Maintenance

CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. Because 32-bit CRC transmits longer data streams at faster rates, it provides better ongoing error detection with less retransmits. However, both the sender and the receiver must use the same setting.

The default for all serial interfaces is for 16-bit CRC. To enable 32-bit CRC on an interface, specify the slot and port address of the interface followed by the command crc32. In the example that follows, the first serial port on an FSIP in interface processor slot 2 is configured for 32-bit CRC:

7010# configure terminal
interface serial 2/0
crc32 
^z

To disable 32-bit mode and return to the default 16-bit setting on a specific interface, specify the slot and port address of the interface and use the no crc32 command.

For a brief overview of CRCs, refer to the section "Cyclic Redundancy Checks (CRCs)" in the chapter "Preparing for Installation." For complete command descriptions and instructions, refer to the related software documentation.

Configuring 4-Bit Cyclic Redundancy Check

The E1-G.703/G.704 interface supports 4-bit CRC in framed mode only. CRC-4 is not enabled by default.

To enable CRC-4 on the E1-G.703/G.704 interface, specify the slot and port address of the interface followed by the command crc4. In the example that follows, the top port on an FSIP in interface processor slot 3 is configured for CRC:

Router# configure terminal
interface serial 3/0
crc4 
^z

To disable CRC-4 and return to the default of no CRC error checking, specify the slot and port address and use the no crc4 command. For complete command descriptions and instructions, refer to the related software documentation.

Replacing Serial Port Adapter Cables

The port adapter cable connected to each FSIP port determines the electrical interface type and mode of the port. The FSIP ports are not configured for either DTE or DCE mode by default. When there is no cable attached to a port, the software identifies the port as Universal, Cable Unattached rather than either a DTE or DCE interface. When a cable is attached, the port recognizes the mode and automatically uses the clock signal from the appropriate source (external for DTE or internal for DCE).

Although you do not have to configure a clock source for the ports, you do have to define the clock speed the first time you configure a port as a DCE interface. Because the ports automatically use the appropriate clock source for the type (mode) of cable it detects, you can configure a clock rate for a DCE interface and later replace the DCE cable with a DTE cable; the FSIP will ignore the internal clockrate unless it detects that a DCE cable is attached. This configuration allows you to perform a loopback test on a serial port without a port adapter cable attached.

Following is an example of the show controller cxbus command that shows an interface port (2/0) that has an EIA/TIA232 DTE cable attached, and a second port (2/1) that does not have a cable attached:

7010# show controller cxbus

Switch Processor 7, hardware version 11.1, microcode version 1.4
  512 Kbytes of main memory, 128 Kbytes cache memory, 299 1520 byte buffers
  Restarts: 0 line down, 0 hung output, 0 controller error
 FSIP 2, hardware version 3, microcode version 1.0
  Interface 16 - Serial2/0, electrical interface is RS-232 DTE
    31 buffer RX queue threshold, 101 buffer TX queue limit, buffer size 1520
    Transmitter delay is 0 microseconds
  Interface 17 - Serial2/1, electrical interface is Universal (cable unattached)
    31 buffer RX queue threshold, 101 buffer TX queue limit, buffer size 1520

To change the electrical interface type or mode of a port on line, replace the serial adapter cable and use software commands to restart the interface and, if necessary, reconfigure the port for the new interface. At system startup or restart, the FSIP polls the interfaces and determines the electrical interface type of each port (according to the type of port adapter cable attached). However, it does not necessarily repoll an interface when you change the adapter cable on line. To ensure that the system recognizes the new interface type, shutdown and reenable the interface after changing the cable.

Perform the following steps to change the mode or interface type of a port by replacing the adapter cable. If you are replacing a cable with one of the same interface type and mode, these steps are not necessary. (Simply replace the cable without interrupting operation.)

Step 1 Locate and remove the adapter cable to be replaced.

Step 2 Connect the new cable between the FSIP port and the network connection. Tighten the thumbscrews at both ends of the cable to secure it in the ports.

