Comtech EF Data SLM-5650A - Manual (Page 196)

SLM-5650A Satellite Modem Revision 8
Network Processor (NP) Interface MN-SLM5650A
8–34
Multi-TDM Tunneling Mode (ViperSat Hub or ViperSat Hub Expansion Mode
only)
Multi-TDM Tunneling is a technique where a VLAN “tunnel” is set up between the Hub unit and
any expansion units that are being used to create an SCPC link with a Remote that is Home Stated
to the specified Hub Time-Division Multiplexing (TDM) Modem.
When an Expansion unit is configured by VMS for an SCPC link, it queries its assigned hub for
the correct VLAN ID. If the feature is turned off, the Hub unit responds with a zero (0). If the
feature is enabled, the Hub will respond with a VLAN tag that is unique on the current LAN
segment.
Select Off, Automatic, or Manual. Note the following:
Selection Description
Off In this mode, the feature is not used and there is no VLAN tag used.
Automatic
In this mode, the Hub generates the VLAN tag from the last 12 bits of its IP Address. In
most cases, this will guarantee a unique value.
Manual
This mode SHOULD ONLY BE USED if the network is configured in such a way that two
or more hub units on the LAN segment may have the same value in the low order 12 bits
of their IP Address. Once this mode is selected, a text box will appear to allow entry of a
unique ID in the range from 2 to 4095.
In Manual mode, it is the user’s responsibility to ensure that each Hub box on the
segment is given a unique value in that range.
Click [Submit] to save the desired Multi-TDM Tunneling Mode setting.
Flow Control Enable
Ethernet Flow Control is a technique by which the receiver sends a message to the sender to
back-off traffic once congestion is encountered.
With Flow Control enabled, the NP Interface monitors the QOS queue depths to identify the
congestion, if any, of the QOS queue sizes. If the queue reaches 90% of the configurable QOS
queue depth, then the interface sends Ethernet Pause Frames (IEEE 802.3) with pass time 0xFFFF
to the LAN ports. Upon dropping all of the QOS depths to 50%, the interface again sends Pause
frames with pass time 0x0000 to resume the traffic back.
Using the drop-down menu, set Flow Control Enable as Enabled or Disabled. Click [Submit]
once this selection has been made.
Click [Submit] to save the desired Flow Control Enable setting.
Proxy ARP Enable
Proxy ARP (Address Resolution Protocol) is a technique by which an NP Interface in Router
Mode on a given network answers the ARP queries for a network address that is not on this
network, but is reachable via the NP Interface.