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NetAtlas Enterprise Ethernet Switch Manager User’s Guide
165 Chapter 18 IP Configuration
18.2 OSPF
OSPF (Open Shortest Path First) is a link-state protocol designed to distribute routing
information within an autonomous system (AS). An autonomous system is a collection of
networks using a common routing protocol to exchange routing information.
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.
18.2.1 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.
18.2.2 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.
Direction The Direction field controls the sending and receiving of RIP packets. When set to:
• Both - the switch will broadcast its routing table periodically and incorporate the RIP
information that it receives.
• Incoming - the switch will not send any RIP packets but will accept all RIP packets
received.
• Outgoing - the switch will send out RIP packets but will not accept any RIP packets
received.
• None - the switch will not send any RIP packets and will ignore any RIP packets received.
Version Select the RIP version from the drop-down list box. Choices are RIP-1 , RIP-2B and RIP-
2M .
Apply Click Apply to save the changes.
Table 85 IP Configuration: RIP (continued)
LABEL DESCRIPTION
Table 86 OSPF vs. RIP
OSPF RIP
Network Size Large Small (with up to 15 routers)
Metrics Bandwidth, hop count, throughput, round
trip time and reliability.
Hop count
Convergence Fast Slow