Quick Answer: Which Of The Following Best Describes OSPF?

What layer is OSPF?

OSI layer designation IS-IS runs on the data link layer (Layer 2) Open Shortest Path First (OSPF) is encapsulated in IP, but runs only on the IPv4 subnet, while the IPv6 version runs on the link using only link-local addressing.

IGRP, and EIGRP are directly encapsulated in IP..

What is OSPF used for?

The OSPF (Open Shortest Path First) protocol is one of a family of IP Routing protocols, and is an Interior Gateway Protocol (IGP) for the Internet, used to distribute IP routing information throughout a single Autonomous System (AS) in an IP network.

Does OSPF use TCP or UDP?

OSPF messages ride directly inside of IP packets as IP protocol number 89. Because OSPF does not use UDP or TCP, the OSPF protocol is fairly elaborate and must reproduce many of the features of a transport protocol to move OSPF messages between routers.

How does OSPF avoid loops?

Because inter-area OSPF is distance vector, it is vulnerable to routing loops. It avoids loops by mandating a loop-free inter-area topology, in which traffic from one area can only reach another area through area 0.

Is OSPF Classful or classless?

Classful routing protocols do not carry subnet masks; classless routing protocols do. Older routing protocols, including RIP and IGRP, are classful. Newer protocols, including RIP-2, EIGRP, and OSPF, are classless.

Is OSPF open standard?

The Open Shortest Path First (OSPF) protocol is a link state protocol that handles routing for IP traffic. Its newest implementation, version 2, which is explained in RFC 2328, is an open standard. Open Shortest Path First (OSPF) is an open standard (not proprietary) and it will run on most routers independent of make.

What OSI layer is BGP?

Layer 4BGP is a Layer 4 protocol that sits on top of TCP.

What does an OSPF area contain?

An OSPF network can be divided into areas that are logical groupings of hosts and networks. An area includes its connecting router having interfaces connected to the network. Each area maintains a separate link-state database whose information may be summarized towards the rest of the network by the connecting router.

What are the main differences between the OSPF and IS IS routing protocols?

What are the main differences between the OSPF and IS-IS routing protocols? OSPF requires an area 0, while IS-IS does not. OSPF is a classful protocol, while IS-IS is a classless protocol. OSPF is a link state protocol, while IS-IS is not.

Why We Use Area in OSPF?

In OSPF, a single autonomous system (AS) can be divided into smaller groups called areas. This reduces the number of link-state advertisements (LSAs) and other OSPF overhead traffic sent on the network, and it reduces the size of the topology database that each router must maintain.

Why do we use AREA 0 in OSPF?

Because OSPF is link state the LSDB must be identical within an area. This is to ensure that the SPF calculation is consistent and to prevent routing loops. If running single area OSPF any area can be used, there is no requirement to have area 0. … An ABR is a router with adjacency in area 0 and at least one other area.

What is Area 0 called in OSPF?

backbone areaThe backbone area (Area 0) is the core of an OSPF network. All other areas are connected to it and all traffic between areas must traverse it. All routing between areas is distributed through the backbone area.