ATM OAM Ping

The ATM OAM Ping feature modifies the pingcommand, which can be used to send an OAM packet to verify PVC connectivity. The status of the PVC is displayed when a response to the OAM packet is received. This is a common method for testing the accessibility of devices.

The ping atm interface atm command provides two ATM OAM ping options:

• End loopback--Verifies end-to-end PVC integrity.
• Segment loopback--Verifies PVC integrity to the immediate neighboring ATM device.

The ping atm interface atm command is used to determine the following:

• Whether a remote host is active or inactive.
• The round-trip delay in communicating with the host.
• Packet loss.

The simpler ping command provides an interactive mode for testing ATM network connectivity. The ping command first sends an OAM command loopback cell to the destination and then waits for an OAM response loopback cell. The ping is successful only when the following criteria are met:

• The OAM command loopback cell reaches the destination.
• The destination is able to send an OAM loopback response cell back to the source within a predetermined time called a timeout . The default value of the timeout is 2 seconds on Cisco routers.

1.    enable

2.    ping atm interface atm interface-number vpi-value [vci-value [end-loopback[repeat [timeout]]| seg-loopback [repeat [timeout]]]]

1.    enable

2.    ping

To terminate a ping session, type the escape sequence--by default, Ctrl-Shift-6.

The following example verifies the connectivity of a specific PVC by sending an ATM OAM packet and confirms the connectivity when it is successful:

Router# show atm pvc 10/100 
ATM1/1/0.100: VCD: 3, VPI: 10, VCI: 100 
UBR, PeakRate: 100000 (235850 cps) 
AAL5-LLC/SNAP, etype:0x0, Flags: 0x40, VCmode: 0x0, Encapsize: 12 
OAM frequency: 0 second(s), OAM retry frequency: 1 second(s) 
OAM up retry count: 3, OAM down retry count: 5 
OAM Loopback status: OAM Disabled 
Last cell looped No 
Loop detect state 0, Last cell looped 0, OAM Retries 0, Loop Retries 0 
OAM VC Status: Not Managed 
ILMI VC status: Not Managed 
InARP frequency: 15 minutes(s) 
Transmit priority 3 
InPkts: 78310, OutPkts: 78310, InBytes: 218651435, OutBytes: 218651435 
InPRoc: 0, OutPRoc: 16, Broadcasts: 15 
InFast: 0, OutFast: 0, InAS: 78310, OutAS: 78281 
InPktDrops: 0, OutPktDrops: 0 
CrcErrors: 0, SarTimeOuts: 0, OverSizedSDUs: 0, LengthViolation: 0, CPIErrors: 0 
Out CLP=1 Pkts: 0 
OAM cells received: 315 
F5 InEndloop: 310, F5 InSegloop: 5, F5 InAIS: 0, F5 InRDI: 0 
OAM cells sent: 315 
F5 OutEndloop: 310, F5 OutSegloop: 5, F5 OutAIS: 0, F5 OutRDI: 0 
OAM cell drops: 0 
Status: UP 
VC 10/100 doesn't exist on 2 of 3 ATM interface(s) 
Router# 

The following example shows sample output for the ping atm interface atmcommand in normal mode:

Router# ping atm interface atm1/1/0.1 500
Type escape sequence to abort.
Sending 5, 53-byte end-to-end OAM echoes, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/16/52 ms
Router# ping atm interface atm1/1/0.1 0 500 seg-loopback
Type escape sequence to abort.
Sending 5, 53-byte segment OAM echoes, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
Router# ping atm interface atm1/1/0.1 0 500 end-loopback 100 25
Type escape sequence to abort.
Sending 100, 53-byte end-to-end OAM echoes, timeout is 25 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 4/13/180 ms
Router# ping atm interface atm1/1/0.1 0 500 seg-loopback 50 20
Type escape sequence to abort.
Sending 50, 53-byte segment OAM echoes, timeout is 20 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (50/50), round-trip min/avg/max = 1/1/4 ms
Router# show atm pvc 10/100
 
ATM1/1/0.100: VCD: 3, VPI: 10, VCI: 100 
UBR, PeakRate: 100000 (235850 cps) 
AAL5-LLC/SNAP, etype:0x0, Flags: 0x40, VCmode: 0x0, Encapsize: 12 
OAM frequency: 10 second(s), OAM retry frequency: 1 second(s) 
OAM up retry count: 3, OAM down retry count: 5 
OAM Loopback status: OAM Received 
Last cell looped No 
Loop detect state 0, Last cell looped 0, OAM Retries 0, Loop Retries 0 
OAM VC Status: Verified 
ILMI VC status: Not Managed 
VC is managed by OAM. 
InARP frequency: 15 minutes(s) 
Transmit priority 3 
InPkts: 78310, OutPkts: 78310, InBytes: 218651435, OutBytes: 218651435 
InPRoc: 0, OutPRoc: 16, Broadcasts: 15 
InFast: 0, OutFast: 0, InAS: 78310, OutAS: 78281 
InPktDrops: 0, OutPktDrops: 0 
CrcErrors: 0, SarTimeOuts: 0, OverSizedSDUs: 0, LengthViolation: 0, CPIErrors: 0 
Out CLP=1 Pkts: 0 
OAM cells received: 331 
F5 InEndloop: 326, F5 InSegloop: 5, F5 InAIS: 0, F5 InRDI: 0 
OAM cells sent: 331 
F5 OutEndloop: 326, F5 OutSegloop: 5, F5 OutAIS: 0, F5 OutRDI: 0 
OAM cell drops: 0 
Status: UP 
VC 10/100 doesn't exist on 2 of 3 ATM interface(s) 
Router# 

The following is sample output for the pingcommand in the interactive mode:

router# ping
 
Protocol [ip]: atm 
ATM Interface: atm1/1/0.100 
VPI value [0]: 10 
VCI value [1]: 100 
Loopback - End(0), Segment(1) [0]: 
Repeat Count [5]: 
Timeout [2]: 
Type escape sequence to abort. 
Sending 5, 53-byte end-to-end OAM echoes, timeout is 2 seconds: 
!!!!! 
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms 
Router#