Cisco ASR 9000 Series Aggregation Services Router Interface and Hardware Component Configuration Guide, Release 4.2.x
Configuring Serial Interfaces on the Cisco ASR 9000 Series Router
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Table of Contents

Configuring Serial Interfaces on the Cisco ASR 9000 Series Router

Contents

Prerequisites for Configuring Serial Interfaces

Information About Configuring Serial Interfaces

High-Level Overview: Serial Interface Configuration on Clear-Channel SPAs

High-Level Overview: Serial Interface Configuration on Channelized SPAs

Cisco HDLC Encapsulation

PPP Encapsulation

Multilink PPP

Keepalive Timer

Frame Relay Encapsulation

LMI on Frame Relay Interfaces

Layer 2 Tunnel Protocol Version 3-Based Layer 2 VPN on Frame Relay

Default Settings for Serial Interface Configurations

Serial Interface Naming Notation

IPHC Overview

QoS and IPHC

How to Configure Serial Interfaces

Bringing Up a Serial Interface

Prerequisites

Restrictions

What to Do Next

Configuring Optional Serial Interface Parameters

Prerequisites

Restrictions

What to Do Next

Creating a Point-to-Point Serial Subinterface with a PVC

Prerequisites

Restrictions

What to Do Next

Configuring Optional PVC Parameters

Prerequisites

Restrictions

What to Do Next

Modifying the Keepalive Interval on Serial Interfaces

Prerequisites

Restrictions

How to Configure a Layer 2 Attachment Circuit

Creating a Serial Layer 2 Subinterface with a PVC

Prerequisites

Restrictions

What to Do Next

Configuring Optional Serial Layer 2 PVC Parameters

Prerequisites

Restrictions

What to Do Next

Configuring IPHC

Prerequisites for Configuring IPHC

Configuring the IPHC Slot Level Command

Configuring an IPHC Profile

Configuring an IPHC Profile

Enabling an IPHC Profile on an Interface

Configuration Examples for Serial Interfaces

Bringing Up and Configuring a Serial Interface with Cisco HDLC Encapsulation: Example

Configuring a Serial Interface with Frame Relay Encapsulation: Example

Configuring a Serial Interface with PPP Encapsulation: Example

IPHC Configuration: Examples

IPHC Profile Configuration: Example

IPHC on a Serial Interface Configuration: Examples

IPHC on Multilink Configuration: Example

IPHC on a Serial Interface with MLPPP/LFI and QoS Configuration: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Configuring Serial Interfaces on the Cisco ASR 9000 Series Router

This module describes the configuration of serial interfaces on the Cisco ASR 9000 Series Router.

Before you configure a serial interface, you must configure the clear channel T3/E3 controller or channelized T1/E1controller (DS0 channel) that is associated with that interface.

Feature History for Configuring Serial Controller Interfaces

Release
Modification

Release 3.3.0

This feature was introduced on the Cisco XR 12000 Series Router.

Support was added on the Cisco XR 12000 Series Router for the following hardware:

  • Cisco XR 12000 SIP-401
  • Cisco XR 12000 SIP-501
  • Cisco XR 12000 SIP-601

Support was added on the Cisco XR 12000 Series Router for the following SPAs:

  • Cisco 2-Port and 4-Port Channelized T3/DS0 SPA
  • Cisco 2-Port and 4-Port T3/E3 Serial SPA

Release 3.4.0

Support for the following features was introduced:

  • Subinterfaces with permanent virtual circuits (PVCs)
  • Frame Relay encapsulation on serial main interfaces and PVCs on the following hardware:

Cisco 8-port Channelized T1/E1 SPA

Cisco 2-Port and 4-Port Channelized T3/DS0 SPA

Cisco 2-Port and 4-Port T3/E3 Serial SPA

Cisco 1-Port Channelized OC-3 SPA

Cisco 1-Port Channelized OC-12 SPA

Cisco 1-Port Channelized OC-48 SPA

Cisco 1-Port Channelized OC-12/STM-4 ISE Line Card

Release 3.4.1

This feature was introduced on the Cisco CRS-1 Router.

Support was added on the Cisco CRS-1 Router for the following hardware:

  • Cisco CRS-1 SIP-800
  • Cisco 2-Port and 4-Port Clear Channel T3/E3 SPA

Multilink PPP was supported on serial interfaces on the Cisco XR 12000 Series Router.

Release 3.5.0

Support was added on the Cisco XR 12000 Series Router for the following SPAs:

  • Cisco 1-Port Channelized OC-12/DS0 SPA
  • Cisco 1-Port Channelized OC-48/STM-16 SPA

Release 3.7.0

Support was added on the Cisco XR 12000 Series Router for the 1-Port Channelized OC-48/DS3 Line Card.

Release 3.8.0

Support was added on the Cisco XR 12000 Series Router for quality of service (QoS) on Layer 2 subinterfaces and the following line cards:

  • Cisco 1-Port Channelized OC-12/DS0 Line Card
  • Cisco 4-Port Channelized OC-12/DS3 Line Card

Release 3.9.0

Support for serial interfaces was added on the Cisco ASR 9000 Series Router for the 2-Port Channelized OC-12c/DS0 SPA.

Release 4.0.0

Support for the following features and SPAs was added on the Cisco ASR 9000 Series Router:

  • Support for IPv4 multicast was added for serial interfaces. For more information about multicast configuration on an interface, see the Cisco ASR 9000 Series Aggregation Services Router Multicast Configuration Guide .
  • IPHC was added on the Cisco 2-Port Channelized OC-12c/DS0 SPA.
  • Support for the Cisco 1-Port Channelized OC-48/STM-16 SPA was introduced.

Release 4.0.0

Support for fragmentation counters using the fragment-counter command was added for the following SPAs:

  • Cisco 1-Port Channelized OC-3/STM-1 SPA
  • Cisco 4-Port Channelized T3/DS0 SPA
  • Cisco 8-Port Channelized T1/E1 SPA

Release 4.0.1

Support for the following SPAs was added:

  • Cisco 1-Port Channelized OC-3/STM-1 SPA
  • Cisco 2-Port and 4-Port Clear Channel T3/E3 SPA

Release 4.1.0

Support for the following SPAs was added:

  • Cisco 4-Port Channelized T3/DS0 SPA
  • Cisco 8-Port Channelized T1/E1 SPA

Support for IPHC was added on the following SPAs:

  • Cisco 1-Port Channelized OC-3/STM-1 SPA
  • Cisco 4-Port Channelized T3/DS0 SPA
  • Cisco 8-Port Channelized T1/E1 SPA
  • Cisco 2-Port and 4-Port Clear Channel T3/E3 SPA

Prerequisites for Configuring Serial Interfaces

Before configuring serial interfaces, ensure that the following tasks and conditions are met:

  • You must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
  • You have installed a 2-Port or 4-Port Clear Channel T3/E3 SPA.
  • You should have the following SIP and any one of the following SPAs installed on the Cisco ASR 9000 Series Router:

Cisco SIP 700 SPA Interface Processor

Cisco 1-Port Channelized OC-3/STM-1 SPA

Cisco 2-Port Channelized OC-12c/DS0 SPA

Cisco 1-Port Channelized OC-48/STM-16 SPA

Cisco 2-Port or 4-Port Clear Channel T3/E3 SPA

Cisco 4-Port Channelized T3/DS0 SPA

Cisco 8-Port Channelized T1/E1 SPA

  • Your hardware must support T3/E3 or T1/E1 controllers and serial interfaces.

The following hardware supports T3/E3 controllers and serial interfaces:

Cisco 2-Port and 4-Port Clear Channel T3/E3 SPAs

Cisco 2-Port and 4-Port Channelized T3 SPAs

Cisco 4-Port Channelized OC-12/DS3 line cards

Cisco 1-Port Channelized OC-48/STM-16 SPA and line cards

The following hardware supports T1/E1 controllers and DS0 channels:

Cisco 2-Port and 4-Port Channelized T3 SPAs

Cisco 4-Port Channelized OC-12/DS3 line cards

Cisco 1-Port Channelized OC-12/DS0 SPAs and line cards

Cisco 1-Port Channelized OC-48/DS3 SPAs and line cards

Cisco 1-Port Channelized OC3/STM-1 SPA

Cisco 8-Port Channelized T1/E1 SPA

The following hardware supports serial interfaces:

Cisco 2-Port and 4-Port Clear Channel T3/E3 SPAs

Cisco 2-Port and 4-Port Channelized T3 SPAs

Cisco 4-Port Channelized OC-12/DS3 line cards

Cisco 1-Port Channelized OC-12/DS0 SPAs and line cards

Cisco 1-Port Channelized OC-48/DS3 SPAs and line cards

Cisco 1-Port Channelized OC3/STM-1 SPA

Cisco 8-Port Channelized T1/E1 SPA


NoteThe Cisco 2-Port and 4-Port Channelized T3 SPAs can run in clear channel mode, or they can be channelized into 28 T1 or 21 E1 controllers.



NoteThe Cisco 4-Port Channelized T3/DS0 SPA can run in clear channel mode, or it can be channelized into 28 T1 or 21 E1 controllers.


  • You should have configured the clear channel T3/E3 controller or channelized T3 to T1/E1 controller that is associated with the serial interface you want to configure, as described in the “Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router” module in this manual.

NoteOn channelized T3 to T1/E1 controllers, serial interfaces are automatically created when users configure individual DS0 channel groups on the T1/E1 controllers.


