# Introduction to VLANs

**URL:** <https://forum.networklessons.com/t/introduction-to-vlans/867>\
**Category:** Lessons Discussion\
**Created:** [December 20, 2016, 10:07pm UTC](https://forum.networklessons.com/t/introduction-to-vlans/867 "2016-12-20T22:07:07Z")\
**Posts on this page:** 4\
**Page:** 6

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**Author:** ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis)\
**Post date:** [February 7, 2024, 6:50am UTC](https://forum.networklessons.com/t/introduction-to-vlans/867/102 "2024-02-07T06:50:51Z")

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Hello Jose

That’s great to hear! We wish you success in your endeavor, and we hope NetworkLessons will help you along the way! And if you have any questions, you know where to find us.

Looking forward to seeing you on the forum!

Laz

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**Author:** ![sathish84be](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/s/a88e57/32.png) [@sathish84be](https://forum.networklessons.com/u/sathish84be)\
**Post date:** [June 16, 2024, 9:34pm UTC](https://forum.networklessons.com/t/introduction-to-vlans/867/103 "2024-06-16T21:34:43Z")

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![image](https://forum.networklessons.com/uploads/default/original/2X/9/99823bc8e3ef3289b663581c795f2a192b3f8295.png)  
Hi team, first of all thank you for this forum which helps me build my basics more solidly. Now I am having doubts about the numbers 1536 and 1500 in this snippet which i took from “Ethernet Type Topic”. Are you referring to MTU or something else? Could you please provide a brief explanation? It would be much appreciated.

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**Author:** ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis)\
**Post date:** [June 18, 2024, 10:28am UTC](https://forum.networklessons.com/t/introduction-to-vlans/867/104 "2024-06-18T10:28:17Z")

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Hello Sathish

The snippet you shared comes from the [NetworkLessons note titled Ethernet Frame Types](https://notes.networklessons.com/ethernet-frame-types) . The note explains how a network device distinguishes between an Ethernet II and 802.3 Ethernet frame.

These values are not MTU sizes. They are the numerical values that exist within the field in the header that comes after the Source address.

- If the value of that field is 1536 or larger, then the frame is treated as an Ethernet II frame, and the very next field is interpreted as the EtherType field.
- If the value of that field is 1500 or smaller, then the frame is treated as an 802.3 Ethernet header, and thus the very next field is interpreted as the Length field.

Take a look at the two types of Ethernet frames here:

 ![image](https://forum.networklessons.com/uploads/default/original/2X/b/b685fd7e2ae14f9fe28844b20be734bf84d1f3b9.png)

Depending on the value that is read in the circled fields, as described above, the frame is interpreted accordingly.

The NetworkLessons note I referenced above has more details.

I hope this has been helpful!

Laz

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**Author:** ![sathish84be](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/s/a88e57/32.png) [@sathish84be](https://forum.networklessons.com/u/sathish84be)\
**Post date:** [June 18, 2024, 7:17pm UTC](https://forum.networklessons.com/t/introduction-to-vlans/867/105 "2024-06-18T19:17:38Z")

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Thank you for the explanation

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