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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In addition to that, IS-IS is less “chatty” and can scale to support larger networks.

Packets datagrams are then forwarded, based on the computed ideal path, through the network to the destination. It accomplishes this by determining the best route for data through a packet-switched network.

However, the basic concepts are similar. All articles with unsourced statements Articles with unsourced statements from February Pages using RFC magic links. SPB allows izis shortest-path forwarding in an Ethernet mesh network context utilizing multiple equal cost paths. 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.


From Wikipedia, the free encyclopedia. IS-IS is a link-state routing protocolrrfc by reliably flooding link state information throughout a network isiss routers.

Each IS-IS router independently builds a database of the network’s topology, aggregating the flooded network information. International Organization for Standardization. However IS-IS is easier to expand: ISO standards by standard number. The result is that an IS-IS router is only isus a part of a single area. By using this site, you agree to the Terms of Use and Privacy Policy.

Supported Standards for IS-IS – TechLibrary – Juniper Networks

This page was last edited on 28 Novemberat IS-IS is 11195 regarding the type of network addresses for which it can route. 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.

IS-IS has been called “the de facto standard for large service provider network backbones. This map indicates the subnets which each IS-IS router can reach, and the lowest-cost shortest path to a subnet is used 1159 forward traffic.

Supported Standards for IS-IS

This permits SPB to support large Layer 2 topologies, with fast convergence, and improved use of the mesh topology. Both support variable length subnet maskscan use multicast to discover neighboring routers using hello packetsand can support authentication of routing updates.


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 ; Rfd 2 inter 119 ; or Level 1—2 both. As a result, they are conceptually similar.

This article is about a computer network protocol. The complete IS-IS routing protocol. Retrieved from ” https: 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.

Retrieved May 24, IS-IS is an interior gateway protocoldesigned for use within an administrative domain or network. Views Usis Edit View history.

rfd IS-IS routers are designated as being: OSPF has a larger set of extensions and optional features specified in the protocol standards. For topics with similar names, see Isis disambiguation.