Cisco IOS XR Interface and Hardware Component Configuration Guide, Release 3.2 - Configuring POS Interfaces on Cisco IOS XR Software [Cisco IOS XR Software (End-of-Sale)]

Table Of Contents

Configuring PoS Interfaces on Cisco IOS XR Software

Contents

Prerequisites for Configuring PoS Interfaces

Information About Configuring PoS Interfaces

Default Settings for PoS Interface Configurations

Cisco IOS XR PPP Encapsulation

Cisco IOS XR HDLC Encapsulation

Keepalive Timer

How to Configure a PoS Interface

Creating a Basic PoS Configuration

Configuring Cisco HDLC on a PoS Interface

Prerequisites

Configuring PPP on a PoS Interface

Prerequisites

PPP Encapsulation

PPP Configuration

Configuration Examples for PoS Interfaces

Configuring Basic PoS: Example

Configuring PPP: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Configuring PoS Interfaces on Cisco IOS XR Software

This module describes the configuration of PoS interfaces using both Cisco High-Level Data Link Control (HDLC) protocol and Point-to-Point Protocol (PPP) encapsulation on routers supporting
Cisco IOS XR software.

Packet-over-SONET (PoS) provides secure and reliable transmission of data over SONET and Synchronous Digital Hierarchy (SDH) frames using either HDLC protocol or PPP encapsulation. HDLC is the default for data encapsulation at Layer 2 (data link) of the Open System Interconnection (OSI) stack for efficient packet delineation and error control.

The router identifies a PoS interface address by its physical layer interface module (PLIM) card rack number, slot number, module number, and port number.

The commands for configuring Layer 1 PoS interfaces are provided in the Cisco IOS XR Interface and Hardware Component Command Reference.

Feature History for Configuring PoS Interfaces on Cisco IOS XR Software

Release

Modification

Release 2.0

This feature was introduced on the Cisco CRS-1.

Release 3.0

No modifications.

Release 3.2

Support was added for the Cisco XR 12000 Series Router.

Contents

•Prerequisites for Configuring PoS Interfaces

•Information About Configuring PoS Interfaces

•How to Configure a PoS Interface

•Configuration Examples for PoS Interfaces

•Additional References

Prerequisites for Configuring PoS Interfaces

Before configuring PoS interfaces, be sure that the following conditions are met:

•You must be in a user group associated with a task group that includes the proper task IDs for SONET commands. In addition, for Cisco HDLC and PPP tasks, you must be in a user group associated with a task group that includes the proper task IDs for HDLC and PPP commands.

Task IDs for commands are listed in the Cisco IOS XR Task ID Reference Guide.

•You know the IP address of the interface you will assign to the new PoS interface configuration.

Information About Configuring PoS Interfaces

To configure PoS controller interfaces, you need to understand the following concepts:

•Default Settings for PoS Interface Configurations

•Cisco IOS XR PPP Encapsulation

•Cisco IOS XR HDLC Encapsulation

•Keepalive Timer

Default Settings for PoS Interface Configurations

When an interface is enabled on a PoS modular service card and its associated PLIM, and no additional configuration commands are applied, the default interface settings shown in Table 2 are present. These default settings can be changed by configuration. Default settings do not appear in the output of the show running-config command.

Table 2 PoS Modular Service Card and PLIM Default Interface Settings

Parameter

Configuration File Entry

Default Settings

Keepalive

keepalive [disable]
no keepalive [disable]

keepalive 10 seconds

Encapsulation

encapsulation [hdlc | ppp]

hdlc

Maximum transmission unit (MTU)

mtu bytes

4474 bytes

Cyclic redundancy check (CRC)

crc [16 | 32]

32

Cisco IOS XR PPP Encapsulation

Note The default encapsulation type for the router PoS PLIM card configurations is Cisco HDLC. To configure Cisco HDLC, see the "Configuring Cisco HDLC on a PoS Interface" section.

PPP is a standard protocol used to send data over synchronous serial links. PPP also provides a link control protocol (LCP) for negotiating properties of the link. LCP uses echo requests and responses to monitor the continuing availability of the link.

