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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Supported Standards for IS-IS

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.

It accomplishes this by determining the best route for data through a packet-switched network.

IS-IS has been called “the de facto standard for large service provider network backbones. IS-IS is an interior gateway protocoldesigned for use within an administrative domain or network.

IS-IS is a link-state routing protocoloperating 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.


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

Packets datagrams are then forwarded, based on the computed ideal path, through the network to the destination. As a result, they are conceptually similar. Both support variable length subnet maskscan use multicast to discover neighboring routers using isjs packetsand can support authentication of routing updates. IS-IS is neutral regarding the type of network addresses for which it can route.

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.

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

Level 1—2 routers exchange information with both levels and are used to connect the inter area routers with the intra area routers.

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

The result is that an IS-IS router is only ever a part of a single area. 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 rrfc topology issi a backbone of Level 2 routers with branches of Level 1—2 and Level 1 routers forming the individual areas.


However, the basic concepts are similar. OSPF has a larger set of extensions and optional features specified in the protocol standards. However IS-IS is easier to expand: In addition to that, IS-IS is less “chatty” and can scale to support larger networks. SPB allows for shortest-path izis in an Ethernet mesh network context utilizing multiple equal cost paths.

This rdc SPB to support large Layer 2 topologies, with fast convergence, and improved use of the mesh topology. From Wikipedia, the free encyclopedia.

This article is about a computer network protocol. For topics with similar names, see Isis disambiguation.

Retrieved May 24, International Organization for Standardization. The complete IS-IS routing protocol. ISO standards by standard number.

Retrieved from ” https: All articles iss unsourced statements Articles with unsourced statements from February Pages using RFC magic links. Views Read Edit View history. This page was last edited on 28 Novemberat By using this site, you agree to the Terms of Use and Privacy Policy.