Open Shortest Path First (OSPF) || 2020 || Ser-2
- 1. Pt. Ravishankar Shukla University Raipur (C.G.) A Presentation on OSPF(Open Shortest path first ) Session 2015-16 Submitted by NUTAN SINGH Roll No. 25
- 2. INTRODUCTION OF ROUTING PROTOCOL LINK STATE CONCEPTS OVERVIEW OF OSPF MULTI AREA OSPF AREA TERMINOLOGY ROUTER TYPES IN OSPF ESTABLISHING ADJACENCIES WITH NEIGHBORS OSPF MAINTAINS THREE TABLES CONFIGURING OSPF ADVANTAGES LIMITATIONS CONCLUSION REFERENCES 2
- 3. Routing is the process that a router uses to forward packets toward the destination network. processes for sharing route information allows routers to communicate with other routers to update and maintain the routing tables Examples of routing protocols that support the IP routed protocol are: RIP, IGRP,OSPF, BGP, and EIGRP. Most routing algorithms can be classified into one of two categories: • distance vector • link-state 3
- 4. “Link-state routing algorithms maintain a complex database of topology information”. Link-state routing uses: • Link-state advertisements (LSAs) A link-state advertisement (LSA) is a small packet of routing information that is sent between routers. • Topological database A topological database is a collection of information gathered from LSAs. • SPF algorithm The shortest path first (SPF) algorithm is a calculation performed on the database resulting in the SPF tree. • Routing tables – A list of the known paths and interfaces. 4
- 5. OSPF stand for Open Shortest path first Standard protocol It’s a link state protocol It uses SPF (shortest path first) or dijkistra algorithm Unlimited hop count Metric is cost (cost=10 ^8/B.W.) Administrative distance is 110 It is a classless routing protocol It supports VLSM and CID 5
- 6. It supports only equal cost load balancing Introduces the concept of Area’s to ease management and control traffic Provides hierarchical network design with multiple different areas Must have one area called as area 0 All the areas must connect to area 0 Scales better than Distance Vector Routing protocols. Updates are sent through multicast address 224.0.0.5 Faster convergence. Sends Hello packet every 10 seconds trigger updates 6
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- 9. Router Types In OSPF depending upon the network design and configuration we have different types of routers. 1) Internal Routers are routers whose interfaces all belong to the same area. These routers have a single Link State Database. 2) Area Border Routers (ABR) It connects one or more areas to the backbone area and has at least one interface that belongs to the backbone, Backbone Router Area 0 routers. 3) Autonomous System Boundary Router (ASBR) Router participating in OSPF and other protocols (like RIP, EIGRP and BGP) 9
- 11. 1) Neighbor Table:- Neighbor table contains information about the directly connected ospf neighbors forming adjacency. 2) Database table:- Database table contains information about the entire view of the topology with respect to each router. 3) Routing information Table:- Routing table contains information about the best path calculated by the shortest path first algorithm in the database table. 11
- 12. Syntax:- Router(config)# router ospf <pid> Router(config-router)# network <Network ID> <wildcard mask> area <area id> Example:- Router(config)# router ospf 1 Router(config-router)# network 10.0.0.0 0.255.255.255 area 0 12
- 13. · Open standard · No hop count limitations · Loop free · Faster convergence 13
- 14. ·Consume more CPU resources · Support only equal cost balancing · Support only IP protocol don’t work on IPX and APPLE Talk . Summarization only on ASBR and ABR 14
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