PPP provides Network Control Protocols (NCPs) for negotiating properties of data protocols that will run on the link:

•IP Control Protocol (IPCP) to negotiate IP properties

• Multiprotocol Label Switching control processor (MPLSCP) to negotiate MPLS properties

• Cisco Discovery Protocol control processor (CDPCP) to negotiate CDP properties

•IPv6CP to negotiate IP Version 6 (IPv6) properties

•Open Systems Interconnection control processor (OSICP) to negotiate OSI properties

Cisco IOS XR HDLC Encapsulation

Cisco High-Level Data Link Controller (HDLC) is Cisco's proprietary protocol for sending data over synchronous serial links using HDLC. Cisco HDLC also provides a simple control protocol called Serial Line Address Resolution Protocol (SLARP) to maintain serial link keepalives. HDLC is the default encapsulation for PoS interfaces under Cisco IOS XR software.

Keepalive Timer

The HDLC usage of the keepalive timer also applies to PPP encapsulation to control how often ECHOREQ (echo request) packets are sent out.

Use the keepalive command in interface configuration mode to set how frequently LCP should send out ECHOREQ packets to its peer. To restore the system to the default keepalive interval of 10 seconds, use the keepalive command with no argument. To disable keepalives, use the no keepalive or keepalive disable command. For both PPP and Cisco HDLC, a keepalive of 0 disables keepalives and is reported in the show running-config command output as keepalive disable.

When LCP is running on the peer and receives an ECHOREQ packet, it should respond with an echo reply (ECHOREP) packet, regardless of whether keepalives are enabled on the peer.

Keepalives are independent between the two peers. One peer end can have keepalives enabled; the other end can have them disabled. Even if keepalives are disabled locally, LCP still responds with ECHOREP packets to the ECHOREQ packets it receives. Similarly, LCP also works if the period of keepalives at each end is different.

When the interface has PPP encapsulation, if LCP sends three ECHOREQ packets without an ECHOREP being received then it declares the link down and initiates full LCP negotiation again. If the interface has HDLC encapsulation, the number of resends is only three before the link is taken down. Only when LCP negotiation is complete (for example, when LCP is Open) are ECHOREQ packets sent out.

How to Configure a PoS Interface

This section contains the following procedures:

•Creating a Basic PoS Configuration (Required)

•Configuring Cisco HDLC on a PoS Interface (Optional)

•Configuring PPP on a PoS Interface (Optional)

Creating a Basic PoS Configuration

This task explains how to create a basic PoS configuration. There are many other possible parameters that can be set. Only the most basic are illustrated below.

SUMMARY STEPS

1. show interfaces

2. configure

3. interface type instance

4. ipv4 address ip-address mask

5. encapsulation [hdlc | ppp]

6. pos crc {16 | 32}

7. keepalive {seconds | disable}

8. mtu value

9. no shutdown

10. end
or
commit

11. show interfaces type instance

12. show running-config

DETAILED STEPS
Command or Action

Purpose

Step 1

show interfaces
Example:

RP/0/RP0/CPU0:router# show interfaces

(Optional) Displays configured interfaces.

•Use this command to also confirm that the router recognizes the PLIM card.

Step 2

configure
Example:

RP/0/RP0/CPU0:router# configure

Enters global configuration mode.

Step 3

interface type instance
Example:

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

Specifies the PoS interface name and notation rack/slot/module/port, and enters interface configuration mode.

•The example indicates an OC-192c/STM-64c PoS interface in PLIM card slot 1.

Step 4

ipv4 address ip-address mask
Example:

RP/0/RP0/CPU0:router(config-if)# ipv4 address 172.18.189.38 255.255.255.224

Assigns an IP address and subnet mask to the interface.

Step 5

encapsulation [hdlc | ppp]
Example:

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

(Optional) Configures the interface encapsulation parameters and details such as HDLC or PPP.

Step 6

pos crc {16 | 32}
Example:

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

(Optional) Configures the crc value .

Step 7

keepalive {seconds | disable}
Example:

RP/0/RP0/CPU0:router(config-if)# keepalive 10

(Optional) Configures the keepalive value.

Step 8

mtu value
Example:

RP/0/RP0/CPU0:router(config-if)# mtu 4474

(Optional) Configures the mtu value.

•The default value is 4474; the PoS MTU range is 64-9216 on the Cisco CRS-1.

Step 9

no shutdown
Example:

RP/0/RP0/CPU0:router(config-if)# no shutdown

Removes the shutdown configuration.

