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Serial Interfaces

This topic discusses about the serial interfaces, and how to configure serial line protocol, serial clocking mode, serial signal handling, serial DTR circuit, serial signal polarities, serial loopback capability, and serial line encoding.

Serial Interfaces Overview

Devices that communicate over a serial interface are divided into two classes: data terminal equipment (DTE) and data circuit-terminating equipment (DCE). Juniper Networks Serial Physical Interface Cards (PICs) have two ports per PIC and support full-duplex data transmission. These PICs support DTE mode only. On the Serial PIC. Table 1 specifies the key details of the serial interfaces.

Table 1: Serial Interface Details

Interface Details

Description

Interface name

Serial interface

Supported on

For information about platforms support, see hardware compatibility tool (HCT).

Standards to configure serial interfaces type

  • EIA-530—An Electronics Industries Alliance (EIA) standard.

  • V.35—An ITU-T standard.

  • X.21—An ITU-T standard.

  • RS-232 —A Recommended Standard (RS) known as EIA-232.

  • RS-422/449 —A Recommended Standard (RS). The RS-449 standard (known as EIA-449) is compatible with RS-422 signal levels.

Features supported

  • Serial transmissions

  • Signal polarity

  • Serial clocking modes

  • Serial Line protocol

Logical properties

There are no serial interface-specific logical properties. For information about general logical properties that you can configure, see Configuring Logical Interface Properties. This support on serial interfaces is the same as the existing LFI and MLPPP support on T1 and E1 interfaces.

Serial Transmissions

In basic serial communications, nine signals are critical to the transmission. Each signal is associated with a pin in either the 9-pin or 25-pin connector. Table 2 lists and defines serial signals and their sources.

Table 2: Serial Transmission Signals

Signal Name

Definition

Signal Source

TD

Transmitted data

DTE

RD

Received data

DCE

RTS

Request to send

DTE

CTS

Clear to send

DCE

DSR

Data set ready

DCE

Signal Ground

Grounding signal

CD

Carrier detect

DTR

Data terminal ready

DTE

RI

Ring indicator

Serial line protocol guidelines:

  • The DCE transmits a DSR signal to the DTE, which responds with a DTR signal. This establishes the link and traffic can pass.

  • When the DTE device is ready to receive data:

    • It sets its RTS signal to a marked state all 1s to indicate to the DCE that it can transmit data. If the DTE is not able to receive data—because of buffer conditions, for example—it sets the RTS signal to all 0s.

    • It sets its CTS signal to a marked state to indicate to the DTE that it can transmit data. If the DCE is not able to receive data, it sets the CTS signal to all 0s.

  • When you send the information, it transmits data across the transmitted data (TD) lines and receives data across received data (RD) lines:

    • TD line—Line through which the data transmits from a DTE device to a DCE device

    • RD line—Line through which the data transmits from a DCE device to a DTE device

  • The wire name does not indicate the direction of data flow.

When a serial port is opens, the DTE device sets its DTR signal to a marked state. Similarly, the DCE sets its DSR signal to a marked state. However, because of the negotiation that takes place with the RTS and CTS signals, the DTR and DSR signals are hardly utilized.

The carrier detect and ring indicator signals detect connections with remote modems and these signals are hardly used.

8-Port Synchronous Serial GPIM on SRX devices

A Gigabit-Backplane Physical Interface Module (GPIM) is a network interface card (NIC) that you can install in the front slots of the SRX550 Services Gateway to provide physical connections to a LAN or a WAN. The 8-port synchronous serial GPIM provides the physical connection to serial network media types, receiving incoming packets and transmitting outgoing packets of the network. Besides forwarding packets for processing, the GPIM performs framing and line-speed signaling. This GPIM provides 8 ports that operate in sync mode and supports a line rate of 64 Mbps or 8 Mbps per port.

For information on configuration of 8-Port Serial GPIM, see 8-Port Serial GPIM Basic Configuration.

Features Supported on 8-Port Synchronous Serial GPIM

Table 3 lists the features supported on the 8-port synchronous serial GPIM.

