What is Ospf in Networking | basic configuration | Tamil | IP Software S...

Click here to view my video on youtube for below mentioned case study with real routers

 

Open Shortest Path First:

OSPF is an OPen source Link State Routing Protocol that Makes its metric as Cost which is equal to 10^8 / bandwidth.

• OSPF is a Area Based and process based Routing Protocol.
• It is based on Dijikstra Link State Routing Algorithm
• IT does not send updates often like RIP
• The Complete convergence time is 30 minutes
• It has HEllo timer and dead timer which is 4 times the Hello timer
• It's protocol number is 89
• Ospf maintains link state database (lSA)
• there are 7 types of lsa
• The OSPF's important Aspect is that BACKBONE AREA is 0
• Multicast Address:
  • 224.0.0.5
  • 224.0.0.6
• Hello Interval:
  • default of 10 seconds
• Dead interval
  • four times the Hello interval
• Administrative Distance Value is 110
• Packets in OSPF
  • hello packets
  • Dead Packets
  • update packets
  • LSAs
  • Request
  • acknowledgement
• Tables inOSPF
  • Routing Table- Basic table for routes
  • Topology table - The common database for OSPF routers
  • Neighbor Table- Table which shows the neighbor information
• Router-ID
  • This is actually, the  name of the particular router in OSPF which makes more important in OSPF network
  • It will be assigned automatically and even we can make it manual by
  • router-id a.b.c.d
  • Conditions
    • 1-highest Router loopback interface
    • 2-Highest active physical interface IP address
    • sh ip protocols will verify
  • Router id is used in DR and BDR election and also in neighbor establishment
• Type of Routers in OSPF
  • DR (Designated Router)
  • BDR (Back up Designated Router)
  • ABR (Area Border Router)
    • The router which connects AREA 0 with another area.
  • ASBR (Autonomous System Boundary Router)
    • The Router which connects to the external system or other routing Protocols or other ISP
  • Internal Router
• Note : The concept of Dr and Bdr election will be explained in my next blog

• Type of OSPF networks :

• Point-point network type
• Broadcast network type
• non broadcast network type
• point to multipoint network Type

• States in OSPF

• Down  - No information (hellos) has been received from     neighbor.
• Attempt   - Manually configured neighbors in an NBMA
• Init   - Router has received a hello packet from its      neighbor
• 2-Way   - Bi-directional communication
• Exstart   - DR and BDR are election
• Exchange   - Router exchange database  description (DBD)
• Loading   - Exchange of link state information
• Full   - Routers are fully adjacent with each other

Configurations of OSPF :