Dynamic Transition From Tcp To Smc-D By Using Two Osa-Express Adapters - IBM z13s Technical Manual

SMC-D is a "hybrid" solution as shown in Figure D-13:
It uses a TCP connection to establish the SMC-D connection.
The TCP connection can be either through the OSA adapter or IQD HiperSockets
A TCP option (SMCD) controls switching from TCP to "out of band" SMC-D.
The SMC-D information is exchanged within the TCP data stream.
Socket application data is exchanged through ISM (write operations).
The TCP connection remains to control the SMC-D connection.
This model preserves many critical existing operational and network management
features of TCP/IP.
z/OS LPAR A
Middleware/Application
SMC-D
Data exchanged using
native PCI operations
(PCI STB)
Dynamic (in-line) negotiation for SMC-R&SMC-D is initiated by presence of TCP Options
TCP connection transitions to SMC-D allowing application data to be exchanged using Direct
Figure D-13 Dynamic transition from TCP to SMC-D by using two OSA-Express adapters
The hybrid model of SMC-D uses these key existing attributes:
It follows the standard TCP/IP connection setup.
The hybrid model switches to ISM (SMC-D) dynamically.
The TCP connection remains active (idle) and is used to control the SMC-D connection.
The hybrid model preserves the following critical operational and network management
TCP/IP features:
– Minimal (or zero) IP topology changes
– Compatibility with TCP connection-level load balancers
IBM z13 or z13s
Sockets
TCP
IP
Interf ace
ISM OSA
TCP connection establishment over IP
TCP syn flows (with TCP Options
CLC indicating SMC-R+SMC-D capability)
ISM VCHID (within System z)
IP Network (Ethernet)
Memory Access (LPAR to LPAR)
z/OS LPAR B
Middleware/Application
Sockets
TCP
SMC-D
IP
Interf ace
OSA ISM
data exchanged using
Appendix D. Shared Memory Communications
native PCI operations
(PCI STB)
OSA and ISM
have the same
PNet ID
491