Compatible Systems 5.4 - Manual (Page 169)

Chapter 10 - WAN Link Protocols 163
> Polling Frequency
The router is required to periodically poll the Frame Relay switch at the other
end of the communications link in order to determine whether the link is
active. This field determines how often the router polls the switch, using the
Maintenance Protocol you have selected.
If any three out of four polls go unanswered by the switch, the router will
assume the Frame Relay link is down. Every sixth poll, the router requests a
full status packet from the switch in order to update its table of active perma-
nent virtual circuits (PVCs).
This value is in seconds. The allowable range for the value is 5 to 30. The
default is 10.
Home DLCI
When Static maintenance is used on a WAN broadcast medium, this edit box
can be filled in to provide a statically assigned DLCI (Data Link Control Iden-
tifier) number for this interface.
This number can be configured into other routers’ DLCI Mapping Dialog
Boxes so that they can communicate with this router. In order to reject
packets that were sent out its own interface, this router will ignore any packets
with a sending DLCI number that matches this number.
MTU
This is the Maximum Transmission Unit in bytes for the interface. This
setting may need to be adjusted in order to communicate with switches or
routers from other vendors which do not support full size frame packets. The
allowable range for the value is 262 to 1700. The default for this value is
1500.
v Note: Adjusting the MTU to a smaller size will cause fragmentation of
Frame Relay packets, which will impact performance. This setting should be
left at the default unless it must be changed for compatibility reasons.