Step 3 At the privileged level of the EXEC, specify the port address, shutdown the interface, and write the configuration to NVRAM. Add additional configuration commands, if any, before you exit from the configuration mode (before you press Ctrl-Z.

7010> en

Password:

7010# configure terminal

int serial 2/5

shutdown

^z

7010# write mem

Step 4 Enter the configuration mode again and bring the port back up.

7010# configure terminal

int serial 2/5

no shutdown

^z

These steps will prompt the system to poll the interface and recognize the new interface immediately.

When configuring a port for a DCE interface for the first time, or when setting up a loopback test, you must set the clock rate for the port. When you connect a DCE cable to a port, the interface will remain down, the clock LEDs will remain off, and the interface will not function until you set a clock rate (regardless of the DCE mode default).

If you are changing the mode of the interface from DCE to DTE, you do not need to change the clock rate for the port. After you replace the DCE cable with a DTE cable and the system recognizes the interface as a DTE, it will use the external clock signal from the remote DCE device and ignore the internal clock signal that the DCE interface normally uses. Therefore, once you configure the clock rate on a port for either a DCE interface or loopback, you can leave the clock rate configured and still use that port as a DTE interface.

Replacing Serial Port Adapters

Serial port adapters provide the high-density ports for FSIP serial interfaces. Each port adapter provides two ports, and each port supports any one of the available interface types: EIA/TIA232, EIA/TIA449, V.35, X.21, and EIA-530. The adapter cable connected to the port determines the electrical interface type and mode (DTE or DCE) of the interface. Each FSIP is shipped from the factory with four or eight port adapters installed. Port adapters are field replaceable; if you have spares on hand and have a failure, you can replace interfaces without having to return the FSIP to the factory. You cannot, however, add ports to an FSIP by installing additional port adapters. The four-port FSIP supports only one 4-port module. To change the electrical interface type or mode of a port, you need only replace the adapter cable and reset the interface. When setting up DCE port, you must also set the clock rate. Although DCE is the default mode, you do not need to specify the mode when configuring DTE interfaces. When the port recognizes the DTE interface cable, it automatically uses the clock signal from the remote DCE device.

Caution Remove and install port adapters only when it is necessary to replace interfaces. Do not attempt to isolate faults or to troubleshoot FSIPs or serial interfaces by swapping port adapters. The surface-mount circuitry on the port adapters will not tolerate excessive handling.

All serial interface types support NRZI format and 32-bit CRC, both of which you set with software commands. (Refer to the section "FSIP Configurations" earlier in this section.) For complete command descriptions and instructions, refer to the related software documentation.

Tools Required

You need the following tools to complete this procedure:

• Number 1 Phillips or 3/16-inch flat-blade screwdriver
  

• 3/16-inch nut driver
  

• Wrist strap or other grounding device to prevent ESD damage
  

Removing the FSIP

Two or four port adapters (each port adapter provides two ports) are installed on each FSIP at the factory, so in order to install a new port adapter (or to replace an existing one), you need to remove an existing port adapter. Each four-port module on an FSIP is driven by a CPU; four-port FSIPs contain one processor, and eight-port FSIPs contain two processors. You cannot add additional ports to a four-port FSIP to upgrade it to eight ports.

Follow these steps to remove and replace the FSIP:

Step 1 Disconnect all network interface cables attached to the FSIP ports.

Step 2 Put on a grounding strap and attach the equipment end to one of the captive installation screws on the rear of the chassis.

Step 3 Use a screwdriver to loosen the two captive installation screws on the FSIP.

Step 4 Place your thumbs on the upper and lower ejector levers and simultaneously push the top lever up and the bottom lever down to release the FSIP from the backplane connector.

Step 5 Grasp the FSIP handle with one hand and place your other hand under the carrier to support and guide the FSIP out of the slot. Avoid touching the board.

Step 6 Carefully pull the FSIP straight out of the slot, keeping your other hand under the carrier to guide it. (See Figure 5-2.) Keep the FSIP at a 90-degree orientation to the backplane.

Step 7 Place the removed FSIP on an antistatic mat or antistatic foam and proceed to the section "Removing Port Adapters."

