Application Scenarios; Feature And Hardware Compatibility - HPE FlexNetwork MSR series Configuration Manual

1. When a DTE physically goes up, it sends a full status enquiry message to a DCE to request the
virtual circuit status. At the same time, the T391 timer and the V391 counter start. The T391
timer specifies the polling interval at which the DTE sends status enquiry messages.
When V391<N391, the DTE sends a link integrity verification message and requests only

the link integrity.
When V391=N391, the following events occur:

−
−
2. When the DCE receives a request, the DCE sends a status message that carries the status
requested by the DTE. At the same time, the DCE starts the T392 timer and waits for the next
status enquiry message. If the DCE has not received status enquiry messages when the T392
timer expires, the DCE records the error and increases the error count by one. If the number of
errors exceeds N392 among N393 events, the DCE considers the physical link and all virtual
circuits unavailable and will not use them to forward packets.
3. When the DTE receives a reply, the DTE updates the link status and PVC status. If the DTE has
not received status messages when the T391 timer expires, the DTE records the error and
increases the error count by one. If the number of errors exceeds N392 among N393 events,
the DTE considers that the physical link and all virtual circuits unavailable and will not use them
to forward packets.

Application scenarios

Typically, Frame Relay is used for Frame Relay access. Frame Relay access encapsulates
upper-layer packets on a user device by using Frame Relay and connects the user device to a
Frame Relay network.
With Frame Relay, you can construct a public or private network as shown in
direct connections between data devices as shown in
Figure 70 Interconnecting LANs through a Frame Relay network
Router A
Ser2/1/0
202.38.163.251/24
DLCI=50
DLCI=60
Figure 71 Interconnecting LANs through a dedicated line
Ser2/1/0
202.38.163.251/24
Router A

Feature and hardware compatibility

This feature is supported only on Layer 2 Ethernet ports on the following modules:
V391 is reset to 0.
The DTE sends a full status enquiry message to request not only the link integrity but
also the status of all PVCs.
FR
DLCI=100
Figure 71.
Router B
Ser2/1/0
202.38.163.252/24
DLCI=70
Router C
Ser2/1/0
202.38.163.253/24
DLCI=80
Ser2/1/0
202.38.163.252/24
Router B
225
Figure 70 and construct