Chapter 19 IP Configuration

OSPF offers some advantages over traditional vector-space routing protocols (such as RIP). The following table summarizes some of the major differences between OSPF and RIP.

Table 117 OSPF vs. RIP

 

OSPF

RIP

Network Size

Large

Small (with up to 15 routers)

 

 

 

Metrics

Bandwidth, hop count, throughput, round

Hop count

 

trip time and reliability.

 

 

 

 

Convergence

Fast

Slow

 

 

 

19.8.1 OSPF Autonomous Systems and Areas

An OSPF autonomous system can be divided into logical areas. Each area represents a group of adjacent networks. All areas are connected to a backbone (also known as area 0). The backbone is the transit area to route packets between two areas. A stub area, at the edge of an AS, is not a transit area since there is only one connection to the stub area.

19.8.2 Interfaces and Virtual Links

An OSPF interface is a link between a layer 3 device and an OSPF network. An interface has state information, an IP address and subnet mask associated with it. When you configure an OSPF interface, you first set an interface to transmit OSPF traffic and add the interface to an area.

You can configure a virtual link to establish/maintain connectivity between a non-backbone area and the backbone. The virtual ink must be configured on both layer 3 devices in the non- backbone area and the backbone.

19.8.3 Configuring Basic OSPF Settings

Follow the steps below to activate OSPF and configure basic settings.

1In the Device Panel list, right-click on a device.

2Click Configuration > IP Configuration > OSPF.

 

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NetAtlas Workgroup User’s Guide