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This chapter provides troubleshooting information for connectivity problems in circuit emulation service (CES) environments and network clocking. For more information on CES, refer to the "Circuit Emulation Services and Voice over ATM" chapter in the Guide to ATM Technology , and "Configuring Circuit Emulation Services" chapter in the ATM Switch Router Software Configuration Guide .
Before you begin, make sure that all physical port connections are working correctly. For information on troubleshooting interfaces, refer to "Troubleshooting Switch Router ATM Interface Connections."
This chapter contains the following sections:
CES allows circuits to be transparently extended across an ATM network. CES is typically used to transport voice or video between the ATM switch router and non-ATM telephony devices, such as PBXs and TDMs, or video devices. Voice and video, unlike data traffic, are very sensitive to delay and delay variance. CES uses constant bit rate (CBR) virtual circuits (VCs), which guarantees acceptable delay and delay variation and thus satisfies the requirements of voice and video traffic.
This procedure outlines the steps for performing basic interface checks of the CES circuit configuration. Always check the following when a CES circuit fails to function:
At the ATM switch router, use the following commands to check the CES configuration:
Command | Purpose |
---|---|
show ces circuit interface cbr card/subcard/port circuit-id | Confirms the configuration on the CES interface. |
show atm vp interface atm card/subcard/port vpi | Confirms the configuration of the shaped VP tunnel. |
show dcu leds | Confirms the status of the CES port LEDs. |
Follow these steps to troubleshoot the CES configuration:
Switch# show ces circuit interface cbr 3/1/0 1
Circuit: Name CBR3/1/0:1, Circuit-state ADMIN_UP / oper-state UP Interface CBR3
Port Clocking network-derived, aal1 Clocking Method CESIWF_AAL1_CLOCK_SYNC
Channel in use on this port: 1
Channels used by this circuit: 1
Cell-Rate: 172, Bit-Rate 64000
cas OFF, cell_header 0x100 (vci = 16)
Configured CDV 2000 usecs, Measured CDV unavailable
De-jitter: UnderFlow unavailable, OverFlow unavaliable
ErrTolerance 8, idleCircuitdetect OFF, onHookIdleCode 0x0
state: VcLoc, maxQueueDepth 81, startDequeueDepth 64
Partial Fill: 47, Structured Data Transfer 1
HardPVC
src: CBR3/1/0 vpi 0, vci 16
Dst: ATM1/1/1 vpi 1, vci 101
Step 2 Check the Dst field to confirm that the VPI and VCI values match those assigned by the service provider. If not, reconfigure the CBR interface using the ces pvc command.
Step 3 Use the show atm vp command to display the connection traffic table index configuration for the shaped VP tunnel:
Switch# show atm vp interface atm 1/1/1 1
Interface: ATM1/1/1, Type: oc3suni
VPI = 1
Status: SHAPED TUNNEL
Time-since-last-status-change: 13:59:23
Connection-type: PVP
Cast-type: point-to-point
Usage-Parameter-Control (UPC): pass
Wrr weight: 2
Number of OAM-configured connections: 0
OAM-configuration: disabled
OAM-states: Not-applicable
Threshold Group: 1, Cells queued: 0
Rx cells: 0, Tx cells: 0
Tx Clp0:0, Tx Clp1: 0
Rx Clp0:0, Rx Clp1: 0
Rx Upc Violations:0, Rx cell drops:0
Rx Clp0 q full drops:0, Rx Clp1 qthresh drops:0
Rx connection-traffic-table-index: 10
Rx service-category: CBR (Constant Bit Rate)
Rx pcr-clp01: 4000
Rx scr-clp01: none
Rx mcr-clp01: none
Rx cdvt: 1024 (from default for interface)
Rx mbs: none
Tx connection-traffic-table-index: 10
Tx service-category: CBR (Constant Bit Rate)
Tx pcr-clp01: 4000
Tx scr-clp01: none
Tx mcr-clp01: none
Tx cdvt: none
Tx mbs: none
Step 4 Check the Rx service-category and Tx service-category fields for the CBR service.
Step 5 Check the Rx pcr-clp01 and Tx pcr-clp01 fields to ensure that the peak cell rate (PCR) is within the range contracted with the service provider.
