Installing and Administering LAN/9000 Software

New for the HP-UX 11i Release

The 11i HP-UX release has the following transport (IP, TCP, and UDP)

changes:

• IP address subnet identiﬁers can now be all 1s or all 0s (RFC 1812).

• IP PMTU (Path Maximum Transmission Unit) discovery algorithm

reverts back to 10.20 behavior.

• Virtual IP (VIP) addresses can now be conﬁgured for a system. A

system VIP address is not tied to a speciﬁc physical interface and can

be used to send and receive IP packets on any physical interface of

the system.

• TCP performance enhancements.

TCP was enhanced to support the following features and RFCS:

— Selective Acknowledgment* (SACK, RFC 2018)

— Extensions for High Performance (scaled windows** and

timestamps*, RFC 1323)

— Increasing TCP's Initial Window (RFC 2414)

— TCP Congestion Control (RFC 2581) and NewReno Modiﬁcation

for Fast Recovery (response to partial acknowledgments, RFC

2582)

— Socket structure caching

• TCP FIN WAIT 2 timer*.

• System-wide limits for TCP and UDP socket buffer sizes.

• OLAR

Many of the above changes are controlled by new ndd parameters that

are not documented in the online help text for ndd shipped with 11i. A

summary of the new ndd parameters and parameter changes is provided

at the end of this article and this information will be included in a later

version of ndd.

*By default, many of the TCP performance enhancements will be used

only if the remote system initiates the use of them. Refer to the

subsections below for information on how to conﬁgure the system to