PA-4T+ Synchronous Serial Port Adapter Installation and Configuration
Configuring the PA-4T+ Synchronous Serial Port Adapter
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Table Of Contents

Configuring the PA-4T+ Interfaces

Using the EXEC Command Interpreter

Configuring the Interfaces

Shutting Down an Interface

Performing a Basic Configuration

Configuring Timing (Clock) Signals

Setting the Clock Rate

Inverting the Clock Signal

Inverting the Data Signal

Configuring NRZI Format

Configuring Cyclic Redundancy Checks

Configuring Half-Duplex and Binary Synchronous Communications in Cisco 7200 Series Routers

Checking the Configuration

Using show Commands to Verify the New Interface Status

Using the show version or show hardware Commands

Using the show diag Command

Using the show interfaces Command

Using the ping Command to Verify Network Connectivity

Using loopback Commands


Configuring the PA-4T+ Interfaces


To continue your PA-4T+ port adapter installation, you must configure the serial interfaces. The instructions that follow apply to all supported platforms. Minor differences between the platforms are noted.

This chapter contains the following sections:

Using the EXEC Command Interpreter

Configuring the Interfaces

Configuring Half-Duplex and Binary Synchronous Communications in Cisco 7200 Series Routers

Checking the Configuration

Using the EXEC Command Interpreter

You modify the configuration of your router through the software command interpreter called the EXEC (also called enable mode). You must enter the privileged level of the EXEC command interpreter with the enable command before you can use the configure command to configure a new interface or to change the existing configuration of an interface. The system prompts you for a password if one is set.

The system prompt for the privileged level ends with a pound sign (#) instead of an angle bracket (>). At the console terminal, use the following procedure to enter the privileged level:


Step 1 At the user-level EXEC prompt, enter the enable command. The EXEC prompts you for a privileged-level password as follows:

Router> enable 

Password: 

Step 2 Enter the password (the password is case-sensitive). For security purposes, the password is not displayed.

When you enter the correct password, the system displays the privileged-level system prompt (#):

Router#


Configuring the Interfaces

After you verify that the new PA-4T+ is installed correctly (the enabled LED goes on), use the privileged-level configure command to configure the new interfaces. Be prepared with the information you will need, such as the following:

Protocols you plan to route on each new interface

IP addresses if you will configure the interfaces for IP routing

Whether or not the new interfaces will use bridging

Timing source for each new interface and clock speeds for external timing

If you installed a new PA-4T+ or if you want to change the configuration of an existing interface, you must enter configuration mode using the configure command. If you replaced a PA-4T+ that was previously configured, the system will recognize the new PA-4T+ interfaces and bring each of them up in their existing configurations.

For a summary of the configuration options available and instructions for configuring interfaces on the PA-4T+, refer to the appropriate configuration publications listed in the "Related Documentation" section on page viii.

You execute configuration commands from the privileged level of the EXEC command interpreter, which usually requires password access. Contact your system administrator, if necessary, to obtain password access. (See the "Using the EXEC Command Interpreter" section for an explanation of the privileged level of the EXEC.)

This section contains the following subsections:

Shutting Down an Interface

Performing a Basic Configuration

Configuring Timing (Clock) Signals

Configuring NRZI Format

Configuring Cyclic Redundancy Checks

Shutting Down an Interface

Before you remove an interface that you will not replace, replace a compact serial cable, or replace port adapters, use the shutdown command to shut down (disable) the interfaces to prevent anomalies when you reinstall the new or reconfigured interface processor. When you shut down an interface, it is designated administratively down in the show command displays.

Follow these steps to shut down an interface:


Step 1 Enter the privileged level of the EXEC command interpreter. (See the "Using the EXEC Command Interpreter" section for instructions.)

Step 2 At the privileged-level prompt, enter configuration mode and specify that the console terminal will be the source of the configuration subcommands as follows:

Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#

Step 3 Shut down interfaces by entering the interface serial subcommand (followed by the interface address of the interface), and then enter the shutdown command.

When you have finished, press Ctrl-Z—hold down the Control key while you press Z—or enter end or exit to exit configuration mode and return to the EXEC command interpreter

Table 5-1 shows the shutdown command syntax for the supported platforms.

Table 5-1 Syntax of the shutdown Command for the Supported Platforms 

Platform
Command
Example

Catalyst RSM/VIP2 in Catalyst 5000 family switches

interface, followed by the type (serial) and slot/port (port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter slot 1.

Router(config-if)# interface serial 1/0
Router(config-if)# shutdown
Router(config-if)# interface serial 1/1
Router(config-if)# shutdown
Ctrl-Z
Router#

Catalyst 6000 family FlexWAN module in Catalyst 6000 family switches

interface, followed by the type (serial) and mod_num/bay/port (module-slot-number/
port-adapter-bay-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter bay 0 of a FlexWAN module installed in module slot 3.

Router(config-if)# interface serial 3/0/0
Router(config-if)# shutdown
Router(config-if)# interface serial 3/0/1
Router(config-if)# shutdown
Ctrl-Z
Router#

Cisco 7120 series routers

interface, followed by the type (serial) and slot/port (port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter slot 3.

Router(config-if)# interface serial 3/0
Router(config-if)# shutdown
Router(config-if)# interface serial 3/1
Router(config-if)# shutdown
Ctrl-Z
Router#

Cisco 7140 series routers

interface, followed by the type (serial) and slot/port (port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter slot 4.

Router(config-if)# interface serial 4/0
Router(config-if)# shutdown
Router(config-if)# interface serial 4/1
Router(config-if)# shutdown
Ctrl-Z
Router#

Cisco 7200 series routers and Cisco 7200 VXR routers

interface, followed by the type (serial) and slot/port (port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter slot 6.

Router(config-if)# interface serial 6/0
Router(config-if)# shutdown
Router(config-if)# interface serial 6/1
Router(config-if)# shutdown
Ctrl-Z
Router#

Cisco 7201 router

interface, followed by the type (serial) and slot/port (port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter slot 1.

Router(config-if)# interface serial 1/0
Router(config-if)# shutdown
Router(config-if)# interface serial 1/1
Router(config-if)# shutdown
Ctrl-Z
Router#

Cisco uBR7223 router

interface, followed by the type (serial) and slot/port (port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter slot 1.

Router(config-if)# interface serial 1/0
Router(config-if)# shutdown
Router(config-if)# interface serial 1/1
Router(config-if)# shutdown
Ctrl-Z
Router#

Cisco uBR7246 router

interface, followed by the type (serial) and slot/port (port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter slot 2.

Router(config-if)# interface serial 2/0
Router(config-if)# shutdown
Router(config-if)# interface serial 2/1
Router(config-if)# shutdown
Ctrl-Z
Router#

Cisco 7301 router

interface, followed by the type (serial) and slot/port (port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter slot 1.

Router(config-if)# interface serial 1/0
Router(config-if)# shutdown
Router(config-if)# interface serial 1/1
Router(config-if)# shutdown
Ctrl-Z
Router#

Cisco 7304 PCI Port Adapter Carrier Card in a Cisco 7304 router

interface, followed by the type (serial) and slot/port (module-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in a Cisco 7304 PCI Port Adapter Carrier Card in module slot 3 of a Cisco 7304 router.

Router(config-if)# interface serial 3/0 
Router(config-if)# shutdown 
Router(config-if)# interface serial 3/1
Router(config-if)# shutdown

Ctrl-Z
Router#

Cisco 7401ASR router

interface, followed by the type (serial) and slot/port (port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 0 and interface 1 on a port adapter in port adapter slot 1.

Router(config-if)# interface serial 1/0
Router(config-if)# shutdown
Router(config-if)# interface serial 1/1
Router(config-if)# shutdown
Ctrl-Z
Router#

VIP in Cisco 7000 series routers or Cisco 7500 series routers

interface, followed by the type (serial) and slot/port adapter/port (interface-processor-slot-number/
port-adapter-slot-number/
interface-port-number)

shutdown

The example is for interface 1 and interface 0 on a port adapter in port adapter slot 1 of a VIP installed
in interface processor slot 1.

