# Activation and Deactivation of IPv4 and IPv6 Services in a Dual Stack

You can configure IPv4 and IPv6 services in a dual stack either as independent services or as a combined service. The following sections describe the two types of configurations and their behavior when they are activated and deactivated.

## Independent IPv4 and IPv6 Services in a Dual Stack

To configure separate services for IPv4 and IPv6 interfaces you must create and install separate service definitions on the router. For example, you can create a service definition called iponeV4 to be used for IPv4 traffic and service definition called iponeV6 to be used for IPv6 traffic. Both the services defined for IPv4 and IPv6 must be configured for the subscriber on the RADIUS server. When the subscriber is authenticated using RADIUS authentication, two services, one each for IPv4 and IPv6, are created. The subscriber service sessions are created and activated when the subscriber logs in using the RADIUS Access-Accept messages, Change-of-Authorization-Request (CoA-Request) messages, or CLI commands. After the subscriber service session is activated, the policies defined in the interface profile specified by the activate-profile object in the service macro file are applied to the IPv4 and IPv6 interfaces. Service session profiles provide additional flexibility to the Service Manager application by enabling you to assign one or more supported attributes to a particular activation of a service.

Deactivation of service sessions is also performed for each individual service. If an interface is deleted, all the services associated with that interface are also deleted. For example, if you delete an IPv6 interface, all the services associated with IPv6 are deleted. However, IPv4 subscriber service sessions are not disrupted. When a user logs out of a session, all services associated with the subscriber session are also removed along with the subscriber session. If the subscriber has two services and one of them was not successfully applied to an interface, then that service is removed. For example, if a subscriber has two services, iponev4 and iponev6, configured on the RADIUS server and only one service was successfully configured on an interface, then the failed service is deleted when the service is deactivated.

## Combined IPv4 and IPv6 Service in a Dual Stack

To configure a single service for IPv4 and IPv6 interfaces, you can create and install one service definition on the router that handles the traffic for both these protocols. For example, you can create a service definition called iponeV4V6 to be used for both IPv4 and IPv6 traffic. This service must be configured for the subscriber on the RADIUS server. When the subscriber is authenticated using RADIUS authentication, a single service is created and activated using the RADIUS or CLI client type that Service Manager supports. After the subscriber service session is activated, the policies defined in the interface profile specified by the activate-profile object in the service macro file are applied to both IPv4 and IPv6 interfaces. The elements in the profile to be attached to the interfaces are determined by the type of the interface. The combined service session is active if either of the two conditions is satisfied:

- Both the IPv4 and IPv6 interfaces are up
- Either the IPv4 or IPv6 interface is up

Deactivation of service sessions results in disconnection of services for both IPv4 and IPv6 subscribers.

## Performance Impact on the Router and Compatibility with Previous Releases for an IPv4 and IPv6 Dual Stack

In an environment where only IPv4 subscribers exist, the memory usage on the E Series router is the same as the usage in previous releases. If IPv4 and IPv6 are configured as independent services, memory usage increases because each IPv6 service is counted as a separate service and uses all the system resources than an IPv4 service requires. Memory impact in such a case is proportional to the total number of services configured. You can view the number of service sessions currently active for a subscriber by viewing the Service Sessions field from the output of the show service-management command.

If you configured a combined IP4 and IPv6 service, the memory usage is the same as that required for one subscriber service session. The number of subscribers that are supported by the line modules depends on the number of available resources, such as external parent groups. If you configure services that are to be used in an IPv4 or L2TP network, you need not change the previously defined service macros. However, if a subscriber requires the service macro applied to IPv6 interfaces or wants to apply a combined policy for both IPv4 and IPv6 interfaces, you must modify the macro file for the appropriate service interface type.