PXP) Conﬁguration

Fields

Checksum

enabled (Y/N)

Checksumming is a method of error checking. Enter a Y

(yes) to enable checksumming for all sockets for this

protocol. Enter an N (no) to allow individual sockets to

choose checksumming for themselves.

PXP checksumming causes signiﬁcant overhead, and is

not normally needed for this protocol. Also, error

checking is provided for at the link level. For these

reasons, HP recommends the default value (N) for this

ﬁeld unless communication to a non-HP machine is

desired.

Default value: N

Retransmission

interval

(secs) The time in seconds to wait for a reply from a remote

node before retransmitting a request. In general, the

value to conﬁgure should reﬂect the load on the local

system, the remote system, and the networks through

which the request and the reply must travel. If the

value is set too low, needless retransmissions may

occur, or IPCLOOKUP calls may fail. If the value is set

too high, an unnecessarily long delay will occur when a

packet is lost, and a retransmission will be necessary.

Frequent log messages indicating that retransmissions

are taking place or that requests are failing indicate

that the value needs to be increased.

Default value: 10

Range: 1–600

Maximum

retransmissions

per request This is the number of times that PXP will retransmit a

request when a reply has not been received within the

retransmission interval (explained above).

As in the discussion of retransmission interval above,

this ﬁeld is a tuning parameter. The two values work

together to determine the maximum time that a PXP

user will wait for a reply. This maximum reply time is

calculated as follows:

RTXinterval + (RTXinterval * MAXRTX)

where RTXinterval is the conﬁgured retransmission

interval and MAXRTX is the conﬁgured maximum

retransmissions per packet. Note that excessive values