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BGP Oldest Path

BGP is the predominant dynamic routing protocol used to exchange routes between different autonomous systems. BGP’s popularity lies in the Path Selection process which allows extremely granular control of the path for incoming and outgoing traffic. One of the steps in this process states that if a tie still exists between two paths, BGP will […]

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Communication through Multiple Switches

Communication through Multiple Switches

In a previous article we demonstrated how a single switch functions. One of the most frequent requests I receive is asking how the process would be different if there were multiple switches. This article will illustrate the process using two switches. In the Packet Traveling series, we discussed the four specific functions of a switch: Learning, Flooding, Forwarding, […]

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Address Resolution Protocol (ARP)

arp-series-picture-200-whitebg

An IP address is the logical addressing scheme for nodes on a network. IP Addresses exist at the Network layer of the OSI Model and help facilitate the L3 goal of “end to end” delivery. A MAC address is the physical addressing scheme for individual NIC cards on each node of a network. MAC addresses […]

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ARP Probe and ARP Announcement

We finally come to the last iteration of ARP that this article series will discuss. They are the ARP Probe and the ARP Announcement. Both of these are used in a process known as Duplicate Address Detection. The idea is if a host acquires and puts to use an IP address that happens to already […]

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Gratuitous ARP

We’ve talked about Traditional ARP, where a node is requesting another node’s MAC address. We’ve also talked about Proxy ARP, where a node is answering an ARP request on behalf of another node. Which brings us to another iteration of ARP known as Gratuitous ARP. A Gratuitous ARP is an ARP Response that was not prompted […]