Cabletron Systems SmartStack STS16-20FRM, Installation And User Manual

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SmartStack STS16-20RM/STS16-20FRM Token Ring Switches, P/N: 9032957-01 Switch Overview
CrossLink Connections
Two or more Token-Ring ports can be configured to comprise a CrossLink.
A CrossLink is a collection of identical parallel links between two switches or
between a switch and an end node, aggregated to appear as one single link of the
aggregate capacity. The traffic distribution mechanism attempts to balance the load
on the individual links. If one of the links in a CrossLink fails, the traffic is
automatically moved from this link and distributed among the other links, thus
providing active resilience.
The CrossLink ports on a STS16-20RM series switch can be used to connect to
another STS16-20RM series switch, or a server with multiple RapidFire adapters
using ClearServer for Token-Ring. (Please note that ClearServer for Token-Ring is
supported on selected models of RapidFire adapters only. For details, refer to the
ClearServer for LAN product information.)
The CrossLinks provide load distribution as well as resilience. In normal operation,
the traffic is distributed on the physical ports of the CrossLink according to the
frame MAC addresses. This ensures the sequence of a flow. Should a link fail or
otherwise become inoperative, the switch dynamically redistributes the traffic to
the remaining links. The CrossLink remains in operation as long as there is at least
one link in operation. If a failed link is restored, traffic is once more redistributed
to make use of the restored link.
A CrossLink is in many ways operating as one single link. For example, the
spanning tree protocol will only have one port entity covering all ports in the
CrossLink. The ports will all have the same operating state. As for VLAN and CRF
configuration, the CrossLink is also seen as one link. Configuration changes apply
to all links in the CrossLink.
On the STS16-20RM or STS16-20FRM switch, CrossLinks can also be configured
on the High-Speed Token-Ring ports of the SSIM-R2-02/SSIM-R8-02 High-Speed
Token Ring SmartStack Interface Modules or on the Fast Ethernet ports of the
SSIM-H2-02 Fast Ethernet - Translational Switch SmartStack Interface Module.
CrossLinks on Fast Ethernet ports can only consist of two ports available on the
sameSSIM-H2-02 Fast Ethernet - Translational Switch SmartStack Interface
Module.
The CrossLink concept is designed to be compatible with the coming Link
Aggregation standard, IEEE 802.3ad.
The STS16-20RM or STS16-20FRM switch allows up to eight CrossLinks, each
consisting of up to eight Token-Ring links.
For details about CrossLink configuration, please refer to the section “CrossLink”
on page 109 in Chapter 6, “Switch Configuration”..