Patent ID: 8090760

Claim:
A machine readable medium comprising a non-transitory medium embodying a program of machine-readable instructions executable by a computer system for conducting IP communications over a SAN, to simulate TCP/IP communications over an Ethernet network, by performing communications between a first PPRC pair and communications between a second PPRC pair, and by performing the following operations: establishing the first PPRC pair comprising a first site disk at a local site and a third site disk at a remote site, wherein the first site disk and the third site disk are coupled to a first unidirectional private communication link which provides communications between the local site and the remote site; establishing the second PPRC pair comprising a fourth site disk at the remote site and a second site disk at the local site, wherein the fourth site disk and the second site disk are coupled to a second unidirectional private communication link which provides communications between the remote site and the local site; determining if a TCP/IP network is functioning; and if a determination is made that the TCP/IP network is functioning, conducting IP communications over the TCP/IP network; and performing the following additional operations only if a determination is made that the TCP/IP network is not functioning: opening a first TCP/IP socket at the local site; opening a second TCP/IP socket at the remote site; wherein the first TCP/IP socket and the second TCP/IP socket are members of a simulated TCP/IP socket library simulating TCP/IP communications over an Ethernet network, wherein the TCP/IP communications over the Ethernet network are simulated with communications between the first PPRC pair over the first unidirectional private communication link, and with communications between the second PPRC pair over the second unidirectional private communication link; generating local site communication information; writing the local site communication information to the first TCP/IP socket at the local site, wherein writing the local site communication information to the first TCP/IP socket at the local site comprises storing the local site communication information on the first site disk at the local site and using PPRC to send the local site communication information from the first site disk at the local site over the first unidirectional private communications link to the third site disk at the remote site; storing the local site communication information at the third site disk at the remote site; reading the local site communication information from the third site disk at the remote site; sending the local site communication information read from the third site disk, to the second TCP/IP socket; and reading the local site communication information from the second TCP/IP socket, wherein the local site communication information is read by an application at the remote site.