The most common Frame debug you'll ever run is debug frame lmi, which shows you the yourseen and myseq values. If yourseen is incrementing and myseq isn't, there's a keepalive issue.

R1#debug frame lmi
Frame Relay LMI debugging is on
Displaying all Frame Relay LMI data
R1#
*Mar 1 03:59:52.793: Serial0/0(out): StEnq, myseq 105, yourseen 102, DTE up

*Mar 1 04:00:12.794: Serial0/0(out): StEnq, myseq 106, yourseen 103, DTE up

show frame lmi will also indicate LMI issues via the Num Status Timeouts value. If that's incrementing, there's a keepalive issue.

R1#show frame lmi

LMI Statistics for interface Serial0/0 (Frame Relay DTE) LMI TYPE = ANSI
Invalid Unnumbered info 0 Invalid Prot Disc 0
Invalid dummy Call Ref 0 Invalid Msg Type 0
Invalid Status Message 0 Invalid Lock Shift 0
Invalid Information ID 0 Invalid Report IE Len 0
Invalid Report Request 0 Invalid Keep IE Len 0
Num Status Enq. Sent 1255 Num Status msgs Rcvd 1226
Num Update Status Rcvd 0 Num Status Timeouts 28
Last Full Status Req 00:00:17 Last Full Status Rcvd 00:06:37

show frame map is probably the first frame troubleshooting command you should run.

R1#show frame map
Serial0 (up): ip 172.12.123.3 dlci 123(0x7B,0x1CB0), dynamic
broadcast, CISCO, status defined, active
Serial0 (up): ip 172.12.123.2 dlci 122(0x7B,0x1CB0), dynamic
broadcast, CISCO, status defined, active

show frame pvc contains valuable information regarding the number of BECNs, FECNs, and packets with the DE bit set that the router has seen, both incoming and outgoing.

R1#show frame pvc

PVC Statistics for interface Serial0/0 (Frame Relay DTE)

Active Inactive Deleted Static
Local 2 0 0 0
Switched 0 0 0 0
Unused 0 4 0 0

DLCI = 102, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

input pkts 25 output pkts 25 in bytes 2600
out bytes 2600 dropped pkts 0 in pkts dropped 0
out pkts dropped 0 out bytes dropped 0
in FECN pkts 0 in BECN pkts 0 out FECN pkts 0
out BECN pkts 0 in DE pkts 0 out DE pkts 0
out bcast pkts 0 out bcast bytes 0
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
pvc create time 03:16:48, last time pvc status changed 03:13:15

show interface indicates the frame encapsulation type that's running. The first readout below is from a router running Cisco frame encap; the second is from a router running the industry standard, IETF. You also see the LMIs sent and received, along with the LMI type and DLCI number in use. The keepalive timer is also shown.

R1#show interface s0/0
Serial0/0 is up, line protocol is up
Hardware is PowerQUICC Serial
Internet address is 172.12.123.1/24
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY, loopback not set
Keepalive set (10 sec)
LMI enq sent 1076, LMI stat recvd 1065, LMI upd recvd 0, DTE LMI up
LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0
LMI DLCI 1023 LMI type is CISCO frame relay DTE

R1#show int serial 0/0
Serial0/0 is up, line protocol is up
Hardware is PowerQUICC Serial
Internet address is 172.12.123.1/24
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY IETF, loopback not set

Speaking of the keepalive value, it can be changed with the keepalive command.

R1(config)#int serial0/0
R1(config-if)#keepalive ?
<0-30> Keepalive period (default 10 seconds)
<cr>

The split horizon commands aren't used exclusively in Frame Relay configurations, but they do crop up in Frame configs - it's a good idea to know how and when to use them!

R1(config)#interface serial0
R1(config-if)#no ip split-horizon

R1(config)#interface serial0
R1(config-if)#ip split-horizon

To your success,

Chris Bryant

CCIE #12933