Configuring the SS7 Q.703 High Speed Port Adapter

Transcription

1 CHAPTER 4 Configuring the SS7 Q.703 High Speed Port Adapter This chapter contains the following sections: Using the EXEC Command Interpreter, page 4-1 Configuring the Interfaces, page 4-2 Checking the Configuration, page 4-11 Using the EXEC Command Interpreter You modify the configuration of your router through the software command interpreter called the EXEC. The router boots up in user EXEC mode, indicated by an angle bracket (>) in the prompt. You use the enable command to enable privileged EXEC mode, which is then ndicated by a pound sign (#). The system prompts you for a password if one has been set. From privileged EXEC mode, you can use the configure command to configure a new interface or change the existing configuration of an interface. Step 1 At the user EXEC prompt, enter the enable command. The EXEC prompts you for a privileged EXEC password: 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 indicates that you are in privileged EXEC mode by displaying the privileged EXEC system prompt (#): Router# To configure the new interfaces, proceed to the Configuring the Interfaces section on page

2 Configuring the Interfaces Chapter 4 Configuring the Interfaces After you verify that the new SS7 Q.703 High Speed Port Adapter is installed correctly (the enabled LED goes on), you can configure the new interfaces. If you installed a new SS7 Q.703 High Speed Port Adapter or if you want to change the configuration of an existing interface, you must configure the new interfaces. If you replaced a SS7 Q.703 High Speed Port Adapter that was previously configured, the system recognizes the new interfaces and brings up each interface the existing configuration. This section contains the following subsections: Shutting Down an Interface, page 4-2 Performing a Basic Configuration, page 4-4 Configuring Cyclic Redundancy Checks, page 4-5 Configuring Drop and Insert, page 4-6 Tuning MTP2 Parameters for High Speed Links, page 4-7 Shutting Down an Interface Before you remove an interface that you will not replace, or before you replace port adapters, use the shutdown command to shut down (disable) the interfaces to prevent anomalies when you reinstall the new or reconfigured port adapter. When you shut down an interface, it is designated administratively down in the show command displays. To shut down an interface, follow these steps: Step 1 Step 2 Step 3 Enter privileged EXEC mode. (See the Using the EXEC Command Interpreter section on page 4-1 for instructions.) From the privileged EXEC prompt, specify that the console terminal is the source of the configuration commands, and enter global configuration mode by using the configure command: Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# Specify the interface that you want to shut down by using the interface command and then the shutdown command. Table 4-1 shows the command syntax and example. 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. 4-2

3 Chapter 4 Configuring the Interfaces Table 4-1 Syntax of the shutdown Command Command Purpose Example interface type interface-processor-slot-number/ port-adapter-bay-number/ interface-port-number :channel-group Specifies the interface and enters Interface configuration mode. Router(config)# interface serial5/0/0:0 shutdown Disables the interface. Router(config-if)# shutdown If you need to shut down additional interfaces, enter the interface serial command (followed by the interface address of the interface) for each interface on your port adapter. Use the no shutdown command to enable the interface. Step 4 Step 5 Step 6 Write the new configuration to NVRAM: Router# copy running-config startup-config [OK] Router# The system displays an OK message when the configuration has been stored in NVRAM. Verify that new interfaces are now in the correct state (shut down) using the show interface command: Router# show interface serial 0/0/5:0 Serial0/0/5:0 is up, line protocol is up Hardware is cxbus E1 MTU 1500 bytes, BW 1984 Kbit, DLY usec, reliability 242/255, txload 1/255, rxload 1/255 Encapsulation SS7 HS-MTP2, crc 16, loopback not set Keepalive set (10 sec) Last input 00:00:14, output 00:00:14, output hang never Last clearing of "show interface" counters 00:02:49 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 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 4 packets input, 110 bytes, 0 no buffer Received 0 broadcasts (0 IP multicast) 0 runts, 0 giants, 0 throttles input errors, 20 CRC, 0 frame, 0 overrun, ignored, 3 abort 9 packets output, 144 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out 1 carrier transitions no alarm present Timeslot(s) Used:1-31, subrate: 64Kb/s, transmit delay is 0 flags Reenable interfaces as follows: a. Repeat Step 3 to reenable an interface. Use the no shutdown command instead of 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 interface command followed by the interface type and interface address of the interface. 4-3