•The removal of the shutdown configuration removes the forced administrative down on the interface, enabling it to move to an up or down state (assuming the parent SONET layer is not configured administratively down).
Step 10

end
or

commit
Example:

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

RP/0/0/CPU0:router(config-if)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before  
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Step 11

show interfaces type instance
Example:

RP/0/RP0/CPU0:router# show interfaces POS 0/1/0/0

(Optional) Displays the interface configuration.

Step 12

show running-config
Example:

RP/0/RP0/CPU0:router# show running-config

(Optional) Displays the configuration information currently running on the router.
Configuring Cisco HDLC on a PoS Interface

Perform this task to configure Cisco HDLC encapsulation on a PoS interface.

Prerequisites

To use the keepalive command, you must be in a user group associated with a task group that includes the proper task IDs for HDLC commands. To use the encapsulation hdlc command, you must be in a user group associated with a task group that includes the proper task IDs for interface and HDLC commands.

Task IDs for commands are listed in the Cisco IOS XR Task ID Reference Guide.

Note Cisco HDLC is enabled by default for PoS configurations on the Cisco CRS-1.

Cisco HDLC keepalives are useful for monitoring the link state. Periodic keepalives are sent to and received from the peer at a frequency determined by the value of keepalive. If an acceptable keepalive response is not received from the peer, the link makes the transition to the down state. As soon as an acceptable keepalive response is obtained from the peer or if keepalive is disabled, the link makes the transition to the up state.

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

The Serial Line Address Resolution Protocol (SLARP) packets sent to the peer after keepalive has been configured can be displayed using the debug chdlc slarp packet and other Cisco HDLC debug commands.

SUMMARY STEPS

1. configure

2. interface type instance

3. ipv4 address ip-address mask

4. encapsulation hdlc

5. keepalive {seconds | disable}
or
no keepalive

6. no shutdown

7. end
or
commit

8. show interfaces type instance

9. show running-config

DETAILED STEPS
Command or Action

Purpose

Step 1

configure
Example:

RP/0/RP0/CPU0:router# configure

Enters global configuration mode.

Step 2

interface type instance
Example:

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

Specifies the PoS interface name and notation rack/slot/module/port and enters interface configuration mode.

•The interface command in this example indicates an OC-192c or STM-64c PoS interface in PLIM card
slot 1.

Step 3

ipv4 address ip-address mask
Example:

RP/0/RP0/CPU0:router(config-if)# ipv4 address 172.18.189.38 255.255.255.224

Assigns an IP address and subnet mask to the interface.

Step 4

encapsulation hdlc
Example:

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

Configures the interface encapsulation parameter for HDLC.
Step 5
keepalive {seconds | disable}
or

no keepalive
Example:
RP/0/RP0/CPU0:router(config-if)# keepalive 3
or
RP/0/RP0/CPU0:router(config-if)# no keepalive
Specifies the number of seconds between keepalive messages.

•Use the keepalive disable command, the no keepalive, or the keepalive command with an argument of 0 to disable the keepalive feature.
Step 6

no shutdown
Example:

RP/0/RP0/CPU0:router(config-if)# no shutdown

Removes the shutdown configuration.

•The removal of the shutdown configuration removes the forced administrative down on the interface, enabling it to move to an up or down state (assuming the parent SONET layer is not configured administratively down).
Step 7

end
or

commit
Example:

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

RP/0/0/CPU0:router(config-if)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before  
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Step 8

show interfaces type instance
Example:

RP/0/RP0/CPU0:router# show interfaces POS 0/1/0/0

(Optional) Displays the interface configuration.

Step 9

show running-config
Example:

RP/0/RP0/CPU0:router# show running-config

(Optional) Displays the configuration information currently running on the router.
Configuring PPP on a PoS Interface

Perform this task to configure PPP, an encapsulation scheme that can be used on Packet-over-SONET (PoS) interfaces.

Prerequisites

To use the encapsulation ppp command, you must be in a user group associated with a task group that includes the proper task IDs for interface and PPP commands. To use the ppp authentication command, you must be in a user group associated with a task group that includes the proper task IDs for AAA and PPP commands.

Task IDs for commands are listed in the Cisco IOS XR Task ID Reference Guide.

PPP Encapsulation

Use the encapsulation ppp command to enable PPP encapsulation on an interface.