Router(config-if)# interface serial 1/1/1
Router(config-if)# shutdown
Router(config-if)# interface serial 1/1/0
Router(config-if)# shutdown
Ctrl-Z
Router#


Note If you need to shut down additional interfaces, enter the interface serial command (followed by the interface address of the interface) for each of the interfaces on your port adapter. Use the no shutdown command to enable the interface.


Step 4 Write the new configuration to NVRAM as follows:

Router# copy running-config startup-config
[OK]
Router#

The system displays an OK message when the configuration has been stored.

Step 5 Verify that new interfaces are now in the correct state (shut down) using the show interfaces command (followed by the interface type and interface address of the interface) to display the specific interface.

Table 5-2 provides examples of the show interfaces serial command for the supported platforms.

Table 5-2 Examples of the show interfaces serial Command for the Supported Platforms 

Platform
Command
Example

Catalyst RSM/VIP2 in Catalyst 5000 family switches

show interfaces serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 1.

Router# show interfaces serial 1/0

Serial 1/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Catalyst 6000 family FlexWAN module in Catalyst 6000 family switches

show interfaces serial, followed by mod_num/bay/port (module-slot-number/
port-adapter-bay-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter bay 0 of a FlexWAN module in module slot 3.

Router# show interfaces serial 3/0/0

Serial 3/0/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Cisco 7120 series routers

show interfaces serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 3.

Router# show interfaces serial 3/0

Serial 3/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Cisco 7140 series routers

show interfaces serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 4.

Router# show interfaces serial 4/0

Serial 4/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Cisco 7200 series routers and Cisco 7200 VXR routers

show interfaces serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 6.

Router# show interfaces serial 6/0

Serial 6/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Cisco 7201 router

show interfaces serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 1.

Router# show interfaces serial 1/0

Serial 1/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Cisco uBR7223 router

show interfaces serial, followed by slot/port (port-adapter-slot- number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 1.

Router# show interfaces serial 1/0

Serial 1/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Cisco uBR7246 router

show interfaces serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 2.

Router# show interfaces serial 2/0

Serial 2/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Cisco 7301 router

show interfaces serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 1.

Router# show interfaces serial 1/0

Serial 1/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Cisco 7304 PCI Port Adapter Carrier Card in a Cisco 7304 router

show interfaces serial, followed by slot/port (module-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in a Cisco 7304 PCI Port Adapter Carrier Card in module slot 3 of a Cisco 7304 router.

Router# show interfaces serial 3/0
 
Serial 3/0 is administratively down, 
line protocol is down 
 
[Additional display text omitted from 
this example]

Cisco 7401ASR router

show interfaces serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 1.

Router# show interfaces serial 1/0

Serial 1/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

VIP in Cisco 7000 series routers or Cisco 7500 series routers

show interfaces serial, followed by slot/port adapter/port (interface-processor-slot-number/
port-adapter-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in port adapter slot 1 of a VIP in interface processor slot 1.

Router# show interfaces serial 1/1/0

Serial 1/1/0 is administratively down, 
line protocol is down

[Additional display text omitted from 
this example]

Step 6 Re-enable the interfaces by doing the following:

a. Repeat Step 3 to re-enable an interface. Substitute the no shutdown command for the shutdown command.

b. Repeat Step 4 to write the new configuration to memory. Use the copy running-config startup-config command.

c. Repeat Step 5 to verify that the interfaces are in the correct state. Use the show interfaces command followed by the interface type and interface address of the interface.


For complete descriptions of software configuration commands, refer to the publications listed in the "Related Documentation" section on page viii. Proceed to the following section to configure the new interfaces.

Performing a Basic Configuration

Following are instructions for a basic interface configuration, which includes enabling an interface, specifying IP routing, and setting up external timing on a DCE interface. You might also need to enter other configuration subcommands, depending on the requirements for your system configuration and the protocols you plan to route on the interface. For complete descriptions of configuration subcommands and the configuration options available for serial interfaces, refer to the appropriate software documentation.

In the following procedure, press the Return key after each step unless otherwise noted. At any time you can exit the privileged level and return to the user level by entering disable at the prompt as follows:

Router# disable

Router> 


Step 1 At the privileged-level prompt, enter configuration mode and specify that the console terminal will be the source of the configuration subcommands as follows:

Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#

Step 2 Specify the first interface to configure by entering the interface serial subcommand, followed by the interface address of the interface you plan to configure.

Table 5-3 provides examples of the interface serial subcommand for the supported platforms.

Table 5-3 Examples of the interface serial Subcommand for the Supported Platforms 

Platform
Command
Example

Catalyst RSM/VIP2 in Catalyst 5000 family switches

interface serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a port adapter in port adapter slot 0.

Router(config)# interface serial 0/0
Router(config-if)#

Catalyst 6000 family FlexWAN module in Catalyst 6000 family switches

interface serial, followed by mod_num/bay/port (module-slot-number/
port-adapter-bay-number/
interface-port-number)

The example is for interface 0 of a port adapter in port adapter bay 0 of a FlexWAN module in module slot 3.

Router(config)# interface serial 3/0/0
Router(config-if)#

Cisco 7120 series routers

interface serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a
port adapter in port adapter slot 3.

Router(config)# interface serial 3/0
Router(config-if)#

Cisco 7140 series routers

interface serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a
port adapter in port adapter slot 4.

Router(config)# interface serial 4/0
Router(config-if)#

Cisco 7200 series routers and Cisco 7200 VXR routers

interface serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a
port adapter in port adapter slot 6.

Router(config)# interface serial 6/0
Router(config-if)#

Cisco 7201 router

interface serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a
port adapter in port adapter slot 1.

Router(config)# interface serial 1/0
Router(config-if)#

Cisco uBR7223 router

interface serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a
port adapter in port adapter slot 1.

Router(config)# interface serial 1/0
Router(config-if)#

Cisco uBR7246 router

interface serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a
port adapter in port adapter slot 2.

Router(config)# interface serial 2/0
Router(config-if)#

Cisco 7301 router

interface serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a
port adapter in port adapter slot 1.

Router(config)# interface serial 1/0
Router(config-if)#

Cisco 7304 PCI Port Adapter Carrier Card in a Cisco 7304 router

interface serial, followed by slot/port (module-slot-number/
interface-port-number)

The example is for interface 0 on a port adapter in a Cisco 7304 PCI Port Adapter Carrier Card in module slot 3 of a Cisco 7304 router.

Router(config)# interface serial 3/0 
Router(config-if)# 

Cisco 7401ASR router

interface serial, followed by slot/port (port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a
port adapter in port adapter slot 1.

Router(config)# interface serial 1/0
Router(config-if)#

VIP in Cisco 7000 series or Cisco 7500 series routers

interface serial, followed by slot/port adapter/port (interface-processor-slot-number/
port-adapter-slot-number/
interface-port-number)

The example is for interface 0 of a
port adapter in port adapter slot 1 of a VIP in interface processor slot 1.

Router(config)# interface serial 1/1/0
Router(config-if)#

Step 3 Assign an IP address and subnet mask to the interface (if IP routing is enabled on the system) by using the ip address configuration subcommand, as in the following example:

Router(config-if)# ip address 10.10.10.10 255.255.255.255 

Step 4 Add any additional configuration subcommands required to enable routing protocols and set the interface characteristics.


Note If you are configuring a DTE interface, proceed to Step 6. If you are configuring a DCE interface, you need to configure the external clock signal, as described in the next step.

The example in Step 5 applies to all systems in which the PA-4T+ is supported.


Step 5 Set the clock rate with the clock rate command. (See the "Configuring Timing (Clock) Signals" section.)

Router(config-if)# clock rate 64000

Step 6 Re-enable the interfaces using the no shutdown command. (See the "Shutting Down an Interface" section.)

Step 7 Configure all additional port adapter interfaces as required.

Step 8 When you have included all of the configuration subcommands to complete the configuration, press Ctrl-Z (hold down the Control key while you press Z) or enter end to exit configuration mode and return to the EXEC command interpreter prompt.

Step 9 Write the new configuration to NVRAM as follows:

Router# copy running-config startup-config
[OK]
Router#


This completes the procedure for creating a basic configuration.

