Configuration Tasks
This section describes how to configure the 4-Port Serial Interface SPA for the Cisco ASR 1000 Series Routers and verify the configuration. For information about managing your system images and configuration files, refer to the following:
Configuring the 4-Port Serial Interface SPA
To configure the 4-Port Serial Interface SPA, complete these steps:
SUMMARY STEPS
- Router# configure terminal
- Router(config)# interface serial slot/subslot/port
- Router(config-if)# ip address address mask
- Router(config-if)# clock rate bps
DETAILED STEPS
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
Router# configure terminal |
Enters global configuration mode. |
| Step 2 |
Router(config)# interface serial slot/subslot/port |
Selects the interface to configure and enters interface configuration mode. |
| Step 3 |
Router(config-if)# ip address address mask |
Sets the IP address and subnet mask.
|
| Step 4 |
Router(config-if)# clock rate bps |
Configures the clock rate for the hardware to an acceptable bit rate per second (bps). |
What to do next
 Note |
Each port should first be connected with the appropriate cable before attempting full configuration. Some commands are enabled only based upon the cable type connected to the port. |
Note |
The bandwidth of each interface is 2 MB by default; setting the clock rate does not change the interface bandwidth. We recommend that you configure the bandwidth value with the clock rate command at the DCE and DTE side. |
Note |
A clock rate of 2016000 does not appear in the configuration because it is the default value. |
Verifying 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 and loopback commands to check connectivity. This section includes the following subsections:
Using show Commands
The table below shows the show commands you can use to verify the operation of the 4-Port Serial Interface SPA. Sample displays of the output of selected show commands appear in the following section.
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. |
|
Command |
Purpose |
|---|---|
|
Displays system hardware configuration, the number of each interface type installed, Cisco IOS software version, names and sources of configuration files, and boot images. |
|
Displays all the current interface processors and their interfaces. |
|
Displays serial line statistics. |
|
Displays status information about a specific type of interface (for example, serial). |
|
Displays types of hardware installed in your system and the firmware version. |
|
Displays the running configuration file. |
|
Displays the configuration stored in NVRAM. |
Verification Examples
The following is an example of the show version command with the 4-Port Serial Interface SPA:
Router# show version
Cisco IOS Software, IOS-XE Software (PPC_LINUX_IOSD-ADVIPSERVICESK9-M), Version 12.2(33)XN1, RELEASE SOFTWARE (fc1) Technical Support: http://www.cisco.com/techsupport Copyright (c) 1986-2008 by Cisco Systems, Inc.
Compiled Thu 14-Feb-08 08:59 by
ROM: IOS-XE ROMMON
mcp-2ru-2 uptime is 4 minutes
Uptime for this control processor is 6 minutes System returned to ROM by reload System image file is ''tftp:/tftpboot/mcp-2ru-1/asr1000rp1-advipservicesk9.02.00.01.122-33.XN1.bin''
Last reload reason: Reload command
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cisco ASR1002 (RP1) processor with 1647841K/6147K bytes of memory.
4 Gigabit Ethernet interfaces
6 Serial interfaces
2 Channelized T3 ports
32768K bytes of non-volatile configuration memory.
3728208K bytes of physical memory.
7798783K bytes of eUSB flash at bootflash:.
Configuration register is 0x0
The following is an example of the show controllers serial command with the 4-Port Serial Interface SPA:
Router# show controllers serial 2/1/1
Serial2/1/1 - (SPA-4XT-SERIAL) is up
Encapsulation: Frame Relay
Cable type: RS-232 DTE
mtu 1500, max_buffer_size 1524, max_pak_size 1608 enc 84
loopback: Off, crc: 16, invert_data: Off
nrzi: Off, idle char: Flag
tx_invert_clk: Off, ignore_dcd: Off
rx_clockrate: 552216, rx_clock_threshold: 0
serial_restartdelay:60000, serial_restartdelay_def:60000
RTS up, CTS up, DTR up, DCD up, DSR upNote |
The acronyms are defined as follows: RTS (Request to Send); CTS (Clear To Send); DTR (Data Transmit Ready); DCD (Data Carrier Detect); DSR (Data Set Ready). |
The following is an example of the show interfaces serial command with the 4-Port Serial Interface SPA:
Router# show interfaces serial2/0/0
Serial 2/0/0 is up, line protocol is up
Hardware is SPA-4XT-SERIAL
Internet address is 192.168.33.1/29
MTU 4470 bytes, BW 8000 Kbit, DLY 100 usec, rely 255/255, load 1/255
Encapsulation HDLC, loopback not set, keepalive not set
Clock Source Internal.