4 Configuring the Interfaces Chapter 4 For complete descriptions of software configuration commands, see the publications listed in the Related Documentation section on page viii. Performing a Basic Configuration Specifying the Card Type To complete your SS7 Q.703 High Speed Port Adapter installation and configuration, you must specify the card type as E1, configure a channel group on a port on the SS7 Q.703 High Speed Port Adapter to use all the time slots, configure the interface for SS7 high-speed MTP2 encapsulation, and then assign the interface to a link in a linkset. These tasks are described in the following sections: Specifying the Card Type, page 4-4 Configuring the Controller, page 4-4 Configuring the Interface and Encapsulation, page 4-5 Because the SS7 Q.703 High Speed Port Adapter can be configured for E1 connectivity only, you must specify the card type as E1, as described in the following procedure. There is no default card type. The port adapter is not functional until the card type is set. Information about the port adapter is not indicated in the output of any show command unless the card type has been set to E1. Step 1 Step 2 Enable global configuration mode and specify that the console terminal is the source of the configuration commands by using the configure command in privileged EXEC mode. Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# Specify the SS7 Q.703 High Speed Port Adapter to be E1 by using the card type command in global configuration mode. The following example configures the SS7 Q.703 High Speed Port Adapter in slot 4, bay 0 to be E1: Router(config)# card type e1 4 0 Configuring the Controller The following steps perform a basic controller configuration for the SS7 Q.703 High Speed Port Adapter: Step 1 Step 2 Enter configuration mode and specify that the console terminal is the source of the configuration commands: Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# Specify a controller by entering the controller e1 command, followed by the address of the interface you plan to configure. The following example specifies a controller for the first interface of a port adapter in port adapter bay 0 of interface processor slot 6: Router(config)# controller e1 6/0/0 Router(config-controller)# 4-4

5 Chapter 4 Configuring the Interfaces Step 3 Configure a channel group on a port on the SS7 Q.703 High Speed Port Adapter to use all the time slots. For E1 the time slot value is 1 to 31. Use the channel-group command in controller configuration mode: Router(config-controller)# channel-group 0 timeslots 1-31 Router(config-controller)# shutdown To exit controller configuration mode and return to global configuration mode, use the exit command. To exit configuration mode and return to privileged EXEC mode, use the end command or press Ctrl-Z. Configuring the Interface and Encapsulation Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Enter configuration mode and specify that the console terminal is the source of the configuration commands, as follows: Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# Specify the first interface to configure by entering the interface serial command, followed by the address of the interface you plan to configure: Router(config)# interface serial5/0/0: Router(config-if)# Configure the serial interface to use SS7 high-speed MTP2 encapsulation: Router(config-if)# encapsulation hs-mtp2 Assign the interface to a link in a linkset by using the cs7 linkset command to specify a linkset and then use the link command to associate the interface with a link in the linkset. Router(config-if)# cs7 linkset to_raleigh Router(config-cs7-ls)# link 0 Serial 4/0/0:0 After including all of the configuration commands 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. Write the new configuration to NVRAM as follows: Router# copy running-config startup-config [OK] Router# Configuring Cyclic Redundancy Checks 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. 4-5

6 Configuring the Interfaces Chapter 4 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. Table 4-2 summarizes cyclic redundancy check (CRC) commands. Table 4-2 CRC Commands Command Purpose Example crc size Enable 32-bit CRC The following example enables 32-bit CRC on a serial interface: Router(config)# interface serial 3/0:0 Router(config-if)# crc 32 no crc size Return to default 16-bit CRC The following example disables 32-bit CRC on a serial interface and returns to the default 16-bit CRC: Router(config)# interface serial 3/0:0 Router(config-if)# no crc 32 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, see the Configuration Fundamentals Configuration Guide publication. For more information, see the Related Documentation section on page viii. To check the interface configuration using show commands, proceed to the Checking the Configuration section on page Configuring Drop and Insert Perform the steps in this section if you are setting up Drop and Insert. Step 1 Step 2 Step 3 Step 4 Enter the command to set up TDM channel groups for the Drop-and-Insert function, as in the following example: Router(config-controller)# tdm-group tdm-group-no timeslots timeslot-list Router(config-controller)# The argument tdm-group-no is a value that identifies the group. The valid range for E1 is from 0 to 30. The group numbers for controller groups must be unique. The argument timeslot-list can be a single number, numbers separated by commas, or a pair of numbers separated by a hyphen to indicate a range of time slots. The valid range for E1 is from 1 to 31. Activate the controller with the no shutdown command, as in the following example: Router(config-controller)# no shutdown Router(config-controller)# Exit controller configuration mode, as follows: Router(config-controller)# exit Router(config)# Set up the connection between two E1 TDM groups of time slots for Drop and Insert. Router(config)# connect id e1 slot/port-1 tdm-group-no-1 e1 slot/port-2 tdm-group-no-2 Router(config)# 4-6