Information About Configuring Serial Interfaces

To configure serial interfaces, study the following concepts:

On the Cisco ASR 9000 Series Router, a single serial interface carries data over a single interface using PPP, Cisco HDLC, or Frame Relay encapsulation.

High-Level Overview: Serial Interface Configuration on Clear-Channel SPAs

Table 14 provides a high-level overview of the tasks required to configure a T3 serial interface on the Cisco 2-Port and 4-Port Clear Channel T3/E3 SPA.

 

Table 14 Overview: Configuring a T3 Serial Interface on a Clear Channel SPA

Step
Task
Module
Section

1.

Use the hw-module subslot command to set serial mode for the SPA to be T3, if necessary.

Note By default, the 2-Port and 4-Port Clear Channel T3/E3 SPA is set to run in T3 mode.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Setting the Card Type

2.

Configure the T3 controller.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Setting the Card Type

3.

Configure the serial interface that is associated with the T3 controller you configured in Step 2.

“Configuring Serial Interfaces on the Cisco ASR 9000 Series Router”

“How to Configure Serial Interfaces”

Table 15 provides a high-level overview of the tasks required to configure an E3 serial interface on a 2-Port and 4-Port Clear Channel T3/E3 SPA.

 

Table 15 Overview: Configuring an E3 Serial Interface on a Clear Channel SPA

Step
Task
Module
Section

1.

Use the hw-module subslot command to set serial mode for the SPA to be E3.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Setting the Card Type

2.

Configure the E3 controller.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Setting the Card Type

3.

Configure the serial interface that is associated with the E3 controller you configured in Step 2.

Configuring Serial Interfaces on the Cisco ASR 9000 Series Router

How to Configure Serial Interfaces

High-Level Overview: Serial Interface Configuration on Channelized SPAs

Table 16 Table 17 provides a high-level overview of the tasks required to configure a T1 serial interface on the following SPAs and line cards.

  • Cisco 2-Port and 4-Port Channelized T3 SPA
  • Cisco 4-Port Channelized OC-12/DS3 line cards
  • Cisco 1-Port Channelized OC-12/DS0 SPAs and line cards
  • Cisco 1-Port Channelized OC-48/STM-16 SPA and line cards
  • Cisco 2-Port Channelized OC-12c/DS0 SPA

 

Table 16 Overview: Configuring a Serial Interface on a T1 DS0 Channel

Step
Task
Module
Section

1.

Configure the T3 controller parameters and set the SPA mode to be T3.

28 T1 controllers are automatically created.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Setting the Card Type

Configuring a Channelized T3 Controller

2.

Create and configure DS0 channel groups on the T1 controllers.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Configuring a T1 Controller

3.

Configure the Serial interfaces that are associated channel groups you created in Step 2.

“Configuring Serial Interfaces on the Cisco ASR 9000 Series Router”

How to Configure Serial Interfaces

 

Table 17 Overview: Configuring a Serial Interface on a T1 DS0 Channel

Step
Task
Module
Section

1.

Configure the SONET controller parameters and STS stream for T3 mode.

“Configuring Channelized SONET/SDH on the Cisco ASR 9000 Series Router”

Configuring SONET T3 and VT1.5-Mapped T1 Channels

2.

Configure the T3 controller parameters and set the mode to T1.

28 T1 controllers are automatically created.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Configuring a Channelized T3 Controller

3.

Create and configure DS0 channel groups on the T1 controllers.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Configuring a T1 Controller

4.

Configure the Serial interfaces that are associated channel groups you created in Step 2.

“Configuring Serial Interfaces on the Cisco ASR 9000 Series Router”

How to Configure Serial Interfaces

Table 18 provides a high-level overview of the tasks required to configure an E1 serial interface on the following SPAs and line cards.

  • 2-Port and 4-Port Channelized T3 SPA
  • 4-Port Channelized OC-12/DS3 line cards
  • 1-Port Channelized OC-12/DS0 SPAs and line cards
  • 1-Port Channelized OC-48/DS3 SPAs and line cards
  • 1-Port Channelized OC-3/STM-1 SPA
  • 2-Port Channelized OC-12c/DS0 SPA

 

Table 18 Overview: Configuring a Serial Interface on an E1 DS0 Channel

Step
Task
Module
Section

1.

Configure the T3 controller parameters and set the SPA mode to be E3.

21 E1 controllers are automatically created.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Configuring a Channelized T3 Controller

2.

Create and configure DS0 channel groups on the E1 controllers.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Configuring an E1 Controller

3.

Configure the Serial interfaces that are associated channel groups you created in Step 2.

Configuring Serial Interfaces on the Cisco ASR 9000 Series Router

How to Configure Serial Interfaces

 

Table 19 Overview: Configuring a Serial Interface on a E1 DS0 Channel

Step
Task
Module
Section

1.

Configure the SONET controller parameters and STS stream for T3 mode.

“Configuring Channelized SONET/SDH on the Cisco ASR 9000 Series Router”

Configuring SONET T3 and VT1.5-Mapped T1 Channels

2.

Configure the T3 controller parameters and set the mode to E1.

21 E1 controllers are automatically created.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Configuring a Channelized T3 Controller

3.

Create and configure DS0 channel groups on the E1 controllers.

“Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router”

Configuring an E1 Controller

4.

Configure the Serial interfaces that are associated channel groups you created in Step 2.

“Configuring Serial Interfaces on the Cisco ASR 9000 Series Router”

How to Configure Serial Interfaces

Table 20 provides a high-level overview of the tasks required to configure a T3 serial interface on the 1-Port Channelized OC-48/STM-16 SPA

 

Table 20 Overview: Configuring a Serial Interface on a T3 Channel

Step
Task
Module
Section

1.

Configure the SONET controller parameters and STS stream.

“Configuring Channelized SONET/SDH on the Cisco ASR 9000 Series Router”

Configuring a Clear Channel SONET Controller for T3

2.

Configure the STS stream mode for T3 and configure the T3 controller parameters.

“Configuring Channelized SONET/SDH on the Cisco ASR 9000 Series Router”

Configuring a Clear Channel SONET Controller for T3

3.

Configure the Serial interfaces.

“Configuring Serial Interfaces on the Cisco ASR 9000 Series Router”

How to Configure Serial Interfaces

Cisco HDLC Encapsulation

Cisco High-Level Data Link Controller (HDLC) is the Cisco 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 type for serial interfaces under Cisco IOS XR software. Cisco 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.


NoteCisco HDLC is the default encapsulation type for the serial interfaces.


Cisco HDLC uses keepalives to monitor the link state, as described in the “Keepalive Timer” section.


NoteUse thedebug chdlc slarp packet command to display information about the Serial Line Address Resolution Protocol (SLARP) packets that are sent to the peer after the keepalive timer has been configured.


PPP Encapsulation

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.


NoteWhen an interface is configured with PPP encapsulation, a link is declared down, and full LCP negotiation is re-initiated after five ECHOREQ packets are sent without receiving an ECHOREP response.


PPP provides the following 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

PPP uses keepalives to monitor the link state, as described in the “Keepalive Timer” section.

PPP supports the following authentication protocols, which require a remote device to prove its identity before allowing data traffic to flow over a connection:

  • Challenge Handshake Authentication Protocol (CHAP)—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 name of the remote device 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.
  • Microsoft Challenge Handshake Authentication Protocol (MS-CHAP)—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.
  • Password Authentication Protocol (PAP)—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.

NoteFor more information on enabling and configuring PPP authentication protocols, see the“Configuring PPP on the Cisco ASR 9000 Series Router” module in this manual.


Use the ppp authentication command in interface configuration mode to enable CHAP, MS-CHAP, and PAP on a serial interface.


NoteEnabling or disabling PPP authentication does not effect the local router’s willingness to authenticate itself to the remote device.


Multilink PPP

Multilink Point-to-Point Protocol (MLPPP) is supported on the following SPAs:

  • 1-Port Channelized OC-12/DS0 SPAs and line cards
  • 2-Port and 4-Port Channelized T3 SPAs
  • 8-Port Channelized T1/E1 SPA
  • 1-Port Channelized OC-3/STM-1 SPA
  • 2-Port Channelized OC-12/DS0 SPA

MLPPP provides a method for combining multiple physical links into one logical link. The implementation of MLPPP combines multiple PPP serial interfaces into one multilink interface. MLPPP performs the fragmenting, reassembling, and sequencing of datagrams across multiple PPP links.

MLPPP provides the same features that are supported on PPP Serial interfaces with the exception of QoS. It also provides the following additional features:

  • Fragment sizes of 128, 256, and 512 bytes
  • Long sequence numbers (24-bit)
  • Lost fragment detection timeout period of 80 ms
  • Minimum-active-links configuration option
  • LCP echo request/reply support over multilink interface
  • Full T1 and E1 framed and unframed links

For more information about configuring MLPPP on a serial interface, see the “Configuring PPP on the Cisco ASR 9000 Series Router” module in this document.

Keepalive Timer

Cisco 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 the keepalive timer. 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 keepalives are disabled, the link makes the transition to the up state.


NoteThekeepalive command applies to serial interfaces using HDLC or PPP encapsulation. It does not apply to serial interfaces using Frame Relay encapsulation.


For each encapsulation type, a certain number of keepalives ignored by a peer triggers the serial interface to transition to the down state. For HDLC encapsulation, three ignored keepalives causes the interface to be brought down. For PPP encapsulation, five ignored keepalives causes the interface to be brought down. ECHOREQ packets are sent out only when LCP negotiation is complete (for example, when LCP is open).

