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

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Important fields for the netstat –p ip command include the statistics for dropped fragments, which
should have low values. For example:
# netstat -p ip
ip:
12278434 total packets received
0 bad IP headers
257 fragments received
0 fragments dropped (dup or out of space)
62 fragments dropped after timeout
0 packets forwarded
0 packets not forwardable
The fragments dropped due to out of space can arise from packet loss rates and settings on the limits of
memory consumed by IP fragment reassembly (refer to ndd tunable ip_reass_mem_limit in Appendix
B). The only time there should be fragments dropped after timeout is when there is packet loss in
the network.
# netstat –p ipv6
ipv6:
6240733 total packets received
5 bad IPv6 headers
3206 fragments received
3 fragments dropped
The bad IPv6 headers are due to malformed IPv6 headers or IPv6 extension headers. The fragments
dropped could be due to the loss rate or the configured maximum amount of memory for IPv6 fragment
reassembly (Refer to the ndd tunable ip6_reass_mem_limit in Appendix B). It can also be related to
the timeout while waiting for missing fragments (Refer to ndd tunable ip6_fragment_timeout in
Appendix B).
For an annotated output of netstat –p protocol, refer to Appendix A.
6.1.3 Monitoring link level statistics with lanadmin
Use the output of lanadmin –g command to check for input errors, output errors, and collisions. Compare
the values in these fields with the total number of packets sent. High values may indicate a network
problem. For example, cables may not be connected properly or the Ethernet may be saturated.
# lanadmin -g 0
LAN INTERFACE STATUS DISPLAY
Wed, May 2, 2007 13:30:17
PPA Number = 0
Description = lan0 HP PCI Core I/O 1000Base-T Release
B.11.31.01
Type (value) = ethernet-csmacd(6)
MTU Size = 1500
Speed = 100000000
Station Address = 0x306e4c1c52
Administration Status (value) = up(1)
Operation Status (value) = up(1)
Last Change = 100
Inbound Octets = 310558225
Inbound Unicast Packets = 125478
Inbound Non-Unicast Packets = 26469103