Configuring IP-in-IP on the Cisco Service Control Engine Platform

Table Of Contents

Configuring IPinIP on the SCE Platform

Introduction

ip-tunnel IPinIP skip

ip-tunnel IPinIP DSCP-marking-skip

show interface linecard ip-tunnel IPinIP

Configuring IPinIP on the SCE Platform

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OL-15415-01

This note describes the IP in IP tunneling protocol option. This option is supported beginning with SCOS release 3.1.5.

Introduction

IPinIP is an IP-based tunneling protocol; therefore the system must be specifically configured to recognize the flows inside the tunnel. The SCE platform will then skip the external IP header, reaching the internal IP, which is the actual subscriber traffic.

When IPinIP skip is disabled, the system treats the external IP header as the subscriber traffic, resulting in all IPinIP traffic being reported as generic IP.

The commands described in this document can be used to configure IPinIP tunneling.

Fragmentation

Fragmentation should be avoided whenever possible. If it is not possible to avoid fragmentation, it is recommended to opt for internal fragmentation. If that is also not possible, the SCE platform can be operated under conditions of external fragmentation.

ip-tunnel IPinIP skip

Enables the recognition of IPinIP tunnels and skipping into the internal IP packet. Use the no form of this command to disable IPinIP skip.

ip-tunnel IPinIP skip

no ip-tunnel IPinIP skip

Syntax Description

This command has no arguments or keywords.

Defaults

By default, IPinIP skip is disabled.

Command Modes

Interface Linecard Configuration

Usage Guidelines

•IPinIP and other tunnels: IPinIP is supported simultaneously with plain IP traffic and any other tunneling protocol supported by the SCE platform.

•Overlapping IP addresses: There is no support for overlapping IP addresses within different IPinIP tunnels.

•DSCP marking: For IPinIP traffic, DSCP marking can be done on either the external or the internal IP header exclusively.

See the ip-tunnel IPinIP DSCP-marking-skip command.

Authorization: admin

Examples

The following example shows how to use this command.

SCE>enable 10 
Password:<cisco> 
SCE# configure 
SCE(config)#interface linecard 0 
SCE(config if)#>ip-tunnel IPinIP skip 

Related Commands

Command	Description
ip-tunnel IPinIP DSCP-marking-skip
show interface linecard ip-tunnel IPinIP

ip-tunnel IPinIP DSCP-marking-skip

Configures the SCE platform to perform DSCP marking on the internal IP header of IPinIP traffic. Use the no form of the command, to perform DSCP marking on the external IP header.

ip-tunnel IPinIP DSCP-marking-skip

no ip-tunnel IPinIP DSCP-marking-skip

Syntax Description

This command has no arguments or keywords.

Defaults

By default, DSCP marking of IPinIP traffic is done on the external IP header ( no form of the command).

Command Modes

Interface Linecard Configuration

Usage Guidelines

DSCP marking modifies the DSCP bits of the IPv4 header. In IPinIP tunnels there are at least two IP headers. By default, DSCP marking is performed only on the external IP header. Use this command to mark the DSCP bits of the internal IP header.

Figure 1 IPinIP DSCP Marking

This command takes effect only when IPinIP skip is enabled (see the ip-tunnel IPinIP skip command, above).

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Note DSCP marking should be enabled and configured through SCA BB console. Refer to the section "How to Manage DSCP ToS Marker Values" in the chapter "Using the Service Configuration Editor: Traffic Control" in the Cisco Service Control Application for Broadband User Guide for further information.

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Authorization: admin

Examples

The following example shows how to configure the SCE platform to perform DSCP marking on the internal IP header of an IPinIP flows.

SCE>enable 10 
Password:<cisco> 
SCE# configure 
SCE(config)#interface linecard 0 
SCE(config if)#>ip-tunnel IPinIP DSCP-marking-skip 

Related Commands

Command	Description
ip-tunnel IPinIP skip
show interface linecard ip-tunnel IPinIP

show interface linecard ip-tunnel IPinIP

Displays the current IPinIP configuration.

show interface linecard slot-number IP-tunnel IPinIP

Syntax Description

slot-number

The number of the identified slot. Enter a value of 0.

Defaults

This command has no default settings.

Command Modes

User Exec

Usage Guidelines

Authorization: viewer

Examples

The following example shows how to use this command.

SCE>enable 5 
Password:<cisco> 
SCE>show interface linecard 0 ip-tunnel IPinIP  
IPinIP skip mode is enabled 
IPinIP DSCP skip mode is disabled 
SCE>

Related Commands

Command	Description
ip-tunnel IPinIP skip
ip-tunnel IPinIP DSCP-marking-skip