Last input 00:00:01, output 00:00:00, output hang never
Last clearing of "show interface" counters 1h
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 parity
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 applique, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
The following is an example of the show platform command:
Router# show platform
Chassis type: ASR1002
Slot Type State Insert time (ago)
--------- ------------------- --------------------- -----------------
0 ASR1002-SIP10 ok 5d04h
0/0 4XGE-BUILT-IN ok 5d04h
0/1 SPA-4XT-SERIAL ok 4d05h
0/2 SPA-4XT3/E3 ok 4d04h
0/3 SPA-8XCHT1/E1 ok 4d04h
R0 ASR1002-RP1 ok, active 5d04h
F0 ASR1000-ESP5 ok, active 5d04h
P0 ASR1002-PWR-AC ok 5d04h
P1 ASR1002-PWR-AC ok 5d04h
Slot CPLD Version Firmware Version
--------- ------------------- ---------------------------------------
0 07092701 12.2(33r)XN2
R0 07100216 12.2(33r)XN2
F0 07091401 12.2(33r)XN2
The following is an example of the show running-config command with the 4-Port Serial Interface SPA:
Router# show running-config serial
Building configuration...
Current configuration : 54 bytes
!
interface Serial2/0/0
no ip address
shutdown
end
The following is an example of the show running interface command with the 4-Port Serial Interface SPA:
Router# show running interface ser2/0/1
Building configuration...
Current configuration : 54 bytes
!
interface Serial2/0/1
no ip address
shutdown
end
The following is an example of the show startup-config command with the 4-Port Serial Interface SPA:
Router# show startup-config | b Serial2/0/0
interface Serial2/0/0
no ip address
shutdown
!
interface Serial2/0/1
no ip address
shutdown
!
interface Serial2/0/2
no ip address
shutdown
!
interface Serial2/0/3
no ip address
shutdown
!Using the ping Command to Verify Network Connectivity
Use the ping command to verify if an interface port is functioning properly. This 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 timeout 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:
Router# ping 10.0.0.10
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echoes to 10.0.0.10, 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 destination and that the device is active (powered on), and repeat the ping command.
Proceed to the next section to check the network connectivity.
Using loopback Commands
With the loopback test, you can detect and isolate equipment malfunctions by testing the connection between the 4-Port Serial Interface SPA and a remote device such as a modem or a channel service unit (CSU) or a data service unit (DSU). The loopback command places an interface in loopback mode, which enables test packets that are generated from the ping command to loop through a remote device or compact serial cable. If the packets complete the loop, the connection is good. If not, you can isolate a fault to the remote device or compact serial 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 compact serial cable is attached to the 4-Port Serial Interface SPA port, or if a data communication equipment (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 data terminal equipment (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 4-Port Serial Interface SPA and compact serial cable. (The X.21 DTE interface cable does not support this loopback test.)
Note |
The X.21 interface definition does not include a loopback definition. On the 4-Port Serial Interface SPA, the X.21 DTE interface does not support the loopback function. Because of the internal clock signal present on the 4-Port Serial Interface SPAs, loopback will function on an X.21 DCE interface. |
Specifying the Interface Address on a SPA
SPA interface ports begin numbering with “0” from left to right. Single-port SPAs use only the port number 0. To configure or monitor SPA interfaces, you need to specify the physical location of the SIP, SPA, and interface in the CLI. The interface address format is slot/ subslot/ port , where:
- slot—Specifies the chassis slot number in the Cisco ASR 1000 Series Router where the SIP is installed.
- subslot—Specifies the secondary slot of the SIP where the SPA is installed.
- port—Specifies the number of the individual interface port on a SPA.
The following example shows how to specify the first interface (0) on a SPA installed in the first subslot of a SIP (0) installed in chassis slot 2:
Router(config)# interface serial 2/0/0
For more information about identifying slots and subslots, see the “Identifying Slots and Subslots for the SIPs and SPAs” section in the Configuring the SIP chapter.
Optional Configurations
There are several standard, but optional, configurations that might be necessary to complete the configuration of your serial SPA.
Configuring Timing Signals
All interfaces support both DTE and DCE mode, depending on the mode of the compact serial cable attached to the port. To use a port as a DTE interface, you need only connect a DTE compact serial 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 compact serial 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.
Use the following commands when configuring timing signals:
|
Command |
Purpose |
|---|---|
|
Router# configure terminal |
Enters global configuration mode. |
|
Router(config)# interface serial slot/subslot/port |
Selects the interface to configure and enters interface configuration mode. |
|
Router(config-if)# invert txclock |
Inverts the transmit clock signal. When the EIA/TIA-232 interface is a DTE, the invert txclock command inverts the TxC signal the DTE receives from the remote DCE. When the EIA/TIA-232 interface is a DCE, the invert txclock command inverts the clock signal to the remote DTE port. The no form of this command changes the clock signal back to its original phase. |
|
Router(config-if)# clock rate bps |
Set standard clock rate, in bits per second: 1200, 2400, 4800, 9600, 19200, 38400, 56000, 64000, 72000, 125000, 148000, 250000, 500000, 800000, 1000000, 1300000, 2000000, 4000000, or 8000000. Any nonstandard clock rates that are entered are rounded off to the nearest hardware-supported clock rate. The actual clock rate is then displayed on the console. The no form of this command removes a clock rate that has been set. |
|
Router(config-if)# invert data |
Inverts the data signal. The no form of this command disables the inversion of the data signal. |
Note |
Clock rates supported for EIA/TIA-232: 1.2K, 2.4K, 4.8K, 9.6K, 14.4K, 19.2K, 28.8K, 32K, 38.4K, 56K, 64K, 128K. |
Note |
Clock rates supported for EIA-530, EIA-530A, EIA-449, V.35(bps): 1.2K, 2.4K, 4.8K, 9.6K, 14.4K, 19.2K, 28.8K, 32K, 38.4K, 56K, 64K, 72K, 115.2K, 2.048M, 2.341M, 2.731M, 3.277M, 4.09M, 5.461M, 8.064K. |
Note |
Clock rates supported for X.21: 1.2K, 2.4K, 4.8K, 9.6K, 14.4K, 19.2K, 28.8K, 32K, 38.4K, 56K, 64K, 72K, 115.2K, 2.016M. |
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 4-Port Serial Interface SPA port is reporting a high number of error packets, a phase shift might be the problem; inverting the clock might correct this phase shift.