7 Chapter 4 Configuring the Interfaces The argument id is a name for the connection. The argument slot/bay/port identify each controller by its location. The arguments tdm-group-no-1 and tdm-group-no-2 identify the TDM group numbers (from 0 to 30) on the specified controller. The groups were established in Step 1. Tuning MTP2 Parameters for High Speed Links The following sections describe the MTP2 parameters that you can tune, and describes two methods for specifying MTP2 parameters for a link: Understanding the MTP2 Parameters, page 4-7 Specifying MTP2 Parameters in a CS7 Profile, page 4-8 Specifying MTP2 Parameters Individually, page 4-10 Understanding the MTP2 Parameters To control and influence the MTP2 behavior, you can customize MTP2 protocol parameters for timers, bundling, and transmit queue depth. MTP2 Timers Table 4-3 lists the values for MTP2 timers for high-speed links. Table 4-3 Timer Values for High Speed MTP2 Links Timer Description ITU Range ITU Default ANSI Range ANSI Default T1 Alignment ready timer 25 to 350 seconds T2 Not aligned timer 5 to 150 seconds 300 seconds 165 to 200 seconds 170 seconds 5 seconds 5 to 14 seconds 11.5 seconds T3 Aligned timer 1 to 2 seconds 1.5 seconds 5 to 14 seconds 11.5 seconds T4n Normal proving period timer 3 to 70 seconds 30 seconds 27 to 33 seconds 30 seconds T4e Emergency proving period timer 400 to 600 T5 Sending SIB timer 80 to 120 T6 Remote congestion timer T7 T8 Excessive delay of acknowledgement Interval timer for errored interval monitor to 5.5 seconds 80 to seconds to 6 seconds 3 seconds 1 to 6 seconds 1 second 500 to to seconds 500 to to

8 Configuring the Interfaces Chapter 4 Bundling MTP2 packet bundling is supported on the Cisco 7500 router only. The bundling parameter is used to set the bundling interval (a period of time to wait for packets before sending the bundle). We recommend that bundling be enabled for high packet rates (1000 pps or higher) with small packets (50 bytes and lower). Bundling can be less than optimal for lower data rates with small or large packets because of the transmission delay. Bundling is effective for large packets at high data rates in networks with symmetrical traffic. Applications with low data rates should disable bundling if the increase in round-trip time is undesirable. We recommend that bundling be enabled for applications sending small packets that may start with low data rates, but that are capable of increasing to higher sustained data rates. The default bundling delay is 5. Transmit Queue The tx-queue exists to absorb inevitable traffic bursts. The tx-queue-depth parameter is used to determine the onset and abate thresholds for congestion on transmit queue.the tx-queue-depth parameter controls the number of packets allowed on the transmit queue. The range for the tx-queue-depth for high speed MTP links is 250 to 5000 packets. The default tx-queue-depth is 5000 packets. Specifying MTP2 Parameters in a CS7 Profile You can create a CS7 profile that specifies MTP2 parameters, then apply the profile to a link. Step 1 Create a CS7 profile. A CS7 profile can specify values for MTP2 timers, bundling, and transmit queue depth. To create the profile use the following commands, beginning in global configuration mode: Command Router(config)# cs7 profile name Router(config-cs7-profile)# hs-mtp2 Router(config-cs7-profile-hs-mtp2)# bundling msec Router(config-cs7-profile-mtp2)# timer {t1 t2 t3 t4e t4n t5 t6 t7 t8} msec Purpose Names the CS7 profile and enables CS7 profile submode. Enables the CS7 profile submode for configuring link profile parameters for high-speed MTP2. Enables bundling and specifies the bundling interval (the length of time to wait for packets before sending a bundle). MTP2 packet bundling is supported only on the Cisco 7500 router. Specifies the following MTP2 timers for high-speed links: 1 t1 -- T1 (alignment ready) t2 -- T2 (not aligned) t3 -- T3 (aligned) t4e --T4E (emergency proving period) t4n -- T4N (normal proving period) t5 -- T5 (sending SIB) t6 -- T6 (remote congestion) t7 -- T7 (excessive delay of acknowledgment) t8 -- T8 (monitoring interval for errored interval timer) 4-8

