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Configuring the Data Link Layer Protocol for E1, T1, and Serial Interfaces
Troubleshooting Logical Interfaces
Table 6-14. Status of the PVC
Information about each PVC is listed under the sublink’s DLCI and subinter-
face numbers. Check the settings listed in Table 6-15.
Table 6-15. Checking the Frame Relay Settings
View LMI Messages. To receive real-time messages, enter the following
command from the enable mode context:
ProCurve# debug frame-relay lmi
Status of the PVC Explanation
active The PVC is functional, end-to-end, from the local router to the switch
and then to the far-end router
inactive The PVC is functional from the router to the Frame Relay switch. The
other side of the connection is not configured or is down.
deleted The PVC was announced to the Frame Relay switch but was then
deleted. This status appears if the DLCI on the router does not match
the DLCI configured for this PVC at the Frame Relay switch.
Status of the PVC Explanation
DLCI Misconfiguring the DLCI can prevent traffic from reaching its
destination. Verify that the sublink’s DLCI is valid. You should configure
a unique DLCI in a separate subinterface for each site to which you
want to make a Frame Relay connection.
dropped packets The interface may drop more packets when the Frame Relay network
is congested or when the two endpoints of a PVC use different amounts
of bandwidth.
FECN/BECN
packets
The endpoint that is transmitting data sends forward explicit
congestion notification (FECN) packets when the receiver is sending
too many requests for data. When its queues fill, the endpoint that is
receiving data sends backward explicit congestion notification (BECN)
packets to request the source to stop sending so many packets.
Endpoints use these messages to minimize the number of dropped
packets.
A large number of incoming FECN and BECN packets indicate that the
other end of the circuit cannot transmit and receive data as quickly as
this interface. This discrepancy can lead to dropped packets.
DE packets When the interface bursts data across the PVC at rates beyond its CIR,
the excess packets are marked with the DE bit. If the network becomes
congested, these packets will be the first to be dropped.
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