Step 6 Use the show dcu leds command to display the status of the CES port LEDs:
NewLs1010# show dcu leds
CBR3/1/0 [20]: idle
CBR3/1/1 [21]: idle
CBR3/1/2 [22]: Red (loss of signal and loss of cells)
CBR3/1/3 [23]: Red (loss of cells)
Step 7 If the port LED status is RED, do the following:
For detailed interface configuration information about CES, refer to the "Configuring Circuit Emulation Services" chapter in the ATM Switch Router Software Configuration Guide .
In the example network in Figure 9-1, the ATM switch routers in the administration building and the remote sales building are each connected to a PBX and the WAN:
This network example is used to describe the CES troubleshooting examples in the rest of this chapter.
For detailed configuration information about CES, refer to the "Configuring Circuit Emulation Services" chapter in the ATM Switch Router Software Configuration Guide .
This section describes initial troubleshooting steps that you should perform when beginning to troubleshoot a CES connection.
At the ATM switch router, use the following commands to check the CES configuration:
Command | Purpose |
---|---|
Confirms the status of the CES circuits. | |
Confirms the configuration of the CES PVCs. | |
show ces circuit interface cbr card/subcard/port circuit-id | Confirms the configuration on the CES interface. |
show interfaces cbr card/subcard/port | Confirms the status of the CES interface. |
Use the following command to confirm that the configured CES circuit is up:
AdminFl1Ls1# show ces status
Interface IF Admin Port C
hannels in
Name Status Status Type use
------------- -------- --------- ----------- -----------
CBR3/1/0 UP UP T1 1-3,7,20-22,24
CBR3/1/1 DOWN UP T1 1-24
CBR3/1/2 DOWN UP T1 24
CBR3/1/3 UP UP T1 10-13
AdminFl1Ls1#
Step 2 Check the IF and Admin Status fields to confirm that they are up.
If the interface is down, check for the following:
If administratively down, the interface has been administratively taken down. Use the no shutdown interface configuration command to reenable the interface.
For detailed interface configuration information about CES, refer to the "Configuring Circuit Emulation Services" chapter in the ATM Switch Router Software Configuration Guide .
Follow these steps to confirm that CES circuits are configured correctly:
Switch# show ces circuit interface cbr 3/1/0 0
Circuit: Name CBR-PVC-A, Circuit-state ADMIN_UP / oper-state UP Interface CBR3/
Port Clocking network-derived, aal1 Clocking Method CESIWF_AAL1_CLOCK_SYNC
Channel in use on this port: 1-31
Channels used by this circuit: 1-31
Cell-Rate: 5447, Bit-Rate 2048000
cas OFF, cell_header 0x100 (vci = 16)
Configured CDV 2000 usecs, Measured CDV 1769 usecs
De-jitter: UnderFlow 42, OverFlow 0
ErrTolerance 8, idleCircuitdetect OFF, onHookIdleCode 0x0
state: VcAlarm, maxQueueDepth 823, startDequeueDepth 435
Partial Fill: 47, Structured Data Transfer 0
Passive SoftVC
Src: atm addr 47.0091.8100.0000.00e0.f75d.0401.4000.0c81.9030.10 vpi 0, vci 16
Switch#
Step 2 Check the oper-state field to confirm that it is up.
If down, verify that the aal1 Clocking Method field for each end of the circuit shows the same configuration.
Step 3 Check the Underflow and Overflow fields to confirm that the network clocking is synchronized.
Buffer overflows and underflows indicate a slight clocking difference between the devices. Buffer overflows occur when the transmitting device is faster than the receiving device; such a condition results in frame drops. Buffer underflows occur when the transmitting device is slower than the receiving device; such a condition results in frame resends. Check with your service provider to reduce the cell delay variation (CVD).
Step 4 Check the Src and Dst fields for the correct addresses.
Use the show atm status, show ces status, show atm address, and show ces address commands to confirm the source and destination address configuration.
For detailed interface configuration information about CES, refer to the "Configuring Circuit Emulation Services" chapter in the ATM Switch Router Software Configuration Guide . For detailed physical interface troubleshooting information, see the "Troubleshooting CES T1 and CES E1 Interfaces" section.
Follow these steps to confirm the CES interface configuration on the ATM switch router:
Switch# show ces circuit
Interface Circuit Circuit-Type X-interface X-vpi X-vci Status
CBR3/1/0 0 Passive SoftVC ATM-P3/1/3 0 3088 UP
CBR3/1/1 0 Passive SoftVC ATM-P3/1/3 0 2064 UP
CBR3/1/2 0 Active SoftVC ATM-P3/1/3 0 1040 UP
CBR3/1/3 0 Active SoftVC ATM-P3/1/3 0 16 UP
Switch#
Step 2 Check the Circuit-Type field. It should contain the correct type for the circuit.
