GarrettCom MNS-6K Manual De Usuario

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M A G N U M   6 K   S W I T C H E S ,     M N S - 6 K   U S E R   G U I D E  
 
•  The ring is made up of devices which are managed switches only from 
Magnum 6K family of switches 
•  Each of the switches in the ring topology are configured for RSTP 
•  The RS-Ring product license key is configured on each switch in the ring 
 
 
S-Ring and LLL concepts
 
S-Ring is built upon networking software standards such as 
IEEE 802.1d Spanning Tree Protocol (STP) or Rapid 
Spanning Tree Protocol (RSTP) based on IEEE 802.1w. 
The purpose of S-Ring is to define two ports which participate in the RSTP/STP 
tree structure in a ring topology as opposed to a meshed topology. S-Ring running 
on the ring manager switch leverages this capability to recover quickly from fault 
situations. The recovery times for S-Ring based networks are within a few hundred 
milliseconds. Recovery time for STP devices is in tens of seconds (typically 30-50 
seconds in most networks) or sub second to a few seconds for RSTP networks. The 
biggest advantage of S-Ring, besides the fast recovery time, is the defined ring 
topology which makes the network manageable. S-Ring can also be an overall lower 
cost solution as there are hubs as well as switches which can be used in the ring. 
 
In the Magnum 6K family of switches as well as in other unmanaged switches such 
as the ESD42, a feature called Link-Loss-Learn™ (LLL) can be activated to 
immediately flush its address buffer and relearn the MAC addresses that route 
packets around the fault. This procedure, which is similar to switch initialization, 
occurs within milliseconds, resulting in fast ring recovery. An S-Ring implementation 
watches for link-loss as well as for STP/RSTP BPDU packet failures and responds 
to whichever occurs first. In most instances the link-loss will be detected faster than 
the two-second interval at which the BPDU packets are successfully passed around 
the ring. Typical ring recovery times using S-Ring software and mP62 edge switches 
with the LLL feature enabled on the ring ports is less than 250 milliseconds, even 
with 50 or more Magnum 6K family of switches in a ring structure. Without LLL 
activation, the Magnum 6K family of switches address buffer aging time (5 minutes 
default) could be the gating factor in ring recovery time. LLL is used on S-Ring and 
helps speed up the ring recovery time. 
 
S-Ring operates from specifically defined port pairs that participate in a ring-
topology. Multiple rings of different pairs on the same switch are also supported; 
however, intersecting rings or a “ring of rings” or “overlapping rings” is not 
supported in the current version. While S-Ring builds upon the foundation of RSTP 
or STP, S-Ring offers an additional topology option to network architects. The two 
ends of a ring must be connected to two ports in a Magnum 6K Switch that is 
enabled with the S-Ring software. The end points of the ring provide an alternate 
path to reach the switch that has failed. The in-out pairs of the ports to other devices 
in the ring have to be enabled with LLL. Some items to be aware of with S-Ring are 
as follows: 
 
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