Is OSPF Link State?

Where is OSPF used?

People use OSPF when they discover that RIP just isn’t going to work for their larger network, or when they need very fast convergence..

What is BGP AS number?

An Autonomous System Number (AS number or just ASN) is a special number assigned by IANA used primarilly with Border Gateway Protocol which uniquely identifies an network under a single technical administration that has a unique routing policy, or is multi-homed to the public internet.

What algorithm does BGP use?

Introduction. Border Gateway Protocol (BGP) routers typically receive multiple paths to the same destination. The BGP best path algorithm decides which is the best path to install in the IP routing table and to use for traffic forwarding.

IS IS routing protocol vs OSPF?

Differences between OSPF and IS-IS Routing Protocols OSPF supports NBMA and point-to-multipoint links, whereas IS-IS does not support. IS-IS runs on the data link layer, whereas OSPF runs on the network layer. OSPF supports virtual link, whereas IS-IS does not support.

Is OSPF TCP or UDP?

OSPF Packets OSPF routers communicate using IP packets. 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.

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.

Why OSPF is used in MPLS?

In an MPLS network, OSPF is not used to route customer traffic. It is only used to provide routing for the internal provider network so that labels can be generated. LDP is used to advertise these labels to neighboring label-switched routers.

Does OSPF use hop count?

Like EIGRP, OSPF bases its metric by default on link bandwidth, so that OSPF makes a better choice than simply relying on the router hop-count metric used by RIP. But OSPF uses much different internal logic, being a link-state routing protocol rather than a distance vector protocol.

Why is BGP used?

Border Gateway Protocol (BGP) is used to Exchange routing information for the internet and is the protocol used between ISP which are different ASes. The protocol can connect together any internetwork of autonomous system using an arbitrary topology.

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.

OSPF is not a distance-vector protocol like RIP, but a link-state protocol with a set of metrics that can be used to reflect much more about a network than just the number of routers encountered between source and destination. In OSPF, a router attempts to route based on the “state of the links.”

The OSPF protocol is a link-state routing protocol, which means that the routers exchange topology information with their nearest neighbors. The topology information is flooded throughout the AS, so that every router within the AS has a complete picture of the topology of the AS.

Is BGP distance vector?

“Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information between autonomous systems (AS) on the Internet. The protocol is often classified as a path vector protocol but is sometimes also classed as a distance-vector routing protocol.”

Why BGP is path vector protocol?

BGP is a path vector routing protocol and does not contain a complete topology of the network-like link state routing protocols. BGP behaves similar to distance vector protocols to ensure a path is loop free.