Step 3 Check the X-interface field. It should contain the correct destination interface for the circuit.
Step 4 Check the Status field. It should read "UP."
If the rest of the fields for the interface are correct but the status is "DOWN," then check the X-interface status using the show interfaces command. If the interface is administratively down, use the no shutdown command to reenable it.
If you determine that the physical interface is configured incorrectly, refer to the "Configuring Interfaces" chapter in the ATM Switch Router Software Configuration Guide .
For detailed interface configuration information about CES, refer to the "Configuring Circuit Emulation Services" chapter in the ATM Switch Router Software Configuration Guide .
This section describes debug commands that you can use to troubleshoot CES circuits on an ATM switch router.
Use the following commands to debug CES connections on an ATM switch router:
Command | Purpose |
---|---|
debug ces-iwf connection | Debugs CES circuit connection events. |
debug ces-iwf createloc cbr card/subcard/port [vpi] {on | off} | Enables cell loss for debugging purposes. |
debug ces-iwf dcu | Debugs CBR-DCU internal events. |
debug ces-iwf internal | Debugs CES internal events. |
no debug all | Turns off all debugging. |
For detailed interface configuration information, refer to the "Configuring Circuit Emulation Services" chapter in the ATM Switch Router Software Configuration Guide .
This section describes how to troubleshoot problems with the network clocking configuration. For more information on network clocking, refer to the "Network Clock Synchronization" chapter in the Guide to ATM Technology and the "Initially Configuring the ATM Switch Router" chapter in the
ATM Switch Router Software Configuration Guide .
Network clocking facilities generate or derive a clock signal and distribute it throughout a network to ensure synchronized network operation. This is important in delay-sensitive data types, such as voice and video, because these types of data must be received and transmitted at the same rate at every step, or hop, in a connection. If network synchronization is lost, data might be lost due to buffer overflow or underflow; cyclic redundancy check (CRC) errors might also occur.
Table 9-1 provides a summary of network clocking features.
Platform | Up/Down Detection | Loss of Synchronization Detection | Phase Adjustment Cutover | Stratum 3 Clock | BITS1 Port | Clock Source Preference |
---|---|---|---|---|---|---|
Catalyst 8540 MSR with network clock module | Yes | Yes | Yes | Yes | Yes | Best |
Catalyst 8510 MSR | Yes | Yes | Yes | No | No | Medium |
LightStream 1010 with FC-PFQ | Yes | Yes | Yes | No | No | Medium |
Catalyst 8540 MSR without network clock module | Yes | No | No | No | No | Poor |
LightStream 1010 with FC-PCQ | Yes | No | No | No | No | Poor |
1BITS = Building Integrated Timing Supply |
The network clock module faceplate LEDs provide status information for the BITS ports and the alarm port. The LEDs are described in Table 9-2.
LED | Status | Description |
---|---|---|
POWER | Green | The switch is powered on and the processor is functioning. |
STATUS | Green | The clock module is the primary network clock source. |
MAJOR ALARM | Red | A major alarm condition has occurred. |
MINOR ALARM | Red | A minor alarm condition has occurred. |
CRITICAL ALARM | Red | Not supported. |
The following are major alarm conditions:
The following are minor alarm conditions:
Use the following commands to troubleshoot the network clock source configuration:
Command | Purpose |
---|---|
Confirms the network clock configuration. | |
Debugs network clock events. | |
no debug all | Turns off all debugging. |
Follow these steps to troubleshoot the network clocking configuration on an ATM switch that does not have the network clock module installed:
Switch# show network-clocks
clock configuration is NON-Revertive
Priority 1 clock source: ATM0/0/0(down)
Priority 2 clock source: No clock
Priority 3 clock source: No clock
Priority 4 clock source: No clock
Priority 5 clock source: System clock
Current clock source:System clock, priority:5
Step 2 Check the clock configuration field to confirm that the clock switchover mode is configured correctly. If it is not, use the network-clock-select command to correctly configure the clock switchover mode.
Step 3 Check the clock source fields to confirm that the desired clock sources are configured. Use the network-clock-select command to configure the clock sources. See Table 9-1 for a list of network clock source features.
