Network technologies and trends » OSPFv2 http://itknowledgeexchange.techtarget.com/network-technologies Wed, 15 May 2013 18:52:38 +0000 en-US hourly 1 OSPF from CCNA- ICND2 perspective – Series 2 http://itknowledgeexchange.techtarget.com/network-technologies/ospf-from-ccna-icnd2-perspective-series-2/ http://itknowledgeexchange.techtarget.com/network-technologies/ospf-from-ccna-icnd2-perspective-series-2/#comments Sun, 31 Oct 2010 18:36:07 +0000 Yasir Irfan http://itknowledgeexchange.techtarget.com/network-technologies/ospf-from-ccna-icnd2-perspective-series-2/ Most people were introduced to OSPF as the first link-sate routing protocol and some of the features of OSPF are as follows,

  • Consists of areas and autonomous systems
  • Minimizes routing update traffic
  • Allows scalability
  • Supports VLSM/CIDR
  • Has unlimited hop count
  • Allows multi-vendor deployment (open standard)

Do know these features well from CCNA point of view.

The below table compares OSPF with the distance vector routing protocols like RIP1 and RIP2

Characteristic OSPF RIP2 RIP1
Type of protocol Link state Distance vector Distance vector
Classless support Yes Yes No
VLSM support Yes Yes No
Auto-summarization No Yes Yes
Manual summarization Yes No No
Discontiguous support Yes Yes No
Route propagation Multicast on change Periodic multicast Periodic broadcast
Path metric Bandwidth Hops Hops
Hop count limit None 15 15
Convergence Fast Slow Slow
Peer authentication Yes Yes No
Hierarchical network Yes (using areas) No (flat only) No (flat only)
Updates Event triggered Route table updates Route table updates
Route computation Dijkstra Bellman-Ford Bellman-Ford
]]> http://itknowledgeexchange.techtarget.com/network-technologies/ospf-from-ccna-icnd2-perspective-series-2/feed/ 0 OSPF from CCNA- ICND2 perspective – Series 1 http://itknowledgeexchange.techtarget.com/network-technologies/ospf-from-ccna-icnd2-perspective-series-1/ http://itknowledgeexchange.techtarget.com/network-technologies/ospf-from-ccna-icnd2-perspective-series-1/#comments Sat, 30 Oct 2010 10:55:05 +0000 Yasir Irfan http://itknowledgeexchange.techtarget.com/network-technologies/ospf-from-ccna-icnd2-perspective-series-1/ If you are preparing for your CCNA or ICND2 certification exam for sure you are going to encounter OSPF. Open Shortest Path First (OSPF) is a better choice when you have a heterogeneous network, yes it’s a open standard routing protocol which over comes the major draw backs of Distance vector protocols like RIP 1 and RIP2. OSPF is a link state protocol, which can be quite useful on a large network with hundreds of routers.

Unlike Distance vector protocols OSPF will not exchange full route updates at short interval rather the routing updates are send once there is a change in routing topology. Using the  Dijkstra algorithm,OSPF first constructs the shortest path tree and then the routing table is populated which results in best paths to the destination. Due to this behavior, OSPF is able to recalculate the routes very fast in case of topology changes or a failure in link occurred. One of the OSPF’s advantage is convergence occurs quite fast and its scalable. Currently OSPFv2 is used with IPv4 networks and IPv6 networks use OSPFv3. OSPF also supports Variable-Length Subnet Masking (VLSM) and Classless Inter-Domain-Routing (CIDR).

In upcoming post I will talk about how OSPF works? and I will compare it with RIP1 and RIP2

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