Use the keepalive command in interface configuration mode to set the frequency at which LCP sends 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 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 .


NoteDuring Minimal Disruptive Restart (MDR) keepalives may fail. Therefore the keepalive timers, on both ends, should be either disabled or set to an interval longer than the MDR time.



NoteBefore performing a Minimal Disruptive Restart (MDR) upgrade, we recommend disabling keepalives on a Cisco XR 12000 Series Router.



NoteBefore performing a Minimal Disruptive Restart (MDR) upgrade, we recommend configuring a keepalive interval of 10 seconds or more on a Cisco CRS-1 Router.


When LCP is running on the peer and receives an ECHOREQ packet, it responds 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.


NoteUse thedebug chdlc slarp packet command and other Cisco HDLC debug commands to display information about the Serial Line Address Resolution Protocol (SLARP) packets that are sent to the peer after the keepalive timer has been configured.


Frame Relay Encapsulation

When Frame Relay encapsulation is enabled on a serial interface, the interface configuration is hierarchical and comprises the following elements:

1. The serial main interface comprises the physical interface and port. If you are not using the serial interface to support Cisco HDLC and PPP encapsulated connections, then you must configure subinterfaces with permanent virtual circuits (PVCs) under the serial main interface. Frame Relay connections are supported on PVCs only.

2. Serial subinterfaces are configured under the serial main interface. A serial subinterface does not actively carry traffic until you configure a PVC under the serial subinterface. Layer 3 configuration typically takes place on the subinterface.

3. Point-to-point PVCs are configured under a serial subinterface. You cannot configure a PVC directly under a main interface. A single point-to-point PVC is allowed per subinterface. PVCs use a predefined circuit path and fail if the path is interrupted. PVCs remain active until the circuit is removed from either configuration. Connections on the serial PVC support Frame Relay encapsulation only.


NoteThe administrative state of a parent interface drives the state of the subinterface and its PVC. When the administrative state of a parent interface or subinterface changes, so does the administrative state of any child PVC configured under that parent interface or subinterface.


To configure Frame Relay encapsulation on serial interfaces, use the encapsulation frame-relay command.

Frame Relay interfaces support two types of encapsulated frames:

  • Cisco (default)
  • IETF

Use the encap command in PVC configuration mode to configure Cisco or IETF encapsulation on a PVC. If the encapsulation type is not configured explicitly for a PVC, then that PVC inherits the encapsulation type from the main serial interface.


NoteCisco encapsulation is required on serial main interfaces that are configured for MPLS. IETF encapsulation is not supported for MPLS.


Before you configure Frame Relay encapsulation on an interface, you must verify that all prior Layer 3 configuration is removed from that interface. For example, you must ensure that there is no IP address configured directly under the main interface; otherwise, any Frame Relay configuration done under the main interface will not be viable.

LMI on Frame Relay Interfaces

The Local Management Interface (LMI) protocol monitors the addition, deletion, and status of PVCs. LMI also verifies the integrity of the link that forms a Frame Relay UNI interface. By default, cisco LMI is enabled on all PVCs. However, you can modify the default LMI type to be ANSI or Q.933, as described in the “Modifying the Default Frame Relay Configuration on an Interface” section of the “Configuring Frame Relay on the Cisco ASR 9000 Series Router” module in this manual.

If the LMI type is cisco (the default LMI type), the maximum number of PVCs that can be supported under a single interface is related to the MTU size of the main interface. Use the following formula to calculate the maximum number of PVCs supported on a card or SPA:

(MTU - 13)/8 = maximum number of PVCs


NoteThe default setting of themtu command for a serial interface is 1504 bytes. Therefore, the default numbers of PVCs supported on a serial interface configured with cisco LMI is 186.


Layer 2 Tunnel Protocol Version 3-Based Layer 2 VPN on Frame Relay

The Layer 2 Tunnel Protocol Version 3 (L2TPv3) feature defines the L2TP protocol for tunneling Layer 2 payloads over an IP core network using Layer 2 virtual private networks (VPNs).

L2TPv3 is a tunneling protocol used for transporting Layer 2 protocols. It can operate in a number of different configurations and tunnel a number of different Layer 2 protocols and connections over a packet-switched network.

Before you can configure L2TPv3, you need to configure a connection between the two attachment circuits (ACs) that will host the L2TPv3 psuedowire. Cisco IOS XR software supports a point-to-point, end-to-end service, where two ACs are connected together.

This module describes how to configure a Layer 2 AC on a Frame Relay encapsulated serial interface.


NoteSerial interfaces support DLCI mode layer 2 ACs only; layer 2 port mode ACs are not supported on serial interfaces.


For detailed information about configuring L2TPv3 in your network, see the “ Implementing Layer 2 Tunnel Protocol Version 3” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router. For detailed information about configuring L2VPNs, see the “ Implementing MPLS Layer 2 VPNs” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router.

For detailed information about configuring L2TPv3 in your network, see the “ Implementing Layer 2 Tunnel Protocol Version 3 on Cisco IOS XR Software” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco XR 12000 Series Router. For detailed information about configuring L2VPNs, see the “ Implementing MPLS Layer 2 VPNs on Cisco IOS XR Software” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco XR 12000 Series Router.

Default Settings for Serial Interface Configurations

When an interface is enabled on a T3/E3 SPA, and no additional configuration commands are applied, the default interface settings shown in Table 21 are present. These default settings can be changed by configuration.

 

Table 21 Serial Interface Default Settings

Parameter
Configuration File Entry
Default Settings

Keepalive

Note The keepalive command applies to serial interfaces using HDLC or PPP encapsulation. It does not apply to serial interfaces using Frame Relay encapsulation.

keepalive [ disable ]
no keepalive

keepalive 10 seconds

Encapsulation

encapsulation [ hdlc | ppp | frame-relay [ ietf ]]

hdlc

Maximum transmission unit (MTU)

mtu bytes

1504 bytes

Cyclic redundancy check (CRC)

crc [ 16 | 32]

16

Data stream inversion on a serial interface

invert

Data stream is not inverted

Payload scrambling (encryption)

scramble

Scrambling is disabled.

Number of High-Level Data Link Control (HDLC) flag sequences to be inserted between the packets

transmit-delay

Default is 0 (disabled).


NoteDefault settings do not appear in the output of the show running-config command.


Serial Interface Naming Notation

The naming notation for serial interfaces on a clear channel SPA is rack / slot / module / port , as shown in the following example:

interface serial 0/0/1/2
 

The naming notation for T1, E1, and DS0 interfaces on a channelized SPA is rack / slot / module / port / channel-num:channel-group-number , as shown in the following example:

interface serial 0/0/1/2/4:3
 

If a subinterface and PVC are configured under the serial interface, then the router includes the subinterface number at the end of the serial interface address. In this case, the naming notation is rack / slot / module / port [/ channel-num:channel-group-number ]. subinterface, as shown in the following examples:

interface serial 0/0/1/2.1
interface serial 0/0/1/2/4:3.1

NoteA slash between values is required as part of the notation.


The naming notation syntax for serial interfaces is as follows:

  • rack : Chassis number of the rack.
  • slot : Physical slot number of the modular services card or line card.
  • module : Module number. Shared port adapters (SPAs) are referenced by their subslot number.
  • port : Physical port number of the controller.
  • channel-num : T1 or E1 channel number. T1 channels range from 0 to 23; E1 channels range from 0 to 31.
  • channel-group-number : Time slot number. T1 time slots range from 1 to 24; E1 time slots range from 1 to 31. The channel-group-number is preceded by a colon and not a slash.
  • subinterface : Subinterface number.

Use the question mark ( ? ) online help function following the serial keyword to view a list of all valid interface choices.

IPHC Overview

IP header compression (IPHC) is based on the premise that most of the headers in the packets of a particular transmission remain constant throughout the flow. Only a few fields in the headers of related packets change during a flow.

IPHC compresses these headers so that the compressed header contains only the fields that change from packet to packet. All fields that remain the same from packet to packet are eliminated in the compressed headers. Full headers are sent between compressed headers.

Full headers are uncompressed headers that contain all the original header fields along with additional information (context ID) to identify the flow. The interval at which full headers are sent between compressed packets is configurable using the refresh max-period and refresh max-time commands.

IPHC contexts are used by the compressor (sender) and decompressor (receiver) of compressed packets to encode and decode the packets in a flow. A context is stored on the compressor and decompressor and is used in the delta calculation at both ends. The number of contexts allowed on a particular interface is configurable. The maximum size of the header that can be compressed is also configurable.

IPHC supports the compression and decompression of RTP and UDP traffic and the decompression of CN on TCP and CTCP traffic.

Users may choose one of the following types of compression formats:

  • Internet Engineering Task Force (IETF) standard format.
    Uses RFC2507 and RFC2508 compression schemes.
  • IPHC format.
    Provides options similar to IETF.

Table 22 shows the IPHC features, the values of the features, and their defaults:

 

Table 22 IPHC features and default setttings

IPHC Feature

Values

Defaults

TCP contexts

0 to 255

1

Non-TCP contexts

1 to 6000

16

Compression Format Options

IETF or IPHC

Feedback Messages

Enable or Disable

Enabled

Maximum Refresh Period Size

1 to 65535 packets

256

Maximum Refresh Time Period

0 to 255 seconds

5

Maximum Header Size

20 to 40 bytes

40

Real Time Protocol (RTP)

Enable or Disable

Enabled

Refresh RTP

Enable or Disable

Disable

Currently, only IPv4 unicast packets with UDP in the protocol field of the IP header are compressed.

