RADIUS Route-Download Server for Route Distribution Overview

The JunosE RADIUS route-download server provides periodic automatic distribution of IPv4 static access routes, which enables preconfiguration and preadvertising of access routes before they are assigned to clients. Using the route-download server helps eliminate routing protocol storms and other delays in client service activation that can be caused by protocol convergence or a large number of simultaneous customer activations.

The RADIUS route-download server periodically sends a RADIUS Access-Request message to the RADIUS server to request that routes be downloaded. The RADIUS server then responds with an Access-Accept message and downloads the configured routes. When the download operation is complete, the route-download server installs the access routes in the routing table.

JunosE Software supports the creation of one RADIUS route-download server per chassis.

Format of Downloaded Routes

The RADIUS server sends the downloaded routes to the RADIUS route-download server in the following format:

[ { vir | virtual-router } virtualRouterName ] [ vrf vrfName ] prefix-mask [ { null0 | null 0 } [ cost ] ] [ tag tagValue ]

The route-download server accepts downloaded routes in either the Framed-Route attribute (RADIUS attribute 22) or the Cisco-AVpair attribute (Cisco VSA 26-1).

Downloaded Route Format Examples

Framed-Route (RADIUS attribute 22)

NAS-1 Password = “14raddlsvr” User-Service-Type = Outbound-UserFramed-Route = “192.168.3.0 255.255.255.0 null0” Framed-Route = “vrf vrfboston 192.168.1.0/24 null 0 0 tag 6” Framed-Route = “vir host1 vrf vrfsunny 192.168.0.0/16 null0 0 tag 8”

Cisco-AVPair (Cisco VSA 26-1)

NAS-1 Password = “14raddlsvr” User-Service-Type = Outbound-Usercisco-avpair = “ip:route = 192.168.3.0 255.255.255.0 null0” cisco-avpair = “ip:route = vrf vrfboston 192.168.1.0/24 null 0 0 tag 6” cisco-avpair = “ip:route = vir host1 vrf vrfsunny 192.168.0.0/16 null0 0 tag 8”

Note: The prefix-mask entry in downloaded routes can be in the form of prefix length, prefix mask, or prefix. If prefix is used, the mask is determined by the IP address class of the prefix.

How the Route-Download Server Downloads Routes

The route-download server starts the initial route-download operation (for example, after a system reboot or the first time the route-download server is enabled) as soon as IP is established in the virtual router in which the download is performed. After the initial route-download process is established, the router repeats the route download operation based on either the default download schedule or the schedule you specify. You can also initiate an immediate route download at any time.

The RADIUS route-download server downloads routes in two stages—first, all routes are downloaded from the RADIUS server to the router’s download database and examined for errors. Next, the router updates the routing table with the new routes, using the following guidelines:

Adds all downloaded routes that are not already installed in the routing table
Does not add downloaded routes that are already installed in the routing table
Deletes routes from the routing table that do not appear in the newly downloaded group