RADIUS: Framed-Route and Framed-IPv6-Route

RADIUS attribute [22] Framed-Route can be specified in a RADIUS Access-Accept message to associate an IPv4 route with an IPv4 routed subscriber host and Radius attribute [99] Framed-IPv6-Route can be used to associate an IPv6 route with an IPv6 routed subscriber wan host (DHCPv6 IA-NA or SLAAC). These routes are populated in the routing table as ‟Remote Managed” routes. Up to sixteen managed routes can be installed for a routed subscriber host; this corresponds with up to sixteen Framed-Routes and sixteen Framed-IPv6-Routes for a dual-stack routed subscriber. Framed-IPv6-Routes cannot be associated with a Prefix Delegation host (DHCP IA-PD).

The Framed-Route and Framed-IPv6-Route attributes should be formatted as:

"<ip-prefix>[/<prefix-length>] <space> <gateway-address> [<space> <metric>] [<space> tag <space> <tag-value>] [<space> pref <space> <preference-value>]”


<space> is a white space or blank character.

<ip-prefix>[/prefix-length] is the managed route to be associated with the routed subscriber host. The prefix-length is optional for an IPv4 managed route. When not specified, a class-full class A,B or C subnet is assumed. The prefix-length is mandatory for an IPv6 managed route.

<gateway-address> must be the routed subscriber host IP address. ‟” is automatically interpreted as the host IPv4 address for managed IPv4 routes.

‟::” and ‟0:0:0:0:0:0:0:0” are automatically interpreted as the wan-host IPv6 address for managed IPv6 routes.

[<metric>] Optional. Installed in the routing table as the metric of the managed route. If not specified, metric zero is used. Value = [0 to 65535].

[tag <tag-value>] Optional. The managed route is tagged for use in routing policies. If not specified, or tag-value = 0, then the route is not tagged. Value = [0 to 4294967295].

[pref <preference-value>] Optional. Installed in the routing table as protocol preference for this managed route. If not specified, preference zero is used. Value = [0..255].

If the optional metrics (metric, tag, or preference) are specified in a wrong format or with out of range values, then the defaults are used for all metrics: metric=0, no tag and preference=0. No event is logged.

If the Framed-Route or Framed-IPv6-Route is invalid (for example because the gateway address specified does not match the host wan IP address or because the host bits are not zero) then the routed subscriber host is instantiated without the ill-defined managed route. An event is logged in this case.

Equal Cost Multi-Path (ECMP) is supported for Framed-Route and Framed-IPv6-Route:

The maximum number of equal cost paths in a routing instance is configured with:

        ecmp <max-ecmp-routes>

If an identical managed route is associated with different routed subscriber hosts in the context of the same IES/VPRN service, up to max-ecmp-routes managed routes are installed in the routing table. Candidate ECMP Framed-Routes/Framed-IPv6-Routes have:

A tie breaker determines if more candidate ECMP Framed-Routes/Framed-IPv6-Routes are available than the configured <max-ecmp-routes> is: Lowest ip next-hop.

Other identical managed routes are shadowed and an event is logged.

Note that Candidate ECMP Framed-Routes/Framed-IPv6-Routes can belong to hosts of the same or different subscriber.

Valid Framed-Routes and Framed-IPv6-Routes are persistent (stored in the persistency file for recovery after reboot) and synchronized in a Multi-Chassis Redundancy configuration.

RADIUS-learned Framed-Route/Framed-IPv6-Route and static host associated managed routes that are installed in the routing table can be identified in routing policies for redistribution as protocol ‟managed”.

To display the managed routes associated with a routed subscriber host, use following commands:

show service id service-id dhcp lease-state detail

show service id service-id dhcp6 lease-state detail

show service id service-id slaac host detail

show service id service-id ppp session detail

show service id service-id pppoe session detail

show service id service-id arp-host detail

Valid RADIUS-learned managed routes can be included in RADIUS accounting messages with the following configuration:

        radius-accounting-policy <name> 

Associated managed routes for an instantiated routed subscriber host are included in RADIUS accounting messages independent of the state of the managed route (Installed, Shadowed, HostInactive, and so on).

For a PPP session, when a Framed-Route or Framed-IPv6-Route is available while the corresponding routed subscriber host is not yet instantiated, the managed route is in the state ‟notYetInstalled” and is not included in RADIUS accounting messages.