Unicast Routing
20-14
20
Configuring the Open Shortest Path First Protocol
Open Shortest Path First (OSPF) is more suited for large area networks which
experience frequent changes in the links. It also handles subnets much better than
RIP. OSPF protocol actively tests the status of each link to its neighbors to generate
a shortest path tree, and builds a routing table based on this information. OSPF then
utilizes IP multicast to propagate routing information. A separate routing area
scheme is also used to further reduce the amount of routing traffic.
Note:
The OSPF protocol implemented in this device is based on RFC 2328 (Version 2).
It also supports RFC 1583 (early Version 2) compatibility mode to ensure that the
same method is used to calculate summary route costs throughout the network
when older OSPF routers exist; as well as the not-so-stubby area option
(RFC 3101).
Command Usage
• OSPF looks at more than just the simple hop count. When adding the shortest path
to any node into the tree, the optimal path is chosen on the basis of delay,
throughput and connectivity. OSPF utilizes IP multicast to reduce the amount of
routing traffic required when sending or receiving routing path updates. The
separate routing area scheme used by OSPF further reduces the amount of routing
traffic, and thus inherently provides another level of routing protection. In addition,
all routing protocol exchanges can be authenticated. Finally, the OSPF algorithms
have been tailored for efficient operation in TCP/IP Internets.
backbone
normal
area
NSSA
isolated
area
stub
Autonomous System A
Autonomous System B
external network
Router
ABR
ABR
ABR
ABR
ASBR
ASBR
ASBR
virtual
link
Summary of Contents for 8926EM
Page 6: ...ii ...
Page 34: ...Getting Started ...
Page 44: ...Introduction 1 10 1 ...
Page 62: ...Initial Configuration 2 18 2 ...
Page 64: ...Switch Management ...
Page 76: ...Configuring the Switch 3 12 3 ...
Page 118: ...Basic Management Tasks 4 42 4 ...
Page 164: ...User Authentication 6 28 6 ...
Page 176: ...Access Control Lists 7 12 7 ...
Page 284: ...Quality of Service 14 8 14 ...
Page 294: ...Multicast Filtering 15 10 15 ...
Page 300: ...Domain Name Service 16 6 16 ...
Page 310: ...Dynamic Host Configuration Protocol 17 10 17 ...
Page 320: ...Configuring Router Redundancy 18 10 18 ...
Page 344: ...IP Routing 19 24 19 ...
Page 356: ...Unicast Routing 20 12 20 Web Click Routing Protocol RIP Statistics Figure 20 5 RIP Statistics ...
Page 386: ...Unicast Routing 20 42 20 ...
Page 388: ...Command Line Interface ...
Page 400: ...Overview of the Command Line Interface 21 12 21 ...
Page 466: ...SNMP Commands 24 16 24 ...
Page 520: ...Access Control List Commands 26 18 26 ...
Page 546: ...Rate Limit Commands 30 2 30 ...
Page 612: ...VLAN Commands 34 24 34 ...
Page 626: ...Class of Service Commands 35 14 35 ...
Page 670: ...DHCP Commands 39 16 39 ...
Page 716: ...IP Interface Commands 41 36 41 ...
Page 768: ...IP Routing Commands 42 52 42 ...
Page 770: ...Appendices ...
Page 791: ......