Since it is not performing L2 blocking, configure the EAPS transit core switch as the DR by using a higher OSPF priority value. The EAPS master core switch is configured as the BDR. The aggregation transit switches need not perform DR/BDR duties for the backbone VLAN, so their OSPF priority is configured at 0 to force ODR behavior.
Core-Switch#1 OSPF configuration:
* CORE-SWITCH#1.12 # configure vlan backbone ipaddress 192.168.1.1/24 * CORE-SWITCH#1.13 # enable ipforwarding vlan backbone * CORE-SWITCH#1.14 # configure ospf routerid 192.168.1.1 * CORE-SWITCH#1.15 # configure ospf add vlan backbone area 0.0.0.0 * CORE-SWITCH#1.16 # configure ospf vlan backbone priority 110 * CORE-SWITCH#1.17 # enable ospf
Core-Switch#2 OSPF configuration:
* CORE-SWITCH#2.12 # configure vlan backbone ipaddress 192.168.1.2/24 * CORE-SWITCH#2.13 # enable ipforwarding vlan backbone * CORE-SWITCH#2.14 # configure ospf routerid 192.168.1.2 * CORE-SWITCH#2.15 # configure ospf add vlan backbone area 0.0.0.0 * CORE-SWITCH#2.16 # configure ospf vlan backbone priority 100 * CORE-SWITCH#2.17 # enable ospf
Agg-Switch#1 OSPF configuration:
* AGG-SWITCH#1.11 # configure vlan backbone ipaddress 192.168.1.3/24 * AGG-SWITCH#1.12 # enable ipforwarding vlan backbone * AGG-SWITCH#1.13 # configure ospf add vlan backbone area 0.0.0.0 * AGG-SWITCH#1.14 # configure ospf vlan backbone priority 0
Agg-Switch#2 OSPF configuration:
* AGG-SWITCH#2.11 # configure vlan backbone ipaddress 192.168.1.4/24 * AGG-SWITCH#2.12 # enable ipforwarding vlan backbone * AGG-SWITCH#2.13 # configure ospf add vlan backbone area 0.0.0.0 * AGG-SWITCH#2.14 # configure ospf vlan backbone priority 0