Table 3: Supported Features

Features

Description

Operation modes (autoselection based on cable, no configuration required)

  • DTE (data terminal equipment)

  • DCE (data communication equipment)

Clocking

  • Tx clock modes

    • DCE clock (only valid in DTE mode)

    • Baud clock (internally generated)

    • Loop clock (external)

  • Rx clock modes

    • Baud clock (internally generated)

    • Loop clock (external)

Clock rates (baud rates)

1.2 KHz to 8.0 MHz

Note:

RS-232 serial interfaces might cause an error with a clock rate greater than 200 KHz.

MTU

9192 bytes, default value is 1504 bytes

HDLC features

  • Idle flag/fill (0x7e or all ones), default idle flag is (0x7e)

  • Counters—giants, runts, FCS error, terminate error, align error

Line encoding

NRZ and NRZI

Invert data

Enabled

Line protocol

EIA530/EIA530A, X.21, RS-449, RS-232, V.35

Data cables

Separate cable for each line protocol (both DTE/DCE mode)

Error counters (conformance to ANSI specification)

Enabled

Alarms and defects

  • Rx clock absent

  • Tx clock absent

  • DCD absent

  • RTS/CTS absent

  • DSR/DTR absent

Data signal

Rx clock

Control signals

  • To DTE: CTS, DCD, DSR

  • From DTE: DTR, RTS

Serial autoresync

  • Configurable resync duration

  • Configurable resync interval

Diagnostic features

  • Loopback modes—local, remote, and dce-local loopback

  • Ability to ignore control signals

Layer 2 features

Encapsulation

  • PPP

  • Cisco HDLC

  • Frame Relay

  • MLPPP

  • MLFR

SNMP features

SNMP information receivable at each port

  • IF-MIB - rfc2863a.mib

  • jnx-chassis.mib

Anticounterfeit check

Enabled

Benefits of Serial Interfaces

  • Serial interface are a simple, cost-effective way to connect transmitting and receiving devices or ICs. A serial interface requires fewer conducting wires (often only one) than other interfaces, which eases implementation.

  • Serial interfaces support long-distance communication.

Configuring the Serial Line Protocol

Configuring the Serial Line Protocol

By default, serial interfaces use the EIA-530 line protocol. You can configure each port on the PIC independently to use one of the following line protocols:

  • EIA-530

  • V.35

  • X.21

To configure the serial line protocol:

Include the line-protocol statement, specifying the eia530, v.35, or x.21 option:

You can include these statements at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

For more information about serial interfaces, see the following sections:

Serial Interface Default Settings

Serial Interface Default Settings

EIA-530 Interface Default Settings

If you do not include the line-protocol statement or if you explicitly configure the default EIA-530 line protocol, the default settings are as follows:

Note:

On M Series routers, you can set the DCE clocking mode for EIA-530 interfaces and commit. An error message is not displayed and the CLI is not blocked.

You can include the line-protocol statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

V.35 Interface Default Settings

If you include the line-protocol v.35 statement, the default settings are as follows:

You can include the line-protocol statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

X.21 Interface Default Settings

If you include the line-protocol x.21 statement, the default settings are as follows:

You can include the line-protocol statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

Invalid Serial Interface Statements

The following sections show the invalid configuration statements for each type of serial interface. If you include the following statements in the configuration, an error message indicates the location of the error and the configuration is not activated.

Invalid EIA-530 Interface Statements

If you do not include the line-protocol statement or if you explicitly configure the default EIA-530 line protocol, the following statements are invalid:

You can include the line-protocol statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

Invalid V.35 interface Statements

If you include the line-protocol v.35 statement, the following statements are invalid:

You can include the line-protocol statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

Invalid X.21 Interface Statements

If you include the line-protocol x.21 statement, the following statements are invalid:

You can include the line-protocol statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

Configuring the Serial Clocking Mode

Configuring the Serial Clocking Mode

By default, serial interfaces use loop clocking mode. For EIA-530 and V.35 interfaces, you can configure each port on the PIC independently to use loop, DCE, or internal clocking mode. For X.21 interfaces, only loop clocking mode is supported.

