DTP: Concept Notes

This post is part of a series of revision notes I put together and used for studying CCNP Switch concepts. I am now writing them up on this website so that they might be useful to others.

They formed a part of my notes intended to explain concepts in simple terms. I hope they come in use, but as a reminder, please do not use these notes as any indication of what is sufficient for CCNP level understanding.

Let’s get started.

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TCP 3 Way Handshake

For data to be sent across the Internet, traffic is sent over either TCP or UDP. This post will focus on how a TCP session is established, for more information on the differences between UDP and TCP click here.

In order for a TCP session to be established between 2 devices, a process known as the TCP 3 Way Handshake must occur.

How It Works

We know that TCP uses sequence numbers when sending packets, this is part of how the order of packets are verified, and a great way to identify any missing data that might have been lost in transit.

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Lab: HSRP Example

Building on top of the HSRP Concept Notes I posted previously, here we will demonstrate a practical example of how HSRP is configured and how it works.

Let’s begin.



You work for a company specialising in Car Sales. This company has 2 sites, one in London and the other in Tokyo.

Both sites have 2 Edge Routers connecting to the ISP. Your job is to use HSRP to ensure that regardless of what Edge Router is being used to send/receive traffic between sites, traffic will be continuous and will experience minimal disruption if either Edge Router fails.

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