9 Chapter 4 Configuring the Interfaces Command Router(config-cs7-profile-mtp2)# tx-queue-depth msec Router(config-cs7-profile-mtp2)# exit Router(config-cs7-profile)# exit 1. For detailed information about MTP2 timers, refer to the appropriate standards. Purpose Specifies the number of packets that MTP2 will queue for transmission. Exits the CS7 profile submode for MTP2. Exits the CS7 profile submode and returns you to global configuration mode. Step 2 Apply the profile to all of the links in a linkset. After you have created the profile, apply it to a linkset by using the following commands, beginning in global configuration mode: Command Router(config)# cs7 linkset ls-name Router(config-cs7-ls)# profile name Purpose Specifies the linkset to which you will apply the profile, and enters linkset configuration mode. Applies the parameter values specified in the profile to all the links in the linkset. (The no version of this command removes the profile from the linkset and resets the MTP2 parameters to the default values. Whenever you change the CS7 profile, the revised profile automatically applies to the linkset. You can override an MTP2 parameter applied with the profile by configuring the specific parameter on the link. 4-9

10 Configuring the Interfaces Chapter 4 Specifying MTP2 Parameters Individually You can specify or change the values of MTP2 timers, bundling, and transmit queue depth individually at the link level. To tune the MTP2 timers, use the following command in CS7 link submode: Command Router(config-cs7-ls-link)# hs-mtp2-timer {t1 t2 t3 t4e t4n t5 t6 t7 t8} msec Purpose Specifies the following MTP2 timers: 1 t1 -- T1 (alignment ready) t2 -- T2 (not aligned) t3 -- T3 (aligned) t4e --T4E (emergency proving period) t4n -- T4N (normal proving period) t5 -- T5 (sending SIB) t6 -- T6 (remote congestion) t7 -- T7 (excessive delay of acknowledgment t8 -- T8 (monitoring interval for errored interval timer) 1. For detailed information about MTP2 timers, refer to the appropriate ANSI and ITU standards. To enable bundling of packets sent between MTP3 on the RSP and MTP2 on the VIP, and to specify the bundling interval for the link, use the following command in CS7 link submode: Command Router(config-cs7-ls-link)# bundling msec Purpose Enables bundling and specifies the bundling interval (the length of time to wait for packets before sending a bundle). Bundling of MTP2 packets is supported on the Cisco 7500 router only. You can adjust the number of packets that can be queued for transmission before reaching a state of transmit congestion. This parameter is known as the transmit queue depth. The values for this parameter vary, depending on the type of link. For an MTP2 link, the range is 25 to 5000 packets with a default of 500 packets. For an SCTP link, the range is 100 to packets, with a default of 1000 packets. To tune the transmit queue depth for the link, use the following command in CS7 link submode: Command Router(config-cs7-ls-link)# tx-queue-depth packets Purpose Specifies the number of packets allowed on the transmit queue. 4-10

11 Chapter 4 Checking the Configuration Checking the Configuration 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: Using show Commands to Verify the New Interface Status, page 4-11 Using the ping cs7 Command to Verify Network Connectivity between ITPs, page 4-14 Using loopback Commands, page 4-14 Using show Commands to Verify the New Interface Status Table 4-4 demonstrates how you can use the show commands to verify that new interfaces are configured and operating correctly and to verify that the SS7 Q.703 High Speed Port Adapter 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, see the publications listed in the Related Documentation section on page viii. Troubleshooting Tips If information about the SS7 Q.703 High Speed Port Adapter is not indicated in show command output, it is probably because the card type has not been specified. Because the SS7 Q.703 High Speed Port Adapter can be configured for E1 connectivity only, you must specify the card type as E1, as described in Performing a Basic Configuration section on page 4-4. There is no default card type. The port adapter is not functional until the card type is set. 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 4-4 Using show Commands Command Function Example show version or show hardware show controllers show diag slot show interfaces type interface-processor-slot-number/ port-adapter-bay-number interface-port-number Displays system hardware configuration, the number of each interface type installed, the Cisco IOS software version, the names and sources of configuration files, and the boot images. Displays all the current interface processors and their interfaces. Displays types of port adapters installed in your system and information about a specific port adapter slot, interface processor slot, or chassis slot. Displays status information about a specific type of interface (for example, serial) in a router. Router# show version Router# show controllers Router# show diag 2 Router# show interfaces serial 5/0/0:0 4-11

12 Checking the Configuration Chapter 4 Table 4-4 Using show Commands Command Function Example show protocols Displays protocols configured for the entire system and Router# show protocols for specific interfaces. 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, page 4-12 Using the show diag Command, page 4-12 Using the show interfaces Command, page 4-13 Choose the subsection appropriate for your system. When you have finished using the show commands, proceed to the Using the ping cs7 Command to Verify Network Connectivity between ITPs section on page Using the show version or show hardware Commands Use the show version (or show hardware) command to 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,. 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. 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 router. 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 command that shows an SS7 Q.703 High Speed Port Adapter in interface processor slot 0 of a Cisco 7513 router: Router# show diag Slot 0: Physical slot 0, ~physical slot 0xF, logical slot 0, CBus 0 Microcode Status 0x4 Master Enable, LED, WCS Loaded Board is analyzed Pending I/O Status: None EEPROM format version

