HP-UX 11i September 2001 Release Notes
Internet and Networking Services
Network Transport (new at 11i original release)
Chapter 10
160
caching can increase system performance if there are many short-lived connections on
the system.
6) Initial TCP congestion window size is now configurable: tcp_cwnd_init sets the
sender’s initial congestion window size according to the following formula:
Min((tcp_cwnd_init * MSS), max(2 * MSS, 4380)),
where MSS is the maximum segment size for the underlying link. Default 4: (TCP
implements RFC 2414). Range: 1-4
7) ip_pmtu_strategy ‘2’ is not supported for 11i: A local system can no longer send its
expected Path Maximum Transmission Unit (PMTU) value within an ICMP_ECHO
request to a remote system or router. This change prevents a type of Denial-of-Service
attack.
Type ndd -h for an online description of tunable parameters and other documentation.
Compatibility Issues
For the following commands,
ndd -get /dev/ip ip_tcp_status
ndd -get /dev/ip ip_udp_status
ndd -get /dev/ip ip_raw_status
ndd displays IP addresses using the IP version 6 (IPv6) format. When ndd maps IP
version 4 (IPv4) addresses to IPv6 addresses, ndd displays the IPv4 addresses with the
prefix “::ffff:”.
ndd displays the remainder of the IPv4 address in dotted-decimal notation. This could
cause scripts that are looking for a given output to fail.
Performance
None of the features will degrade performance. Enabling socket caching using
tcp_conn_strategy could potentially increase performance by 10 to 20%.
netstat
netstat displays the statistics and configuration of the networking kernel. There are
two changes to netstat. One is to netstat -r and the other to netstat -I.
netstat -r no longer updates the “Use” field. Therefore, netstat -r no longer displays
this field.
Beginning at HP-UX 11i, netstat -I <
interface
> displays statistics accumulated
since the last system reboot. This matches netstat -I output for HP-UX releases 10.20
and earlier.
Compatibility Issues
There could be some compatibility problems with scripts where they look for the “Use”
field.