Comtech EF Data MDX420 SkyWire Manual - Manual (Page 70)

MDX420 SkyWire™ Satellite Network Gateway SkyWire Controller (GUI)
MN-MDX420 Revision 6 7–14
7.4.2 Configure Terrestrial Interface
The Terrestrial Interface window allows access to setup Control port and Data port parameters.
Ethernet controls like flow control and Quality of Service are supported. QoS offers the ability to
provide different priority to different applications, users, or data flows to guarantee a certain level
of performance to a data flow. Refer to Figure 7.4.2-1.
Figure 7.4.2-1 Terrestrial Interface
 In Band Control: When In-Band Control is checked, the MDX-420 will allow itself to be monitored
and controlled locally through Control Ports J1 & J2 or by a remote gateway over the satellite link
without an external connection between the control port and the data port. When unchecked, a
SNMP session can only occur locally through Control Ports J1 or J2.
 FLOW CONTROL: When checked it auto-negotiates rate of data transmission with the device
connected to the MDX420. When unchecked no back pressure is applied to connecting routers
or switches for flow control.
 DAISY CHAIN MODE: Daisy Chain Mode can be used whenever a single site is demodulating
more than 4 share groups as is commonly seen in Hub and Spoke applications or in larger MESH
networks with 5 or more share groups. This mode is used where one (1) MDX-420 is transmitting
into a share group and demodulating 1-4 share groups and there are additional MDX-420 units
that are only used to demodulate additional share groups (not transmitting). Looking at Figure
7.4.2-2, the proper way to eliminate layer 2 issues such as spanning tree or endless loop when
multiple MDX420 units are used is to connect the devices in the following manner. When Daisy
Chain Mode is selected on a unit, traffic entering Port J4 will be forwarded to Port J3 and MAC
learning and aging will be disabled on Port J4. By doing this none of the destination MAC
address that come in on Port 4 will be associated to either the LAN or WAN side of the link.
The MDX-420 that is being used to transmit traffic must have “Daisy Chain Mode” checked (we
will call this MDX-T). The MDX-420 that is being used as a demod only (we will call this MDX-R1)
must connect MDX-R1 Port J3 to MDX-T Port J4. It is a good idea to also check “Daisy Chain
Mode” on MDX-R1 in case future share groups are added. It would then be possible to connect
future MDX-420s being used in a demod only configuration (MDX-R2) by again connecting MDX-
R2 Port J3 to MDX-R1 Port J4.
 QUALITY of SERVICE (QoS): Two types supported NORMAL and PORT BASED.