When the EIA/TIA-232 interface is a DTE, the invert-txclock command inverts the TxC signal the DTE receives from the remote DCE. When the EIA/TIA-232 interface is a DCE, the invert-txclock command inverts the clock signal to the remote DTE port. Use the no invert-txclock command to change the clock signal back to its original phase.
Use the following commands when inverting the clock signal:
|
Command |
Purpose |
|---|---|
|
Router# configure terminal |
Enters global configuration mode. |
|
Router(config)# interface serial slot/subslot/port |
Selects the interface to configure and enters interface configuration mode. |
|
Router(config-if)# invert txclock |
Inverts the transmit clock signal. When the EIA/TIA-232 interface is a DTE, the invert txclock command inverts the TxC signal the DTE receives from the remote DCE. When the EIA/TIA-232 interface is a DCE, the invert txclock command inverts the clock signal to the remote DTE port. The no form of this command changes the clock signal back to its original phase. |
|
Router(config-if)# invert data |
Invert the data signal. The no form of this command disables the inversion of the data stream. |
Configuring NRZI Format
All EIA/TIA-232 interfaces on the 4-Port Serial Interface SPA support non-return-to-zero (NRZ) and non-return-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 signal transition. NRZI uses relational encoding to interpret signals rather than determining absolute values.
Use the following commands when configuring NRZI format:
|
Command |
Purpose |
|---|---|
|
Router# configure terminal |
Enters global configuration mode. |
|
Router(config)# interface serial slot/subslot/port |
Selects the interface to configure and enters interface configuration mode. |
|
Router(config-if)# nrzi-encoding |
Enables NRZI encoding. |
|
Router(config-if)# no nrzi-encoding |
Disables NRZI encoding. |
Configuring Cyclic Redundancy Checks
Cyclic redundancy checking (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 designators 16 and 32 indicate the length (in bits) of the frame check sequence (FCS). 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.
To set the length of the cyclic redundancy checks (CRC), use the following commands:
|
Command |
Purpose |
|---|---|
|
Router# configure terminal |
Enters global configuration mode. |
|
Router(config)# interface serial slot/subslot/port |
Selects the interface to configure and enters interface configuration mode. |
|
Router(config-if)# crc {16 | 32 } |
Specifies the length of the CRC, where:
To set the CRC length to the default value, use the no form of this command. |
Configuring Encapsulation
When traffic crosses a WAN link, the connection needs a Layer 2 protocol to encapsulate traffic. To set the encapsulation method, use the following commands:
|
Command |
Purpose |
|---|---|
|
Router# configure terminal |
Enters global configuration mode. |
|
Router(config)# interface serial slot /subslot /port |
Selects the interface to configure and enters interface configuration mode. |
|
Router(config-if)# encapsulation encapsulation-type {hdlc | ppp | frame-relay } |
Sets the encapsulation type on the interface.
|
Verifying Encapsulation
Use the show interfaces serial command to display the encapsulation method:
Router# show interfaces serial3/1/1
Serial3/1/1 is up, line protocol is down
Hardware is SPA-4XT-SERIAL
MTU 1500 bytes, BW 2016 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY, crc 16, loopback not set
Keepalive set (10 sec)
LMI enq sent 13698, LMI stat recvd 0, LMI upd recvd 0, DTE LMI down
LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0
LMI DLCI 1023 LMI type is CISCO frame relay DTE
FR SVC disabled, LAPF state down
Broadcast queue 0/64, broadcasts sent/dropped 0/0, interface broadcasts 0
Last input never, output 00:00:05, output hang never
Last clearing of show interface counters 1d14h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 3
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
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
19344 packets output, 254168 bytes, 0 underruns
0 output errors, 0 collisions, 2283 interface resets
0 output buffer failures, 0 output buffers swapped out
4566 carrier transitions
RTS up, CTS up, DTR up, DCD up, DSR upSaving the Configuration
To save your running configuration to nonvolatile random-access memory (NVRAM), use the following command in privileged EXEC configuration mode:
|
Command |
Purpose |
|---|---|
|
Router# copy running-config startup-config |
Writes the new configuration to NVRAM. |
For more information about managing your system image and configuration files, refer to the Cisco IOS Configuration Fundamentals Configuration Guide and the Cisco IOS Configuration Fundamentals Command Reference publications for your Cisco IOS software release.
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