The three clocking modes work as follows:

  • Loop clocking mode—Uses the DCE’s RX clock to clock data from the DCE to the DTE.

  • DCE clocking mode—Uses the TXC clock, which is generated by the DCE specifically to be used by the DTE as the DTE’s transmit clock.

  • Internal clocking mode—Also known as line timing, uses an internally generated clock. You can configure the speed of this clock by including the clock-rate statement at the [edit interfaces se-pim/0/port serial-options] or [edit interfaces se-fpc/pic/port dte-options] hierarchy levels. For more information about the DTE clock rate, see Configuring the DTE Clock Rate.

Note that DCE clocking mode and loop clocking mode use external clocks generated by the DCE.

Figure 1 shows the clock sources of loop, DCE, and internal clocking modes.

Figure 1: Serial Interface Clocking ModeSerial Interface Clocking Mode

To configure the clocking mode of a serial interface, include the clocking-mode statement:

You can include this statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

Inverting the Serial Interface Transmit Clock

When an externally timed clocking mode (DCE or loop) is used, long cables might introduce a phase shift of the DTE-transmitted clock and data. At high speeds, this phase shift might cause errors. Inverting the transmit clock corrects the phase shift, thereby reducing error rates.

By default, the transmit clock is not inverted. To invert the transmit clock, include the transmit-clock invert statement:

You can include this statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

Configuring the DTE Clock Rate

By default, the serial interface has a clock rate of 16.384 MHz. For EIA-530 and V.35 interfaces with internal clocking mode configured, you can configure the clock rate.

To configure the clock rate, include the clock-rate statement:

You can include this statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

You can configure the following interface speeds:

  • 2.048 MHz

  • 2.341 MHz

  • 2.731 MHz

  • 3.277 MHz

  • 4.096 MHz

  • 5.461 MHz

  • 8.192 MHz

  • 16.384 MHz

Although the serial interface is intended for use at the default rate of 16.384 MHz, you might need to use a slower rate if any of the following conditions prevail:

  • The interconnecting cable is too long for effective operation.

  • The interconnecting cable is exposed to an extraneous noise source that might cause an unwanted voltage in excess of +1 volt measured differentially between the signal conductor and circuit common at the load end of the cable, with a 50-ohm resistor substituted for the generator.

  • You need to minimize interference with other signals.

  • You need to invert signals.

For detailed information about the relationship between signaling rate and interface cable distance, see the following standards:

  • EIA-422-A, Electrical Characteristics of Balanced Voltage Digital Interface Circuits

  • EIA-423-A, Electrical Characteristics of Unbalanced Voltage Digital Interface Circuits

Configuring the Serial Signal Handling

By default, normal signal handling is enabled for all signals. For each signal, the normal option applies to the normal signal handling for that signal, as defined by the following standards:

  • TIA/EIA Standard 530

  • ITU-T Recommendation V.35

  • ITU-T Recommendation X.21

Table 4 shows the serial interface modes that support each signal type.

Table 4: Signal Handling by Serial Interface Type

Signal

Serial Interfaces

From-DCE signals

Clear to send (CTS)

EIA-530 and V.35

Data carrier detect (DCD)

EIA-530 and V.35

Data set ready (DSR)

EIA-530 and V.35

Indication

X.21 only

Test mode (TM)

EIA-530 only

To-DCE signals

Control signal

X.21 only

Data transfer ready (DTR)

EIA-530 and V.35

Request to send (RTS)

EIA-530 and V.35

You configure serial interface signal characteristics by including the dce-options or dte-options statement:

You can include these statements at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

For EIA-530 and V.35 interfaces, configure to-DCE signals by including the dtr and rts statements, specifying the assert, de-assert, or normal option:

For X.21 interfaces, configure to-DCE signals by including the control-signal statement, specifying the assert, de-assert, or normal option:

Assertion is when the positive side of a given signal is at potential high-level output voltage (Voh), while the negative side of the same signal is at potential low-level output voltage (Vol). Deassertion is when the positive side of a given signal is at potential Vol, while the negative side of the same signal is at potential Voh.