Configuring Timing (Clock) Signals

All PA-4T+ interfaces support both DTE and DCE mode, depending on the mode of the interface cable attached to the port. To use a port as a DTE interface, you need only connect a DTE cable to the port. When the system detects the DTE mode cable, it automatically uses the external timing signal. To use a port in DCE mode, you must connect a DCE interface cable and set the clock speed with the clock rate configuration command. You must also set the clock rate to perform a loopback test. This section describes how to set the clock rate on a DCE port and, if necessary, how to invert the clock to correct a phase shift between the data and clock signals. Table 5-4 summarizes some of the commands used to configure the clock rate. See the specific sections that follow for further details.

The PA-4T+ provides four synchronous serial ports, and each port supports full-duplex operations at T1 and E1 speeds. A single port can support up to E2 speeds.

Speed is controlled by three variables:

the number of ports in use

the maximum speed allowed by the port adapter

the maximum speed of the attached CSU/DSU.

The CSU/DSU determines the maximum speed of the full-duplex port. No configuration is necessary. If a CSU/DSU runs at a maximum speed of 1.55 Mbps (T1 speed), using only one port in the port adapter will not make this CSU/DSU run at E2 speed. On the other hand, if a CSU/DSU is capable of E2 speed (8 Mbps), this CSU/DSU will take the maximum bandwidth of the port adapter. To ensure this speed, no other port can be used. If you use another port, the speed of the CSU/DSU capable of E2 speed is reduced, because the port adapter shares the bandwidth between the two ports.

The PA-T4+ maximum speed can be attained only if the maximum aggregate speed per port adapter is 8 Mbps (E2) when only one full-duplex port is in use. When two full-duplex ports are in use, the maximum speed for each is 4 Mbps. When four full-duplex ports are in use, the maximum speed for each is 1.55 Mbps (T1) or 2.048 Mbps (E1).

Table 5-4 Clock Rate Configuration Commands 

Purpose
Command
Example
Additional Information

Set standard clock rate.

clock rate

The example is for a serial interface with a standard clock rate of 72 kbps.

Router(config)# interface serial 3/0
Router(config-if)# clock rate 7200

"Setting the Clock Rate"

Set nonstandard clock rate.

clock rate

The example is for a serial interface with a nonstandard clock rate of 1234567 kbps.

Router(config)# interface serial 3/0
Router(config-if)# clock rate 1234567

"Setting the Clock Rate"

Remove a clock rate that has been set.

no clock rate

The example is for a serial interface and removes a standard clock rate of 72 kbps.

Router(config)# interface serial 3/0
Router(config-if)# clock rate 7200
Router(config-if)# no clock rate

"Setting the Clock Rate"

Invert the transmit clock signal.

invert-txc

The example inverts the transmit clock signal for a serial interface.

Router(config)# interface serial 3/0
Router(config-if)# invert-txc

"Inverting the Clock Signal"

Change the clock signal back to its original phase.

no invert-txc

The example sets the transmit clock signal for a serial interface back to its original phase.

Router(config)# interface serial 3/0
Router(config-if)# no invert-txc

"Inverting the Clock Signal"

Invert the data signal.

invert data

The example inverts the data stream for both transmit and receive for a serial interface:

Router(config)# interface serial 3/0
Router(config-if)# invert-txc

"Inverting the Data Signal"


Setting the Clock Rate

The default operation on a PA-4T+ DCE interface is for the DCE device to generate its own clock signal (TxC) and send it to the remote DTE. The remote DTE device returns the clock signal to the DCE (PA-4T+). Set the clock rate of an interface using the clock rate subcommand, which specifies the clock rate as a bits-per-second value. This subcommand functions in the same way on all supported platforms.

Before you can assign a clock rate, you must use the interface serial command (followed by the interface address of the interface) to select the interface to which you want to assign the clock rate value.

In the following example, the clock rate is specified as 72 kbps:

Router(config-if)# clock rate 72000

The preceding command example applies to all systems in which the PA-4T+ is supported. Use the no clock rate command to remove the clock rate.

Following are the standard clock rates:

1200, 2400, 4800, 9600, 19200 38400 , 56000 , 64000 ,
72000 , 125000 148000 , 250000, 500000, 800000, 1000000,
1300000, 2000000, 4000000, 8000000

When you have finished, press Ctrl-Z—hold down the Control key while you press Z—or enter end or exit to exit configuration mode and return to the EXEC command interpreter prompt. Then write the new configuration to NVRAM using the copy running-config startup-config command.


Note Cisco IOS Release 11.2(7a)P or later, or 11.1(10)CA or later loaded on your Cisco 7200 series router, Cisco 7000 series router, or Cisco 7500 series router with a VIP2-40(=) support nonstandard clock rates (any value from 1200 to 8000000) on PA-4T+ interfaces.

Cisco IOS Release 12.0(3)T or later, or 12.0(1)XE or later support nonstandard clock rates on PA-4T+ interfaces installed in Cisco 7204VXR router and Cisco 7206VXR router.

Cisco IOS Release 11.3(6)NA or later loaded on your Cisco uBR7200 series router supports nonstandard clock rates (any value from 1200 to 8000000) on PA-4T+ interfaces.


Set a nonstandard clock rate for an interface using the clock rate subcommand. Before you can assign a nonstandard clock rate, you must use the interface serial command (followed by the interface address of the interface) to select the interface to which you want to assign the nonstandard clock rate value.

In the following example, a nonstandard clock rate of 1234567 bps is specified:

Router(config-if)# clock rate 1234567

The preceding command example applies to all systems in which the PA-4T+ is supported. Use the no clock rate command to remove the clock rate.

When you have finished, press Ctrl-Z—hold down the Control key while you press Z—or enter end or exit to exit configuration mode and return to the EXEC command interpreter prompt.

Then write the new configuration to NVRAM using the copy running-config startup-config command.

The following example shows how to use the show running-config command to determine the exact clock rate to which the nonstandard clock rate was rounded:

Router# show running-config
Building configuration...
...
!
interface Serial1/0 (interface Serial3/1/0 on a VIP2 or FlexWAN module)

 no ip address
 clockrate 1151526
!
...

In the preceding example, only the relevant output from the show running-config command is shown; other information is omitted.

Inverting the Clock Signal

Systems that use long cables or cables that are not transmitting the TxC (clock) signal might experience high error rates when operating at higher transmission speeds. If a PA-4T+ DCE port is reporting a high number of error packets, a phase shift might be the problem. Inverting the clock might correct this shift.

When the PA-4T+ interface is a DTE, the invert-txc command inverts the TxC signal it receives from the remote DCE. When the PA-4T+ interface is a DCE, this command inverts the clock signal to the remote DTE port. Use the no invert-txc command to change the clock signal back to its original phase.

Inverting the Data Signal

If the interface on the PA-4T+ synchronous serial port adapter is used to drive a dedicated T1 line that does not have B8ZS encoding (a method to avoid 15 zeros), the data stream must be inverted (both TxD and RxD) either in the connecting CSU/DSU or the interface. To invert the data stream coming out of the PA-4T+, use the invert data command. By inverting the (HDLC) data stream, the HDLC zero insertion algorithm becomes a ones insertion algorithm that satisfies the T1 requirements.


Note Invert data only on the PA-4T+ interface or on the CSU/DSU; inverting both cancels out both data inversions.


Configuring NRZI Format

All PA-4T+ interfaces support nonreturn-to-zero (NRZ) and nonreturn-to-zero inverted (NRZI) formats. Both formats use two different voltage levels for transmission. NRZ signals maintain constant voltage levels with no signal transitions (no return to a zero voltage level) during a bit interval and are decoded using absolute values (0 and 1). NRZI uses the same constant signal levels but interprets the absence of data (a space) at the beginning of a bit interval as a signal transition and the presence of data (a mark) as no transition. NRZI uses relational encoding to decode signals rather than determining absolute values.

Table 5-5 summarizes NRZI format commands.

Table 5-5 NRZI Format Commands

Command
Purpose
Example

nrzi-encoding [mark]1

Enable NRZI encoding.

The example is for a serial interface with NRZI mark encoding specified:

Router(config)# interface serial 3/0
Router(config-if)# nrzi-encoding mark

The example is for a serial interface with NRZI space encoding specified:

Router(config)# interface serial 3/0
Router(config-if)# nrzi-encoding

no nrzi-encoding

Disable NRZI encoding.

