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Bury the hatchet

OSPF DR/BDR Election Myth

OSPF DR/BDR election process is something that is full of many details, i hope that in the following thread i can cover its main aspects. Each multi-access segment (ex: Ethernet Segment), will have 1 DR and 1 BDR. Each router on the segment forms a Full adjacency with the DR/BDR. Keep in mind that a router might be a DR/BDR on one of its attached multi-access networks, and it might not be the DR/BDR on another of its attached multi-access networks. In other words, the DR/BDR is a property of a router’s interface, not the entire router. Now, how are …

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OSPF RID Story

Understanding the need for OSPF RID and how to control it is indeed a very important aspect to take care of when dealing with OSPF. The RID is a dotted decimal value used by OSPF routers to identify the other OSPF routers. Beside being used in OSPF operations, and to identify the neighbors in the output of the show commands, OSPF depends on the RID in many configuration aspects such as virtual-links, manipulating distance per neighbor, and others. Cisco routers derive their Router IDs by the following means: 1. If the Router ID has been manually configured using the router-id …

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The ip route-cache command – Bury the hatchet series

From what I’ve seen in the practical life, this command puzzles many people, i hope to cover it throughly. Controlling the packet switching method depends upon which method we are talking about, in the case of CEF Switching its all about the ingress interface and has nothing to do with the egress interface, accordingly despite the configuration under the egress interface, if the ingress interface was CEF enabled then the traffic will be CEF Switched (the packet will be handled via an interrupt routine rather than the IP Input process). While in the case of Fast Switching the IOS builds …

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