BGP - What is the MED BGP Attribute?

The Multi Exit Discriminator (MED), which is sometimes simply called the metric, is another attribute that is used by the BGP best path algorithm to determine the best path. MED is ideal for influencing how traffic enters a particular autonomous system (AS). In this video, we'll explain the MED attribute, how it works, and how it falls into place within the whole scheme of things.

Border Gateway Protocol, or BGP, is a routing protocol that uses a series of attributes to determine the best path through large networks such as the Internet. These attributes are examined in a standardized and predefined sequential order.

If you want to find out more about the BGP routing protocol, or the method by which attributes are used to determine the best path, take a look at some of my other videos linked below (after the chapter list...)

Chapter list:
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00:00 Introduction
00:28 What is MED?
02:35 Adjusting the MED
03:37 Characteristics of MED
05:02 Summary

Related links and videos:
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#bgp #bgpattribute #med #metric #pathalgorithm #lazarusagapidis

[SajadAhmadi-uoth]

Thank you for your exact and precise though simple and understandable explanations. I am looking forward to making more of these kind of topics from you. I love short but comprehensive videos.

[veekee_kay]

Lazarus, you are such wonderful teacher. Love your videos.

[saihanmarshall]

Very helpful video! You explain this very well, thank you.

[Peppe]

Thank you so much for your content. I have a question: you said that the MED value should be discussed with the neighboring AS administrator before implementing any change to it, because it might be seen as a hostile action. But why in the case of AS Path Prepending haven't you pointed out this detail? The purpose of of both AS Path Prepending and MED is to influence the incoming traffic to our AS. Therefore, what is the difference in this case?

[afaqshah]

Hey Lazarus i have a question if u can pls explain it .

Let say i have two connections from different ISPs then how can i control or manipulate the incoming traffic ?

[majiddehbi]

simple question what's a difference between metrics and attributs?

[rangiert]

Can you do a Video on BGP Communities?

[AshikKhan-lgxx]

Hi @Lazarus.telecomTech, kindly let me know if my understanding is correct.
We could have configure weight/localPreference in R3 to control the exit path via R1/R2. But there might be scenarios, like if we are connecting to ISP(which we can't control neither have access). So from R1/R2 we are trying to influence the traffic which is incoming to us. So in glance when we are configuring weight/localPreference to control the exit path, we are using #bgp <neighbor> routemap <XXX> IN --> As it it incoming traffic to the neighbor. And while for entry path we are doing #bgp <neighbor> routemap <XXX> OUT --> as it is outgoing traffic for the neighbor.