Ccna

One of the greatest functions of the OSI specifications is to assist in data transfer between disparate hosts regardless if they’re Unix, Windows or Mac based. But keep in mind that the OSI model isn’t a physical model; it’s a conceptual and comprehensive yet fluid set of guidelines, which application developers utilize to create and implement applications that run on a network. It also provides a framework for creating and implementing networking standards, devices, and internetworking schemes. The OSI model has seven layers:
■■ Application (Layer 7)
■■ Presentation (Layer 6)
■■ Session (Layer 5)
■■ Transport (Layer 4)
■■ Network (Layer 3)
■■ Data Link (Layer 2)
■■ Physical (Layer 1)

Configuring OSPF 1

OSPF essential design is extremely basic. Much the same as with other routing protocols covered so far (RIP, EIGRP) first you have to empower OSPF on a router. This is finished by utilizing the router OSPF PROCESS-ID worldwide design direction. Next, you have to characterize on which interfaces OSPF will run and what networks will be advertised. This is finished by utilizing the network IP_ADDRESS WILDCARD_MASK AREA_ID order from the OSPF configuration mode.

OSPF (Open Shortest Path First) is a connection state routing protocol. Since it is an open standard, it is executed by an assortment of system merchants. OSPF will keep running on most routers that don’t really need to be Cisco routers (not at all like EIGRP which can be run just on Cisco routers).

Here are the most imperative highlights of OSPF:

• a classless routing protocol
• underpins VLSM, CIDR, manual route synopsis, level with cost stack adjusting
• incremental updates are upheld
• utilizes just a single parameter as the metric – the interface cost.
• the administrative distance of OSPF courses is, as a matter of course, 110.
• utilizes multicast addresses 224.0.0.5 and 224.0.0.6 for routing updates.

Routers running OSPF need to build up neighbor connections before trading routes. Since OSPF is a connection state routing protocol, neighbors don’t trade steering tables. Rather, they trade data about network topology. Each OSFP router at that point runs SFP calculation to ascertain the best routes and adds those to the routing table. Since every switch knows the whole topology of a router, the shot for a routing circle to happen is negligible.

RIPv1 is a Distance-Vector Routing protocol

• RIPv1 is a Classful routing protocol. Classful routing protocols bolster just the systems which are not subnetted. Classful routing protocols don’t send subnet veil data with their routing updates. As it were, on the off chance that you have a subnetted arrange in your RIPv1 directing area, RIPv1 will declare that network to different as un subnetted organize.

RIPv1 does not support VLSM (Variable Length Subnet Masking)

• RIPv1 bolster greatest metric (jump tally) estimation of 15. Any switch more remote than 15 jumps away is considered as inaccessible.

Inside Gateway Protocol (IGP): A routing protocol that was outlined and proposed for use inside a solitary self-sufficient framework (AS)

Known Interior Gateway Protocols (IGP) are Routing Information Protocol (RIP), Interior Gateway Routing Protocol (IGRP), Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS)

Outside Gateway Protocol (EGP): A routing protocol that was composed and planned for use between various self-sufficient frameworks Exterior Gateway Protocol (EGP) is ordinarily utilized on the Internet to trade directing table data. There is just a single Exterior Gateway Protocol (EGP) exists and it is Border Gateway Protocol (BGP).