For the DTR signal, you can configure normal signal handling using the signal for automatic resynchronization by including the dtr statement, and specifying the auto-synchronize option:

The pulse duration of resynchronization can be from 1 through 1000 milliseconds. The offset interval for resynchronization can be from 1 through 31 seconds.

For EIA-530 and V.35 interfaces, configure from-DCE signals by including the cts, dcd, and dsr statements, specifying the ignore, normal, or require option:

For X.21 interfaces, configure from-DCE signals by including the indication statement, specifying the ignore, normal, or require option:

For EIA-530 interfaces only, you can configure from-DCE test-mode (TM) signaling by including the tm statement, specifying the ignore, normal, or require option:

To specify that the from-DCE signal must be asserted, include the require option in the configuration. To specify that the from-DCE signal must be ignored, include the ignore option in the configuration.

Note:

For V.35 and X.21 interfaces, you cannot include the tm statement in the configuration.

For X.21 interfaces, you cannot include the cts, dcd, dsr, dtr, and rts statements in the configuration.

For EIA-530 and V.35 interfaces, you cannot include the control-signal and indication statements in the configuration.

For a complete list of serial options statements that are not supported by each serial interface mode, see Invalid Serial Interface Statements.

To return to the default normal signal handling, delete the require, ignore, assert, de-assert, or auto-synchronize statement from the configuration, as shown in the following example:

To explicitly configure normal signal handling, include the control-signal statement with the normal option:

You can configure the serial interface to ignore all control leads by including the ignore-all statement:

You can include the ignore-all statement in the configuration only if you do not explicitly enable other signal handling options at the [edit interfaces se-pim/0/port serial-options dce-options] or [edit interfaces se-fpc/pic/port serial-options dte-options] hierarchy levels.

You can include the control-signal, cts, dcd, dsr, dtr, indication, rts, and tm statements at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options dte-options]

  • [edit interfaces se-fpc/pic/port serial-options dte-options]

Configuring the Serial DTR Circuit

A balanced circuit has two currents that are equal in magnitude and opposite in phase. An unbalanced circuit has one current and a ground; if a pair of terminals is unbalanced, one side is connected to electrical ground and the other carries the signal. By default, the DTR circuit is balanced.

For EIA-530 and V.35 interfaces, configure the DTR circuit by including the dtr-circuit statement:

You can include this statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

Configuring Serial Signal Polarities

Serial interfaces use a differential protocol signaling technique. Of the two serial signals associated with a circuit, the one referred to as the A signal is denoted with a plus sign, and the one referred to as the B signal is denoted with a minus sign; for example, DTR+ and DTR–. If DTR is low, then DTR+ is negative with respect to DTR–. If DTR is high, then DTR+ is positive with respect to DTR–.

By default, all signal polarities are positive. You can reverse this polarity on a Juniper Networks serial interface. You might need to do this if signals are miswired as a result of reversed polarities.

For EIA-530 and V.35 interfaces, configure signal polarities by including the cts-polarity, dcd-polarity, dsr-polarity, dtr-polarity, rts-polarity, and tm-polarity statements:

You can include these statements at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

For X.21 interfaces, configure signal polarities by including the control-polarity and indication-polarity statements:

You can include these statements at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

Configuring Serial Loopback Capability

From the router, remote line interface unit (LIU) loopback loops the TX (transmit) data and TX clock back to the router as RX (receive) data and RX clock. From the line, LIU loopback loops the RX data and RX clock back out the line as TX data and TX clock, as shown in Figure 2.

Figure 2: Serial Interface LIU LoopbackSerial Interface LIU Loopback

DCE local and DCE remote control the EIA-530 interface-specific signals for enabling local and remote loopback on the link partner DCE. Local loopback is shown in Figure 3.

