Welcome back.
And in this lesson, I want to talk about jumbo frames,
as well as how they're supported within AWS.
Now let's jump in straight away and get started.
So what is a jumbo frame?
Well, the maximum Ethernet V2 frame size is 1,500 bytes.
That's what you should think about
when you think of a standard frame.
Anything bigger than this is classified as a jumbo frame,
but generally when most people refer to jumbo frames,
they mean a frame with a maximum size of 9,000 bytes.
Now let's visually explore what jumbo frames are
and how they help improve performance
in certain networking situations.
Imagine the situation where you have four EC2 instances,
A, B, C, and D.
Now, A and B are connected, and C and D are connected.
A and B are using standard frames to communicate,
and C and D are using jumbo frames.
All frames have a static part,
which is known as the frame overhead.
Regardless of the size of the frame,
this is largely a standard size.
And then, there's the frame payload,
and this varies in size based on the data
that the frame is carrying up to a maximum size.
For normal frames, this is up to 1,500 bytes.
For jumbo frames,
this maximum increases to 9,000 bytes in size.
So this is what communications
between instance A and B might look like.
And remember, they're using standard frames.
Well, data is split between frames,
and the frames are transmitted on the shared medium.
And there are two things that you should consider.
First, there's always this frame overhead,
regardless of the payload size.
And second, there's always space between frames,
time where nothing is being transmitted.
This is used as one method of demarcation between frames.
So with normal frames,
you have a high ratio of overhead to payload size,
and this is pretty inefficient.
You also have more frames
because each frame can carry up to 1,500 bytes.
This means more frames per amount of data,
and this means more space between frames,
and logically, this means more wasted time on the medium.
Now compare this to how the same transfer might look
with jumbo frames.
See the difference.
You have more payload data per frame.
This means that the frame overhead represents
a much smaller component of the overall frame,
and this is more efficient.
Also larger frames mean more data per frame.
This means less frames for a given amount of data.
Less frames means you have less waste of the medium,
so the space between those frames,
and this is more efficient.
So that's why jumbo frames are good.
They're much more efficient when you're dealing
with demanding network applications.
But as always, there are some considerations
that you need to be aware of.
First, since ethernet, which is layer two,
generally carries higher level data inside the frames,
if you're communicating between two devices using IP,
for example, then you need to make sure
that every step supports the same size of jumbo frames,
because if you don't, you could have fragmentation.
Also not everything within AWS supports jumbo frames,
which means that if you have a communication pathway,
you do choose to use jumbo frames,
and part of it isn't compatible with jumbo frames,
then you will get fragmentation
and that will cause you problems.
So these are all things to keep in mind
if you do decide to use jumbo frames.
Now let's quickly step through some areas of AWS,
which do and don't support jumbo frames
before we finish this lesson.
So first, any traffic, which is outside of a single VPC
does not support jumbo frames.
Traffic over an inter-region VPC peering connection
doesn't support jumbo frames.
Same region VPC peering is compatible.
So that's important to understand.
Traffic over a VPN does not support jumbo frames.
Traffic using an internet gateway
does not support jumbo frames.
You are able to use jumbo frames over a direct connect
and transit gateway can support frames,
which are larger than usual but only up to 8,500 bytes.
So that's everything I wanted to cover in this lesson.
It's been brief, but it's an important part
of what you need to know for the exam.
With that being said, go ahead and complete this video,
and when you're ready,
I'll look forward to your joining me in the next.