GarrettCom 6K8 Manual De Usuario

Magnum 6K8-Series Industrial Field Switch             Installation and User Guide   (04/07) 

Magnum 6K8-Series’s are store-and-forward switches.  Each frame (or packet) 

is loaded into the Switch’s memory and inspected before forwarding can occur.  This 

technique ensures that all forwarded frames are of a valid length and have the correct 

CRC, i.e., are good packets.  This eliminates the propagation of bad packets, enabling all 

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 6K8-Series 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 fraction of a second and is transparent to an observer.  

Another feature implemented in Magnum 6K8-Series 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. The flow control option is user configurable (enable/disable) through the setport 

command of MSN-6K software as per the requirement of a network. 

 
2.2.10  Managed Network Software (MNS-6K) for Magnum 6K8-Series 

Magnum 6K8-Series comes with licensed MNS-6K Firmware (Rel 3.2), which 

allows the configuration of the Magnum 6Ks as a Managed Switch and also allows other 

 
 

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