Figure 3: Serial Interface Local LoopbackSerial Interface Local Loopback

For EIA-530 interfaces, you can configure DCE local, DCE remote, local, and remote (LIU) loopback capability.

For V.35, you can configure remote LIU and local loopback capability. DCE local and DCE remote loopbacks are not supported on V.35 and X.21 interfaces. Local and remote loopbacks are not supported on X.21 interfaces.

To configure the loopback capability on a serial interface, include the loopback statement, specifying the dce-local, dce-remote, local, or remote option:

You can include this statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

To disable the loopback capability, remove the loopback statement from the configuration:

You can determine whether there is an internal or external problem by checking the error counters in the output of the show interface se-fpc/pic/port extensive command:

To Configure Serial Loopback Capability:

  1. To determine the source of a problem, loop the packets on the local router, the local DCE, the remote DCE, and the remote line interface unit (LIU).
  2. To do this, include the no-keepalives and encapsulation cisco-hdlc statements at the [edit interfaces se-fpc/pic/port] hierarchy level, and the loopback local option at the [edit interfaces se-pim/0/port serial-options] or [edit interfaces se-fpc/pic/port serial-options] hierarchy level. With this configuration, the link stays up, so you can loop ping packets to a remote router. The loopback local statement causes the interface to loop within the PIC just before the data reaches the transceiver.

Configuring Serial Line Encoding

By default, serial interfaces use non-return to zero (NRZ) line encoding. You can configure non-return to zero inverted (NRZI) line encoding if necessary.

To have the interface use NRZI line encoding, include the encoding statement, specifying the nrzi option:

To explicitly configure the default NRZ line encoding, include the encoding statement, specifying the nrz option:

You can include this statement at the following hierarchy levels:

  • [edit interfaces se-pim/0/port serial-options]

  • [edit interfaces se-fpc/pic/port serial-options]

When setting the line encoding parameter, you must set the same value for paired ports. Ports 0 and 1 must share the same value.

Configure Serial Interfaces on SRX devices

In this example you learn how to complete the initial configuration on a serial interface, how to delete a serial interface and how to configure serial interface 8-Port Synchronous Serial GPIM.

For information on installation of a serial PIM in the SRX Series device, see SRX Series Services Gateways for the Branch Physical Interface Modules Hardware Guide.

In this example:

  1. Create a new interface on a serial interface, se-1/0/0.

  2. Set the encapsulation type to ppp and create the basic configuration for se-1/0/0.

  3. Set the logical interface to 0 and logical unit number can range from 0 through 16,384.

  4. Enter additional values for properties you need to configure on the logical interface, such as logical encapsulation or protocol family.

  5. Set IPv4 address 10.10.10.10/24 on se-1/0/0.

When you delete the se-1/0/0 interface, the interface is disabled and removed from the software configuration. Network interfaces remain physically present, and their identifiers continue to appear on J-Web pages.

Basic Serial Interface Configuration

In this example, you create a serial interface called se-1/0/0 and set the encapsulation type to ppp. To quickly configure this example, use CLI quick configuration at the [edit] hierarchy level, and commit from configuration mode.

To configure the serial interface, se-1/0/0:

  1. Create the interface.
  2. Set the encapsulation type for se-1/0/0.
  3. Add logical interfaces.
  4. Specify an IPv4 address for the interface.

After completing the configuration successfully, view the parameters by using the show interfaces se-1/0/0 command.

Delete the Serial Interface

In this example, you delete a serial interface se-1/0/0. No configuration beyond device initialization is required before configuring an interface.

To delete the serial interface, se-1/0/0:

  1. Specify the interface you want to delete.
  2. After you are done configuring the device, commit the configuration.

After completing the configuration successfully, to verify the configuration use the show interfaces command.

Example: Configure serial interface on 8-Port Synchronous Serial GPIM

In this example, you can perform a basic back-to-back device configuration with an 8-port synchronous serial GPIM. The devices are shown as both data communication equipment (DCE) and data terminal equipment (DTE). In certain deployment scenarios, the DTE can be a serial modem or an encryptor or decryptor.

