Avaya 8800 Planning And Engineering page 142

Layer 3 network design
Figure 56: Example 2: OSPF on two subnets in one area
The routers in example 2 have the following settings:
• S1 has an OSPF router ID of 1.1.1.1, and the OSPF port is configured with an IP address
of 192.168.10.1.
• S2 has an OSPF router ID of 1.1.1.2, and two OSPF ports are configured with IP
addresses of 192.168.10.2 and 192.168.20.1.
• S3 has an OSPF router ID of 1.1.1.3, and the OSPF port is configured with an IP address
of 192.168.20.2.
The general method used to configure OSPF on each routing switch is:
1. Enable OSPF globally.
2. Insert IP addresses, subnet masks, and VLAN IDs for the OSPF ports on S1 and
3. Enable OSPF for each OSPF port allocated with an IP address.
When all three switches are configured for OSPF, they elect a DR and BDR for each subnet
and exchange hello packets to synchronize their link state databases.
Example 3: OSPF on two subnets in two areas
The following figure shows an example where OSPF operates on two subnets in two OSPF
areas. S2 becomes the ABR for both networks.
142 Planning and Engineering — Network Design
S3 and for the two OSPF ports on S2. The two ports on S2 enable routing and
establish the IP addresses related to the two networks.
November 2010