Cluster I/O Protocols (CIP) Configuration and Management Manual (H06.16+, J06.05+)

Socket Options
Some socket options that are supported by NonStop TCP/IPv6 are not supported by or have
changed with CIP and require application changes. These options are set by the Guardian
setsockopt, setsockopt_nw library calls or the OSS setcsockopt system call.
Socket Options Supported Differently
These socket options are supported differently in CIP:
Level IPPROTO_TCP
This TCP_SACKENA socket option for level IPPROTO_TCP, which enables TCP selective
acknowledgements, is supported differently in CIP. Use the CLIMCMD {clim–name |
ip–address} climconfig sysctl command to set the net.ipv4.tcp_sack parameter.
SO_PMTU
This socket option, which turns path discovery on and off, is not supported in CIP. Use the CLIMCMD
{clim–name | ip–address} climconfig sysctl command to change the net.ipv4.ip_no_pmtu_disc
parameter.The SO_PMTU
TCP_RXMTCNT
CIP does not support the socket option TCP_RXMTCNT but you can configure the interfaces to
achieve the same result. Use the CLIMCMD {clim–name | ip–address} climconfig sysctl
command to change the net.ipv4.tcp_retries2 parameter.
Unsupported Socket Options
These socket options are not supported by CIP.
Level IPPROTO_TCP
Some NonStop TCP/IPv6 socket options for level IPPROTO_TCP are not supported by CIP:
• TCP_DROP_IDLE
This socket option, which was supported but not documented, is no longer supported. See
Table 18 (page 193) for default behavior.
• IP_RECVDSTADDR
This socket option, which was supported but not documented, is no longer supported. See
Table 18: Differences in Socket Options Defaults (page 193) for default behavior.
• TCP_KEEPINIT
This socket option, which was supported but not documented, is no longer supported. See
Table 18: Differences in Socket Options Defaults (page 193) for default behavior.
• TCP_MINRXMT
The TCP_MINRXMT socket option, which sets the minimum time for TCP retransmission timeouts
is not supported in CIP.
• TCP_MAXRXMT
The TCP_MAXRXMT socket option, which sets the maximum time for TCP retransmission timeouts,
is not supported in CIP.
• TCP_NODELACK
This socket option, which was supported but not documented, is no longer supported. See
Table 18: Differences in Socket Options Defaults (page 193) for default behavior.
Application Programming Differences Between NonStop TCP/IPv6 and CIP 191