Removing Port Adapters

Port adapters are installed on each FSIP at the factory. You must remove an existing port adapter in order to replace or install a new one. Each port adapter is anchored to the FSIP with two double-row vertical board-to-board (BTB) connectors and two Phillips-head screws that extend down into the standoffs. (See Figure 5-15.) The port adapter is also anchored to the carrier faceplate with four jackscrews with lock washers (two per port).

Caution The surface-mounted components on the port adapters are extremely susceptible to ESD damage. Keep each port adapter in a separate antistatic bag until you are ready to install it. Always wear a ground strap and handle boards as little as possible. When you must handle the board, limit contact to the board edges only, avoiding contact between the board and clothing.

To remove a port adapter from the FSIP perform the following steps:

Step 1 Ensure that the FSIP is resting on an antistatic mat or on antistatic foam. You should still be wearing an ESD-prevention ground strap.

Step 2 Position the FSIP so that it is in the same orientation as shown in Figure 5-15.

Step 3 Locate the port adapter to be replaced. Use a 3/16-inch nut driver to loosen the four jackscrews, one on either side of both serial connector ports.

Step 4 Remove the jackscrews and washers and put them aside. You may need them to install the new port adapter.

Step 5 Use a Phillips screwdriver to loosen and remove the two standoff screws. (See Figure 5-15.) You will need the standoff screws to install the new port adapter.

Step 6 While avoiding contact with any traces or components on the board, insert your thumb and forefinger into the finger holes on the sides of the port adapter and gently lift it upward to dislodge the BTB connectors. If the port adapter resists, rock it very slightly from side to side until it pulls free of the FSIP connector.

Figure 5-15 : Removing FSIP Port Adapters

Caution Do not use a screwdriver or other tool to pry the port adapter up or out of the BTB connectors. In particular, do not use the board stiffener for leverage, or you will damage the FSIP board.

Step 7 When the port adapter BTB connector is completely disconnected from the BTB connector on the FSIP, tilt the back of the port adapter up at about a 70-degree angle from vertical and slowly pull it upward and outward (up and out using the orientation shown in Figure 5-15) away from the faceplate. The serial port connector will pull out of the cutouts in the faceplate.

Step 8 Immediately place the removed port adapter into an antistatic bag.

Step 9 Proceed to the next section to install a new port adapter.

Caution Do not reinstall the FSIP in the chassis unless all port adapters are in place. The empty port will allow cooling air to escape freely through the cutouts in the faceplate, which could misdirect the airflow inside the chassis and allow components on other boards to overheat.

Installing Port Adapters

The FSIP should already be out of the chassis and have an empty space available for the new port adapter. If it is not, refer to the two previous sections to remove the FSIP from the chassis and remove a port adapter from the FSIP. Refer to Figure 5-16 while performing the following steps.

Step 1 Ensure that the FSIP is resting on an antistatic mat or on antistatic foam, and position it with the same orientation as that shown in Figure 5-16. You should still be wearing an ESD-prevention ground strap.

Step 2 Carefully remove the new port adapter from its antistatic bag. Handle the port adapter by the board edges only.

Step 3 If jackscrews are installed on the sides of the connectors, remove them and the four lock washers by turning them counterclockwise. If necessary, use a 3/16-inch nut driver to loosen them. Put the screws and washers aside.

Step 4 While still handling the board edges only, position the port adapter so that it is in the orientation shown in Figure 5-16: at about a 70-degree angle from vertical, component side down, standoffs on the underside, and the external interface port connectors facing the inside of the carrier faceplate.

Step 5 As shown in Figure 5-16, partially insert the port connectors through the back of the cutouts in the carrier faceplate. Do not force the connectors through the cutouts until the standoffs and BTB connectors are aligned.

Step 6 With the port connectors partially inserted into the faceplate cutouts, slowly lower the back (opposite) side of the port adapter and continue to ease the port connectors through the cutouts until the BTB connectors on the FSIP and port adapter meet, and the standoffs on the underside of the port adapter are aligned with the standoff holes in the FSIP. Shift the port adapter until the port connectors are fully inserted through the cutouts, and the standoffs are aligned with the standoff holes.

