Magnum 6K25 Managed Fiber Switch Installation and User Guide (04/06)
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of the available bandwidth to be used for valid information.
While other switching technologies (such as "cut-through" or
"express") impose minimal frame latency, they will also permit bad frames to propagate
out to the Ethernet segments connected. The "cut-through" technique permits collision
fragment frames (which are a result of late collisions) to be forwarded which add to the
network traffic. Since there is no way to filter frames with a bad CRC (the entire frame
must be present in order for CRC to be calculated), the result of indiscriminate cut-
through forwarding is greater traffic congestion, especially at peak activity. Since
collisions and bad packets are more likely when traffic is heavy, the result of store-and-
forward operation is that more bandwidth is available for good packets when the traffic
load is greatest.
When the Magnum 6K25 Switch detects that its free buffer queue space is low,
the Switch sends industry standard (full-duplex only) PAUSE packets out to the devices
sending packets to cause “flow control”. This tells the sending devices to temporarily
stop sending traffic, which allows a traffic catch-up to occur without dropping packets.
Then, normal packet buffering and processing resumes. This flow-control sequence
occurs in a small fraction of a second and is transparent to an observer.
Another feature implemented in Magnum 6K25 Switches is a collision-based flow-
control mechanism (when operating at half-duplex only). When the Switch detects that
its free buffer queue space is low, the Switch prevents more frames from entering by
forcing a collision signal on all receiving half-duplex ports in order to stop incoming
traffic.
2.2.11 Managed Network Software ( MNS-6K ) for Magnum 6K25-Series
Magnum 6K25-Series’s come with licensed MNS-6K Firmware (Rel 3.2),
which allows to configure the Magnum 6Ks as a Managed Switch and other Software
enabled features. For additional information about MNS-6K, see the Magnum 6K25-
Series MNS
Software User guide
in pdf format, a separate document normally accessed
via your web-browser, at
ftp://ftp.garrettcom.com/
or FTP client program by
ftp.GarrettCom.com
using
user : m6kuser
password : m6kuser
All MNS-6K software information, including new releases and upgrades related to MNS-
6K software,
can be accessed and download from GarrettCom’s FTP site.
Alternatively, for documentation and latest information,
or needed
GarrettCom proprietary MIBs
for SNMP-
