Table Of Contents

Packet-over-SONET/SDH Interface Commands on Cisco IOS XR Software

crc (POS)

encapsulation (POS)

interface pos

keepalive (POS)

pos

show interfaces pos

transmit-delay

Packet-over-SONET/SDH Interface Commands on Cisco IOS XR Software

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This module describes the Cisco IOS XR commands used to configure, monitor, and troubleshoot Packet-over-SONET/SDH (POS).

POS provides a method for efficiently carrying data packets in SONET or Synchronous Digital Hierarchy (SDH) frames. High-bandwidth capacity and efficient link utilization are characteristics that make POS largely preferred for building the core of data networks. POS uses PPP in High-Level Data Link Control (HDLC)-like framing for data encapsulation at Layer 2 (data link) of the Open System Interconnection (OSI) stack. This method provides efficient packet delineation and error control.

In addition to high-bandwidth efficiency, POS offers secure and reliable transmission for data. Reliable data transfer depends on timing integrity.

The real-time POS functionality is performed in hardware, according to the hardware configuration setup. Configured hardware events are detected by the framer application-specific integrated circuits (ASICs) and the control is passed to the software. The generic POS driver is responsible for providing a mechanism to configure the hardware on a per-interface basis, to handle interface state transitions, and to collect POS-related statistics.

crc (POS)

To set the length of the cyclic redundancy check (CRC) on a Packet-over-SONET/SDH (POS) interface, use the crc command in POS configuration mode. To return the CRC setting on a POS interface to the 32-bit default setting, use the no form of this command.

crc {16 | 32}

no crc {16 | 32}

Syntax Description

16	Sets 16-bit CRC mode.
32	Sets 32-bit CRC mode. The default is 32 bits.

Defaults

The default CRC mode is 32 bits.

Command Modes

POS configuration

Command History

Release	Modification
Release 2.0	This command was introduced on the Cisco CRS-1.
Release 3.0	No modification.
Release 3.2	This command was first supported on the Cisco XR 12000 Series Router.
Release 3.3.0	No modification.
Release 3.4.0	No modification.
Release 3.5.0	No modification.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The designators 16 and 32 indicate the length (in bits) of the frame check sequence (FCS). A CRC of 32 bits provides more powerful error detection, but adds overhead. Both the sender and receiver must use the same setting.

CRC-16, the most widely used error checking method throughout the United States and Europe, is used extensively with WANs. CRC-32 is specified by IEEE standard 802 and as an option by some point-to-point transmission standards. It is often used on Switched Multimegabit Data Service (SMDS) networks and LANs.

Task ID

Task ID	Operations
pos-dpt	read, write

Examples

In the following example, the 32-bit CRC on POS interface 0/1/0/2 is enabled:

RP/0/RP0/CPU0:router(config)# interface POS 0/1/0/2

RP/0/RP0/CPU0:router(config-if)# POS

RP/0/RP0/CPU0:router(config-if-pos)# crc 32

Related Commands

Command	Description
transmit-delay	Specifies a number of flag sequences to be inserted between the packets.

encapsulation (POS)

To set the Layer 2 encapsulation of an interface, use the encapsulation command in interface configuration mode. To restore the system to the default encapsulation, use the no form of this command.

encapsulation {hdlc | ppp | frame-relay}

no encapsulation

Syntax Description

hdlc	Enables Cisco High-Level Data Link Control (cHDLC) encapsulation on the interface. This is the default encapsulation type.
ppp	Enables Point-to-Point Protocol (PPP) encapsulation on the interface.
frame-relay	Enables Frame Relay encapsuation on the interface.

Defaults

For Packet-over-SONET/SDH (POS) interfaces, the default encapsulation is HDLC.

Command Modes

Interface configuration

Command History

Release	Modification
Release 2.0	This command was introduced on the Cisco CRS-1.
Release 3.0	No modification.
Release 3.2	This command was first supported on the Cisco XR 12000 Series Router.
Release 3.3.0	No modification.
Release 3.4.0	Frame Relay encapsulation was supported on POS interfaces.
Release 3.5.0	No modification.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

Task ID

Task ID	Operations
hdlc	read, write
interface	read, write

Examples

In the following example, PPP encapsulation is set on POS interface 0/3/0/1:

RP/0/RP0/CPU0:router(config)# interface POS 0/3/0/1

RP/0/RP0/CPU0:router(config-if)# encapsulation ppp

Related Commands

Command	Description
show interface	Displays statistics for all interfaces configured on the router.
show ppp interfaces	Displays PPP state information for an interface.

interface pos

To enter interface configuration mode for a POS interface, use the interface pos command in global configuration mode. To delete a POS configuration, use the no form of this command.

interface POS instance[.subinterface [point-to-point]]

no interface POS instance[.subinterface [point-to-point]]

Syntax Description

instance	Either a physical interface instance or a virtual interface instance: •Physical interface instance. Naming notation is rack/slot/module/port, and a slash between values is required as part of the notation. –rack—Chassis number of the rack. –slot—Physical slot number of the card. –module—Module number. A physical layer interface module (PLIM) is always 0. –port—Physical port number of the interface. •Virtual interface instance. Range of numbers varies depending on interface type. For more information about the syntax for the router, use the question mark (?) online help function.
.subinterface	(Optional) Subinterface instance. Naming notation is .subinterface. The period in front of the subinterface value is required as part of the notation. Replace subinterface with the virtual interface number to be associated with the physical interface. Note For more information about the syntax for the router, use the question mark (?) online help function.
point-to-point	(Optional) Interface functions as one endpoint of a point-to-point link.