In this scenario, you can configure serial interface using two interfaces. You can configure all ports with different encapsulations, such as Cisco High-Level Data Link Control (HDLC), Frame Relay, and Point-to-Point Protocol (PPP). When Frame Relay is set, then the data link connection identifier (in this example, 111) must also be set. All the eight ports on Device 1 (SRX650) are configured in DTE mode and their respective eight ports on Device 2 (SRX650) are configured in DCE mode.

In this example, for device 1:

  • Set the encapsulation type to ppp and the logical interface to 0. The logical unit number can range from 0 through 16,384.

  • Enter additional values for properties you need to configure on the logical interface, such as logical encapsulation or protocol family.

  • Set the IPv4 address to 10.10.10.1/24 on the serial port.

For Device 2, you follow a procedure similar to Device 1, but you set the clocking mode to dce.

Figure 4 shows the topology used in this example.

Figure 4: Basic Back-to-Back Device ConfigurationBasic Back-to-Back Device Configuration

To quickly configure this example, CLI at the [edit] hierarchy level:

Device 1

Device 2

To configure the interfaces on Device 1:

  1. Specify the maximum transmission unit (MTU) value for the interface.
  2. Set the encapsulation type.
  3. Set the serial options, such as the clocking mode.
  4. Set the IPv4 address on the serial port.
  5. Specify the static route information.

    Repeat the same configuration for the other seven ports on Device 1.

  6. After you are done configuring the device, commit the configuration.

To configure the interfaces on Device 2:

  1. Specify the MTU value for the interface.

  2. Set the encapsulation type.

  3. Set the serial options, such as the clocking mode.

  4. Set the IPv4 address on the serial port.

  5. Specify the static route information.

    Repeat the same configuration for the other seven ports on Device 2.

  6. After you are done configuring the device, commit the configuration.

Verification

Purpose

Display information about the parameters configured on the serial interfaces.

Action

  • You can use the ping tool on each peer address in the network to verify that all interfaces on the device are operational. To verify the link state of all interfaces:

    For each interface on the device:

    1. In the J-Web interface, select Troubleshoot > Ping Host.

    2. In the Remote Host box, type the address of the interface for which you want to verify the link state.

    3. Click Start. The output appears on a separate page.

    If the interface is operational, it generates an ICMP response. If this response is received, the round-trip time, in milliseconds, is listed in the time field.

  • To verify that the interface properties are correct, use the show interfaces detail command to display a summary of interface information. Verify the following information:

    • The physical interface is Enabled. If the interface is shown as Disabled, do one of the following:

      • In the CLI configuration editor, delete the disable statement at the [edit interfaces se-1/0/0] level of the configuration hierarchy.

      • In the J-Web configuration editor, clear the Disable check box on the Interfaces > se-1/0/0 page.

    • The physical link is Up. A link state of Down indicates a problem with the interface module, interface port, or physical connection (link-layer errors).

    • The Last Flapped time is an expected value. It indicates the last time the physical interface became unavailable and then available again. Unexpected flapping indicates likely link-layer errors.

    • The traffic statistics reflect expected input and output rates. Verify that the number of inbound and outbound bytes and packets matches expected throughput for the physical interface. To clear the statistics and see only new changes, use the clear interfaces statistics se-1/0/0 command.

  • To verify and that the interface link status is up, use the enter the show interface terse se-7/0/* command:

    The output displays a list of all interfaces configured. If the Link column displays up for all interfaces, the configuration is correct. This verifies that the GPIM is up and end-to-end ping is working.

  • To verify the interface statistics for DCE, use the show interface se-7/0/0 extensive | no-more command:

    The output displays a list of all DCE verification parameters and the mode configured. If the local mode displays DCE, the configuration is correct.

  • To verify the interface statistics for DTE, use the show interface se-3/0/0 extensive | no-more command:

    The output displays a list of all DTE verification parameters and the mode configured. If the local mode displays DTE, the configuration is correct.