IPHC is configured on an interface as follows:

  • Configure the IPHC slot level command
  • Create an IPHC profile
  • Configure IPHC attributes in the profile
  • Attach the profile to an interface

IPHC profiles must contain the rtp command to enable Real Time Protocol (RTP) on the interface, or the profile is not enabled. The refresh rtp command must be used to enable the configured refresh settings for RTP packets. By default, refresh RTP is disabled and only the first packet in the flow is sent as a ‘full-header’ packet.

If some attributes, such as feedback messages, maximum refresh period size, maximum refresh time period, and maximum header size, are not configured in the profile, the default values for those attributes apply when the profile is enabled on the interface.

Currently, IPHC is supported only on serial interfaces with PPP encapsulation and on multilink with PPP encapsulation interfaces.

IPHC is typically configured between the Customer Edge (CE) and Provide Edge (PE) ends of an interface and must be configured at both ends of the interface to work. The PPP protocol negotiates the IPHC specific parameters between the two ends of the interface and settles on the lowest value configured between the two ends.

QoS and IPHC

An IPHC profile can be enabled on an interface so that the IPHC profile applies only to packets that match a Quality of Service (QoS) service policy. In this case, the QoS service-policy class attributes determine which packets are compressed. This allows users to fine tune IPHC with greater granularity.

Policy maps are attached to an interface using the service-policy command. IPHC action applies only to output service policies. IPHC is not supported on input service policies.

The user can configure IPHC using QoS as follows:

  • Create a QoS policy-map with the compress header ip action.
  • Attach the IPHC profile to the interface using the ipv4 iphc profile profile_name mode service-policy command.
  • Attach the QoS policy-map with compress header ip action using the service-policy output command.

See “IPHC on a Serial Interface with MLPPP/LFI and QoS Configuration: Example” section for an example of how to configure IPHC using QoS.

For complete information on configuring QoS, refer to the Cisco XR 12000 Series Router Modular Quality of Service Configuration Guide and the Cisco XR 12000 Series Router Modular Quality of Service Command ReferenceCisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Configuration Guide and the Cisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Command Reference .

How to Configure Serial Interfaces

After you have configured a channelized or clear channel T3/E3 controller, as described in the “Configuring Clear Channel T3/E3 and Channelized T3 and T1/E1 Controllers on the Cisco ASR 9000 Series Router” module in this document, you can configure the serial interfaces associated with that controller.

The following tasks describe how to configure a serial interface:

Creating a Serial Layer 2 Subinterface with a PVC

Configuring Optional Serial Layer 2 PVC Parameters

Configuring the IPHC Slot Level Command

Configuring an IPHC Profile

Configuring an IPHC Profile

Enabling an IPHC Profile on an Interface

Bringing Up a Serial Interface

This task describes the commands used to bring up a serial interface.

Prerequisites

The Cisco XR 12000 Series Router must have at least one of the SIPs and one of the SPAs or line cards installed and be running Cisco IOS XR software:

  • Cisco XR 12000 SIP-401
  • Cisco XR 12000 SIP-501
  • Cisco XR 12000 SIP-601
  • 2-Port and 4-Port T3/E3 Serial SPA
  • 2-Port and 4-Port Channelized T3/DS0 Serial SPA
  • 4-Port Channelized OC-12/DS3 line cards
  • 1-Port Channelized OC-12/DS0 SPAs and line cards
  • 1-Port Channelized OC-48/DS3 SPAs and line cards
  • 1-Port Channelized OC3/STM-1 SPA
  • 8-Port Channelized T1/E1 SPA

The Cisco CRS-1 Router must have the following SIP and SPA installed and running Cisco IOS XR software:

  • Cisco CRS-1 SIP-800
  • 2-Port and 4-Port T3/E3 Serial SPA

The Cisco ASR 9000 Series Router must have the following SIP and at least one of the following SPAs installed and running Cisco IOS XR software:

  • SIP 700 SPA Interface Processor
  • 1-Port Channelized OC-3/STM-1 SPA
  • 2-Port Channelized OC-12c/DS0 SPA
  • 1-Port Channelized OC-48/STM-16 SPA
  • 4-Port Channelized T3/DS0 SPA
  • 2-Port and 4-Port Clear Channel T3/E3 SPA
  • 8-Port Channelized T1/E1 SPA

Restrictions

The configuration on both ends of the serial connection must match for the interface to be active.

SUMMARY STEPS

1. show interfaces

2. configure

3. interface serial interface-path-id

4. ipv4 address ip-address

5. no shutdown

6. end
or
commit

7. exit

8. exit

9. Repeat Step 1 through Step 8 to bring up the interface at the other end of the connection.

10. show ipv4 interface brief

11. show interfaces serial interface-path-id

DETAILED STEPS

 

Command or Action
Purpose

Step 1

show interfaces

 

RP/0/0RP0RSP0/CPU0:router# show interfaces

(Optional) Displays configured interfaces.

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

Step 2

configure

 

RP/0/0RP0RSP0/CPU0:router# configure

Enters global configuration mode.

Step 3

interface serial interface-path-id

 

RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/1/0/0

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

Step 4

ipv4 address ip-address

 

RP/0/0RP0RSP0/CPU0:router(config-if)# ipv4 address 10.1.2.1 255.255.255.224

Assigns an IP address and subnet mask to the interface.

Note Skip this step if you are configuring Frame Relay encapsulation on this interface. For Frame Relay, the IP address and subnet mask are configured under the subinterface.

Step 5

no shutdown

 

RP/0/0RP0RSP0/CPU0:router (config-if)# no shutdown

Removes the shutdown configuration.

Note Removal of the shutdown configuration eliminates 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 6

end

or

commit

 

RP/0/0RP0RSP0/CPU0:router (config-if)# end

or

RP/0/0RP0RSP0/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 7

exit

 

RP/0/0RP0RSP0/CPU0:router (config-if)# exit

Exits interface configuration mode and enters global configuration mode.

Step 8

exit

 

RP/0/0RP0RSP0/CPU0:router (config)# exit

Exits global configuration mode and enters EXEC mode.

Step 9

show interfaces

configure

interface serial interface-path-id

no shut

exit

exit

 
RP/0/0RP0RSP0/CPU0:router# show interfaces

RP/0/0RP0RSP0/CPU0:router# configure

RP/0/0RP0RSP0/CPU0:router (config)# interface serial 0/1/0/1

RP/0/0RP0RSP0/CPU0:router(config-if)# ipv4 address 10.1.2.2 255.255.255.224

RP/0/0RP0RSP0/CPU0:router (config-if)# no shutdown

RP/0/0RP0RSP0/CPU0:router (config-if)# commit

RP/0/0RP0RSP0/CPU0:router (config-if)# exit

RP/0/0RP0RSP0/CPU0:router (config)# exit

Repeat Step 1 through Step 8 to bring up the interface at the other end of the connection.

Note The configuration on both ends of the serial connection must match.

Step 10

show ipv4 interface brief

 

RP/0/0RP0RSP0/CPU0:router # show ipv4 interface brief

Verifies that the interface is active and properly configured.

If you have brought up a serial interface properly, the “Status” field for that interface in the show ipv4 interface brief command output displays “Up.”

Step 11

show interfaces serial interface-path-id

 

RP/0/0RP0RSP0/CPU0:router# show interfaces serial 0/1/0/0

(Optional) Displays the interface configuration.

What to Do Next

To modify the default configuration of the serial interface you just brought up, see the “Configuring Optional Serial Interface Parameters” section.

Configuring Optional Serial Interface Parameters

This task describes the commands used to modify the default configuration on a serial interface.

Prerequisites

Before you modify the default serial interface configuration, you must bring up the serial interface and remove the shutdown configuration, as described in the “Bringing Up a Serial Interface” section.

Restrictions

The configuration on both ends of the serial connection must match for the interface to be active.

SUMMARY STEPS

1. configure

2. interface serial interface-path-id

3. encapsulation [ hdlc | ppp | frame-relay [ IETF ]

4. serial

5. crc length

6. invert

7. scramble

8. transmit-delay hdlc-flags

9. end
or
commit

10. exit

11. exit

12. exit

13. show interfaces serial [ interface-path-id ]

 

Command or Action
Purpose

Step 1

configure

 

RP/0/0RP0RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

interface serial interface-path-id

 

RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/1/0/0

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

Step 3

encapsulation [ hdlc | ppp | frame-relay [ IETF ]

 

RP/0/0RP0RSP0/CPU0:router(config-if)# encapsulation hdlc

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

Note The default encapsulation is hdlc.

Step 4

serial

 

RP/0/0RP0RSP0/CPU0:router(config-if)# serial

(Optional) Enters serial submode to configure the serial parameters.

Step 5

crc length

 

RP/0/0RP0RSP0/CPU0:ios(config-if-serial)# crc 32

(Optional) Specifies the length of the cyclic redundancy check (CRC) for the interface. Enter the 16 keyword to specify 16-bit CRC mode, or enter the 32 keyword to specify 32-bit CRC mode.

Note The default is CRC length is 16.

Step 6

invert

 

RP/0/0RP0RSP0/CPU0:ios(config-if-serial)# inverts

(Optional) Inverts the data stream.

