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To continue your OC3 POS line card installation, you must configure the OC-3 interfaces. This chapter contains the following sections:
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 change the existing configuration of an interface. The system prompts you for a password if one has been 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 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 (#):
To configure the new interfaces, proceed to the "Configuring the Interfaces" section.
After you verify that the new OC3 POS line card is installed correctly (the STATUS LED goes on), use the privileged-level configure command to configure the new interface. Have the following information available:
If you installed a new OC3 POS line card or if you want to change the configuration of an existing interface, you must enter configuration mode to configure the new interfaces. If you replaced an OC3 POS line card that was previously configured, the system recognizes the new interfaces and brings each of them up in their existing configuration.
For a summary of the configuration options available and instructions for configuring the interface on an OC3 POS line card, refer to the appropriate configuration publications listed in the "Related Documentation" section.
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.)
On power up, the OC-3 POS interface on a new OC3 POS line card is shut down. To enable the interface, you must enter the no shutdown command in configuration mode.
When the OC-3 POS interface is enabled (taken out of shutdown) with no additional arguments, the interface configuration file parameters use the default values. (See Table 4-1 for parameters and default values.)
Table 4-1 OC3 POS Line Card Configuration Default Values
| Parameter | Configuration Commands | Default Value |
|---|---|---|
This section describes the procedures for performing a basic configuration: enabling an interface (with the no shutdown command) and specifying IP routing. 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.
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:
Step 2 Specify the new interface to configure by entering the interface pos subcommand, followed by the interface address of the interface you plan to configure. Table 4-2 gives examples.
Table 4-2 Examples of the interface pos Subcommand
| Platform | Command | Example |
|---|---|---|
interface pos, followed by slot/interface (slot-number/ |
The example is for the first OC-3 POS interface of an OC3 POS line card in slot 5. |
Step 3 Assign an IP address and subnet mask to the interface (if IP routing is enabled on the system) with the ip address configuration subcommand, as in the following example:
Step 4 Change the shutdown state to up and enable the interface as follows:
The no shutdown command passes an enable command to the interface and causes the OC3 POS line card to configure itself based on the previous configuration commands sent.
Step 5 Add any additional configuration subcommands required to enable routing protocols and adjust the interface characteristics.
Step 6 After including all of the configuration subcommands to complete your configuration, 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.
Step 7 Write the new configuration to NVRAM as follows:
You can change the default values of all configuration parameters to match your network environment. Use the interface subcommands in the following sections if you need to customize the OC3 POS line card configuration:
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Note The interface subcommands that follow function the same regardless of the platform in which your
OC3 POS line card is installed; however, all of these commands require that you first enter the
interface pos subcommand to select the interface that you want to configure. In all of the configuration examples that follow, the interface address argument for the interface pos subcommand is 3/0 (slot 3, interface 0) for a Cisco 7304 router. For the appropriate interface pos subcommand syntax to use for your particular platform, see Table 4-2. |
The default maximum transmission unit (MTU) size is 4470 bytes. To set the MTU size, enter the mtu bytes command, where bytes is a value in the range of 64 through 9216.
To restore the default of 4470 bytes, enter the no mtu command.
The default framing setting is SONET. To configure for SDH, enter the pos framing sdh command:
To change back to SONET, enter the no pos framing sdh command.
The clocking default specifies that the OC3 POS line card uses the recovered receive (RX) clock to provide transmit (TX) clocking (called loop timing). To specify that the OC3 POS line card generates the transmit clock internally, enter the clock source internal command:
To restore loop timing, enter the no clock source internal command or the clock source line command.
The cyclic redundancy check (CRC) default is for a 16-bit CRC. The CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The OC3 POS line card also supports a 32-bit CRC. The sender of a data frame calculates the frame check sequence (FCS). The sender appends the FCS value to outgoing messages. The receiver recalculates the FCS and compares it to the FCS from the sender. If a difference exists, the receiver assumes that a transmission error occurred. To configure an interface for a 32-bit CRC, enter the crc 32 command:
To disable the 32-bit CRC and return the interface to the default 16-bit CRC, enter the no crc 32 or crc 16 command.
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Note Both ends of the connection must be set to the same CRC mode. |
SONET payload scrambling applies a self-synchronous scrambler (x^43+1) to the Synchronous Payload Envelope (SPE) of the OC-3 POS interface to ensure sufficient bit-transition density. The default is for SONET payload scrambling disabled.
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Note Both ends of the connection must use the same scrambling algorithm. |
You enable SONET payload scrambling by using the pos scramble-atm command. (This command has no keywords or arguments.)
To enable SONET payload scrambling, use the following command sequence:
To verify the SONET payload scrambling is enabled on an interface, enter the show running-config command. If scrambling is enabled, the following line is displayed in the configuration:
To disable SONET payload scrambling, use the no pos scramble-atm command.
A trigger is an alarm that, when asserted, causes the line protocol to go down. The following sections discuss line triggers and path triggers, which you configure with the pos delay triggers command.