To enable Challenge Handshake Authentication Protocol (CHAP) or Password Authentication Protocol (PAP) or both, and to specify the order in which CHAP, MS-CHAP, and PAP authentication is selected on the interface, use the ppp authentication command in interface configuration mode.

When you enable CHAP or PAP authentication (or both), the local router requires the remote device to prove its identity before allowing data traffic to flow. PAP authentication requires the remote device to send a name and a password, which are checked against a matching entry in the local username database or in the remote security server database. CHAP authentication sends a challenge message to the remote device. The remote device encrypts the challenge value with a shared secret and returns the encrypted value and its name to the local router in a response message. The local router attempts to match the remote device's name with an associated secret stored in the local username or remote security server database; it uses the stored secret to encrypt the original challenge and verify that the encrypted values match.

You can enable CHAP, MS-CHAP, or PAP in any order. If you enable all three methods, the first method specified is requested during link negotiation. If the peer suggests using the second method, or refuses the first method, the second method is tried. Some remote devices support only one method. Base the order in which you specify methods on the remote device's ability to correctly negotiate the appropriate method, and on the level of data line security you require. PAP usernames and passwords are sent as clear text strings, which can be intercepted and reused.

MS-CHAP is the Microsoft version of CHAP. Like the standard version of CHAP, MS-CHAP is used for PPP authentication; in this case, authentication occurs between a personal computer using Microsoft Windows NT or Microsoft Windows 95 and a Cisco router or access server acting as a network access server.

Enabling or disabling PPP authentication does not affect the local router's willingness to authenticate itself to the remote device.

Caution If you use a list-name value that was not configured with the aaa authentication ppp command, you will disable PPP on the interface. For details on implementing the aaa authentication command with the ppp keyword, see the Authentication, Authorization, and Accounting Commands on Cisco IOS XR Software module of the Cisco IOS XR System Security Command Reference and the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.

SUMMARY STEPS

1. configure

2. interface type instance

3. encapsulation ppp

4. ppp authentication protocol list-name

5. end
or
commit

6. show interfaces type instance

7. show running-config

DETAILED STEPS
Command or Action

Purpose
Step 1
configure
Example:
RP/0/RP0/CPU0:router# configure
Enters global configuration mode.
Step 2
interface type instance
Example:
RP/0/RP0/CPU0:router(config)# interface POS 
0/4/0/1
Enters the interface configuration mode.
Step 3
encapsulation ppp
Example:
RP/0/RP0/CPU0:router(config-if)# encapsulation 
ppp
Configures the interface encapsulation parameter for PPP.
Step 4
ppp authentication protocol list-name
Example:
RP/0/RP0/CPU0:router(config-if)# ppp 
authentication chap MIS-access
Enables the CHAP, MS-CHAP, or PAP protocol and specifies the order of selection on the interface.

•The allowed values for protocol are:

–chap—Enables CHAP on a serial interface

–ms-chap—Enables Microsoft's CHAP on a serial interface

–pap—Enables PAP on a serial interface
Step 5

end
or

commit
Example:

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

RP/0/0/CPU0:router(config-if)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before  
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Step 6

show interfaces type instance
Example:

RP/0/RP0/CPU0:router# show interfaces POS 0/1/0/0

(Optional) Displays the interface configuration.

Step 7

show running-config
Example:

RP/0/RP0/CPU0:router# show running-config

(Optional) Displays the configuration information currently running on the router.
PPP Configuration

You can configure the following PPP functionality in Cisco IOS XR:

•A common Challenge Handshake Authentication Protocol (CHAP) or MS-CHAP secret password for a collection of routers.

• Denial of CHAP and MS-CHAP authentication from peers requesting it.

•A specified number of authentication retries before a PPP interface resets itself.

•The maximum number of configure requests without response permitted before all requests are stopped.

•The maximum number of consecutive Configure Negative Acknowledgments (CONFNAKs) permitted before terminating a negotiation.

•The maximum number of terminate requests (TermReqs) without response permitted before the Link Control Protocol (LCP) or Network Control Protocol (NCP) is closed.

•Denial of Password Authentication Protocol (PAP) authentication from peers requesting it.

•Time limit for the successful negotiation of at least one network layer protocol after a PPP connection is established.

•PPP authentication timeout parameters.

•PPP timeout retry parameters.