Step 7

scramble

 

RP/0/0RP0RSP0/CPU0:ios(config-if-serial)# scramble

(Optional) Enables payload scrambling on the interface.

Note Payload scrambling is disabled on the interface.

Step 8

transmit-delay hdlc-flags

 

RP/0/0RP0RSP0/CPU0:ios(config-if-serial)# transmit-delay 10

(Optional) Specifies a transmit delay on the interface. Values can be from 0 to 128.

Note Transmit delay is disabled by default (the transmit delay is set to 0).

Step 9

end

or

commit

 

RP/0/0RP0RSP0/CPU0:router (config-if)# end

or

RP/0/0RP0RSP0/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 10

exit

 

RP/0/0RP0RSP0/CPU0:router(config-if-serial)# exit

Exits serial configuration mode.

Step 11

exit

 

RP/0/0RP0RSP0/CPU0:router (config-if)# exit

Exits interface configuration mode and enters global configuration mode.

Step 12

exit

 

RP/0/0RP0RSP0/CPU0:router (config)# exit

Exits global configuration mode and enters EXEC mode.

Step 13

show interfaces serial [ interface-path-id ]

 

RP/0/0RP0RSP0/CPU0:router# show interface serial 0/1/0/0

(Optional) Displays general information for the specified serial interface.

What to Do Next

Creating a Point-to-Point Serial Subinterface with a PVC

The procedure in this section creates a point-to-point serial subinterface and configures a permanent virtual circuit (PVC) on that serial subinterface.


NoteSubinterface and PVC creation is supported on interfaces with Frame Relay encapsulation only.


Prerequisites

Before you can create a subinterface on a serial interface, you must bring up the main serial interface with Frame Relay encapsulation, as described in the “Bringing Up a Serial Interface” section.

Restrictions

Only one PVC can be configured for each point-to-point serial subinterface.

SUMMARY STEPS

1. configure

2. interface serial interface-path-id . subinterface point-to-point

3. ipv4 address ipv4_address / prefix

4. pvc dlci

5. end
or
commit

6. Repeat Step 1 through Step 5 to bring up the serial subinterface and any associated PVC at the other end of the connection.

DETAILED STEPS

 

Command or Action
Purpose

Step 1

configure

 

RP/0/0RP0RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

interface serial interface-path-id . subinterface point-to-point

 

RP/0/0RP0RSP0/CPU0:router (config)# interface serial 0/1/0/0.1

Enters serial subinterface configuration mode.

Step 3

ipv4 address ipv4_address/prefix

 
RP/0/0RP0RSP0/CPU0:router (config-subif)#ipv4 address 10.46.8.6/24

Assigns an IP address and subnet mask to the subinterface.

Step 4

pvc dlci

 

RP/0/0RP0RSP0/CPU0:router (config-subif)# pvc 20

Creates a serial permanent virtual circuit (PVC) and enters Frame Relay PVC configuration submode.

Replace dlci with a PVC identifier, in the range from 16 to 1007.

Note Only one PVC is allowed per subinterface.

Step 5

end

or

commit

 

RP/0/0RP0RSP0/CPU0:router (config-subif)# end

or

RP/0/0RP0RSP0/CPU0:router(config-subif)# 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

configure

interface serial interface-path-id

pvc dlci

commit

 

RP/0/0RP0RSP0/CPU0:router# configure

RP/0/0RP0RSP0/CPU0:router (config)# interface serial 0/1/0/1.1

RP/0/0RP0RSP0/CPU0:router (config-subif)#ipv4 address 10.46.8.5/24

RP/0/0RP0RSP0/CPU0:router (config-subif)# pvc 20

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# commit

Repeat Step 1 through Step 5 to bring up the serial subinterface and any associated PVC at the other end of the connection.

Note The DLCI (or PVC identifier) must match on both ends of the subinterface connection.

Note When assigning an IP address and subnet mask to the subinterface at the other end of the connection, keep in mind that the addresses at both ends of the connection must be in the same subnet.

What to Do Next

Configuring Optional PVC Parameters

This task describes the commands you can use to modify the default configuration on a serial PVC.

For additional information about Frame Relay options, see the “Configuring Frame Relay on Cisco IOS XR Software” module in the Cisco IOS XR Interface and Hardware Component Configuration Guide for the Cisco XR 12000 Series Router.

For additional information about Frame Relay options, see the “Configuring Frame Relay on the Cisco ASR 9000 Series Router” module in the Cisco IOS XR Interface and Hardware Component Configuration Guide for the Cisco ASR 9000 Series Router.

Prerequisites

Before you can modify the default PVC configuration, you must create the PVC on a serial subinterface, as described in the “Creating a Point-to-Point Serial Subinterface with a PVC” section.

Restrictions

  • The DLCI (or PVI identifier) must match on both ends of the PVC for the connection to be active.
  • To change the PVC DLCI, you must delete the PVC and then add it back with the new DLCI.

SUMMARY STEPS

1. configure

2. interface serial interface-path-id . subinterface

3. pvc dlci

4. encap [ cisco | ietf ]

5. service-policy { input | output } policy-map

6. end
or
commit

7. Repeat Step 1 through Step 6 to configure the PVC at the other end of the connection.

8. show frame-relay pvc dlci-number

9. show policy-map interface serial interface-path-id.subinterface { input | output }
or
show policy-map type qos interface serial interface-path-id.subinterface { input | output }

 

Command or Action
Purpose

Step 1

configure

 

RP/0/0RP0RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

interface serial interface-path-id . subinterface

 

RP/0/0RP0RSP0/CPU0:router (config)# interface serial 0/1/0/0.1

Enters serial subinterface configuration mode.

Step 3

pvc dlci

 

RP/0/0RP0RSP0/CPU0:router (config-subif)# pvc 20

Enters subinterface configuration mode for the PVC.

Step 4

encap [ cisco | ietf ]

 

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# encap ietf

(Optional) Configures the encapsulation for a Frame Relay PVC.

Note If the encapsulation type is not configured explicitly for a PVC, then that PVC inherits the encapsulation type from the main serial interface.

Step 5

service-policy { input | output } policy-map

 

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# service-policy output policy1

Attaches a policy map to an input subinterface or output subinterface. Once attached, the policy map is used as the service policy for the subinterface.

Step 6

end

or

commit

 

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# end

or

RP/0/0RP0RSP0/CPU0:router(config-fr-vc)# 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 7

configure

interface serial interface-path-id . subinterface

pvc dlci

encap [ cisco | ietf ]

commit

 

RP/0/0RP0RSP0/CPU0:router# configure

RP/0/0RP0RSP0/CPU0:router (config)# interface serial 0/1/0/1.1

RP/0/0RP0RSP0/CPU0:router (config-subif)# pvc 20

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# encap cisco

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# commit

Repeat Step 1 through Step 6 to bring up the serial subinterface and any associated PVC at the other end of the connection.

Note The configuration on both ends of the subinterface connection must match.

Step 8

show frame-relay pvc dlci-number

 

RP/0/0RP0RSP0/CPU0:router# show frame-relay pvc 20

(Optional) Verifies the configuration of specified serial interface.

Step 9

show policy-map interface serial interface-path-id . subinterface { input | output }

or

show policy-map type qos interface serial interface-path-id . subinterface { input | output }

 

RP/0/0RP0RSP0/CPU0:router# show policy-map interface serial 0/1/0/0.1 output

or

RP/0/0RP0RSP0/CPU0:router# show policy-map type qos interface serial 0/1/0/0.1 output

(Optional) Displays the statistics and the configurations of the input and output policies that are attached to a subinterface.

What to Do Next

Modifying the Keepalive Interval on Serial Interfaces

Perform this task to modify the keepalive interval on serial interfaces that have Cisco HDLC or PPP encapsulation enabled.


NoteWhen you enable Cisco HDLC or PPP encapsulation on a serial interface, the default keepalive interval is 10 seconds. Use this procedure to modify that default keepalive interval.



NoteCisco HDLC is enabled by default on serial interfaces.


Prerequisites

Before modifying the keepalive timer configuration, ensure that Cisco HDLC or PPP encapsulation is enabled on the interface. Use the encapsulation command to enable Cisco HDLC or PPP encapsulation on the interface, as described in the “Configuring Optional Serial Interface Parameters” section.

Restrictions

Is there a comparable recommendation for ASR9k with keepalives for MDR upgrade? XR12k recommends disabling keepalives and CRS recommends setting interval to greater than or equal to 10 sec.

  • Before performing a Minimal Disruptive Restart (MDR) upgrade, we recommend disabling keepalives on a Cisco XR 12000 Series Router.
  • Before performing a Minimal Disruptive Restart (MDR) upgrade, we recommend configuring a keepalive interval of 10 seconds or more on a Cisco CRS-1 Router.

SUMMARY STEPS

1. configure

2. interface serial interface-path-id

3. keepalive { seconds | disable }
or
no keepalive

4. end
or
commit

5. show interfaces type interface-path-id

DETAILED STEPS

 

Command or Action
Purpose

Step 1

configure

 

RP/0/0RP0RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

interface serial interface-path-id

 

RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/1/0/0

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

Step 3

keepalive { seconds | disable }

or

no keepalive

 
RP/0/0RP0RSP0/CPU0:router(config-if)# keepalive 3

or

RP/0/0RP0RSP0/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.
  • The range is from 1 to 30 seconds. The default is 10 seconds.
  • If keepalives are configured on an interface, use the no keepalive command to disable the keepalive feature before configuring Frame Relay encapsulation on that interface.

