Workgroup Switches
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The ATM Multimode Fiber UFC
supports switched virtual connections
(SVCs) only and does not support
permanent virtual connections (PVCs).
This UFC can terminate up to 1032
virtual channel connections (VCCs),
requiring one VCC for each unique
source/destination LEC pair. The ATM
Multimode Fiber UFC does not support
the VPI field of the Virtual Path/Channel
Identifier. This UFC assembles/
disassembles LAN frames from/to ATM
cells according to ATM Adaptation
Layer 5 (AAL-5) specifications.
The LAN Emulation Client (LEC)
component of the ATM Multimode Fiber
UFC can be preconfigured with the
address of its required LAN Emulation
Server (LES) and, as an alternative, can
discover the address of its LES dynami-
cally by communication with a LAN
Emulation Configuration Server (LECS).
The LEC on the ATM UFC is compatible
with LES/LECS Version 1.0 implementa-
tions.
For example, the LEC on this UFC can
communicate with the LES and LECS
components that are part of the IBM
8285 ATM Workgroup Switch (LES), the
IBM 8210 Multiprotocol Switching
Services (MSS) Server (LES or LECS),
and the Multiprotocol Switching
Services (MSS) Server Module for the
8260/8285 (LES and LECS). The ATM
Multimode Fiber UFC supports Best
Effort (Unspecified QoS), Variable Bit
Rate (VBR) and Constant Bit Rate
(CBR) connections only; other QoS
modes, such as Available Bit Rate
(ABR), are not supported.
The ATM Multimode Fiber UFC
switches frames between physical
LANs connected to the LAN switch and
emulated LANs within an ATM network.
Each UFC can provide connections to
multiple emulated LANs, each repre-
sented by a logical emulated LAN port
(ELP) within the UFC and all sharing the
same physical link to the ATM network.
Each ELP is designated by distinct ATM
station addresses and is associated
with a separate LEC instance within the
UFC. ELPs are analogous to physical
LAN ports and support the LAN switch
functions that apply to physical LAN
ports (for example, enable/disable,
virtual switch/domain grouping, and so
on).
The products within the IBM 8270 family
of LAN switches are not designed to be
ATM switches. The ATM UFC does not
support two ELPs on a single ATM UFC
assigned to the same virtual switch/
domain. A second ATM UFC can be
installed in the 8270 containing ELPs in
the same domain as the first. This
configuration is allowed for backup and
redundancy. Attempting to switch traffic
at high data rates from one ATM UFC to
another may exceed the design
limitations of this device. An ATM switch,
such as the 8265, should be used
instead if you have this requirement. A
maximum of eight ELPs (and emulated
LANs) can be within a single ATM UFC.
In Token-Ring LAN switches configured
for source route switching, ATM emu-
lated Token-Ring LAN segments in a
single virtual switch/domain will have
the same ring number, (this is also true
for physical Token-Ring LAN seg-
ments.)
This ATM UFC is supported in an IBM
8270 configured with the source-route
bridging function enabled.
The following management interfaces
will be provided or enhanced by the
ATM Multimode Fiber UFC; these
interfaces are accessible via the SNMP
agent within the base IBM 8270.
• LEC MIB (ATM Forum LEC Manage-
ment Specification Version 1.0)
• AToM MIB (RFC 1695)
• Interface group of MIB-II (RFC 1213 and
1573) enhanced to include ATM.
The switch’s SNMP agent is accessible
through any of the Token-Ring LAN
ports. When the LAN switch is config-
ured with an ATM UFC, the switch’s
SNMP agent is also accessible via an
emulated LAN connection across an
ATM port. Though the ATM UFC
provides and uses an Interim Local
Management Interface (ILMI) 3.0 and
3.1 interface for ATM configuration
management, the switch’s SNMP agent
is not accessible using this ILMI.
4-Port Token-Ring/Enhanced UTP/STP
Universal Feature Card (FC 5092, PN
85H5092):
The 4-Port Token-Ring card
provides four Token-Ring ports for each
UFC installed in the IBM 8270. Each or
all of these UFC ports can be config-
ured to be used in multilink TokenPipe
connections and/or configured to be
included in virtual switches. These UFC
ports support address filters, support
BootP/TFTP, Telnet, or SNMP sessions,
and can participate in the TokenProbe
facilities of the IBM 8270 (either as
monitoring ports or as monitored ports).
The 4-Port Token-Ring/Enhanced UTP/
STP Universal Feature Card ports
support Token-Ring twisted pair (UTP/
STP media via RJ-45 connectors. Any of
these four UFC ports can be configured
to provide either shared (half-duplex) 4
or 16-Mbps Token-Ring connections or
16 Mbps (dedicated) or 32-Mbps
(dedicated, full-duplex) connections. In
addition to the RJ-45 connectors for the
Token-Ring ports, there are 14 LEDs
(one set of three for each port plus two
for the UFC overall) on the faceplate of
this Universal Feature Card that
indicate the operational status of the
UFC and the ports.