13 Chapter 4 Checking the Configuration VIP6-80 RM7000B controller, FRU: VIP6-80, HW rev 2.01, board revision A0 Serial number: Part number: Test history: 0x00 RMA number: Flags: cisco 7000 board; 7500 compatible EEPROM contents (hex): 0x20: 01 4E B3 58 D1 49 1F B x30: Slot database information: Flags: 0x4 Insertion time: 0x3270 (00:04:00 ago) Controller Memory Size: 256 MBytes CPU SDRAM, 64 MBytes Packet SDRAM Startup time: 8712 msec PA Bay 0 Information: PA-MCX-4TE1-Q PA, 4ports EEPROM format version 4 HW rev 1.00, Board revision 02 Serial number: MIC G Part number: Using the show interfaces Command The show interfaces command displays status information (including the physical slot and interface address) for the interfaces you specify. 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 serial command. In this example, the SS7 Q.703 High Speed Port Adapter is located in port adapter slot 0. Router# show interface serial 0/0/5:0 Serial0/0/5:0 is up, line protocol is up Hardware is cxbus E1 MTU 1500 bytes, BW 1984 Kbit, DLY usec, reliability 242/255, txload 1/255, rxload 1/255 Encapsulation SS7 HS-MTP2, crc 16, loopback not set Keepalive set (10 sec) Last input 00:00:14, output 00:00:14, output hang never Last clearing of "show interface" counters 00:02:49 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 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 4 packets input, 110 bytes, 0 no buffer Received 0 broadcasts (0 IP multicast) 0 runts, 0 giants, 0 throttles input errors, 20 CRC, 0 frame, 0 overrun, ignored, 3 abort 9 packets output, 144 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out 1 carrier transitions no alarm present Timeslot(s) Used:1-31, subrate: 64Kb/s, transmit delay is 0 flags Router# 4-13

14 Checking the Configuration Chapter 4 Using the ping cs7 Command to Verify Network Connectivity between ITPs To verify connectivity to another ITP, use the following command in EXEC mode: Command Router# ping cs7 [-duration seconds] [-ni network-indicator] [-rate MSU-per-second] [-size bytes] [-sls value round-robin] [stop] point-code Purpose Verify that you can reach ITP nodes. The following is typical output for the cs7 ping command: Router# ping cs d19h:%CS7PING-6-RTT:Test Q :MTP Traffic test rtt 16/16/16 3d19h:%CS7PING-6-STAT:Test Q :MTP Traffic test 100% successful (1/1) 3d19h:%CS7PING-6-TERM:Test Q :MTP Traffic test terminated. If the connection fails, verify that you have the correct point code for the ITP and that the ITP is active (powered on), and repeat the ping cs7 command. Using loopback Commands E1 Loopback Examples With the loopback test, you can detect and isolate equipment malfunctions by testing the connection between the SS7 Q.703 High Speed Port Adapter interface and a remote device such as a modem or a CSU/DSU. The loopback command places an interface in loopback mode, which enables test packets that are generated from the ping cs7 command to loop through a remote device or compact serial cable. If the packets complete the loop, the connection is good. If the packets do not complete the loop, you can isolate a fault to the remote device or compact serial cable in the path of the loopback test. Depending on the mode of the port, using the loopback command checks the following path: When no compact serial cable is attached to the SS7 Q.703 High Speed Port Adapter interface port, 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 SS7 Q.703 High Speed Port Adapter interface and compact serial cable. Use the loopback command to specify loopback for an E1 controller. There are two main loopback modes: diagnostic and local (line and payload). Specify the loopback format using the loopback [diagnostic local] command. To shut down the E1 controller, use the shutdown command at the controller prompt. Examples of specific loopback modes follow: The syntax of the loopback diagnostic command is as follows: loopback [diagnostic] Set the first E1 into diagnostic loopback. Router# config t Enter configuration commands, one per line. End with CNTL/Z. 4-14

15 Chapter 4 Checking the Configuration Router(config)# controller E1 2/0/0 Router(config-controller)# loopback diagnostic In the preceding example, the loopback diagnostic command loops the outgoing transmit signal back to the receive signal and sends an AIS out to the network. The syntax of the loopback local command is as follows: loopback [local {payload line}] Set the first E1 into local loopback. Router# config t Enter configuration commands, one per line. End with CNTL/Z. Router(config)# controller E1 2/0/0 Router(config-controller)# loopback local payload In the preceding example, the loopback local command loops the incoming signal back to the line. 4-15

16 Checking the Configuration Chapter