IEEE 802.1ad Access Network


It seems like 802.1ad is basically Q-in-Q, which I know how to setup, but on the Cisco switches i get 802.1q packets when doing Q-in-Q. I’m curious if there’s a way to get 802.1ad packets. I’ve had a try at the Chapter: Configuring IEEE 802.1ad on the Cisco configuration guides but I never seem to acquire 802.1ad packets through wireshark when following that guide.

Hello Ethan

One of the things that happens with telecom and networking is that some names seem to stick even though they have been officially changed. What I mean by this is that when you applied 802.1ad, and you looked it up in wireshark, you probably saw the 802.1Q Virtual LAN statement in wireshark and figured that it’s still using 802.1q and not 802.1ad. Well, the truth is that even though 802.1ad has superseded 802.1q in 2011, many professionals, and organizations still refer to the feature as 802.1Q. This is especially prevalent in the term QinQ. It just sounds so cool, that people couldn’t stop using it. Try saying ADinAD… it just doesn’t work :stuck_out_tongue:.

So when you tried implementing 802.1ad and “failed” I believe you actually succeeded. Why? Take a look at the following wireshark output. It says 802.1Q but actually, it is 802.1ad. You can verify this by the fact that it indicates a Drop Eligibility Indicator (DEI) field. 802.1ad replaced the Canonical Format Identifier (CFI) with the DEI field, so this is indeed 802.1ad.

I hope this has been helpful!