Caution Before seating the port adapter onto the FSIP, ensure that the port adapter is aligned properly with the BTB connectors and the standoffs. Forcing a misaligned port adapter into place can damage the port adapter or the FSIP and cause immediate or intermittent failures.

Step 7 Place your fingers along the back edge of the port adapter board and press down firmly until the BTB connectors mate. If the connectors resist, do not force them. Shift the port adapter around until the connectors mate properly.

Step 8 Insert the two long Phillips-head screws through the two standoffs and finger-tighten them. These screws extend through the standoffs and the FSIP board and thread into the metal carrier.

Step 9 Install a lockwasher on each of the four jackscrews.

Step 10 On the front of the carrier faceplate, insert the four jackscrews through the front of the faceplate and into the holes on either side of both port connectors.

Step 11 When all screws and connectors are aligned properly, use a Phillips screwdriver to tighten the standoff screws and a 3/16-inch nut driver to tighten the four jackscrews. Do not overtighten any of the screws.

Step 12 Proceed to the next section to reinstall the FSIP in the chassis.

Figure 5-16 : Installing FSIP Port Adapters

Replacing the FSIP in the Chassis

There should now be four or eight port adapters installed on the FSIP. If there are not, do not install the FSIP until you install all port adapters or until you install a blank interface processor filler in the FSIP slot.

Caution Handle interface processors by the handles and carrier edges only to prevent ESD damage.

Caution Do not reinstall the FSIP unless all port adapters are installed. The empty port will allow cooling air to escape freely through the cutouts in the faceplate, which could misdirect the airflow inside the chassis and allow components on other boards to overheat.

Step 1 Grasp the FSIP handle with one hand and place your other hand under the carrier to support the FSIP and guide it into the slot. (See Figure 5-2.) Avoid touching the board.

Step 2 Place the back of the FSIP in the slot and align the notch on the bottom of the carrier with the groove in the slot. (See Figure 5-1.)

Step 3 While keeping the FSIP at a 90-degree orientation to the backplane, carefully slide the carrier into the slot until the FSIP faceplate makes contact with the ejector levers. (See Figure 5-1.)

Step 4 Using the thumb and forefinger of each hand, simultaneously push the top lever down and the bottom lever up (as shown in Figure 5-1) to fully seat the FSIP in the backplane connector.

Step 5 Use a number 1 Phillips or a 3/16-inch flat-blade screwdriver to tighten the captive installation screws on the top and bottom of the FSIP.

Step 6 Reconnect the network interface cables or other connection equipment to the FSIP interface ports.

Step 7 When you insert the new FSIP, the console terminal will display several lines of status information about the OIR as it reinitializes the interfaces. Change the state of the interfaces to up and verify that the configuration matches that of the interfaces you replaced.

Step 8 Use the configure command or the setup command facility to configure the new interfaces. You do not have to do this immediately, but the interfaces will not be available until you configure them and bring them up.

Step 9 After you configure the interfaces, use the show controller serial or the show interfaces command to display the status of the new interfaces.

This completes the port adapter replacement procedure. For complete command descriptions and instructions, refer to the related software documentation.

MIP Configurations

Following are procedures for configuring T1 and E1 interfaces on the MIP.

Configuring the Interfaces

If you installed a new MIP or if you want to change the configuration of an existing controller, you must enter the configuration mode. If you replaced the MIP that was previously configured, the system will recognize the new MIP and bring it up in the existing configuration.

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

• T1 or E1 information, for example clock source (for T1), line code, and framing type
  

• Channel-group information and timeslot mapping
  

• Protocols and encapsulations you plan to use on the new interfaces
  

• Internet protocol (IP) addresses if you will configure the interfaces for IP routing
  

• Whether the new interface will use bridging
  

Refer to the Router Products Configuration Guide and Router Products Command Reference publications for a summary of the configuration options available and instructions for configuring the MIP controller.