Step 4

end

or

commit

 

RP/0/0RP0RSP0/CPU0:router(config-if)# end

or

RP/0/0RP0RSP0/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 5

show interfaces serial interface-path-id

 

RP/0/0RP0RSP0/CPU0:router# show interfaces serial 0/1/0/0

(Optional) Verifies the interface configuration.

How to Configure a Layer 2 Attachment Circuit

The Layer 2 AC configuration tasks are described in the following procedures:


NoteAfter you configure an interface for Layer 2 switching, no routing commands such asipv4 address are permissible. If any routing commands are configured on the interface, then the l2transport command is rejected.


Creating a Serial Layer 2 Subinterface with a PVC

The procedure in this section creates a Layer 2 subinterface with a PVC.

Prerequisites

Before you can create a subinterface on a serial interface, you must bring up a serial interface, as described in the “Bringing Up a Serial Interface” section.

Restrictions

Only one PVC can be configured for each serial subinterface.

SUMMARY STEPS

1. configure

2. interface serial interface-path-id . subinterface l2transport

3. pvc vpi / vci

4. end
or
commit

5. Repeat Step 1 through Step 4 to bring up the serial subinterface and any associated PVC at the other end of the AC.

DETAILED STEPS

 

Command or Action
Purpose

Step 1

configure

 

RP/0/0RP0/CPU0:router# configure

Enters global configuration mode.

Step 2

interface serial interface-path-id . subinterface l2transport

 

RP/0/0RP0/CPU0:router(config)# interface serial 0/1/0/0.1 l2transport

Creates a subinterface and enters serial subinterface configuration mode for that subinterface.

Step 3

pvc vpi / vci

 

RP/0/0RP0/CPU0:router(config-if)# pvc 5/20

Creates a serial permanent virtual circuit (PVC) and enters serial Layer 2 transport PVC configuration mode.

Note Only one PVC is allowed per subinterface.

Step 4

end

or

commit

 

RP/0/0RP0/CPU0:router(config-fr-vc)# end

or

RP/0/0RP0/CPU0:router(config-fr-vc)# 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 5

Repeat Step 1 through Step 4 to bring up the serial subinterface and any associated PVC at the other end of the AC.

Brings up the AC.

Note The configuration on both ends of the AC must match.

What to Do Next

  • To configure optional PVC parameters, see the “Configuring Optional Serial Layer 2 PVC Parameters” section.
  • For detailed information about configuring L2TPv3 in your network, see the “ Implementing Layer 2 Tunnel Protocol Version 3” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router. For detailed information about configuring L2VPNs, see the “ Implementing MPLS Layer 2 VPNs” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router.
  • For detailed information about configuring L2TPv3 in your network, see the “ Implementing Layer 2 Tunnel Protocol Version 3 on Cisco IOS XR Software” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco XR 12000 Series Router. For detailed information about configuring L2VPNs, see the “ Implementing MPLS Layer 2 VPNs on Cisco IOS XR Software” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco XR 12000 Series Router.

Configuring Optional Serial Layer 2 PVC Parameters

This task describes the commands you can use to modify the default configuration on a serial Layer 2 PVC.

Prerequisites

Before you can modify the default PVC configuration, you must create the PVC on a Layer 2 subinterface, as described in the “Creating a Serial Layer 2 Subinterface with a PVC” section.

Restrictions

The configuration on both ends of the PVC must match for the connection to be active.

SUMMARY STEPS

1. configure

2. interface serial interface-path-id . subinterface l2transport

3. pvc dlci

4. encap [ cisco | ietf ]

5. service-policy { input | output } policy-map

6. fragment end-to-end fragment-size

7. fragment-counter

8. end
or
commit

9. Repeat Step 1 through Step 7 to configure the PVC at the other end of the AC.

10. show policy-map interface serial interface-path-id.subinterface { input | output }
or
show policy-map type qos interface serial interface-path-id.subinterface { input | output }

DETAILED STEPS

 

Command or Action
Purpose

Step 1

configure

 

RP/0/0RP0/CPU0:router# configure

Enters global configuration mode.

Step 2

interface serial interface-path-id . subinterface l2transport

 

RP/0/0RP0/CPU0:router(config)# interface serial 0/1/0/0.1 l2transport

Enters serial subinterface configuration mode for a Layer 2 serial subinterface.

Step 3

pvc dlci

 

RP/0/0RP0/CPU0:router(config-if)# pvc 100

Enters serial Frame Relay PVC configuration mode for the specified PVC.

Step 4

encap { cisco | ietf }

 

RP/0/0RP0/CPU0:router(config-fr-vc)# encapsulation aal5

Configures the encapsulation for a Frame Relay PVC.

Step 5

service-policy { input | output } policy-map

 

RP/0/0RP0/CPU0:router (config-subif)# service-policy output policy1

Attaches a policy map to an input subinterface or output subinterface. Once attached, the policy map is used as the service policy for the subinterface.

Step 6

fragment end-to-end fragment-size

 

RP/0/0/CPU0:router(config-fr-vc)# fragment end-to-end 100

Enables fragmentation of Frame Relay frames on an interface.

Replace fragment-size with the number of payload bytes from the original Frame Relay frame that will go into each fragment. This number excludes the Frame Relay header of the original frame.

On the Cisco 8-Port Channelized T1/E1 SPA, valid values are 128, 256, and 512.

Step 7

fragment-counter

 

RP/0/0/CPU0:router(config-fr-vc)# fragment-counter

Enables fragmentation counters for a Frame Relay subinterface and PVC.

Step 8

end

or

commit

 

RP/0/0RP0/CPU0:router(config-serial-l2transport-
pvc)# end

or

RP/0/0RP0/CPU0:router(config-serial-l2transport-pvc)# 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 9

Repeat Step 1 through Step 7 to configure the PVC at the other end of the AC.

Brings up the AC.

Note The configuration on both ends of the connection must match.

Step 10

show policy-map interface serial interface-path-id . subinterface { input | output }

or

show policy-map type qos interface serial interface-path-id . subinterface { input | output }

 

RP/0/0RP0/CPU0:router# show policy-map interface pos 0/1/0/0.1 output

 

or

RP/0/0RP0/CPU0:router# show policy-map type qos interface pos 0/1/0/0.1 output

(Optional) Displays the statistics and the configurations of the input and output policies that are attached to a subinterface.

What to Do Next

  • To configure a point-to-point pseudowire XConnect on the AC you just created, see the “ Implementing Layer 2 Tunnel Protocol Version 3” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router.
  • To configure an L2VPN, see the “ Implementing MPLS Layer 2 VPNs” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router.
  • To configure a point-to-point pseudowire XConnect on the AC you just created, see the “ Implementing Layer 2 Tunnel Protocol Version 3 on Cisco IOS XR Software” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco XR 12000 Series Router.
  • To configure an L2VPN, see the “ Implementing MPLS Layer 2 VPNs on Cisco IOS XR Software” module of the Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco XR 12000 Series Router.

Prerequisites for Configuring IPHC

IP header compression (IPHC) is supported on the following cards:

  • Cisco 1-Port Channelized OC-12/STM-4
  • Cisco 1-Port Channelized OC-48/STM-16
  • Cisco 1-Port Channelized STM-1/OC-3
  • Cisco 8-Port Channelized T1/E1 SPA
  • Cisco 2-Port and 4-Port Clear Channel T3/E3 SPA
  • Cisco 2-Port and 4-Port Channelized T3 SPA
  • Cisco Multirate 10G IP Services Engines SIPs

Cisco 12000-SIP-600

Cisco 12000-SIP-401

Cisco 12000-SIP-501

Cisco 12000-SIP-601

  • SIP 700 SPA Interface Processor
  • Cisco 2-Port Channelized OC-12c/DS0 SPA
  • Cisco 1-Port Channelized OC-3/STM-1 SPA
  • Cisco 4-Port Channelized T3/DS0 SPA
  • Cisco 8-Port Channelized T1/E1 SPA
  • Cisco 2-Port and 4-Port Clear Channel T3/E3 SPA

Configuring the IPHC Slot Level Command

This section describes how to configure the IP header compression (IPHC) slot level command, which reserves the IPHC resources, enables IPHC on the line card, and defines the maximum number of TCP and non-TCP connections for the nodes. This configuration must be done before an IPHC profile can be created.


NoteIPHC slot level configuration is required on both the peer routers.


SUMMARY STEPS

To configure the IP header compression (IPHC) slot level, perform the following steps.

1. config

2. iphc tcp connections max-number location node-id

3. iphc non-tcp connections max-number location node-id

4. commit

DETAILED STEPS

 

Command or Action
Purpose

Step 1

config

 

RP/0/0/CPU0:router# configure

Enters global configuration mode.

Step 2

iphc tcp connections max-number location node-id

 

RP/0/0/CPU0:router(config)# iphc tcp connections 2000 location 0/1/cpu0

Sets the maximum number of TCP connections that may be configured for IPHC on a line card.

The range is 1 to 2000.

Step 3

iphc non-tcp connections max-number location node-id

 

RP/0/0/CPU0:router(config)# iphc non-tcp connections 20000 location 0/1/cpu0

Sets the maximum number of non-TCP connections that may be configured for IPHC on a line card.

The range is 1 to 20000.

