Exchanging Between RIP and OSPF Example

(RIP to OSPF and OSPF to RIP export)

In this example Gateway 1 (GW-1) is connected to a RIP network and is redistributing the RIP routes from and to OSPF for the DIGITAL OSPF Backbone. Gateway 3 (GW-3) is connected to a subnet of UNIX workstations that are running routed, this Gateway must do OSPF to RIP redistribution.


routed is a program that is runs by default on most UNIX workstations. This program listens to RIP network updates and chooses a default route based upon what is advertised. This eliminates the need for static routes and provides for route redundancy. Because routed does not send route updates it is called a passive RIP listener. We categorize this subnet (26.77/28) as a stub network, meaning that there will be no RIP routing updates that will come from that subnet.




Exchanging Routes from RIP to OSPF External - If the RIP interface belongs to a non-stub network (Has downstream RIP routes.)

Gateway 1 to Corporate Net RIP Router

Routes are redistributed from the Corporate network to the DIGITAL Network.

  1. Make sure that Corporate net RIP router is advertising RIP on the interface connected to the DIGITAL network. It must be receiving and transmitting RIP updates. DIGITAL does not currently support the notion of trusted hosts for authentication of RIP routes.
  2. Connect to Gateway 1 using clearVISN IP Switch Manager.
  3. Click .
  4. Click Route Redistribution in the Routing Configuration section.
  5. Click the RIP to OSPF External link in the redistribution table.
  6. Click the on Radio Button in the Enable export of routes from RIP into OSPF External Field
  7. Click .
  8. If you are running RIP on more than one interface on Gateway 1 you should not chose to advertise all interfaces to OSPF, only those interfaces you want advertised into the rest of the OSPF network.
    1. If you want to export all routes click the on radio button in the Export all RIP into OSPF External field.
      -OR-
    2. (Optional) If you do not want to export all RIP routes into OSPF externals: define a route filter to advertise only certain RIP routes into OSPF externals. In the Route Filters area, enter the network prefix in New Route Filter edit box and enter the length of the subnet mask (in bits) in Mask Length edit box. Click .
    3. (Optional) If you do not want to export all RIP Routes into OSPF externals: change the cost metric for RIP Routes into OSPF Externals. Enter the new cost metric in Metric for routes into ospfase edit box; Click .
  9. Click .
  10. (Optional) Enter a new cost metric in Metric for routes into ospfase field; click .

    You will now see your RIP routes, 24.0/24, 22.0/24, and 0.0.0.0/0 (the default) in the DIGITAL routing tables. A ping will fail at this point. You should not see any of your DIGITAL networks in your RIP network, so an ICMP message does not know how to return to the DIGITAL network.

    Continue to the next step.


Exchanging Routes from OSPF to RIP - If the OSPF interface belongs to a non-stub network (Has downstream OSPF routes)

Routes are redistributed from the DIGITAL network to the Corporate Network.

  1. Use the clearVISN IP Switch Managerconnection to Gateway 1 you have from the previous procedure.
  2. Click .
  3. Click Route Redistribution in the Routing Configuration section.
  4. Click the OSPF to RIP link in the redistribution table.
  5. Click the on radio button in the Enable export of routes from OSPF into RIP Field.
  6. Click .
  7. You should generally export all OSPF routes into RIP as this will assure full connectivity.
    1. If you want to export all OSPF routes into RIP click the on radio button in the Export all OSPF into RIP field. Click .
      -OR-
    2. (Optional) If you do not want to export all OSPF Routes into RIP, define a route filter to advertise only certain OSPF routes into RIP. In the Route Filters Area, Enter a network prefix in New route filter field. Enter the length of the subnet mask (in bits) in Mask length edit box. Click .
    3. (Optional) If you do not watn to export all OSPF Routes into RIP, change the hop count metric for OSPF routes into RIP. Enter a new hop count metric in Metric for routes into RIP field. Click .

    You will now see all of the routes from the DIGITAL Network in your RIP network. This includes the address of the remote subnets of Gateway 3 and the point-to-point DIGITAL ATM networks. Everyone in the corporate network should be able to get to every subnet connected to the DIGITAL equipment and all of the subnets connected to the DIGITAL equipment should be able to reach everywhere on the corporate network.

Exchanging Routes from RIP to OSPF External - If the RIP interface belongs to a stub network (No downstream RIP routes)

Routes are redistributed from the DIGITAL network to the subnet with the workstations that run routed.

This subnet is called a stub network, which means that no routing information should originate from this network. If you have larger UNIX machines, such as SUN or SGI machines with many network interfaces installed, routed acts like a router and forwards packets between interfaces, confusing the rest of the "true" routers on the network. Making the network with these servers or workstation a stub network is the preferred method of which to advertise RIP routes to the UNIX hosts running routed.

  1. Initiate a clearVISN IP Switch Manager session with Gateway 3.
  2. When enabling RIP on the interface associated with the stub network set the options to: RIP in (off) and RIP out (on). See RIP Configuration.
  3. Click .
  4. Click the Route Redistribution link in the Routing Configuration section.
  5. Click the OSPF to RIP link in the Redistribution Table.
  6. Click the on radio button in the Enable export of routes from OSPF into RIP Field.
  7. Click .
  8. If you want to export all OSPF routes into RIP, click the on radio button in the Export all OSPF into RIP field. Click .
  9. (Optional) If you do not want to export all OSPF routes into RIP, define a route filter to advertise only certain OSPF routes into RIP. In the Route Filters area, Enter the network prefix in New route filter field. Enter the length of the subnet mask (in bits) in Mask Length field. Click .
  10. (Oprional) If you do not want to export all OSPF routes into RIP, change the hop count metric for OSPF routes into RIP. Enter a new hop count metric in the Metric for routes into RIP edit box. Click .

    Your UNIX workstations should then be receiving the routing information from the DIGITAL gateway. The default route on the workstation should be set dynamically and correspond to the interface that the stub network is plugged into.


Copyright © 1997 Ipsilon Networks, Inc.
Portions copyright © Digital Equipment Corporation 1998. All rights reserved.
Updated January 8, 1998
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