Title: DECbrouter90 example IP static routes over Frame Relay subinterfaces

Product: DECbrouter90 V10.x

Question: How are static routes for IP configured on Frame-Relay subinterfaces?

Solution:

        This is an example of how to configure static IP routes across a
Frame-Relay cloud between two DBR90's. This example uses subinterfaces for
the FR connection which allows the DBR90 to treat a FR circuit as a WAN, or
point-to-point circuit, instead of as a LAN.

                
                        ------------------
                        |                |
                        |  Frame-Relay   |
                        |     cloud      |
                        |  -----------   |
                        |  |         |   |
                        |  |         |   |
                        ------------------
                       DCE |         | DCE
                DLCI #101  |         | DLCI #100
                           |         | 
                           /         \
                          /           \
                         /             \
           17.1.1.251   /               \   17.1.1.252
                  DTE  /                 \  DTE
                ---------               ---------
                |  S0   |               |  S0   |
                | BRUTK |               | BRUTL |
                |  E0   |               |  E0   |
                ---------               ---------
        16.1.1.251 |                        | 18.1.1.252        
                   |                        | 
        -------------------------       ---------
            |               |
        ----------      ----------
        |   IP   |      |   IP   |
        | HOST   |      |  Host  |
        ----------      ----------
        16.1.1.1        16.1.1.2


********************************************************************************
                EXAMPLE DBR90 BRUTL CONFIGURATION
********************************************************************************

BRUTL#show config
!
version 10.0
!
! This is the version of the DECbrouter 90 code I used.
!
interface Ethernet0
!
ip address 18.1.1.252 255.255.255.0
!
! This IP address enables RIP routing on this interface.
!
interface Serial0
!
encapsulation frame-relay
!
! This command enables Frame Relay encapsulation running CHDLC.
!
frame-relay lmi-type ansi
!
! This command sets up the LMI type whether it be CISCO, ANSI or CCITT. You 
! need to ask your frame relay service provide what this should be configured
! for.
!
keepalive 15
!
! This is needed for LMI heart beat signals.
!
interface Serial0.1 point-to-point
!
! This command configures a subinterface and allows the DBR90 to treat FR as a
! WAN circuit instead of a LAN.
!
ip address 17.1.1.252 255.255.255.0
!
! This IP address enables RIP routing on this subinterface.
!
frame-relay interface-dlci 100
!
! There is NO requirement to map to the remote IP address (17.1.1.251) because
! this subinterface is treated as a WAN circuit. So we just need to map to the
! DLCI. 100 is the DLCI going to that remote router.
!
router rip
!
! This enables the RIP routing protocol on this router
!
network 18.0.0.0
!
! This command allows RIP to run on any interface with this assigned network
! address.
!
network 17.0.0.0
!
! This command allows RIP to run on any interface with this assigned network
! address.
!
redistribute static
!
! This command allows for an static defined routes to be advertised into RIP.
!
passive-interface Serial0.1
!
! This command disables RIP on the serial 0 interface. We need this to prevent
! the DECbrouter from sending RIP updates. The remote router should also have 
! this same command on its subinterface because this disables sending routing 
! updates but not receiving them.
!
ip route 16.1.1.251 255.255.255.255 17.1.1.251
!
! This command creates a static route to a remote IP host on the other side of 
! the frame-relay cloud. Notice that the mask is set to all 1's because we 
! want to map to a host address. The 17.1.1.251 is the remote WAN address of 
! BRUTK.
!
end

BRUTL#ping 16.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 16.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/11/16 ms

BRUTL#ping 16.1.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 16.1.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

BRUTL#show ip route
Codes: I - IGRP derived, R - RIP derived, O - OSPF derived
       C - connected, S - static, E - EGP derived, B - BGP derived
       i - IS-IS derived, D - EIGRP derived
       * - candidate default route, IA - OSPF inter area route
       E1 - OSPF external type 1 route, E2 - OSPF external type 2 route
       L1 - IS-IS level-1 route, L2 - IS-IS level-2 route
       EX - EIGRP external route

Gateway of last resort is not set

     16.0.0.0 is subnetted (mask is 255.255.255.255), 2 subnets
S       16.1.1.1 [1/0] via 17.1.1.251
     17.0.0.0 is subnetted (mask is 255.255.255.0), 1 subnets
C       17.1.1.0 is directly connected, Serial0.1
     18.0.0.0 is subnetted (mask is 255.255.255.0), 1 subnets
C       18.1.1.0 is directly connected, Ethernet0