Step 4

end

or

commit

 

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.

Configuring an IPHC Profile

This section describes how to create and configure an IP header compression (IPHC) profile. This procedure is for TCP and non-TCP compression.

SUMMARY STEPS

To configure an IP header compression (IPHC) profile, perform the following steps.

1. configure

2. iphc profile profile-name type { ietf | iphc}

3. tcp compression

4. tcp context absolute number-of-contexts

5. non-tcp compression

6. non-tcp context absolute number-of-contexts

7. rtp

8. refresh max-period { max-number | infinite }

9. refresh rtp

10. feedback disable

11. max-header number-of-bytes

12. end
or
commit

DETAILED STEPS

 

Command or Action
Purpose

Step 1

configure

 

RP/0/0/CPU0:router# configure

Enters global configuration mode.

Step 2

iphc profile profile-name type { ietf | iphc}

 

RP/0/0/CPU0:router(config)# iphc profile Profile_1 type iphc

Creates an IPHC profile, sets the compression format type. and enters the IPHC profile configuration mode.

Step 3

tcp compression

 

RP/0/0/CPU0:router(config-iphc-profile)# tcp compression

Enables TCP compression in an IPHC profile.

Step 4

tcp context absolute number-of-contexts

 

RP/0/0/CPU0:router(config-iphc-profile)# tcp context absolute 255

Configures the maximum number of TCP contexts that are allowed for IPHC on a line card.

Step 5

non-tcp compression

 

RP/0/0/CPU0:router(config-iphc-profile)# non-tcp compression

Enables non-TCP compression in an IPHC profile.

Step 6

non-tcp context absolute number-of-contexts

 

RP/0/0/CPU0:router(config-iphc-profile)# non-tcp context absolute 255

Configures the maximum number of non-TCP contexts that are allowed for IPHC on a line card.

Step 7

rtp

 

RP/0/0/CPU0:router(config-iphc-profile)# rtp

Configures Real Time Protocol (RTP) on the interface.

Step 8

refresh max-period { max-number | infinite }

 

RP/0/0/CPU0:router(config-iphc-profile)# refresh max-period 50

Configures the maximum number of compressed IP header packets that are exchanged on a link before the IPHC context is refreshed.

Step 9

refresh rtp

 

RP/0/0/CPU0:router(config-iphc-profile)# refresh rtp

Enables the configured context refresh settings for RTP packets.

Step 10

feedback disable

 

RP/0/0/CPU0:router(config-iphc-profile)# feedback disable

Disables the IPHC context status feedback messages on an interface.

Step 11

max-header number-of-bytes

 

RP/0/0/CPU0:router(config-iphc-profile)# max-header 20

Configures the maximum size (in bytes) of a compressed IP header.

Step 12

end

or

commit

 

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.

Configuring an IPHC Profile

This section describes how to create and configure an IP header compression (IPHC) profile. This procedure is for TCP and non-TCP compression.

SUMMARY STEPS

To configure an IP header compression (IPHC) profile, perform the following steps.

1. configure

2. iphc profile profile-name type { cisco | ietf | iphc }

3. tcp compression

4. tcp context absolute number-of-contexts

5. non-tcp compression

6. non-tcp context absolute number-of-contexts

7. rtp

8. refresh max-period { max-number | infinite }

9. refresh max-time { max-time | infinite }

10. refresh rtp

11. feedback disable

12. max-header number-of-bytes

13. end
or
commit

DETAILED STEPS

 

Command or Action
Purpose

Step 1

config

 

RP/0/RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

iphc profile profile-name type { cisco | ietf | iphc }

 

RP/0/RSP0/CPU0:router(config)# iphc profile Profile_1 type iphc

Creates an IPHC profile, sets the compression format type, and enters the IPHC profile configuration mode.

Step 3

tcp compression

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# tcp compression

Enables TCP compression in an IPHC profile.

Step 4

tcp context absolute number-of-contexts

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# tcp context absolute 255

Configures the maximum number of TCP contexts that are allowed for IPHC on a line card.

Step 5

non-tcp compression

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# non-tcp compression

Enables non-TCP compression in an IPHC profile.

Step 6

non-tcp context absolute number-of-contexts

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# non-tcp context absolute 255

Configures the maximum number of non-TCP contexts that are allowed for IPHC on a line card.

Step 7

rtp

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# rtp

Configures Real Time Protocol (RTP) on the interface.

Step 8

refresh max-period { max-number | infinite }

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# refresh max-period 50

Configures the maximum number of compressed IP header packets that are exchanged on a link before the IPHC context is refreshed.

Step 9

refresh max-time { max-time | infinite }

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# refresh max-time 10

Configures the maximum time between context refreshes.

Step 10

refresh rtp

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# refresh rtp

Enables the configured context refresh settings for RTP packets.

Step 11

feedback disable

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# feedback disable

Disables the IPHC context status feedback messages on an interface.

Step 12

max-header number-of-bytes

 

RP/0/RSP0/CPU0:router(config-iphc-profile)# max-header 20

Configures the maximum size (in bytes) of a compressed IP header.

Step 13

end

or

commit

 

RP/0/RSP0/CPU0:router(config-if)# end

or

RP/0/RSP0/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.

Enabling an IPHC Profile on an Interface

This section describes how to enable an IP header compression (IPHC) profile on an interface by attaching the profile directly to the interface.

SUMMARY STEPS

To configure to enable an IPHC profile on an interface, perform the following steps.

1. config

2. interface type interface-path-id

3. encapsulation ppp

4. ipv4 iphc profile profile-name [ mode service-policy ]

5. service policy input | output | type service-policy-name

6. commit

DETAILED STEPS

 

Command or Action
Purpose

Step 1

config

 

RP/0/0RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

interface type interface-path-id

 

RP/0/0RSP0/CPU0:router(config)# interface serial 0/1/0/1

Specifies the interface.

Note Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark ( ? ) online help function.

Step 3

encapsulation { hdlc | ppp | frame-relay | mfr }

 

RP/0/0RSP0/CPU0:router(config-if)# encapsulation ppp

Specifies Layer 2 encapsulation for the interface.

Step 4

ipv4 iphc profile profile-name [ mode service-policy ]

 

RP/0/0RSP0/CPU0:router(config-if)# ipv4 iphc profile Profile_1

or

RP/0/0RSP0/CPU0:router(config-if)# ipv4 iphc profile Profile_1 mode service-policy

Attaches an IPHC profile to the interface:

  • profile-name —Text name of the IPHC profile to attach to the interface.
  • mode service-policy —Specifies that the IPHC profile applies only to a QoS service policy.

Step 5

service policy output service-policy-name

 

RP/0/0RSP0/CPU0:router(config-if)# service policy input | output | type service-policy-name

 

(Optional) Specifies the name of the QoS service policy to which the IPHC profile applies. Only output service policies are allowed.

Used only when mode service-policy is specified in Step 2.

Step 6

end

or

commit

 

RP/0/0RSP0/CPU0:router(config-if)# end

or

RP/0/0RSP0/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.

Configuration Examples for Serial Interfaces

This section provides the following configuration examples:

Bringing Up and Configuring a Serial Interface with Cisco HDLC Encapsulation: Example

The following example shows how to bring up a basic serial interface with Cisco HDLC encapsulation:

RP/0/0RP0RSP0/CPU0:Router#config
RP/0/0RP0RSP0/CPU0:Router(config)# interface serial 0/3/0/0/0:0
RP/0/0RP0RSP0/CPU0:Router(config-if)# ipv4 address 192.0.2.2 255.255.255.252
RP/0/0RP0RSP0/CPU0:Router(config-if)# no shutdown
RP/0/0RP0RSP0/CPU0:router(config-if)# end
Uncommitted changes found, commit them? [yes]: yes
 

The following example shows how to configure the interval between keepalive messages to be 10 seconds:

RP/0/0RP0RSP0/CPU0:router# configure
RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/3/0/0/0:0
RP/0/0RP0RSP0/CPU0:router(config-if)# keepalive 10
RP/0/0RP0RSP0/CPU0:router(config-if)# commit
 

The following example shows how to modify the optional serial interface parameters:

RP/0/0RP0RSP0/CPU0:router# configure
RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/3/0/0/0:0
RP/0/0RP0RSP0/CPU0:Router(config-if)# serial
RP/0/0RP0RSP0/CPU0:Router(config-if-serial)# crc 16
RP/0/0RP0RSP0/CPU0:Router(config-if-serial)# invert
RP/0/0RP0RSP0/CPU0:Router(config-if-serial)# scramble
RP/0/0RP0RSP0/CPU0:Router(config-if-serial)# transmit-delay 3
RP/0/0RP0RSP0/CPU0:Router(config-if-serial)# commit
 

The following is sample output from the show interfaces serial command:

RP/0/0RP0RSP0/CPU0:Router# show interfaces serial 0/0/3/0/5:23
Serial0/0/3/0/5:23 is down, line protocol is down
Hardware is Serial network interface(s)
Internet address is Unknown
MTU 1504 bytes, BW 64 Kbit
reliability 143/255, txload 1/255, rxload 1/255
Encapsulation HDLC, crc 16, loopback not set, keepalive set (10 sec)
Last clearing of "show interface" counters 18:11:15
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
2764 packets input, 2816 bytes, 3046 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
3046 input errors, 1 CRC, 0 frame, 0 overrun, 2764 ignored, 281 abort
2764 packets output, 60804 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 a Serial Interface with Frame Relay Encapsulation: Example