Defaults

No default behavior or values

Command Modes

Global configuration

Command History

Release	Modification
Release 2.0	This command was introduced on the Cisco CRS-1.
Release 3.0	No modification.
Release 3.2	This command was first supported on the Cisco XR 12000 Series Router.
Release 3.3.0	No modification.
Release 3.4.0	No modification.
Release 3.5.0	No modification.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

Task ID

Task ID	Operations
interface	read, write

Examples

The following example shows how to enter interface configuration mode for a POS interface:

RP/0/RP0/CPU0:router(config)# interface pos 0/1/0/0

RP/0/RP0/CPU0:router(config-if)#

The following example shows how to create a subinterface on a POS interface in slot 1, subslot 1,
port 2 and enter subinterface configuration mode:

RP/0/0/CPU0:Router(config)# interface pos 0/1/1/2.1

RP/0/0/CPU0:Router(config-if)# 

Related Commands

Command	Description
show interfaces pos	Displays information about a POS interface.

keepalive (POS)

To set the keepalive timer for a specific interface, use the keepalive command in interface configuration mode. To reset the keepalive timer to the default of 10 seconds, use the no form of this command.

keepalive {seconds | disable}

no keepalive

Syntax Description

seconds	Number of seconds that define the keepalive interval. Range is from 0 through 32767seconds. Default is 10 seconds.
disable	Turns off the keepalive timer.

Defaults

seconds = 10 seconds

Command Modes

Interface configuration

Command History

Release	Modification
Release 2.0	This command was introduced on the Cisco CRS-1.
Release 3.0	No modification.
Release 3.2	This command was first supported on the Cisco XR 12000 Series Router.
Release 3.3.0	No modification.
Release 3.4.0	No modification.
Release 3.5.0	No modification.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

cHDLC keepalives require that the keepalive command is configured the same way on both routers. The two connected routers have no way of negotiating the keepalive value, because there is no way for the routers to tell each other what their configured values are. The keepalive value configured on each router (local and partner) sets the rate at which the Cisco IOS XR software sends packets. It also sets the rate at which the local end expects to receive incoming packets.

To set the keepalive value to the default value, use the keepalive command without specifying a value for the seconds argument.

If three keepalives are sent to the peer and no response is received from the peer, then the link makes the transition to the down state.

Task ID

Task ID	Operations
hdlc	read, write

Examples

The following example shows how to configure keepalives for 3 seconds on POS interface 0/7/0/1:

RP/0/RP0/CPU0:router(config)# interface POS 0/7/0/1

RP/0/RP0/CPU0:router(config-if)# keepalive 3

pos

To access the POS configuration submode, use the pos command in interface configuration mode.

pos

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Interface configuration

Command History

Release	Modification
Release 2.0	This command was introduced on the Cisco CRS-1.
Release 3.0	No modification.
Release 3.2	This command was first supported on the Cisco XR 12000 Series Router.
Release 3.3.0	No modification.
Release 3.4.0	No modification.
Release 3.5.0	No modification.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

When you issue the pos command in interface configuration mode for a POS interface, the CLI prompt changes to "config-if-pos," indicating that you have entered POS configuration submode. In the following sample output, the question mark (?) online help function displays all the commands available under POS configuration submode:

RP/0/RP0/CPU0:router(config)# interface POS 0/1/0/2

RP/0/RP0/CPU0:router(config-if)# POS

RP/0/RP0/CPU0:router(config-if-pos)# ?

  commit          Commit the configuration changes to running

  crc             Set the CRC on a POS interface

  describe        Describe a command without taking real actions

  do              Run an exec command

  exit            Exit from this submode

  no              Negate a command or set its defaults

  show            Show contents of configuration

  transmit-delay  Set POS transmit delay on an interface

Task ID

Task ID	Operations
pos-dpt	read, write

Examples

The following example shows how to access the POS configuration submode from the POS configuration mode:

RP/0/RP0/CPU0:router(config)# interface POS 0/1/0/2

RP/0/RP0/CPU0:router(config-if)# POS

RP/0/RP0/CPU0:router(config-if-pos)# 

Related Commands

Command	Description
crc (POS)	Sets the length of the CRC on a POS interface.
transmit-delay	Specifies a number of flag sequences to be inserted between the packets.

show interfaces pos

To display information about a POS interface, use the show interfaces pos command in EXEC mode.