Configuring Jumper J6 on the E1 Port Adapter

By default, channelized E1 port adapters are set with capacitive coupling between the receive (Rx) shield and chassis ground. This provides direct current (DC) isolation between the chassis and external devices, as stated in the G.703 specification. Jumper J6 controls this function. To make changes, remove the E1 port adapter from the mother board, place one of the spare jumpers on J6 pins one and two or pins two and three (refer to Table 5-10), and replace the port adapter on the mother board. Pin 1 of J6 is designated with a square. (See Figure 5-17.)

For procedures on removing the E1 port adapter from the MIP, refer to the section "Removing and Replacing MIP Port Adapters" in this chapter.

Figure 5-17 : Location of Jumper J6 on the E1 Port Adapter---Partial View

Table 5-10 : Jumper Settings and Functions

Jumper	Pins and Impedance	Function
J6	1 and 2 for 120 ohm 2 and 3 for 75 ohm	Controls capacitive coupling for either 120-ohm or 75-ohm operation. An installed jumper directly connects the Rx shield to chassis ground.

Warning To prevent problems with the E1 interface and to reduce the potential for injury, jumper J6 should be installed by trained service personnel only. For either impedance option, a jumper installed at J6 bypasses the AC-decoupling capacitor to ground, thereby coupling the interface directly to AC. This is a setting that could pose a risk of severe injury. By default and for safety, J6 has no jumper installed.

After you set jumper J6, proceed to the section "Removing and Replacing MIP Port Adapters" in this chapter.

Using the EXEC Command Interpreter

Before you use the configure command, you must enter the privileged level of the EXEC command interpreter with the enable command. The system will prompt 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, enter the privileged level as follows:

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.

Step 3 When you enter the correct password, the system displays the privileged-mode system prompt (#) as follows:

Router#

Step 4 Proceed to the following section to configure the MIP controller.

Using the Configure Commands

Following are instructions for a configuration: enabling a controller 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.

The channel-groups must be mapped before the MIP controller can be configured.

For complete descriptions of configuration subcommands and the configuration options available, refer to the Router Products Configuration Guide and Router Products Command Reference publications, which are available on UniverCD.

Table 5-11 list commands used to map the channel-group, with the default variable is listed first.

Table 5-11 : Channel Group Mapping Commands

Commands for T1	Commands for E1
controller t1 slot/applique	controller e1 slot/applique
clock source [line | internal]	Not required for E1
linecode [ami | b8zs]	linecode [hdb3 | ami]
framing [sf | esf]	framing [crc4 | no-crc4]
loopback [local | remote]	loopback
shutdown	shutdown
channel-group number timeslots list [speed {56 | 48 | 64}] For speed, 56 is the default.1	channel-group number timeslots list [speed {56 | 48 |64}] For speed, 64 is the default.1.

¹ Number is the channel-group 0 to 23 for T1 and 0 to 29 for E1.Timeslots list is a number between 1 to 24 for T1 and 1 to 31 for E1. It conforms to D3/D4 numbering for T1. Timeslots may be entered individually and separated by commas or as a range that is separated by a hyphen (for example, 1-3, 8, 9-18). For E1 and T1, 0 is illegal.Speed specifies the DSO speed of the channel-group: T1 default is 56 kbps and E1 default is 64 kbps.

Router> show version

GS Software (GS7), Version 10.0(5187) (for E1, 10.3[1])

Copyright (c) 1986-1994 by cisco Systems, Inc. 

Compiled Wed 02-Feb-94 15:52

ROM: System Bootstrap, Version 4.6(1) [fc2], SOFTWARE 

Router uptime is 42 minutes
System restarted by reload
System image file is "wmay/gs7-k", booted via tftp from 131.108.13.111 

RP (68040) processor with 16384K bytes of memory. X.25 software, Version 2.0, NET2, BFE 

and GOSIP compliant. Bridging software.
1 Switch Processor.
1 EIP controller (6 Ethernet).
1 TRIP controller (4 Token Ring).
1 FSIP controller (4 Serial).
1 MIP controller (1 T1). (or 1 E1, and so forth)
6 Ethernet/IEEE 802.3 interfaces.
4 Token Ring/IEEE 802.5 interfaces.
6 Serial network interfaces.
1 FDDI network interface.
128K bytes of non-volatile configuration memory. 
4096K bytes of flash memory sized on embedded flash.
Configuration register is 0x100

