[j-nsp] Bonding multiple L2 Services with OSPF

[Ben Dale]

Hi all,

I have a couple of J-Series plugged into a VPLS service (so  
essentially a large layer 2 domain).  I have a single subnet  
containing the WAN interfaces of each router, and I'm running an OSPF  
in order to distribute the LAN-facing subnets of each box.

At one of my sites, the carrier was unable to deliver a single 1Mbps  
service, so instead they have delivered 2x 512Kbps circuits.  I have  
assigned each of the interfaces on the attached router an address in  
the same subnet (which JUNOS warns about, but commits anyway).  OSPF  
establishes on both interfaces, but the LAN subnet is only being  
learnt by other routers via one of the interfaces (presumably because  
the Router ID from both advertisements is the same).  Are there any  
knobs to get around this, or alternatively is there another way to  
bond the two interfaces (other than advertising half the LAN out each  
link)?  The usual per-packet forwarding ECMP options don't work here,  
because there aren't two prefixes being learnt by other routers.

Lab config shown:

ge-0/0/2 {
     description "RegionA LAN";
     unit 0 {
         family inet {
             address 192.168.102.254/24;
         }
     }
}
ge-0/0/2 {
     description "xxx VPLS Link 1";
     unit 0 {
         family inet {
             address 172.16.0.4/24;
         }
     }
}
ge-0/0/3 {
     description "xxx VPLS Link 2";
     unit 0 {
         family inet {
             address 172.16.0.3/24;
         }
     }
}
protocols {
     ospf {
         export export-direct;
         area 0.0.0.0 {
             interface ge-0/0/3.0;
             interface ge-0/0/2.0;
         }
     }
}
policy-options {
     policy-statement export-direct {
         from {
             protocol direct;
             route-filter 192.168.0.0/16 prefix-length-range /24-/24;
         }
         then accept;
     }
}

bdale at RegionB# run show ospf neighbor
Address          Interface              State     ID                
Pri  Dead
172.16.0.1       ge-0/0/2.0             Full      10.0.0.238        
128    36
172.16.0.2       ge-0/0/2.0             Full      10.0.0.237        
128    35
172.16.0.1       ge-0/0/3.0             Full      10.0.0.238        
128    36
172.16.0.2       ge-0/0/3.0             Full      10.0.0.237        
128    35
...
bdale at DCRegion> show ospf route
Topology default Route Table:

Prefix             Path   Route       NH   Metric  NextHop       Nexthop
                    Type   Type        Type         Interface     addr/ 
label
10.0.0.236         Intra  AS BR       IP        1  ge-0/0/3.0     
172.16.0.4
10.0.0.238         Intra  AS BR       IP        1  ge-0/0/3.0     
172.16.0.1
172.16.0.0/24      Intra  Network     IP        1  ge-0/0/3.0
192.168.100.0/24   Ext2   Network     IP        0  ge-0/0/3.0     
172.16.0.1
192.168.102.0/24   Ext2   Network     IP        0  ge-0/0/3.0     
172.16.0.4


Cheers,

Ben