Visara FEP-4600 Planning Guide - Manual (Page 15)

37x5 to FEP-4600 Migration and Planning Guide
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Ethernet DLSw-attached PU 2.1 Platforms
PU 2.1 platforms can be supported downstream from the FEP-4600 across IP networks
through the use of DLSw (Data Link Switching). The upstream connection is through the
XCA gateway interface. Typically you need a device on each end of the IP network to
convert LLC or SDLC traffic to DLSw traffic (SNA over IP). The FEP-4600 offers
internal DLSw support eliminating the need to pass LLC traffic over the local network.
When using internal DLSw, only IP traffic emerges over the Ethernet interface. External
routing of the IP traffic is still required by the FEP-4600 to move traffic beyond the local
network. The FEP-4600 requires another DLSw capable platform to reside at the remote
location to convert the DLSw traffic back to either LLC or SDLC.
Token Ring LLC-attached PU 2.0 Platforms
PU 2.0 platforms are supported downstream from the FEP-4600 on Token Ring networks
using LLC2 protocol. Upstream, PU2 traffic is routed through an XCA connection to
VTAM. Using this method up to 255 downstream PU 2.0 platforms can be supported
through a single XCA communication pipe. Up to 8 XCA communication pipes may be
defined for use with a single Token Ring interface (total of 2048 downstream PUs). Each
XCA Major Node definition uses one of the available 256 subchannels provided by the
ESCON interface.
You could also define a Channel Attached Major Node PU TYPE=2 in the VTAM
definitions and UNIT=3174 in the CNTLUNIT and IODEVICE macros. Using this
method the number of downstream PUs will depend on the number of Channel Attached
Major Nodes defined. Each Channel Attached Major Node requires one of the available
256 subchannels provided by the ESCON interface. If support for DLSw is required, a
switch/router must be used to provide the LLC2/DLSw protocol conversion.