IS-IS also differs from OSPF in the methods by which it reliably floods topology and topology change information through the network.

PNNI uses the same shortest-path-first algorithm used by OSPF and IS-IS to route IP packets to share topology information between switches and select a route through a network.

Dijkstra's algorithm is used in SPF, Shortest Path First, which is used in the routing protocols OSPF and IS-IS.

MPLS Traffic Engineering relies upon the use of TE extensions to Open Shortest Path First ( OSPF ) or Intermediate System To Intermediate System ( IS-IS ) and RSVP.

Interior routing mostly uses link-state routing protocols such as OSPF and IS-IS.

Like the OSPF protocol, IS-IS uses Dijkstra's algorithm for computing the best path through the network.

IS-IS was developed at roughly the same time that the Internet Engineering Task Force IETF was developing a similar protocol called OSPF.

Both IS-IS and OSPF are link state protocols, and both use the same Dijkstra algorithm for computing the best path through the network.

While OSPF is natively built to route IP and is itself a Layer 3 protocol that runs on top of IP, IS-IS is natively an OSI network layer protocol ( it is at the same layer as CLNS ).

In OSPF, areas are delineated on the interface such that an area border router ( ABR ) is actually in two or more areas at once, effectively creating the borders between areas inside the ABR, whereas in IS-IS area borders are in between routers, designated as Level 2 or Level 1-2.

The logical view is that OSPF creates something of a spider web or star topology of many areas all attached directly to Area Zero and IS-IS by contrast creates a logical topology of a backbone of Level 2 routers with branches of Level 1-2 and Level 1 routers forming the individual areas.

Given the same set of resources, IS-IS can support more routers in an area than OSPF.

* OSPF and IS-IS: A Comparative Anatomy by Dave Katz, Juniper

* IS-IS and OSPF difference discussion ( Vishwas Manral, Manav Bhatia and Yasuhiro Ohara )

RFC 3717 documents work in optical routing for IP, based on " constraint-based " extensions to OSPF and IS-IS.

In most current networking environments, RIP is not the preferred choice for routing as its time to converge and scalability are poor compared to EIGRP, OSPF, or IS-IS ( the latter two being link-state routing protocols ), and ( without RMTI ) a hop limit severely limits the size of network it can be used in.

As a result, the shortest path first is widely used in network routing protocols, most notably IS-IS and OSPF ( Open Shortest Path First ).

Examples of link-state routing protocols include OSPF and IS-IS.

The technique was later adapted for use in the contemporary link-state routing protocols IS-IS and OSPF.

Link-state routing protocols such as Open Shortest Path First ( OSPF ) and IS-IS elect a designated router on every link to perform flooding of topology information.

Since link-state routing requires the topology database to be synchronized across the network, OSPF and IS-IS perform topology flooding using a reliable algorithm.

Protocols that support some form of adjacency setup, such as OSPF or IS-IS, may also be used to bootstrap a BFD session.

BFD's operation in conjunction with Open Shortest Path First ( OSPF ) and IS-IS protocols has also been outlined in RFC 5881.

One version of RIP served as one of the initial so-called interior gateway protocols for the growing Internet, before the arrival of the more modern OSPF and IS-IS.

NSAP-style addresses are used in the IS-IS routing protocol.

The IS-IS protocol was developed by Digital Equipment Corporation as part of DECnet Phase V. It was standardized by the ISO in 1992 as ISO 10589 for communication between network devices which are termed Intermediate Systems ( as opposed to end systems or hosts ) by the ISO.

IS-IS routers are designated as being: Level 1 ( intra-area ); Level 2 ( inter area ); or Level 1-2 ( both ).

The family of classless routing protocols are RIPv2, Open Shortest Path First, EIGRP, IS-IS and Border Gateway Protocol.

Networking advances IEEE 802. 1aq ( SPB ) include the use of the link-state routing protocol IS-IS to allow larger networks with shortest path routes between devices.

Intermediate System To Intermediate System ( IS-IS ), usually called is-is, is a routing protocol designed to move information efficiently within a computer network, a group of physically connected computers or similar devices.

IS-IS has been called " the de facto standard for large service provider network backbones.

IS-IS ( pronounced " i-s i-s ") is an interior gateway protocol, designed for use within an administrative domain or network.

IS-IS is a link-state routing protocol, operating by reliably flooding link state information throughout a network of routers.

Each IS-IS router independently builds a database of the network's topology, aggregating the flooded network information.

The purpose of IS-IS was to make possible the routing of datagrams using the ISO-developed OSI protocol stack called CLNS.

IS-IS was later extended to support routing of < em > datagrams </ em > in the Internet Protocol ( IP ), the Network Layer protocol of the global Internet.

IS-IS does not use IP to carry routing information messages.

IS-IS is neutral regarding the type of network addresses for which it can route.

This allowed IS-IS to be easily used to support IPv6.

IS-IS routers build a topological representation of the network.

This map indicates the subnets which each IS-IS router can reach, and the lowest-cost ( shortest ) path to a subnet is used to forward traffic.