VLAN tagging and Google Wifi

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taylorjamesbarr

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#243331 6-Dec-2018 14:56

I recently got Google Wifi and had it all set up on my network just fine, connecting through a D-Link Router on Voyager fibre. I asked Voyager to disable VLAN tagging so that Google Wifi could connect directly to the ONT.

That's all done and it works perfectly fine.

My question is: What's the risk/benefit to having VLAN tagging enabled or disabled. Couldn't find much online about this.

jnimmo

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#2140631 6-Dec-2018 15:16

Ah I should let someone else answer this as feeling a bit rusty on it, but I believe the benefit of having tagging enable allows you to designate some traffic to use a 2.5Mbps high priority channel; i.e. for VoIP traffic (assuming your ISP is also tagging the downstream traffic as high priority).

Essentially meaning you can protect 2.5Mbps of upstream bandwidth to your ISP for a specific purpose, but keeping in mind it is also limited to 2.5Mbps.

Untagged traffic defaults to low priority which has a 2.5Mbps committed information rate (with burst up to your connection speed)

Real world I wouldn't expect to be any benefits.

cyril7

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#2140638 6-Dec-2018 15:35

Hi, jnimmo nearly had it right. By having tagged traffic you can utilise traffic priority, this is a parameter thats embedded within the tag, if the traffic is untagged then there is no way to set the priority.

Reality however is that you are unlikely to ever use it or need it.

Cyril

lucky015

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#2140641 6-Dec-2018 15:47

cyril7:

Hi, jnimmo nearly had it right. By having tagged traffic you can utilise traffic priority, this is a parameter thats embedded within the tag, if the traffic is untagged then there is no way to set the priority.

Reality however is that you are unlikely to ever use it or need it.

Cyril

Agree with it not being overly necessary however I'm aware of at least one provider who's default hardware uses the CIR for DNS and SIP traffic so by default so I'd assume there would be others that do the same.

Realistically the provisioned service speed will define if it's worth while as with a 30/10 service you have less headroom than in a Max/500 (1000/500) service.

qwerty123

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#2140752 6-Dec-2018 17:48

cyril7:

if the traffic is untagged then there is no way to set the priority.

Offtopic :) but what about ToS/DSCP byte of IP header?

cyril7

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#2140757 6-Dec-2018 18:02

Hi, Chorus only provide a Layer2 transit, therefore for "their" network to understand que priority they need to use the vlan tag. The transport and honour of layer3 DSCP etc I doubt anyone would honour or care about over the "internet" at large.

Cyril

qwerty123

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#2140768 6-Dec-2018 18:43

cyril7:

Hi, Chorus only provide a Layer2 transit, therefore for "their" network to understand que priority they need to use the vlan tag. The transport and honour of layer3 DSCP etc I doubt anyone would honour or care about over the "internet" at large.

Cyril

I doubt the provider mentioned by lucky015 does CIR for DNS/SIP using L2 prioritisation either. And anyway any meaningful prioritisation would involve a provider-supplied CPE rather than Google Wifi.

taylorjamesbarr:

My question is: What's the risk/benefit to having VLAN tagging enabled or disabled. Couldn't find much online about this.

Main purpose of VLAN tagging is segregation of traffic and confinement of broadcast traffic traversing through the same link. So the benefit is ease of administration for ISP. Risk for end user when VLAN tagging disabled is possible flood of packets from unrelated networks.