Expand Configuration and Management Manual (G06.24+)

Subsystem Description
Expand Configuration and Management Manual—523347-008
18-54
Expand-to-IP Interface
Expand-to-IP Interface
This subsection describes how the Expand-over-IP line-handler process accesses an
Internet Protocol (IP) network. You should be familiar with the information presented in
this subsection before attempting to configure, manage, or troubleshoot an Expand
network that includes IP connections.
Topics discussed in this subsection include
•
NonStop TCP/IP Processes on page 18-54
•
Expand-over-IP Connection Establishment on page 18-55
•
Sending and Receiving Data on page 18-57
•
Forwarding Expand-over-IP Packets to Other Expand Line-Handler Processes on
page 18-58
NonStop TCP/IP Processes
Expand-over-IP line-handler processes do not use the Data Link Layer (OSI Layer 2)
services of the Expand End-to-End protocol; instead, these line-handler processes use
the NETIP protocol at Layer 2 to communicate with a NonStop TCP/IP, Parallel Library
TCP/IP (TCPSAM), or NonStop TCP/IPv6 (TCP6SAM) process. The QIO mechanism
is used to transfer data between the Expand-over-IP line-handler process and its
associated NonStop TCP/IP, TCPSAM, or TCP6SAM process.
NonStop TCP/IP, TCPSAM, and TCP6SAM processes provide a Guardian file-system
interface to the Transmission Control Protocol (TCP) and the User Datagram Protocol
(UDP), as well as raw (direct) access to the Internet Protocol (IP). (However, raw-
socket support is limited with the Parallel Library TCP/IP and NonStop TCP/IPv6
subsystems. See the TCP/IP and TCP/IPv6 Programming Manual for information
about raw-socket programming limitations. (The limitations documented in the TCP/IP
and TCP/IPv6 Programming Manual apply to Parallel Library TCP/IP as well.)) The
Expand-over-IP line-handler process uses the UDP services provided by the TCP/IP
subsystem to transmit data across an IP network. UDP is a minimal datagram protocol
Note. This subsection refers to modifiers that allow you to control various aspects of the
Expand-to-IP interface. For detailed information about these modifiers, refer to Section 17,
Expand Modifiers.
Note. Because the QIO mechanism involves data sharing, the Expand-over-IP line-handler
process and its associated NonStop TCP/IP process must reside in the same processor pair.
However, the Parallel Library TCP/IP architecture removes this restriction so when either the
Parallel Library TCP/IP or NonStop TCP/IPv6 subsystems are used for TCP/IP connectivity,
the Expand-over-IP line-handler process does not need to reside in the same processor pair as
the TCPSAM and TCP6SAM processes.