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Edge Router

  Edge router : Also called a Provider Edge router, is placed at the edge of an ISP network. The

router uses External BGP to EBGP protocol routers in other ISPs, or a large

enterprise Autonomous System. 

INGRIS RouterAn egress router is a Label Switch Router that is an end point (drain) for a given Label SwitchedPath (LSP). An egress router may be an ingress router or an intermediate router for any otherLSP(s). Hence the role of egress and ingress routers is LSP specific. Usually, the MPLS label isattached with an IP packet at the ingress router and removed at the egress router, whereas labelswapping is performed on the intermediate routers. Core RouterA core router is a router designed to operate in the Internet backbone, or core. To fulfill this role, arouter must be able to support multiple telecommunications interfaces of the highest speed in use inthe core Internet and must be able to forward IP packets at full speed on all of them. It must alsosupport the routing protocols being used in the core. A core router is distinct from an edge router: edge routers sit at the edge of a backbone network and connect to core routers. 

Fast Switching in Routers

Process switching requires the CPU to be personally involved with every forwarding decision.

Fast switching still uses the CPU, but after a packet has been forwarded, information about how to reach thedestination is stored in a fast-switching cache. This way, when another packet going to the same destination is seen,

the next hop information can be re-used from the cache, so the processor doesn’t have to look up and assemble allthe information again. If the information is not cached, (for example a first packet for a given destination network) theCPU will have a similar workload, for that packet, as if fast switching was not in use.

Cisco Express Forwarding (CEF), is the evolution of optimizing the router to make it be able to forward more packetsfaster. CEF cheats a little, by building a Forwarding Information Base (FIB), and an adjacency table. The FIB isaccessed very quickly based on how they built it (it is Cisco proprietary), and contains pre-computed reverse lookups,next hop information for routes including the interface and L2 information to use. (All the stuff a router would have toconsider when forwarding a packet).

In short:

Process switching is like doing math, long hand.

Fast switching, using the cache, is like doing a problem once long hand, and subsequent problems you remember the

answer for, (from memory, or the cache).

CEF is like having programmed an excel spreadsheet, and when the numbers hit the cells, the answer is alreadycalculated.

How many types of Plan in Routers & how it works...

Data Plans & Control Plans

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O & M Plan

User Plan