Visara FEP-4600 Planning Guide - Manual (Page 25)

37x5 to FEP-4600 Migration and Planning Guide
707117-003 2-7
Downstream PUs are typically set up to dynamically connect through the XCA to request
connection to the Switched Major Node definition. Individual PUs are not locked to a
specific XCA interface in the host gen unless the host is expected to initiate the
connection (typically SDLC environments only). Connecting to a specific XCA is usually
left up to the configuration of the downstream device. The downstream device is typically
configured for its upstream gateway’s MAC address and SAP number. This MAC
address and SAP are tied to a specific XCA gateway when the XCA gets activated in
VTAM.
If multiple XCA’s are defined to the same VTAM, the downstream PU can connect
through any of them to establish a session with VTAM. Access to a particular XCA pipe
is controlled by the SAP assigned to it. Parallel connections to the same VTAM typically
make use of the same SAP assignment. VTAM maintains a connection through only one
of the XCAs to a specific PU at a time. If connection is lost, the downstream PU can
establish a new connection through the same or through a different XCA. Token Ring,
Ethernet, and SDLC attached PUs are supported through the XCA interface on the FEP-
4600.
XCA Pipe
XCA Pipe
ESCON
VTAM
FEP-4600
Switched
Definitions
Ethernet
Ethernet
ETH0
ETH1
SAP04
SAP08
LLC2 Traffic
LLC2 Traffic