The example disables NRZI encoding on a serial interface:

Router(config)# interface serial 3/0
Router(config-if)# no nrzi-encoding

1 Mark is an optional argument. When mark is used, it means there is no signal transition; there is data (a mark) at the beginning of a bit interval. When mark is not used, it means there is a signal transition; there is no data (a space) at the beginning of a bit interval.


NRZ format, the factory default on all interfaces, is most common. NRZI format, which is configured with a software command, is commonly used with EIA/TIA-232 connections in IBM environments.

Enable NRZI encoding on any interface using the nrzi-encoding [mark] command, where no argument after the command is interpreted as a signal transition, and mark is interpreted as no signal transition. This command functions in the same way on all supported platforms. Before you can enable NRZI encoding, you must use the interface serial command (followed by the interface address of the interface) to select the interface on which you want to enable NRZI encoding.

In the example that follows, NRZI encoding with a signal transition—no argument—is specified:

Router(config-if)# nrzi-encoding 

In the example that follows, NRZI encoding with no signal transition—with argument—is specified:

Router(config-if)# nrzi-encoding mark 

Use the no nrzi-encoding command to disable NRZI encoding.

When you have finished, press Ctrl-Z—hold down the Control key while you press Z—or enter end or exit to exit configuration mode and return to the EXEC command interpreter prompt. Then write the new configuration to NVRAM using the copy running-config startup-config command.

For complete command descriptions and instructions, refer to the Configuration Fundamentals Configuration Guide on Cisco.com.

Configuring Cyclic Redundancy Checks

Cyclic redundancy check (CRC) is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. All interfaces use a 16-bit CRC (CRC-CITT) by default, but also support a 32-bit CRC. The sender of a data frame calculates the frame check sequence (FCS). Before it sends a frame, the sender appends the FCS value to the message. The receiver recalculates the FCS and compares its calculation to the FCS from the sender. If there is a difference between the two calculations, the receiver assumes that a transmission error occurred and sends a request to the sender to resend the frame.

Table 5-6 summarizes CRC commands.

Table 5-6 CRC Commands

Command
Purpose
Example

crc size

Enable 32-bit CRC

The example enables 32-bit CRC on a serial interface:

Router(config)# interface serial 3/0
Router(config-if)# crc 32

no crc size

Return to default 16-bit CRC.

The example disables 32-bit CRC on a serial interface and returns to the default 16-bit CRC:

Router(config)# interface serial 3/0
Router(config-if)# no crc 32

Enable 32-bit CRC using the crc 32 command. Before you can enable 32-bit CRC, you must use the interface serial command (followed by the interface address of the interface) to select the interface on which you want to enable 32-bit CRC. This command functions in the same way on all supported platforms.

In the example that follows, 32-bit CRC is specified:

Router(config-if)# crc 32

The preceding command example applies to all systems in which the PA-4T+ is supported. Use the no crc 32 command to disable CRC-32 and return the interface to the default CRC-16 (CRC-CITT) setting.

When you have finished, press Ctrl-Z—hold down the Control key while you press Z—or enter end or exit to exit configuration mode and return to the EXEC command interpreter prompt. Then write the new configuration to NVRAM using the copy running-config startup-config command.

For command descriptions, refer to the Configuration Fundamentals Configuration Guide on Cisco.com.


Note If you are configuring a PA-4T+ in a Cisco 7200 series router and you want to configure the interface for half-duplex or Bisync operation, proceed to the next section, "Configuring Half-Duplex and Binary Synchronous Communications in Cisco 7200 Series Routers"; otherwise, proceed to the "Checking the Configuration" section.


Configuring Half-Duplex and Binary Synchronous Communications in Cisco 7200 Series Routers

This section explains how to configure PA-4T+ interfaces for half-duplex and Bisync operation in Cisco 7200 series routers, including Cisco 7200 VXR routers and Cisco 7201 routers.


Note Cisco IOS Release 11.2(7a)P or a later release of 11.2P supports half-duplex and Bisync operation on the PA-4T+ in Cisco 7200 series routers.

Cisco IOS Release 11.1(19)CC1 or a later release of 11.1 CC, or Release 11.3(4)AA or a later release of 11.3AA supports half-duplex and Bisync operation on the PA-4T+ installed in Cisco 7202 routers.

Cisco IOS Release 12.0(3)T or a later release of 12.0T, or Release 12.0(2)XE or a later release of 12.0XE supports half-duplex and Bisync operation on the PA-4T+ in the Cisco 7204VXR router and Cisco 7206VXR router.

The Catalyst RSM/VIP2, Catalyst 6000 family FlexWAN module, Cisco 7100 series routers, Cisco uBR7200 series routers, and the VIP do not support half-duplex and Bisync operation on the PA-4T+.


Use the half-duplex command to configure PA-4T+ interfaces for half-duplex mode; full-duplex mode is the default for low-speed serial interfaces. Serial DCE interfaces in half-duplex mode can be configured for controlled-carrier mode or constant-carrier mode; constant-carrier mode is the default. Controlled-carrier mode sets the PA-4T+ interface to deactivate data carrier detect (DCD) until a transmission is sent to the interface. After a transmission is received, DCD is activated and the interface waits a user-configured amount of time, and then transmits the data. After the transmission, the interface waits a user-configured amount of time and then deactivates DCD. Constant-carrier mode activates DCD at all times.

Use the half-duplex controlled-carrier command to configure a PA-4T+ interface for controlled-carrier mode. Use the no half-duplex controlled-carrier command to return the interface to constant-carrier mode.

Follow these steps to configure controlled-carrier mode on a PA-4T+ interface:


Step 1 Enter configuration mode and specify that the console terminal is the source of the configuration subcommands, as follows:

Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#

Step 2 Specify the interface to configure for controlled-carrier mode using the interface serial subcommand (followed by the interface address of the interface) and then enter the half-duplex controlled-carrier subcommand.

The following example is for the first interface of the port adapter in port adapter slot 1:

Router(config)# interface serial 1/0
Router(config-if)# half-duplex controlled-carrier

Step 3 Specify the length of the timer delay the interface uses when it is configured for controlled-carrier mode by using the following command:

Router(config-if)# half-duplex timer {cts-delay value | cts-drop-timeout value | 
dcd-drop-delay value | dcd-txstart-delay value | rts-drop-delay value | rts-timeout value 
| transmit-delay value}


where value is the length of the timer delay in milliseconds.

The following example specifies a Data Carrier Detect (DCD) drop delay of 100 milliseconds on the first interface of a port adapter in port adapter slot 1:

Router(config)# interface serial 1/0
Router(config-if)# half-duplex timer dcd-drop-delay 100 ms

Table 5-7 lists the default delay settings and the value argument for each timer you can use with the half-duplex timer command.

Table 5-7 Half-Duplex Timer Default Delay Settings

Timer
Command Syntax
Default Settings 1

CTS delay2

half-duplex timer cts-delay

0

CTS drop timeout

half-duplex timer cts-drop-timeout

250

DCD drop delay3

half-duplex timer dcd-drop-delay

100

DCD transmission start delay

half-duplex timer dcd-txstart-delay

100

RTS drop delay4

half-duplex timer rts-drop-delay

3

RTS timeout

half-duplex timer rts-timeout

3

Transmit delay

half-duplex transmit-delay

0

1 In milliseconds (ms).

2 Clear To Send (CTS).

3 Data Carrier Detect (DCD).

4 Request To Send (RTS).


Step 4 Complete the configuration by pressing Ctrl-Z—hold down the Control key while you press Z—or entering end or exit to exit configuration mode and return to the EXEC command interpreter prompt.

Step 5 Write the new configuration to NVRAM as follows:

Router# copy running-config startup-config
[OK]
Router#


This completes the procedure for configuring controlled-carrier mode on a PA-T4+ interface. For additional information on configuring half-duplex operation on low-speed serial interfaces, refer to the chapter "Configuring Interfaces" of the Configuration Fundamentals Configuration Guide on Cisco.com.


Note To configure PA-4T+ interfaces for Binary Synchronous (Bisync) operation in Cisco 7200 series series routers, refer to the "Block Serial Tunneling (BSTUN)" section of the "Configuring Serial Tunnel (STUN) and Block Serial Tunnel (BSTUN)" chapter of the Bridging and IBM Networking Configuration Guide on Cisco.com.


