Later adapted to carry IP prefixes in addition to CLNP. (known as Integrated or Dual IS-IS) as described in. RFC ▫ Predominantly used in ISP environment . Unused Features Some features defined in RFC are not in current use. Parker Informational [Page 2] RFC Interoperable IP Networks using IS-IS May. Intermediate System to Intermediate System is a routing protocol designed to move information (IP), the Network Layer protocol of the global Internet. This version of the IS-IS routing protocol was then called Integrated IS-IS (RFC ) .

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This article is about a computer network protocol. From Wikipedia, the free encyclopedia. OSPF has a larger set of extensions and optional features specified in the protocol standards. SPB allows for shortest-path forwarding in an Ethernet mesh network context utilizing multiple equal cost paths. The result is that an IS-IS router is only ever a part of a single area. 11995

This permits SPB to support large Layer 2 topologies, with fast convergence, and improved use of the mesh topology. Intermediate System to Intermediate System IS-ISalso written ISIS is a routing protocol designed to move information efficiently within a computer networka group of physically connected computers or similar devices. However IS-IS is easier to expand: This page was last edited on 28 Novemberat ISO standards by standard number.


RFC Use of OSI IS-IS for routing in TCP/IP and dual environments – Wikidata

In addition to that, IS-IS is less “chatty” and can scale to support larger networks. It accomplishes this by determining the best route for data through a packet-switched network. IS-IS is a link-state routing protocoloperating by reliably flooding link state information throughout a network rc routers. IS-IS has been called “the de facto standard for large service provider network backbones.

However, the basic concepts are similar.

The complete IS-IS routing protocol. Packets datagrams are then forwarded, based on the computed ideal path, through the network to the destination. IS-IS is an interior gateway protocoldesigned for use within an administrative domain or network.

International Organization for Standardization. Each IS-IS router independently builds a database of the network’s topology, aggregating the flooded network information.

IS-IS – Wikipedia

IS-IS is neutral regarding the type of network addresses for which it can route. For topics with similar names, see Isis disambiguation.

Both support variable length subnet maskscan use multicast to discover neighboring routers using hello packetsand can support authentication of routing updates. All articles with unsourced statements Articles with unsourced statements from February Pages using RFC magic links.


Level 1—2 routers exchange information with both levels and are used to connect the inter area routers with the intra area routers. Level 1 intra-area ; Level 2 inter area ; or Level 1—2 both. 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 dfc of a backbone of Level 2 routers with branches of Level 1—2 and Level 1 routers forming the individual areas.

119 routers are designated as being: Retrieved from ” https: As a result, they are conceptually similar.

Supported Standards for IS-IS

Routing information is exchanged between Level 1 routers and other Level 1 routers of the same area, and Level 2 routers can only form relationships and exchange information with other Level 2 routers. 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.

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