Lantech LGS-2816C-RPS, User Manual

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
Admin Point To Point - We say a port is a point-to-point link,
from RSTP‘s view, if it is in full-duplex mode but is shared link
if it is in half-duplex mode. RSTP fast convergence can only
happen on point-to-point links and on edge ports. This can
expedite the convergence because this will have the port fast
transited to forwarding state.
There are three parameters, Auto, True and False, used to
configure the type of the point-to-point link. If configure this
parameter to be Auto, it means RSTP will use the duplex mode
resulted from the auto-negotiation. In today‘s switched
networks, most links are running in full-duplex mode. For sure,
the result may be half-duplex, in this case, the port will not
fast transit to Forwarding state. If it is set as True, the port is
treated as point-to-point link by RSTP and unconditionally
transited to Forwarding state. If it is set as False, fast
transition to Forwarding state will not happen on this port.
Default: Auto.

M Check - Migration Check. It forces the port sending out an
RSTP BPDU instead of a legacy STP BPDU at the next
transmission. The only benefit of this operation is to make the
port quickly get back to act as an RSTP port. Click < M
Check > button to send a RSTP BPDU from the port you
specified.

Path Cost – This parameter is used by the STP to determine
the best path between devices. Therefore, lower values should
be assigned to ports attached to faster media, and higher
values assigned to ports with slower media. (Path cost takes
precedence over port priority.)
By default, the system automatically detects the speed and
duplex mode used on each port, and configures the path cost
according to the values shown below.
Table : Recommended STP Path Cost Range
Port Type IEEE 802.1D-1998 IEEE 802.1w-2001
Ethernet 50-600 200,000-20,000,000
Fast Ethernet 10-60 20,000-2,000,000
Gigabit Ethernet 3-10 2,000-200,000
Table : Recommended STA Path Costs
Port Type Link Type IEEE 802.1D-1998 IEEE 802.1w-2001
Ethernet Half Duplex 100 2,000,000
Full Duplex 95 1,999,999
Trunk 90 1,000,000
Fast Ethernet Half Duplex 19 200,000
Full Duplex 18 100,000
Trunk 15 50,000
Gigabit Ethernet Full Duplex 4 10,000
Trunk 3
5,000