Checking the Configuration

After configuring the new interface, use the show commands to display the status of the new interface or all interfaces and the ping and loopback commands to check connectivity.

This section contains the following subsections:

Using show Commands to Verify the New Interface Status

Using the ping Command to Verify Network Connectivity

Using loopback Commands

Using show Commands to Verify the New Interface Status

Table 5-8 demonstrates how you can use the show commands to verify that new interfaces are configured and operating correctly and that the PA-4T+ appears in them correctly. Sample displays of the output of selected show commands appear in the sections that follow. For complete command descriptions and examples, refer to the publications listed in the "Related Documentation" section on page viii.


Note The outputs that appear in this document may not match the output you receive when running these commands. The outputs in this document are examples only.


Table 5-8 Using show Commands 

Command
Function
Example

show version or
show hardware

Displays system hardware configuration, the number of each interface type installed, Cisco IOS software version, names and sources of configuration files, and boot images

Router# show version

show controllers

Displays all the current interface processors and their interfaces

Router# show controllers

show diag slot

Note The slot argument is not required with Catalyst 5000 family switches.

Displays types of port adapters installed in your system and information about a specific port adapter slot, interface processor slot, or chassis slot

Router# show diag 2

show interfaces type 0 or 1/
interface-port-number

Displays status information about a specific type of interface (for example, serial) on a Catalyst RSM/VIP2

Router# show interfaces serial 1/0

show interfaces type module-slot-
number/port-adapter-bay-number/
interface-port-number

Displays status information about a specific type of interface (for example, serial) on a Catalyst 6000 family FlexWAN module

Router# show interfaces serial 3/0/0

show interfaces type 3/interface-port-
number

Displays status information about a specific type of interface (for example, serial) in a Cisco 7120 series router

Router# show interfaces serial 3/1

show interfaces type 4/interface-port-
number

Displays status information about a specific type of interface (for example, serial) in a Cisco 7140 series router

Router# show interfaces serial 4/1

show interfaces type slot-number/interface-port-number

Displays status information about a specific type of interface (for example, serial) on a Cisco 7200 series router, Cisco 7200 VXR routers, Cisco 7201 router, Cisco 7301 router, or Cisco 7401ASR router

Router# show interfaces serial 1/0

show interfaces type 1/interface-port-
number

Displays status information about a specific type of interface (for example, serial) in a Cisco uBR7223 router

Router# show interfaces serial 1/1

show interfaces type 1 or 2/
interface-port-number

Displays status information about a specific type of interface (for example, serial) in a Cisco uBR7246 router

Router# show interfaces serial 2/0

show interfaces type 2 or 3 or 4 or 5/
interface-port-number

Displays status information about a serial interface on a Cisco 7304 PCI Port Adapter Carrier Card in a Cisco 7304 router

Router# show interfaces serial 3/0

show interfaces type interface-processor-
slot-number/port-adapter-slot-number/
interface-port-number

Displays status information about a specific type of interface (for example, serial) on a VIP in a Cisco 7000 series or Cisco 7500 series router

Router# show interfaces serial 3/1/0

show protocols

Displays protocols configured for the entire system and for specific interfaces

Router# show protocols

show running-config

Displays the running configuration file

Router# show running-config

show startup-config

Displays the configuration stored in NVRAM

Router# show startup-config

If an interface is shut down and you configured it as up, or if the displays indicate that the hardware is not functioning properly, ensure that the interface is properly connected and terminated. If you still have problems bringing up the interface, contact a service representative for assistance. This section includes the following subsections:

Using the show version or show hardware Commands

Using the show diag Command

Using the show interfaces Command

Choose the subsection appropriate for your system. Proceed to the "Using the ping Command to Verify Network Connectivity" section when you have finished using the show commands.

Using the show version or show hardware Commands

Display the configuration of the system hardware, the number of each interface type installed, the Cisco IOS software version, the names and sources of configuration files, and the boot images, using the show version (or show hardware) command.


Note The outputs that appear in this document may not match the output you receive when running these commands. The outputs in this document are examples only.


The following sections provide platform-specific output examples using the show version command:

Catalyst RSM/VIP2 in Catalyst 5000 Family Switches—Example Output of the show version Command

Catalyst 6000 Family FlexWAN Module in Catalyst 6000 Family Switches—Example Output of the show version Command

Cisco 7100 Series Routers, Cisco 7200 Series Routers, Cisco 7200 VXR Routers, and Cisco uBR7200 Series Routers—Example Output of the show version Command

Cisco 7201 Router—Example Output of the show version Command

Cisco 7401ASR Router—Example Output of the show version Command

VIP in Cisco 7000 Series Routers and Cisco 7500 Series Routers—Example Output of the show version Command

Catalyst RSM/VIP2 in Catalyst 5000 Family Switches—Example Output of the show version Command

Following is an example of the show version command from a Catalyst 5000 family switch with the PA-4T+ installed:

Router# show version

Cisco Internetwork Operating System Software 
IOS (tm) GS Software (image-name), Version 11.1(8)CA, RELEASED SOFTWARE
Synced to mainline version: 11.1(8)
Copyright (c) 1986-1997 by cisco Systems, Inc.
Compiled Thu 23-Jan-97 18:14 by bellb
Image text-base: 0x60010900, data-base: 0x609EE000

ROM: System Bootstrap, Version 11.5 [kmac 3.2], RELEASED SOFTWARE
ROM: GS Software (image-name), Released version 11.1(5) [sglee 112]

GEN1 uptime is 2 minutes
System restarted by reload
System image file is "image-name", booted via tftp from 10.10.10.1

cisco RSP2 (R4600) processor with 32768K bytes of memory.
R4600 processor, Implementation 32, Revision 2.0
Last reset from power-on
G.703/E1 software, Version 1.0.
SuperLAT software copyright 1990 by Meridian Technology Corp).
Bridging software.
X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.
TN3270 Emulation software (copyright 1994 by TGV Inc).
Chassis Interface.
1 VIP2 controller (4 Ethernet)(4 Serial).
4 Ethernet/IEEE 802.3 interfaces.
4 Network Serial interfaces.
125K bytes of non-volatile configuration memory.

16384K bytes of Flash PCMCIA card at slot 1 (Sector size 128K).
8192K bytes of Flash internal SIMM (Sector size 256K).
Configuration register is 0x0

Catalyst 6000 Family FlexWAN Module in Catalyst 6000 Family Switches—Example Output of the show version Command

Following is an example of the show version command from a Catalyst 6000 family switch with a PA-4T+ installed:

Router# show version

Cisco Internetwork Operating System Software 
IOS (tm) MSFC Software (C6MSFC-JSV-M), Experimental Version 12.1(20000209:134547) 
[amcrae-cosmos_e_nightly 163]
Copyright (c) 1986-2000 by cisco Systems, Inc.
Compiled Wed 09-Feb-00 07:10 by 
Image text-base: 0x60008900, data-base: 0x6140E000

ROM: System Bootstrap, Version 12.0(3)XE, RELEASE SOFTWARE 

const-uut uptime is 5 minutes
System returned to ROM by reload
System image file is "bootflash:c6msfc-jsv-mz.Feb9"

cisco Cat6k-MSFC (R5000) processor with 122880K/8192K bytes of memory.
Processor board ID SAD03457061
R5000 CPU at 200Mhz, Implementation 35, Rev 2.1, 512KB L2 Cache
Last reset from power-on
Channelized E1, Version 1.0.
Bridging software.
X.25 software, Version 3.0.0.
SuperLAT software (copyright 1990 by Meridian Technology Corp).
TN3270 Emulation software.
Primary Rate ISDN software, Version 1.1.
6 FlexWAN controllers (13 Serial)(8 E1)(8 T1)(2 HSSI)(2 ATM)(1 Channelized T3)(1 
Channelized E3)(2 POS).
1 Virtual Ethernet/IEEE 802.3  interface(s)
17 Serial network interface(s)
2 HSSI network interface(s)
2 ATM network interface(s)
2 Packet over SONET network interface(s)
1 Channelized T3 port(s)
1 Channelized E3 port(s)
123K bytes of non-volatile configuration memory.
4096K bytes of packet SRAM memory.

