Cabletron Systems STS16-20D 用户手册
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SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide
Switch Overview
Transmission Priority Queues
To address the needs of delay-sensitive data, such as multimedia, the Token Ring
ports of the SmartStack STS16-20D/STS16-20R have two transmit queues, a high-
priority queue and a low-priority queue.
ports of the SmartStack STS16-20D/STS16-20R have two transmit queues, a high-
priority queue and a low-priority queue.
The queue for a frame is determined by the value of the priority field in the frame
control (FC) byte. If FC priority is above a configurable level (default 3), the frame
is put into the high-priority queue. If an output port becomes congested, you can
dynamically configure the port to transmit all frames at high priority regardless of
the FC byte contents.
control (FC) byte. If FC priority is above a configurable level (default 3), the frame
is put into the high-priority queue. If an output port becomes congested, you can
dynamically configure the port to transmit all frames at high priority regardless of
the FC byte contents.
ClearSession Support
The SmartStack STS16-20RM switch family support the ClearSession high
availability and network redundancy features.
availability and network redundancy features.
ClearSession is a framework for mission critical networks. It prevents session loss by
providing a network failure recovery time of, typically, less than three seconds.
ClearSession consists of a several product features. Some of these, ClearServer,
CrossLinks and Dynamic Source Route Recovery, are supported by the CSmartStack
STS16-20RM switch family. These features provide the following functionality:
providing a network failure recovery time of, typically, less than three seconds.
ClearSession consists of a several product features. Some of these, ClearServer,
CrossLinks and Dynamic Source Route Recovery, are supported by the CSmartStack
STS16-20RM switch family. These features provide the following functionality:
ClearServer
. Token-Ring ClearServer for LAN, allow multiple adapters to be
treated as one virtual adapter in the server, thus allowing multiple connections
between a server and the backbone switch or switches. During normal operation the
traffic is distributed on the links. The SmartStack STS16-20RM switch
familysupport ClearServer for LAN to be used on servers connected to the switch.
between a server and the backbone switch or switches. During normal operation the
traffic is distributed on the links. The SmartStack STS16-20RM switch
familysupport ClearServer for LAN to be used on servers connected to the switch.
CrossLinks.
Any Token-Ring link or dedicated Token-Ring link between
SmartStack STS16-20RM family switches may be expanded to a CrossLink. A
CrossLink is an aggregation of two to eight identical parallel links, working as one
link of the aggregate capacity, providing protection from physical link failure.
Should one of the links fail, the traffic is redistributed among the remaining
operational links.
CrossLink is an aggregation of two to eight identical parallel links, working as one
link of the aggregate capacity, providing protection from physical link failure.
Should one of the links fail, the traffic is redistributed among the remaining
operational links.
Dynamic Source Route Recovery
. DSRR is a feature that enables two or more
SmartStack STS16-20RM family switches performing source route bridging
between a shared-media access ring and a common backbone ring to function as
backup for each other. Should one of the switches fail or lose connectivity to one
of the access rings, the other switch immediately takes over and bridges source-
routed traffic marked with the failed path. DSRR protects source-routed traffic to
and from shared access segments, such as user rings, with redundant connections
to two Token-Ring switches. Traffic to and from such rings that is non-source-
routed relies on the spanning tree.
between a shared-media access ring and a common backbone ring to function as
backup for each other. Should one of the switches fail or lose connectivity to one
of the access rings, the other switch immediately takes over and bridges source-
routed traffic marked with the failed path. DSRR protects source-routed traffic to
and from shared access segments, such as user rings, with redundant connections
to two Token-Ring switches. Traffic to and from such rings that is non-source-
routed relies on the spanning tree.