Note You must configure the interface encapsulation parameter for PPP with the encapsulation ppp command before you can perform PPP configuration on the router.

SUMMARY STEPS

1. configure

2. interface type instance

3. encapsulation ppp

4. (Optional) ppp chap password [0 | 7] password

5. (Optional) ppp chap refuse

6. (Optional) ppp max-bad-auth retries

7. (Optional) ppp max-configure retries

8. (Optional) ppp max-failure retries

9. (Optional) ppp max-terminate number

10. (Optional) ppp pap refuse

11. (Optional) ppp pap sent-username username password [0 | 7] password

12. (Optional) ppp timeout ncp seconds

13. (Optional) ppp timeout authentication seconds

14. (Optional) ppp timeout retry seconds

15. end
or
commit

16. show ppp interfaces {POS interface_instance | all | brief {POS interface_instance | all | location node-id} | detail {POS interface_instance | all | location node-id} | location node-id}

17. show interfaces type instance

DETAILED STEPS
Command or Action

Purpose
Step 1
configure
Example:
RP/0/RP0/CPU0:router# configure
Enters global configuration mode.
Step 2
interface type instance
Example:
RP/0/RP0/CPU0:router(config)# interface POS 
0/4/0/1
Enters the interface configuration mode.
Step 3
encapsulation ppp
Example:
RP/0/RP0/CPU0:router(config-if)# encapsulation 
ppp
Configures the interface encapsulation parameter for ppp.
Step 4
ppp chap password [0 | 7] password

Example:
RP/0/RP0/CPU0:router(config-if)# ppp chap 
password xxxx
(Optional) Enable a router calling a collection of routers to configure a common Challenge Handshake Authentication Protocol (CHAP) or MS-CHAP secret password.

•Enter 0 to select cleartext encryption, or 7 if the password is already encrypted.

•Replace the password argument with a cleartext or already-encrypted password.

•The ppp chap password command is used for remote CHAP authentication only (when routers authenticate to the peer) and does not affect local CHAP authentication.This command is useful for routers that do not support this command (such as routers running older Cisco IOS XR software images).

•The CHAP or MS-CHAP secret password is used by the routers in response to challenges from an unknown peer.
Step 5
ppp chap refuse
Example:
RP/0/RP0/CPU0:router(config-if)# ppp chap 
refuse
(Optional) Refuse Challenge Handshake Authentication Protocol (CHAP) and MS-CHAP authentication from peers requesting it.

•CHAP and MS-CHAP authentication is disabled by default.

•If outbound Password Authentication Protocol (PAP) has been configured (using the ppp authentication command), PAP will be suggested as the authentication method in the refusal packet.
Step 6
ppp max-bad-auth retries
Example:
RP/0/RP0/CPU0:router(config-if)# ppp 
max-bad-auth 3
(Optional) Configure a PPP interface so that a specified number of authentication retries are allowed after an authentication failure.

•If you do not specify the number of authentication retries allowed, the router resets itself immediately after an authentication failure.

•Replace the retries argument with number of retries after which the interface is to reset itself, in the range from 0 through 10.

•The default is 0 retries.

•The ppp max-bad-auth command applies to any Packet-over-SONET (PoS) interface on which PPP encapsulation is enabled.
Step 7
ppp max-configure retries
Example:
RP/0/RP0/CPU0:router(config-if)# ppp 
max-configure 4
(Optional) Specify the maximum number of configure requests to attempt (without response) before stopping the requests.

•Replace the retries argument with the maximum number of configure requests retries, in the range from 4 through 20.

•The default maximum number of configure requests is 10.

•If a configure request message receives a reply before the maximum number of configure requests are sent, further configure requests are abandoned.
Step 8
ppp max-failure retries
Example:
RP/0/RP0/CPU0:router(config-if)# ppp 
max-failure 3
(Optional) Configure the maximum number of consecutive Configure Negative Acknowledgments (CONFNAKs) permitted before a negotiation is terminated.

•Replace the retries argument with the maximum number of CONFNAKs to permit before terminating a negotiation, in the range from 2 through 10.

•The default maximum number of CONFNAKs is 5.
Step 9
ppp max-terminate number
Example:
RP/0/RP0/CPU0:router(config-if)# ppp 
max-terminate 5
(Optional) Configure the maximum number of terminate requests (TermReqs) to send without reply before the Link Control Protocol (LCP) or Network Control Protocol (NCP) is closed.