16384K bytes of Flash internal SIMM (Sector size 256K).
Configuration register is 0x1

Cisco 7100 Series Routers, Cisco 7200 Series Routers, Cisco 7200 VXR Routers, and Cisco uBR7200 Series Routers—Example Output of the show version Command

Following is an example of the show version command from a Cisco 7200 series router with a PA-4T+ installed:

Router# show version

Cisco Internetwork Operating System Software 
IOS (tm) 7200 Software (C7200-J-M), RELEASED VERSION 11.1(8)CA [sglee 108]
Synced to mainline version: 11.1
Copyright (c) 1986-1997 by cisco Systems, Inc.
Compiled Thu 27-Feb-97 23:54 by sglee
Image text-base: 0x600088F0, data-base: 0x6072C000

ROM: System Bootstrap, Version 11.1(5) RELEASED SOFTWARE
ROM: 7200 Software (software-image), Released Version 11.1(8)CA [sglee 101]

pulp uptime is 2 hours, 19 minutes
System restarted by reload
System image file is "image-name", booted via tftp from 10.10.10.1

cisco 7206 (NPE150) processor with 26624K/6144K bytes of memory.
R4700 processor, Implementation 33, Revision 1.0 (512KB Level 2 Cache)
Last reset from power-on
Bridging software.
SuperLAT software copyright 1990 by Meridian Technology Corp).
X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.
TN3270 Emulation software (copyright 1994 by TGV Inc).
Chassis Interface.
3 Ethernet/IEEE 802.3 interfaces.
1 FastEthernet/IEEE 802.3 interface.
4 Serial interfaces.
125K bytes of non-volatile configuration memory.
1024K bytes of packet SRAM memory.

8192K bytes of Flash PCMCIA card at slot 0 (Sector size 128K).
4096K bytes of Flash internal SIMM (Sector size 256K).
Configuration register is 0x0

Cisco 7201 Router—Example Output of the show version Command

Following is an example of the show version command from a Cisco 7201 router:

Router# show version 

Cisco IOS Software, 7200 Software (C7200P-ADVENTERPRISEK9-M), Version 
12.4(biffDEV.061001), INTERIM SOFTWARE Copyright (c) 1986-2006 by Cisco Systems, Inc.
Compiled Sun 01-Oct-06 23:42 by biff
ROM: System Bootstrap, Version 12.4(4r)XD5, RELEASE SOFTWARE (fc1)
BOOTLDR: Cisco IOS Software, 7200 Software (C7200P-KBOOT-M), Version 12.4(TAZ3DEV.060927), 
INTERIM SOFTWARE
c7201alpha1 uptime is 5 days, 18 hours, 32 minutes System returned to ROM by power-on 
System image file is "disk0:c7200p-adventerprisek9-mz.2006-10-01.biffdev"
This product contains cryptographic features and is subject to United States and local 
country laws governing import, export, transfer and use. Delivery of Cisco cryptographic 
products does not imply third-party authority to import, export, distribute or use 
encryption.
Importers, exporters, distributors and users are responsible for compliance with U.S. and 
local country laws. By using this product you agree to comply with applicable laws and 
regulations. If you are unable to comply with U.S. and local laws, return this product 
immediately.
A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html
If you require further assistance please contact us by sending email to export@cisco.com.
Cisco 7201 (c7201) processor (revision A) with 917504K/65536K bytes of memory.
Processor board ID 2222222222222
MPC7448 CPU at 1666Mhz, Implementation 0, Rev 2.2
1 slot midplane, Version 2.255
Last reset from power-on
1 FastEthernet interface
4 Gigabit Ethernet interfaces
2045K bytes of NVRAM.
62443K bytes of USB Flash usbflash0 (Read/Write)
250880K bytes of ATA PCMCIA card at slot 0 (Sector size 512 bytes).
65536K bytes of Flash internal SIMM (Sector size 512K).
Configuration register is 0x2

Cisco 7401ASR Router—Example Output of the show version Command

Following is an example of the show version command from a Cisco 7401ASR router with a PA-4T+ installed:

Router# show version

Cisco Internetwork Operating System Software 
IOS (tm) 7401ASR Software (C7401ASR-J-M), RELEASED VERSION 11.1(8)CA [sglee 108]
Synced to mainline version: 11.1
Copyright (c) 1986-1997 by cisco Systems, Inc.
Compiled Thu 27-Feb-97 23:54 by sglee
Image text-base: 0x600088F0, data-base: 0x6072C000

ROM: System Bootstrap, Version 11.1(5) RELEASED SOFTWARE
ROM: 7401ASR Software (software-image), Released Version 11.1(8)CA [sglee 101]

pulp uptime is 2 hours, 19 minutes
System restarted by reload
System image file is "image-name", booted via tftp from 10.10.10.1

cisco 7206 (NPE150) processor with 26624K/6144K bytes of memory.
R4700 processor, Implementation 33, Revision 1.0 (512KB Level 2 Cache)
Last reset from power-on
Bridging software.
SuperLAT software copyright 1990 by Meridian Technology Corp).
X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.
TN3270 Emulation software (copyright 1994 by TGV Inc).
Chassis Interface.
3 Ethernet/IEEE 802.3 interfaces.
1 FastEthernet/IEEE 802.3 interface.
4 Serial interfaces.
125K bytes of non-volatile configuration memory.
1024K bytes of packet SRAM memory.

8192K bytes of Flash PCMCIA card at slot 0 (Sector size 128K).
4096K bytes of Flash internal SIMM (Sector size 256K).
Configuration register is 0x0

VIP in Cisco 7000 Series Routers and Cisco 7500 Series Routers—Example Output of the show version Command

Following is an example of the show version command from a Cisco 7500 series router with a PA-4T+ installed:

Router# show version

Cisco Internetwork Operating System Software 
IOS (tm) GS Software (image-name), Version 11.1(8)CA, RELEASED SOFTWARE
Synced to mainline version: 11.1(8)
Copyright (c) 1986-1997 by cisco Systems, Inc.
Compiled Thu 23-Jan-97 18:14 by bellb
Image text-base: 0x60010900, data-base: 0x609EE000

ROM: System Bootstrap, Version 11.5 [kmac 3.2], RELEASED SOFTWARE
ROM: GS Software (image-name), Released version 11.1(5) [sglee 112]

GEN1 uptime is 2 minutes
System restarted by reload
System image file is "image-name", booted via tftp from 10.10.10.1

cisco RSP2 (R4600) processor with 32768K bytes of memory.
R4600 processor, Implementation 32, Revision 2.0
Last reset from power-on
G.703/E1 software, Version 1.0.
SuperLAT software copyright 1990 by Meridian Technology Corp).
Bridging software.
X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.
TN3270 Emulation software (copyright 1994 by TGV Inc).
Chassis Interface.
1 VIP2 controller (4 Ethernet)(4 Serial).
4 Ethernet/IEEE 802.3 interfaces.
4 Network Serial interfaces.
125K bytes of non-volatile configuration memory.

16384K bytes of Flash PCMCIA card at slot 1 (Sector size 128K).
8192K bytes of Flash internal SIMM (Sector size 256K).
Configuration register is 0x0

Using the show diag Command

Display the types of port adapters installed in your system (and specific information about each) using the show diag slot command, where slot is the port adapter slot in a Catalyst 5000 family switch, a Cisco 7100 series router, Cisco 7200 series router, Cisco 7200 VXR router, Cisco uBR7200 series, Cisco 7201 router, Cisco 7301 router, and Cisco 7401ASR router, the module slot in a Cisco 7304 PCI Port Adapter Carrier Card in a Cisco 7304 router, and the interface processor slot in a Cisco 7000 series router or Cisco 7500 series router with a VIP. In the FlexWAN module, the show diag command is used without the slot designation.


Note The outputs that appear in this document may not match the output you receive when running these commands. The outputs in this document are examples only.



Note The slot argument is not required for Catalyst 5000 family switches.


