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joegoldman
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MLAG and VLANS

Mon Aug 01, 2022 5:42 pm

Hi,

Consider the following:

Router1->LACP->MLAG->sw1/sw2<-MLAG<-LACP<-Router2

So redundant core, 2 routers MLAG to a set of switches. All ports are in the same one big bridge.

The goal is to plug single handoff providers into 1 of the 2 switches. So say ISP1 plugs into sw1, port 5, VLAN10.
To access this ISP on both routers, must I tag VLAN10 on a trunk port to access devices on sw2, or will ICCP take care of any tagged packets in/out over it's untagged vlan?
I ask as if traffic is coming in on sw1 but sw2 holds the only active MLAG members for one of the routers (assuming a failure state), will sw1 know to send via ICCP port or does it need a trunk port tagged to send it via.

This is all on 7.4 switches with Cisco ASR1000 routers

Thanks in advance for your help
 
adcre
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Re: MLAG and VLANS  [SOLVED]

Tue Aug 02, 2022 1:29 am

Hello,

You have to pass that vlan also on peerport in order to have that redundancy:

see https://help.mikrotik.com/docs/display/ ... tion+Group
the example is done with vlan1, but in your situation you can add vlan 10 (it is needed to be tagged)

Best Regards,

Diego
 
eduplant
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Re: MLAG and VLANS

Tue Aug 02, 2022 8:18 am

It’s not always welcome but when I read scenarios like this I like to raise some questions to make sure that what’s possible is the same as what’s wise.

Using cheaper switches (like Mikrotik) to act as port expanders for expensive ASR ports makes sense, but what exactly is the goal of bridging the two switches together and/or using MLAG? From reading it sounds like some of the providers are only providing one link. Are there others providing a LAG? And what benefit do you get by striping such a LAG across two switches?
 
joegoldman
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Re: MLAG and VLANS

Wed Aug 03, 2022 12:16 am

It’s not always welcome but when I read scenarios like this I like to raise some questions to make sure that what’s possible is the same as what’s wise.

Using cheaper switches (like Mikrotik) to act as port expanders for expensive ASR ports makes sense, but what exactly is the goal of bridging the two switches together and/or using MLAG? From reading it sounds like some of the providers are only providing one link. Are there others providing a LAG? And what benefit do you get by striping such a LAG across two switches?
Redundancy, both in ports and chassis.
Some providers are single hand-off, others we'd like LAG where they let us.
We would also put provider 1 in sw1, but then provider 2 in sw2, so in instance of a switch chassis failure, we do lose one provider until we can re-patch it but the other provider takes over.

It's still not a perfect solution, and the preferred solution was Juniper QFX's at the core but alas, inflated costs and wait times necessitated a partial build to get this site off the ground.
 
joegoldman
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Re: MLAG and VLANS

Wed Aug 03, 2022 12:17 am

Hello,

You have to pass that vlan also on peerport in order to have that redundancy:

see https://help.mikrotik.com/docs/display/ ... tion+Group
the example is done with vlan1, but in your situation you can add vlan 10 (it is needed to be tagged)

Best Regards,

Diego
Hrmm you are right, I used that guide to set it up in the first place and totally glossed over that bit and its application to all other VLANs. Thanks for that, makes sense. I'm happy can use the same link for both ICCP and inter-switch trunking, saves a few extra cables and optics.
 
adcre
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Re: MLAG and VLANS

Wed Aug 03, 2022 1:12 am

You are welcome.

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