•Replace the number argument with the maximum number of TermReqs to send without reply before closing down the LCP or NCP. Range is from 2 to 10.

•The default maximum number of TermReqs is 2.
Step 10
ppp pap refuse
Example:
RP/0/RP0/CPU0:router(config-if)# ppp pap refuse
(Optional) Refuse Password Authentication Protocol (PAP) authentication from peers requesting it.

•If outbound Challenge Handshake Authentication Protocol (CHAP) has been configured (using the ppp authentication command), CHAP will be suggested as the authentication method in the refusal packet.

•PAP authentication is disabled by default.
Step 11
ppp pap sent-username username password [0 | 7] 
password
Example:
RP/0/RP0/CPU0:router(config-if)# ppp pap 
sent-username xxxx password notified
(Optional) Reenable remote Password Authentication Protocol (PAP) support for an interface, and include the sent-username and password commands in the PAP authentication request packet to the peer.

•Replace the username argument with the username sent in the PAP authentication request.

•Enter password 0 to select cleartext encryption for the password, or enter password 7 if the password is already encrypted.

•The ppp pap sent-username command allows you to replace several username and password configuration commands with a single copy of this command on Packet-over-SONET (PoS) interfaces.

•You must configure the ppp pap sent-username command for each interface.

•Remote PAP support is disabled by default.
Step 12
ppp timeout ncp seconds
Example:
RP/0/RP0/CPU0:router(config-if)# ppp timeout 
ncp 255
(Optional) Set a time limit for the successful negotiation of at least one network layer protocol after a PPP connection is established.

•Replace the seconds argument with the maximum time, in seconds, PPP should negotiate for a network layer protocol. If no network protocol is negotiated in the given time, the connection is disconnected. The range is from 20 to 255 seconds.

•The ppp timeout ncp command protects against the establishment of links that are physically up and carrying traffic at the link level, but are unusable for carrying data traffic due to failure to negotiate the capability to transport any network level data. This command is particularly useful for dialed connections, in which it is usually undesirable to leave a telephone circuit active when it cannot carry network traffic.
Step 13
ppp timeout authentication seconds
Example:
RP/0/RP0/CPU0:router(config-if)# ppp timeout 
authentication 20
(Optional) Set PPP authentication timeout parameters.

•Replace the seconds argument with the maximum time, in seconds, to wait for a response to an authentication packet. Range is from 3 to 30 seconds.

•The default authentication time is 10 seconds, which should allow time for a remote router to authenticate and authorize the connection and provide a response. However, it is also possible that it will take much less time than 10 seconds. In such cases, use the ppp timeout authentication command to lower the timeout period to improve connection times in the event that an authentication response is lost.
Step 14
ppp timeout retry seconds
Example:
RP/0/RP0/CPU0:router(config-if)# ppp timeout 
retry 8
(Optional) Set PPP timeout retry parameters.

•Replace the seconds argument with the maximum time, in seconds, to wait for a response during PPP negotiation. Range is from 1 to 10 seconds.

•The default is 3 seconds.
Step 15

end
or

commit
Example:

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

RP/0/0/CPU0:router(config-if)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before  
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Step 16
show ppp interfaces {POS interface_instance | 
all | brief {POS interface_instance | all | 
location node-id} | detail {POS 
interface_instance | all | location node-id} | 
location node-id}
Example:
RP/0/RP0/CPU0:router# show ppp interfaces POS 
0/2/0/0
Displays PPP state information for an interface.

•Enter the POS interface_instance keyword argument to display PPP information for a specific interface.

•Enter the brief the keyword to display brief output for all PoS interfaces on the router, for a specific PoS interface instance, or for all PoS interfaces on a specific node.

•Enter the all keyword to display detailed PPP information for all nodes installed in the router.

•Enter the location node-id keyword argument to display detailed PPP information for the designated node.

There are seven possible PPP states applicable for either the Link Control Protocol (LCP) or the Network Control Protocol (NCP).