The following example shows how to create a serial interface on a SPA with Frame Relay encapsulation and a serial subinterface with a PVC on router 1:

RP/0/0RP0RSP0/CPU0:router# configure
RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/1/0/0
RP/0/0RP0RSP0/CPU0:router(config-if)# encapsulation frame-relay
RP/0/0RP0RSP0/CPU0:router(config-if)#frame-relay intf-type dce
RP/0/0RP0RSP0/CPU0:router(config-if)# no shutdown
RP/0/0RP0RSP0/CPU0:router(config-if)# end
Uncommitted changes found, commit them? [yes]: yes
 
RP/0/0RP0RSP0/CPU0:router# configure
RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/1/0/0.1 point-to-point
RP/0/0RP0RSP0/CPU0:router (config-subif)#ipv4 address 10.20.3.1/24

RP/0/0RP0RSP0/CPU0:router (config-subif)# pvc 16

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# encapsulation ietf

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# commit

RP/0/0RP0RSP0/CPU0:router(config-fr-vc)# exit

RP/0/0RP0RSP0/CPU0:router(config-subif)# exit

RP/0/0RP0RSP0/CPU0:router(config)# exit

 

RP/0/0RP0RSP0/CPU0:router# show interface serial 0/1/0/0

Wed Oct 8 04:14:39.946 PST DST

Serial0/1/0/0 is up, line protocol is up

Interface state transitions: 5

Hardware is Serial network interface(s)

Internet address is 10.20.3.1/24

MTU 4474 bytes, BW 44210 Kbit

reliability 255/255, txload 0/255, rxload 0/255

Encapsulation FRAME-RELAY, crc 16,

Scrambling is disabled, Invert data is disabled

LMI enq sent 0, LMI stat recvd 0, LMI upd recvd 0

LMI enq recvd 880, LMI stat sent 880, LMI upd sent 0 , DCE LMI up

LMI DLCI 1023 LMI type is CISCO frame relay DCE

Last clearing of "show interface" counters 02:23:04

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

858 packets input, 11154 bytes, 0 total input drops

0 drops for unrecognized upper-level protocol

Received 0 runts, 0 giants, 0 throttles, 0 parity

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

858 packets output, 12226 bytes, 0 total output drops

0 output errors, 0 underruns, 0 applique, 0 resets

0 output buffer failures, 0 output buffers swapped out

 

The following example shows how to create a serial interface on a SPA with Frame Relay encapsulation and a serial subinterface with a PVC on router 2, which is connected to router 1:

RP/0/0RP0RSP0/CPU0:router# configure
RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/1/0/1
RP/0/0RP0RSP0/CPU0:router(config-if)# encapsulation frame-relay
RP/0/0RP0RSP0/CPU0:router(config-if)# no shutdown
RP/0/0RP0RSP0/CPU0:router(config-if)# end
Uncommitted changes found, commit them? [yes]: yes
 
RP/0/0RP0RSP0/CPU0:router# configure
RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/1/0/1.1 point-to-point
RP/0/0RP0RSP0/CPU0:router (config-subif)#ipv4 address 10.20.3.2/24

RP/0/0RP0RSP0/CPU0:router (config-subif)# pvc 16

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# encapsulation ietf

RP/0/0RP0RSP0/CPU0:router (config-fr-vc)# commit

RP/0/0RP0RSP0/CPU0:router(config-fr-vc)# exit

RP/0/0RP0RSP0/CPU0:router(config-subif)# exit

RP/0/0RP0RSP0/CPU0:router(config)# exit

 

RP/0/0RP0RSP0/CPU0:router# show interface serial 0/1/0/1

Wed Oct 8 04:13:45.046 PST DST

Serial0/1/0/1 is up, line protocol is up

Interface state transitions: 7

Hardware is Serial network interface(s)

Internet address is Unknown

MTU 4474 bytes, BW 44210 Kbit

reliability 255/255, txload 0/255, rxload 0/255

Encapsulation FRAME-RELAY, crc 16,

Scrambling is disabled, Invert data is disabled

LMI enq sent 1110, LMI stat recvd 875, LMI upd recvd 0, DTE LMI up

LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0

LMI DLCI 1023 LMI type is CISCO frame relay DTE

Last clearing of "show interface" counters 02:22:09

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

853 packets input, 12153 bytes, 0 total input drops

0 drops for unrecognized upper-level protocol

Received 0 runts, 0 giants, 0 throttles, 0 parity

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

853 packets output, 11089 bytes, 0 total output drops

0 output errors, 0 underruns, 0 applique, 0 resets

0 output buffer failures, 0 output buffers swapped out

Configuring a Serial Interface with PPP Encapsulation: Example

The following example shows how to create and configure a serial interface with PPP encapsulation:

RP/0/0RP0RSP0/CPU0:router# configure
RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/3/0/0/0:0
RP/0/0RP0RSP0/CPU0:router(config-if)# ipv4 address 172.18.189.38 255.255.255.224
RP/0/0RP0RSP0/CPU0:router(config-if)# encapsulation ppp
RP/0/0RP0RSP0/CPU0:router(config-if)# no shutdown
RP/0/0RP0RSP0/CPU0:router(config-if)# ppp authentication chap MIS-access
RP/0/0RP0RSP0/CPU0:router(config-if)# end
Uncommitted changes found, commit them? [yes]: yes
 

The following example shows how to configure serial interface 0/3/0/0/0:0 to allow two additional retries after an initial authentication failure (for a total of three failed authentication attempts):

RP/0/0RP0RSP0/CPU0:router# configuration
RP/0/0RP0RSP0/CPU0:router(config)# interface serial 0/3/0/0/0:0
RP/0/0RP0RSP0/CPU0:router(config-if)# encapsulation ppp
RP/0/0RP0RSP0/CPU0:router(config-if)# ppp authentication chap
RP/0/0RP0RSP0/CPU0:router(config-if)# ppp max-bad-auth 3
RP/0/0RP0RSP0/CPU0:router(config-if)# end
Uncommitted changes found, commit them? [yes]: yes

IPHC Profile Configuration: Example

The following example shows how to configure an IPHC Profile:

config
iphc tcp connections 6000 location 0/2/1
iphc non-tcp connections 6000 location 0/2/1
iphc profile Profile_1 type iphc
tcp compression
tcp context absolute 255
non-tcp compression
non-tcp context absolute 255
rtp
refresh max-period 50
refresh max-time 10
refresh rtp
feedback disable
max-header 20
commit

IPHC on a Serial Interface Configuration: Examples

Example 1

The following example shows how to enable an IP header compression (IPHC) profile on a serial interface by attaching the profile directly to the interface:

config
interface serial 0/1/0/1
encapsulation ppp
ipv4 iphc profile Profile_1
commit

Example 2

The following example shows how to enable an IP header compression (IPHC) profile on an interface by specifying a QoS service policy that contains an IPHC profile:

config
interface serial 0/1/0/1:1
encapsulation ppp
ipv4 iphc profile Profile_2 mode service-policy
service-policy output ip_header_compression_policy_map
commit

IPHC on Multilink Configuration: Example

The following example shows how to configure an IP header compression (IPHC) on a multilink interface:

config
interface multilink 0/4/3/0/4
ipv4 address 10.10.10.10
encapsulation ppp
ipv4 iphc profile Profile_1
commit
interface serial 0/1/0/1:1
encapsulation ppp
multilink group 4
commit

IPHC on a Serial Interface with MLPPP/LFI and QoS Configuration: Example

The following example shows how to configure IP header compression (IPHC) on a serial interface with LFI and by specifying a QoS service policy that contains an IPHC profile:

config
interface multilink 0/4/3/0/4
ipv4 address 10.10.10.10
multilink
fragment-size 128
interleave
ipv4 iphc profile Profile_2 mode service-policy
service-policy output SP_2
commit
interface serial 0/1/0/1:2
encapsulation ppp
multilink group 4
commit

Additional References

The following sections provide references related to T3/E3 and T1/E1 controllers and serial interfaces.

Related Documents

 

Related Topic
Document Title

Cisco IOS XR master command reference

Cisco IOS XR Master Commands List

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 Cisco IOS XR software

Cisco IOS XR Getting Started Guide

Cisco IOS XR AAA services configuration information

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

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

Cisco Craft Works Interface Configuration Guide

Standards

 

Standards
Title

FRF.1.2

PVC User-to-Network Interface (UNI) Implementation Agreement - July 2000

ANSI T1.617 Annex D

ITU Q.933 Annex A

MIBs

 

MIBs
MIBs Link

To locate and download MIBs using Cisco IOS XR software, use the Cisco MIB Locator found at the following URL and choose a platform under the Cisco Access Products menu: http://cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

 

RFCs
Title

RFC 1294

Multiprotocol Interconnect Over Frame Relay

RFC 1315

Management Information Base for Frame Relay DTEs

RFC 1490

Multiprotocol Interconnect Over Frame Relay

RFC 1586

Guidelines for Running OSPF Over Frame Relay Networks

RFC 1604

Definitions of Managed Objects for Frame Relay Service

RFC 2115

Management Information Base for Frame Relay DTEs Using SMIv2

RFC 2390

Inverse Address Resolution Protocol

RFC 2427

Multiprotocol Interconnect Over Frame Relay

RFC 2954

Definitions of Managed Objects for Frame Relay Service

Technical Assistance

 

Description
Link

The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/techsupport