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Although modern networks rarely if ever use IPX or AppleTalk, EIGRP can now support IPv6, which is rapidly growing in popularity. Multiprotocol Support: EIGRP was originally designed to support the routing of multiple protocols, including IPv4, IPX, and AppleTalk.Specifically, EIGRP was made an open standard in 2013, and an EIGRP informational RFC (RFC 7868) was published in 2016. Was Cisco-Proprietary: While Cisco originally introduced EIGRP as a Cisco-proprietary routing protocol, in recent years EIGRP has been opened up to other vendors.Specifically, EIGRP for IPv4 uses a multicast address of 224.0.0.10, while EIGRP for IPv6 uses a multicast address of ff02::a. Communicates via Multicast: An EIGRP-speaking router communicates with other EIGRP-speaking routers via multicast.Variable-Length Subnet Mask (VLSM) Support: Unlike RIP version 1, EIGRP sends subnet mask information as part of a route advertisement.This is made possible by the variance feature. However, EIGRP can be configured to load balance across links with unequal costs. Load Balancing Over Unequal Cost Links: By default, both EIGRP and OSPF load balance traffic across more than one link leading to a specific destination network, if the cost (that is, the value of the routing protocol metric) is the same.Highly Scalable: Whereas a routing protocol such as RIP has a limit of fifteen router hops, EIGRP can scale to support very large enterprise networks, such as the Walt Disney World network mentioned earlier.This fast convergence is made possible by EIGRP having a standby route to a network, and that standby route is ready to take over in the event the primary route fails. This typically happens in no more than 3 seconds. Fast Convergence: If a link goes down in a network, in many cases EIGRP can rapidly reroute around the link failure.Let’s being our EIGRP review by reminding ourselves of a few basic EIGRP characteristics: That’s my take, but I certainly won’t harbor any ill feelings for you if you’re on the “hybrid” side of the debate. Rather, EIGRP’s topology table lists available networks, along with information about the “distance” to those networks. EIGRP does not maintain a view of the network’s topology, nor does it run the Dijkstra Algorithm. These routers (speaking routing protocols such as OSPF and IS-IS) then run the Dijkstra Algorithm on that topology to determine the “shortest” path to a destination network from the perspective of a particular router. Here’s my reasoning: Consider the fundamental characteristic of a link state routing protocol, which is routers maintaining a topology table, indicating how routers are interconnected. While I was in the “it’s a hybrid routing protocol” camp for many years, recently I converted to the belief that EIGRP is an “advanced distance vector” routing protocol.
Eigrp ip fast reroute full#
At its essence, is EIGRP a link state routing protocol or a distance vector routing protocol? Or, is it a hybrid routing protocol (that is, a combination of both)? You’ll find lots of literature supporting the notion that EIGRP is a hybrid routing protocol, arguing that EIGRP neighbors initially exchange their full routing table, much like a distance vector routing protocol, and EIGRP only sends routing updates based on network changes, much like a link state routing protocol. There’s a long-running debate about the fundamental nature of EIGRP. Therefore, this series of blog posts is going to review and reinforce those fundamental EIGRP concepts, and even introduce a few other fun facts.
Eigrp ip fast reroute tv#
However, unless you have an eidetic memory (like Sheldon Cooper on The Big Bang Theory TV show), you probably don’t remember every single EIGRP command and concept. If you already have your CCNA R/S certification (or higher), you’re probably well acquainted with EIGRP.
Eigrp ip fast reroute series#
That’s the focus of this blog post, which is the first of a series of posts focusing on EIGRP. What was the routing protocol keeping all of these routers in agreement about available routes? It was Enhanced Interior Gateway Routing Protocol (EIGRP).
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Their massive network contained over 500 Cisco routers (and thousands of Cisco Catalyst switches). I used to work as a Network Design Specialist at Walt Disney World, in Florida.