Note If IPv6 is enabled on the interface, then the IPV6 link-local address appears in the second line of the show ppp interfaces command output.
Step 17

show interfaces type instance
Example:

RP/0/RP0/CPU0:router# show interfaces POS 0/1/0/0

(Optional) Displays the interface configuration.
Configuration Examples for PoS Interfaces

This section provides the following configuration examples:

•Configuring Basic PoS: Example

•Configuring PPP: Example

Configuring Basic PoS: Example

The following example shows how to configure a basic PoS interface with Cisco HDLC:
RP/0/RP0/CPU0:router# configure
RP/0/RP0/CPU0:router(config)# interface POS 0/3/0/0
RP/0/RP0/CPU0:router(config-if)# ipv4 address 172.18.189.38 255.255.255.224
RP/0/RP0/CPU0:router(config-if)# encapsulation hdlc
RP/0/RP0/CPU0:router(config-if)# pos crc 32
RP/0/RP0/CPU0:router(config-if)# keepalive 10
RP/0/RP0/CPU0:router(config-if)# no shutdown
RP/0/RP0/CPU0:router(config-if)# end
Uncommitted changes found, commit them? [yes]: yes
RP/0/RP0/CPU0:router# show interfaces POS 0/3/0/0
POS0/3/0/0 is down, line protocol is down
  Hardware is Packet over SONET
  Internet address is 172.18.189.38/27
  MTU 4474 bytes, BW 2488320 Kbit
     reliability 0/255, txload Unknown, rxload Unknown
  Encapsulation HDLC, crc 32, controller loopback not set, keepalive set
(10 sec)
  Last clearing of "show interface" counters never
  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 total input drops
     0 drops for unrecognized upper-level protocol
     Received 0 broadcast packets, 0 multicast packets
              0 runts, 0 giants, 0 throttles, 0 parity
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 packets output, 0 bytes, 0 total output drops
     Output 0 broadcast packets, 0 multicast packets
     0 output errors, 0 underruns, 0 applique, 0 resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
Configuring PPP: Example

The following example illustrates PPP encapsulation on a PoS interface:
RP/0/RP0/CPU0:router# configure
RP/0/RP0/CPU0:router(config)# interface POS 0/3/0/0
RP/0/RP0/CPU0:router(config-if)# encapsulation ppp
RP/0/RP0/CPU0:router(config-if)# ppp authentication chap MIS-access
RP/0/RP0/CPU0:router(config-if)# end
Uncommitted changes found, commit them? [yes]: yes
RP/0/RP0/CPU0:router# show interfaces POS 0/3/0/0
POS0/3/0/0 is down, line protocol is down
  Hardware is Packet over SONET
  Internet address is 172.18.189.38/27
  MTU 4474 bytes, BW 2488320 Kbit
     reliability 0/255, txload Unknown, rxload Unknown
  Encapsulation PPP, crc 32, controller loopback not set, keepalive set (
10 sec)
  LCP Closed
  Closed: IPCP
  Last clearing of "show interface" counters never
  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 total input drops
     0 drops for unrecognized upper-level protocol
     Received 0 broadcast packets, 0 multicast packets
              0 runts, 0 giants, 0 throttles, 0 parity
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 packets output, 0 bytes, 0 total output drops
     Output 0 broadcast packets, 0 multicast packets
     0 output errors, 0 underruns, 0 applique, 0 resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
The following example shows how to configure PoS interface 0/3/0/1 to allow two additional retries after an initial authentication failure (for a total of three failed authentication attempts):
RP/0/RP0/CPU0:router# configuration
RP/0/RP0/CPU0:router(config)# interface POS 0/3/0/1
RP/0/RP0/CPU0:router(config-if)# encapsulation ppp
RP/0/RP0/CPU0:router(config-if)# ppp authentication chap
RP/0/RP0/CPU0:router(config-if)# ppp max-bad-auth 3
Additional References

The following sections provide references related to PoS interface configuration.

Related Documents

Related Topic

Document Title

Cisco IOS XR master command reference

Cisco IOS XR Master Commands List, Release 3.2

Cisco IOS XR interface configuration commands

Cisco IOS XR Interface and Hardware Component Command Reference

Initial system bootup and configuration information for a router using the Cisco IOS XR software.

Cisco IOS XR Getting Started Guide

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Cisco IOS XR System Security Configuration Guide and
Cisco IOS XR System Security Command Reference

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Information about configuring interfaces and other components on the Cisco CRS-1 from a remote Craft Works Interface (CWI) client management application

Cisco CRS-1 Series Carrier Routing System Craft Works Interface Configuration Guide

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