Step 4 Check the status of the clock sources. If the clock source is listed as "down," check the interface status using the procedure described in "Troubleshooting Switch Router ATM Interface Connections."
Note Once the clock problem is solved, reconfigure the network clock using the network-clock-select command to make sure that the primary clock becomes the present clock source. The no shutdown command does not affect the network clock source status. |
Follow these steps to troubleshoot the network clocking configuration on a switch that uses the network clock module:
Switch# show network-clocks
Network clocking information:
---------------------------------------
Source switchover mode: non-revertive
Netclkd state: Active
Source selection method: provisioned
NCLKM hardware status: installed & usable
NCLKM status: software enabled
Primary clock source: ATM11/1/2 Unlockable
Secondary clock source: ATM12/0/0 one shot triggered
Present clock source: ATM12/0/0 (2) Locked
Step 2 Check the Source switchover mode field to confirm that the clock switchover mode is configured correctly. If it is not, use the network-clock-select command to correctly configure the network clocking mode.
Step 3 Check the clock source fields to confirm that the desired clock sources are configured. Use the network-clock-select command to configure the clock sources. See Table 9-1 for a list of network clock source features.
Step 4 Check the status of the primary and secondary clock sources. The status follows the clock source name.
Note Once the clock problem is resolved, reconfigure the network clock using the network-clock-select command to make sure that the primary clock becomes the present clock source. The no shutdown command does not affect the network clock source status. |
Switch# debug ports netclock
Rhino network clocks debugging is on
Switch# show network-clocks
Network clocking information:
---------------------------------------
Source switchover mode: non-revertive
Netclkd state: Active
Source selection method: provisioned
NCLKM hardware status: installed & usable
NCLKM status: software enabled
Primary clock source: BITS 0 in T1 mode
Secondary clock source: ATM11/1/2 one shot triggered
Present clock source: ATM11/1/2 (2) Locked
bits 0 state :down (32827388)
bits 0 admin state :up
bits 1 state :down (32827388)
bits 1 admin state :up
do_not_switch flag :0
other_holdover flag :0
p_one_shot flag :0
s_one_shot flag :0
p_l_state :Reset
s_l_state :Reset
other_priority :0
other_type :0
ncdp in use :0
Hello tx seq no :0
Hello rx seq no :0
Clock update tx seq no :0
Clock update rx seq no :0
Hello timer :running:1,
Ref lock timer :running:1, time_left:580
<information deleted>
Step 2 Check the state field for the BITS port being used. If it is down, check the cable for damage.
Step 3 Check the BITS port LED. If it is not on, check the interface mode type. The mode type is either T1 or E1. T1 is the default mode. Use the network-clock-select command to change the BITS interface mode type.
For detailed interface configuration information on network clocking, refer to the "Initially Configuring the ATM Switch Router," and Chapter 18, "Configuring Circuit Emulation Services" chapter in the ATM Switch Router Software Configuration Guide .
The clocking configuration of a CES interface might affect the traffic flow on the circuit. If quality of the transmission has degraded, follow these steps to troubleshoot the CES interface clocking for unstructured services:
Switch# show ces interface cbr 3/1/0
Interface: CBR3/1/0 Port-type:E1-120ohms-DCU
IF Status: UP Admin Status: UP
Channels in use on this port: 1
LineType: E1_LT LineCoding: HDB3 LoopConfig: Payload
SignalMode: NoSignalling XmtClockSrc: network-derived
DataFormat: Structured AAL1 Clocking Mode: Synchronous LineLength: 330_440
e1InternationalBits 0x3, e1NationalBits 0x1F, e1MultiFrameBits 0xB
LineState: RcvAIS LoopbackState
Errors in the Current Interval:
PCVs 0 LCVs 0 ESs 0 SESs 0 SEFSs 0
UASs 0 CSSs 0 LESs 0 BESs 0 DMs 0
Errors in the last 24Hrs:
PCVs 0 LCVs 0 ESs 0 SESs 0 SEFSs 0
UASs 0 CSSs 0 LESs 0 BESs 0 DMs 0
Input Counters: 0 cells, 0 bytes
Output Counters: 0 cells, 0 bytes
Step 2 Check the AAL1 Clocking Mode field. Use the ces aal1 clock command to modify the clocking mode to adaptive. Adaptive clocking does not require an external clock source. If the problem ceases when the clocking mode is changed from synchronous to SRTS, the reference clock is the problem.
Posted: Mon Mar 5 19:44:48 PST 2001
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