The pos delay triggers line command is used for Internet router POS interfaces connected to internally-protected Dense Wavelength Division Multiplexing (DWDM) systems. This command is invalid for interfaces that are configured as APS working or protected. Normally, even a few microseconds of line- or section-level alarms brings down the link until the alarm has been clear for ten seconds. If you configure holdoff, this link-down trigger is delayed for 100 ms. If the alarm stays up for more than 100 ms, the link is brought down as it is now. If the alarm clears before 100 ms, the link is not brought down.
By default, the following line and section alarms are triggers for the line protocol to go down:
When one or more of these alarms is asserted, the line protocol of the interface goes down without a delay. You can issue the pos delay triggers line command to delay triggering the line protocol of the interface. You can set the delay from 50 to 10000 ms. If you do not specify a time interval, the default delay is set to 100 ms.
The following path alarms are not triggers by default. You can configure these path alarms as triggers and also specify a delay.
You can issue the pos delay triggers path command to configure various path alarms as triggers and to specify an activation delay between 50 and 10000 ms. The default delay value is 100 ms.
The pos delay triggers path command can also bring down the line protocol when the higher of the B2 and B3 error rates is compared with the signal failure (SF) threshold. If the SF threshold is crossed, the line protocol of the interface goes down.
The pos delay triggers path command was introduced in Cisco IOS Release 12.0(16)S.
After configuring the new interface, use the show commands to display the status of the new interface or all interfaces, and use the ping command to check connectivity. This section includes the following subsections:
Table 4-3 demonstrates how you can use the show commands to verify that new interfaces are configured and operating correctly and that the OC3 POS line card 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.
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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. |
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:
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.
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 by using the show version (or show hardware) command.
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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. |
Following is an example of the show version command from a Cisco 7304 router with the OC3 POS line card:
Display the types of line cards installed in your system (and specific information about each) using the show diag slot command, where slot is the slot in a Cisco 7304 router.
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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. |
Following is an example of the show diag slot command for an OC3 POS line card in slot 1 of a Cisco 7304 router:
Display the types of line cards installed in your system, their status, and insertion time by using the show c7300 command.
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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. |
Following is an example of the show c7300 command for a Cisco 7304 router:
The show interfaces command displays status information (including the physical slot and interface address) for the interfaces you specify. All of the examples that follow specify POS interfaces.
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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. |
Following is an example of the show interfaces command for an OC3 POS line card in slot 4 of a Cisco 7304 router:
Proceed to the next section, "Using the ping Command to Verify Network Connectivity," to check network connectivity between your network and the OC3 POS line card and router.
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 for detailed command descriptions and examples.
The ping command sends echo request packets out to a remote device at an IP address that you specify. After sending an echo request, the system waits a specified time for the remote device to reply. Each echo reply is displayed as an exclamation point (!) on the console terminal; each request 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 a bad connection.
Following is an example of a successful ping command to a remote server with the address 10.0.0.10:
If the connection fails, verify that you have the correct IP address for the destination and that the device is active (powered on), and repeat the ping command.
The loopback test allows you to troubleshoot, detect, and isolate equipment malfunctions by testing the connection between the OC-3 POS interface and a remote device. The loop subcommand places an interface in internal loopback (also called local loopback) or line loopback mode, which enables test packets that are generated from the ping command to loop through a remote device or a cable. If the packets complete the loop, the connection is good. If not, you can isolate a fault to the remote device or the cable in the path of the loopback test.
The default loopback setting is for no loopback. With internal (or local) loopback, packets from the router are looped back in the framer. Outgoing data gets looped back to the receiver without actually being transmitted. Internal loopback is useful for checking that the OC3 POS line card is working. To configure an interface for internal loopback, enter the loop internal command:
To disable internal loopback, enter the no loop internal command.
The default loopback setting is for no loopback. With line loopback, the receive (RX) fiber is logically connected to the transmit (TX) optical fiber cable so that packets from the remote router are looped back to it. Incoming data gets looped around and retransmitted without actually being received. To configure an interface for line loopback, enter the loop line command:
To disable line loopback, enter the no loop line command.
The OC3 POS line card maintains counts of certain errors. Each error counter is 32 bits. Errors include the following:
The error messages you should see are of the following type and format:
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Note Contact the Technical Assistance Center (TAC) for assistance with this error message. To contact the TAC, see the "Obtaining Technical Assistance" section. |
Line cards can be removed from the Cisco 7304 router without disrupting data flow by using the hw-module slot slot # stop/start command in EXEC mode. The hw-module slot slot # stop command will stop traffic, shut down all line card interfaces, and deactivate the line card. The hw-module slot slot # start command resets the line card, puts the line card back online, and turns off the OIR LED. To remove and install an active line card in slot 2 proceed as follows:
When the OIR LED turns green, the line card in slot 2 has been deactivated and can be physically removed and replaced with a new line card (see the "Line Card Removal and Installation" section.)
When the new line card is inserted in slot 2 it is automatically reset, put online, and the OIR LED is turned off.
Posted: Sun Feb 2 21:28:34 PST 2003
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