Router# show controller cbus

Switch Processor 5, hardware version 11.1, microcode version 170.46 
  Microcode loaded from system
  512 Kbytes of main memory, 128 Kbytes cache memory 105 1520 byte buffers, 
  75 4496 byte buffers Restarts: 0 line down, 0 hung output, 0 controller error 
FIP 0, hardware version 2.2, microcode version 170.12
 Microcode loaded from system
  Interface 0 - Fddi0/0, address 0000.0c03.648b (bia 0000.0c03.648b)
  15 buffer RX queue threshold, 37 buffer TX queue limit, buffer size 4496
  ift 0006, rql 13, tq 0000 01A0, tql 37

(text omitted from example)

MIP 2, hardware version 1.0, microcode version 10.0 

 Microcode loaded from system

 Interface 16 - T1 2/0, electrical interface is Channelized T1 

   10 buffer RX queue threshold, 14 buffer TX queue limit, buffer size 1580 ift 0001, rql

   7, tq 0000 05B0, tql 14

   Transmitter delay is 0 microseconds

Router#

Router# show cont t1
T1 4/1 is up.
  No alarms detected.
  Framing is ESF, Line Code is AMI, Clock Source is line
  Data in current interval (0 seconds elapsed): 
     0 Line Code Violations, 0 Path Code Violations 0 Slip Secs, 0 Fr Loss Secs, 
     0 Line Err Secs, 0 Degraded Mins 0 Errored Secs, 0 Bursty Err Secs, 
     0 Severely Err Secs, 0 Unavail Secs 
  Total Data (last 79 15 minute intervals): 
     0 Line Code Violations, 0 Path Code Violations, 0 Slip Secs, 0 Fr Loss Secs, 
     0 Line Err Secs, 0 Degraded Mins, 0 Errored Secs, 0 Bursty Err Secs, 
     0 Severely Err Secs, 0 Unavail Secs 
Router#

Router# show cont e1
E1 4/1 is up.
  No alarms detected.
  Framing is E1-crc, Line Code is hdb3
  Data in current interval (0 seconds elapsed): 
     0 Line Code Violations, 0 Path Code Violations 0 Slip Secs, 0 Fr Loss Secs, 
     0 Line Err Secs, 0 Degraded Mins 0 Errored Secs, 0 Bursty Err Secs, 
     0 Severely Err Secs, 0 Unavail Secs 
  Total Data (last 79 15 minute intervals): 
     0 Line Code Violations, 0 Path Code Violations, 0 Slip Secs, 0 Fr Loss Secs, 
     0 Line Err Secs, 0 Degraded Mins, 0 Errored Secs, 0 Bursty Err Secs, 
     0 Severely Err Secs, 0 Unavail Secs 
Router#

Router# show config

Using 1708 out of 130048 bytes
!
version 10.0 (or 10.3 for E1)
!
hostname Router
!
enable password *****
!
clns routing
!
!
!
controller T1 4/1 (for E1, E1 4/1, and so forth)
framing esf (for E1, crc4, and so forth)
linecode b8zs (for E1, hdb3, and so forth)
channel-group 0 1,3,5,7
channel-group 1 2,4,6,8-10
!
interface Ethernet 1/0
ip address 131.108.43.220 255.255.255.0
no mop enabled
!
interface Ethernet1/1
no ip address
shutdown
!
interface Ethernet1/2
no ip address
shutdown
!
interface Ethernet1/3

   (display text omitted)

Router> show protocols

Global values:
   Internet Protocol routing is enabled
CLNS routing is enabled (address 41.0000.0000.0000.0001.0000.0000.00) Fddi0/0 is down, 

line protocol is down
Internet address is 1.1.20.1, subnet mask is 255.255.255.0
CLNS enabled
Ethernet1/0 is up, line protocol is up
Internet address is 131.108.43.220, subnet mask is 255.255.255.0


(display text omitted)