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6rd Softwires in Next Gen Services

6rd Softwires in Next Gen Services Overview

Next Gen Services supports a 6rd softwire concentrator on the MX-SPC3 services card. 6rd softwires allow IPv6 end users to send traffic over an IPv4 network to reach an IPv6 network. IPv6 packets are encapsulated in IPv4 packets by a softwire initiator at the customer edge WAN, and tunneled to a 6rd softwire concentrator. A softwire is created when IPv4 packets containing IPv6 destination information are received at the softwire concentrator, which decapsulates IPv6 packets and forwards them for IPv6 routing.

6rd softwire flow is shown in Figure 1.

Figure 1: 6rd Softwire Flow6rd Softwire Flow

In the reverse path, IPv6 packets are sent to the 6rd softwire concentrator, which encapsulates them in IPv4 packets corresponding to the proper softwire and sends them to the customer edge WAN.

IPv6 flows are also created for the encapsulated IPv6 payload, and are associated with the specific softwire that carried them in the first place. When the last IPv6 flow associated with a softwire ends, the softwire is deleted. This simplifies configuration and there is no need to create or manage tunnel interfaces.

For more information on 6rd softwires, see RFC 5969, IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) -- Protocol Specification.


  • Rapid deployment of IPv6 service to subscribers on native IPv4 customer edge WANs.

  • No need to create or manage tunnel interfaces.

Configuring Inline 6rd for Next Gen Services

Configuring a 6rd Softwire Concentrator

To configure a 6rd softwire concentrator:

  1. Configure a 6rd softwire concentrator name and IP address.

    For example:

  2. Configure the softwire type as v6rd and specify a name for it.

    For example:

  3. Configure the 6rd domain’s IPv6 prefix.

Configuring a 6rd Softwire Rule

To configure a 6rd softwire rule:

  1. Specify the name of the rule set that the rule belongs to.
  2. Specify the direction of traffic to be tunneled.
  3. Specify the name of the rule.
  4. Specify the softwire to apply if the condition is met.

Configuring Inline Services and an Inline Services Interface

Inline services run on MX line cards that can operate under Next Gen Services, for example MPC3 and MPC4 cards. This topic describes how to enable an inline service.

To enable inline services and an inline services interface:

  1. Enable inline services for the FPC and PIC slot, and define the amount of bandwidth to dedicate to inline services.
  2. Configure the inline services logical interfaces. Inline interfaces use the following interface naming convention:
    • If you are using an interface service set, configure one logical unit, and include units for IPv4 and IPv6:

      For example:

    • If you are using a next-hop service set, configure two logical units and define the inside and outside interfaces for IPv4 and IPv6:

      For example:

Configuring the IPv4-Facing and IPv6-Facing Interfaces for 6rd

To configure the IPv4-facing and IPv6-facing interfaces:

  1. Configure the IPv4-facing interface:
    • To configure an interface to use with an interface-style service set, configure input and output service and specify the service set.

    • To configure an interface to use with a next-hop style service set, omit the service input and service output references.

  2. Configure the IPv6-facing interface.

Configuring the Service Set

To configure the service set for 6rd processing:

  1. Specify a name for the service set.
  2. Configure either an interface service set, which requires a single service interface, or a next-hop service set, which requires an inside and outside service interface.
    • To configure an interface service set:

    • To configure a next-hop service set:

  3. Specify the 6rd rule-set that contains the 6rd rule to be used with the service set.