The following sections provide platform-specific output examples using the show diag command:

Catalyst RSM/VIP2 in Catalyst 5000 Family Switches—Example Output of the show diag Command

Catalyst 6000 Family FlexWAN Module—Example Output of the show diag Command

Cisco 7100 Series Routers, Cisco 7200 Series Routers, Cisco 7200 VXR Routers, and Cisco uBR7200 Series Routers—Example Output of the show diag Command

Cisco 7201 Router—Example Output of the show diag Command

Cisco 7401ASR Router—Example Output of the show diag Command

VIP in Cisco 7000 Series Routers and Cisco 7500 Series Routers—Example Output of the show diag Command

Catalyst RSM/VIP2 in Catalyst 5000 Family Switches—Example Output of the show diag Command

Following is an example of the show diag command that shows a PA-4T+ installed in a Catalyst RSM/VIP2:

Router# show diag 0
Slot 0:
        Physical slot 0, ~physical slot 0x6, logical slot 0, CBus 0
        Microcode Status 0xC
        Master Enable, LED, WCS Loaded
        Board is analyzed 
        Pending I/O Status: Console I/O
        EEPROM format version 1
        VIP2 controller, HW rev 2.2, board revision UNKNOWN
        Serial number: 03517093 Part number: 73-1684-03
        Test history: 0x00        RMA number: 00-00-00
        Flags: cisco 7000 board; 7500 compatible

        EEPROM contents (hex):
          0x20: 01 15 02 03 00 35 AA A5 49 06 94 03 00 00 00 00
          0x30: 50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

        Slot database information:
        Flags: 0x4      Insertion time: 0x5314 (01:20:55 ago)
[Additional display text omitted]

Catalyst 6000 Family FlexWAN Module—Example Output of the show diag Command

Following is an example of the show diag command that shows a PA-4T+ installed in a Catalyst 6000 family FlexWAN module:

Router# show diag 

[Additional display text omitted]

Slot 8: Logical_index 17
     Board is analyzed ipc ready FlexWAN controller

     Slot database information:
     Flags: 0x2004	Insertion time: unknown

     CWAN Controller Memory Size: Unknown

     PA Bay 1 Information:
          Mx Serial PA, 8 ports
          EEPROM format version 0
          HW rev 0.00, Board revision UNKNOWN
          Serial number: 00000000  Part number: 00-0000-00 

Cisco 7100 Series Routers, Cisco 7200 Series Routers, Cisco 7200 VXR Routers, and Cisco uBR7200 Series Routers—Example Output of the show diag Command

Following is an example of the show diag command that shows a PA-4T+ installed in port adapter slot 1 of a Cisco 7200 series router:

Router# show diag 1
Slot 1:
Mueslix serial (RS232) port adapter, 8 ports
Port adapter is analyzed
Port adapter insertion time 2d09h ago
Hardware revision 255.255               Board revision UNKNOWN
Serial number     4294967295    Part number    255-65535-255
Test history      0xFF          RMA number     255-255-255
EEPROM format version 1
EEPROM contents (hex):
0x20: 01 0D FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x30: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

Cisco 7201 Router—Example Output of the show diag Command

Following is an example of the show diag command from a Cisco 7201 router:

Router# show diag 1
Slot 1:
Dual OC3 POS Port adapter, 2 ports
Port adapter is analyzed 
Port adapter insertion time 00:02:19 ago
EEPROM contents at hardware discovery:
Hardware Revision : 1.0
PCB Serial Number : JAE07520DYL
Part Number : 73-8220-02
Board Revision : A0
RMA Test History : 00
RMA Number : 0-0-0-0
RMA History : 00
Deviation Number : 0
Product (FRU) Number : PA-POS-2OC3
Top Assy. Part Number : 800-21857-02
EEPROM format version 4
EEPROM contents (hex):
0x00: 04 FF 40 03 E3 41 01 00 C1 8B 4A 41 45 30 37 35
0x10: 32 30 44 59 4C 82 49 20 1C 02 42 41 30 03 00 81
0x20: 00 00 00 00 04 00 88 00 00 00 00 CB 94 50 41 2D
0x30: 50 4F 53 2D 32 4F 43 33 20 20 20 20 20 20 20 20
0x40: 20 C0 46 03 20 00 55 61 02 FF FF FF FF FF FF FF
0x50: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x60: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x70: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

Cisco 7401ASR Router—Example Output of the show diag Command

Following is an example of the show diag command that shows a PA-4T+ installed in port adapter slot 1 of a Cisco 7401ASR router:

Router# show diag 1
Slot 1:
Mueslix serial (RS232) port adapter, 8 ports
Port adapter is analyzed
Port adapter insertion time 2d09h ago
Hardware revision 255.255               Board revision UNKNOWN
Serial number     4294967295    Part number    255-65535-255
Test history      0xFF          RMA number     255-255-255
EEPROM format version 1
EEPROM contents (hex):
0x20: 01 0D FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x30: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

VIP in Cisco 7000 Series Routers and Cisco 7500 Series Routers—Example Output of the show diag Command

Following is an example of the show diag command that shows a PA-4T+ installed in port adapter slot 0 on a VIP in interface processor slot 3:

Router# show diag 3
Slot 3:
        Physical slot 3, ~physical slot 0x6, logical slot 3, CBus 0
        Microcode Status 0xC
        Master Enable, LED, WCS Loaded
        Board is analyzed 
        Pending I/O Status: Console I/O
        EEPROM format version 1
        VIP2 controller, HW rev 2.2, board revision UNKNOWN
        Serial number: 03517093 Part number: 73-1684-03
        Test history: 0x00        RMA number: 00-00-00
        Flags: cisco 7000 board; 7500 compatible

        EEPROM contents (hex):
          0x20: 01 15 02 03 00 35 AA A5 49 06 94 03 00 00 00 00
          0x30: 50 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

        Slot database information:
        Flags: 0x4      Insertion time: 0x5314 (01:20:55 ago)
 
        Controller Memory Size: 8 MBytes DRAM, 1024 KBytes SRAM

        PA Bay 0 Information:
                Mx Serial PA, 4 ports
                EEPROM format version 1
                HW rev 1.0, Board revision 154
                Serial number: 03699540  Part number: 73-1577-03

        PA Bay 1 Information:
                Ethernet PA, 4 ports
                EEPROM format version 1
                HW rev 1.0, Board revision 160
                Serial number: 02023164  Part number: 73-1556-03

Using the show interfaces Command

Display status information (including the physical slot and interface address) for the interfaces you specify using the show interfaces command.

For complete descriptions of interface subcommands and the configuration options available for the individual platforms, refer to the publications listed in the "Related Documentation" section on page viii.


Note The outputs that appear in this document may not match the output you receive when running these commands. The outputs in this document are examples only.


The following sections provide platform-specific output examples using the show interfaces command:

Catalyst RSM/VIP2 in Catalyst 5000 Family Switches—Example Output of the show interfaces Command

Catalyst 6000 Family FlexWAN Module in Catalyst 6000 Family Switches—Example Output of the show interfaces Command

Cisco 7100 Series Routers, Cisco 7200 Series Routers, Cisco 7200 VXR Routers, and Cisco uBR7200 Series Routers—Example Output of the show interfaces Command

Cisco 7201 Router—Example Output of the show interfaces Command

Cisco 7401ASR Router—Example Output of the show interfaces Command

VIP in Cisco 7000 Series Routers or Cisco 7500 Series Routers—Example Output of the show interfaces Command

Catalyst RSM/VIP2 in Catalyst 5000 Family Switches—Example Output of the show interfaces Command

Following are examples of the show interfaces serial command for a Catalyst 5000 Family switch. In these examples, the eight serial interfaces (0 to 7) are on a port adapter in port adapter slot 1 of a Catalyst RSM/VIP2; also, most of the status information for each interface is omitted. (Interfaces are administratively shut down until you enable them.)