show interfaces pos [instance] [accounting [rates] | brief | description | detail | summary] [location node-id]

instance	(Optional) POS interface instance. Naming notation is rack/slot/module/port and a slash between values is required as part of the notation. –rack—Chassis number of the rack. –slot—Physical slot number of the modular services card or line card. –module—Module number. A physical layer interface module (PLIM) is always 0. –port—Physical port number of the interface. For more information about the syntax for the router, use the question mark (?) online help function.
accounting	(Optional) Displays accounting information for all POS interfaces on the router, for a specific POS interface instance, or for all POS interfaces on a specific node.
rates	(Optional) Displays interface accounting rates for all POS interfaces on the router, for a specific POS interface instance, or for all POS interfaces on a specific node.
brief	(Optional) Displays brief output for all POS interfaces on the router, for a specific POS interface instance, or for all POS interfaces on a specific node.
description	Displays descriptive output for all POS interfaces on the router, for a specific POS interface instance, or for all POS interfaces on a specific node.
detail	(Optional) Displays detailed output for all POS interfaces on the router, for a specific POS interface instance, or for all POS interfaces on a specific node.
location node-id	(Optional) Displays detailed POS information for the designated node. The node-id argument is entered in the rack/slot/module notation.
summary	(Optional) Displays summarized POS interface information.

Defaults

Enter the show interfaces pos command without including any of the optional keywords or arguments to display detailed information about all POS interfaces configured on the router.

Command Modes

EXEC

Command History

Release	Modification
Release 2.0	This command was first introduced on the Cisco CRS-1.
Release 3.0	No modification.
Release 3.2	This command was first supported on the Cisco XR 12000 Series Router.
Release 3.3.0	No modification.
Release 3.4.0	No modification.
Release 3.5.0	No modification.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs.

Task ID

Task ID	Operations
interface	read

Examples

The following example shows how to display summarized information for a POS interface on a specific node:

RP/0/RP0/CPU0:router# show interfaces pos summary location 0/1/CPU0

Interface Type          Total    UP       Down     Admin Down

--------------          -----    --       ----     ----------

ALL TYPES               4        1        1        2

--------------

IFT_POS                 4        1        1        2

Table 28 describes the significant fields shown in the display.

Table 28 show interfaces pos summary Field Descriptions 

Field	Description
Intf Type	Type of interface described in the display.
Total	Total number of configured interfaces of the specified type.
Up	Number of interfaces of the specified type that are in the "Up" state.
Down	Number of interfaces of the specified type that are in the "Down" state.
Admin Down	Number of interfaces of the specified type that are in the "Admin Down" state.

The following example shows how to display brief information for a specific POS interface:

RP/0/RP0/CPU0:router# show interfaces pos 0/2/0/0 brief

              Intf        Intf         LineP              Encap  MTU       BW

              Name        State        State               Type (byte)   (Kbps)

-------------------------------------------------------------------------------

         PO0/2/0/0   admin-down   admin-down               HDLC  4474   2488320

P/0/RP1/CPU0:MiniQ#

Table 29 describes the significant fields shown in the display.

Table 29 show interfaces pos Field Descriptions 

Field	Description
Intf Name	Interface identifier, in the type*rack/slot/module/port notation.
Intf State	Indicates whether the interface is in the admin-up or admin down state.
LineP State	Line protocol state.
Encap Type	Encapsulation type for the specified interface. Can be HDLC or PPP.
MTU (byte)	Maximum transmission unit (MTU) value configured for the specified interface, in bytes.
BW (Kbps)	Bandwidth of the interface, in kbps.

Related Commands

Command	Description
show controllers pos	Displays information on the SONET controllers that are associated with Packet-over-SONET/SDH (POS) interfaces.
show controllers sonet	Displays information about the operational status of SONET layers.

transmit-delay

To specify a number of flag sequences to be inserted between the packets, use the transmit-delay command in POS configuration mode. To restore the default, use the no form of this command.

transmit-delay microseconds

no transmit-delay microseconds

Syntax Description

microseconds

Number of microseconds of minimum delay after sending a packet. Range is from 0 to 1023. Default is 0 (disabled).

Defaults

microseconds = 0 (disabled)

Command Modes

POS configuration

Command History

Releases	Modifications
Release 3.2	This command was introduced on the Cisco CRS-1 and the Cisco XR 12000 Series Router.
Release 3.3.0	No modification.
Release 3.4.0	No modification.
Release 3.5.0	No modification.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

Task ID

Task ID	Operations
pos-dpt	read, write

Examples

In the following example, a delay of 2 microseconds is specified on POS interface 0/1/0/2:

RP/0/0/CPU0:router# configure

RP/0/0/CPU0:router(config)# interface POS 0/1/0/2

RP/0/0/CPU0:router(config-if)# pos

RP/0/0/CPU0:router(config-if-pos)# transmit-delay 2

In the following example, the transmit delay on POS interface 0/1/0/2 is disabled:

RP/0/0/CPU0:router# configure

RP/0/0/CPU0:router(config)# interface POS 0/1/0/2

RP/0/0/CPU0:router(config-if)# pos

RP/0/0/CPU0:router(config-if-pos)# no transmit-delay

Related Commands

Command	Description
show interfaces	Displays statistics for all interfaces configured on the router or on a specific node or on a specific node.