Router# show interfaces serial 1/0
Serial1/0 is up, line protocol is up 
  Hardware is cyBus Serial
  Internet address is 10.10.10.1
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
[Additional display text for remaining interfaces omitted] 

Router# show interfaces serial 1/1
Serial1/1 is up, line protocol is up 
  Hardware is cyBus Serial
  Internet address is 10.10.10.2
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
[Additional display text for remaining interfaces omitted] 

Router# show interfaces serial 1/2
Serial1/2 is up, line protocol is up 
  Hardware is cyBus Serial
  Internet address is 10.10.10.3
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
[Additional display text for remaining interfaces omitted] 

Router# show interfaces serial 1/3
Serial1/3 is up, line protocol is up 
  Hardware is cyBus Serial
  Internet address is 10.10.10.3
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
[Additional display text for remaining interfaces omitted] 

Catalyst 6000 Family FlexWAN Module in Catalyst 6000 Family Switches—Example Output of the show interfaces Command

Following is an example of the show interfaces serial command for a Catalyst 6000 Family FlexWAN module in a Catalyst 6000 family switch. This example shows all of the information specific to interface port 0 on a PA-4T+ installed in port adapter slot 8 (interfaces are administratively shut down until you enable them):

Router# show interfaces serial 8/1/0
Serial8/1/0 is administratively down, line protocol is down 
  Hardware is Serial
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, crc 16, loopback not set
  Keepalive not set
  Last input never, output never, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
     RTS down, CTS down, DTR down, DCD down, DSR down

Cisco 7100 Series Routers, Cisco 7200 Series Routers, Cisco 7200 VXR Routers, and Cisco uBR7200 Series Routers—Example Output of the show interfaces Command

Following are examples of the show interfaces serial command from a Cisco 7100 series routers. In these examples, the eight serial interfaces (0 to 7) are on a port adapter in port adapter slot 1; also, most of the status information for each interface is omitted. (Interfaces are administratively shut down until you enable them.)

Router# show interfaces serial 1/0
Serial1/0 is up, line protocol is up 
  Hardware is M4T
  Internet address is 10.10.10.1
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
(display text omitted]

Router# show interfaces serial 1/1
Serial1/1 is up, line protocol is up 
  Hardware is M4T
  Internet address is 10.10.10.2
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
(display text omitted]

Router# show interfaces serial 1/2
Serial1/2 is up, line protocol is up 
  Hardware is M4T
  Internet address is 10.10.10.3
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
(display text omitted]

Router# show interfaces serial 1/3
Serial1/3 is up, line protocol is up 
  Hardware is M4T
  Internet address is 10.10.10.4
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
(display text omitted]

Following is an example of the show interfaces serial command, which shows all of the information specific to interface port 0 on a PA-4T+ installed in port adapter slot 1:

Router# show interfaces serial 1/0
Serial1/0 is up, line protocol is up 
  Hardware is M4T
  Internet address is 10.10.10.1
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
  LCP Open
  Open: ipcp
  Last input 00:00:09, output 00:00:09, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0 (size/max/drops); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/64/0 (size/threshold/drops) 
     Conversations  0/1 (active/max active)
     Reserved Conversations 0/0 (allocated/max allocated)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     1675 packets input, 26792 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     1676 packets output, 26806 bytes, 0 underruns
     0 output errors, 0 collisions, 3 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

Cisco 7201 Router—Example Output of the show interfaces Command

Following is an example of the show interfaces command from a Cisco 7201 router:

Router# show interfaces
GigabitEthernet0/0 is up, line protocol is up
  Hardware is MV64460 Internal MAC, address is 0019.56c5.2adb (bia
0019.56c5.2adb)
  Internet address is 209.165.200.225 
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec, 
     reliability 255/255, txload 1/255, rxload 45/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is RJ45
  output flow-control is XON, input flow-control is XON
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:07:03, output 00:00:07, output hang never
  Last clearing of "show interface" counters 00:00:04
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 180240000 bits/sec, 430965 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     2222975 packets input, 133378500 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out 

Cisco 7401ASR Router—Example Output of the show interfaces Command

Following is an example of the show interfaces serial command from a Cisco 7401ASR router, which shows all of the information specific to interface port 0 on a PA-4T+ installed in port adapter slot 1:

Router# show interfaces serial 1/0
Serial1/0 is up, line protocol is up 
  Hardware is M4T
  Internet address is 10.10.10.1
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive set (10 sec)
  LCP Open
  Open: ipcp
  Last input 00:00:09, output 00:00:09, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0 (size/max/drops); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/64/0 (size/threshold/drops) 
     Conversations  0/1 (active/max active)
     Reserved Conversations 0/0 (allocated/max allocated)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     1675 packets input, 26792 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     1676 packets output, 26806 bytes, 0 underruns
     0 output errors, 0 collisions, 3 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

VIP in Cisco 7000 Series Routers or Cisco 7500 Series Routers—Example Output of the show interfaces Command

Following are example s of the show interfaces serial command from a VIP. In these examples, the eight serial interfaces (0 to 7) are on a port adapter in port adapter slot 1 of a VIP in interface processor slot 3; also, most of the status information for each interface is omitted. (Interfaces are administratively shut down until you enable them.)

Router# show interfaces serial 3/1/0
Serial3/1/0 is up, line protocol is up
	Hardware is cyBus Serial
  Internet address is 10.0.0.0
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive not set
[Additional display text omitted from this example]

Router# show interfaces serial 3/1/1
Serial3/1/1 is up, line protocol is up
	Hardware is cyBus Serial
  Internet address is 10.0.0.1
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive not set
[Additional display text omitted from this example]

Router# show interfaces serial 3/1/2
Serial3/1/2 is up, line protocol is up
	Hardware is cyBus Serial
  Internet address is 10.0.0.2
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive not set
[Additional display text for remaining interfaces omitted]

Following is an example of the show interfaces serial command, which shows all of the information specific to interface 0 on a port adapter in port adapter slot 1 of a VIP in interface processor slot 3:

Router# show interfaces serial 3/1/0
Serial3/1/0 is up, line protocol is up 
  Hardware is cyBus Serial
  Internet address is 10.0.0.0
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive not set
  Last input 2d18h, output 00:00:54, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0 (size/max/drops); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/64/0 (size/threshold/drops) 
     Conversations  0/1 (active/max active)
     Reserved Conversations 0/0 (allocated/max allocated)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     16 packets input, 1620 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants
     0 input errors, 0 CRC, 0 frame, 0 overrun, 1 ignored, 0 abort
     3995 packets output, 1147800 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     1 carrier transitions
     RTS up, CTS up, DTR up, DCD up, DSR up

Using the ping Command to Verify Network Connectivity

Using the ping command, you can verify that an interface port is functioning properly. This section provides a brief description of this command. Refer to the publications listed in the "Related Documentation" section on page viii for detailed command descriptions and examples.

The ping command sends an echo request out to a remote device at an IP address that you specify. After sending a series of signals, the command waits a specified time for the remote device to echo the signals. Each returned signal is displayed as an exclamation point (!) on the console terminal; each signal that is not returned before the specified time-out is displayed as a period (.). A series of exclamation points (!!!!!) indicates a good connection; a series of periods (.....) or the messages [timed out] or [failed] indicate that the connection failed.

Following is an example of a successful ping command to a remote server with the address 10.10.10.10:

Router# ping 10.10.10.10 <Return>
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echoes to 10.10.10.10, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/15/64 ms
Router#

If the connection fails, verify that you have the correct IP address for the server and that the server is active (powered on), and repeat the ping command.

Using loopback Commands

The loopback test allows you to detect and isolate equipment malfunctions by testing the connection between the PA-4T+ interface and a remote device such as modems or CSU/DSUs. The loopback subcommand sends a series of packets out to and through the device (or cable), and back to the PA-4T+ interface. If the packets complete the loop, the connection is good. If not, you can isolate a fault to the remote device or interface cable in the path of the loopback test.


Note You must configure a clock rate on the port before performing a loopback test. However, if no cable is attached to the port, the port is administratively up, and the port is in loopback mode, you do not have to configure a clock rate on the port before performing a loopback test.


Depending on the mode of the port, issuing the loopback command checks the following path:

When no interface cable is attached to the PA-4T+ interface, or if a DCE cable is attached to a port that is configured as line protocol up, the loopback command tests the path between the network processing engine and the interface port only (without leaving the network processing engine and port adapter).

When a DTE cable is attached to the port, the loopback command tests the path between the network processing engine and the near (network processing engine) side of the DSU or modem to test the PA-4T+ interface and interface cable.


Note The X.21 interface definition does not include a loopback definition. On the PA-4T+, the X.21 DTE interface does not support the loopback function. Because of the internal clock signal present on the PA-4T+ interfaces, loopback will function on an X.21 DCE interface.