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George90
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Minimal mtu for VPLS

Mon Dec 11, 2017 6:12 am

I want to replace existing EoIP tunnels with VPLS. They are used to transport pppoe form AP to main location where is pppoe server located.
For some links ubiquiti equipment is used and their max MTU is 1500.

Is there any benefit switching to VPLS in my case?
What is max MTU that I can get on VPLS tunnels?

Of course, I want to avoid packet fragmentation.
Reading wiki and this forum I figured out that 1500 is not enough for VPLS. By default /mpls interface MTU value is set to 1508.
 
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Kickoleg
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Re: Minimal mtu for VPLS

Mon Dec 11, 2017 8:29 am

 
sup5
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Re: Minimal mtu for VPLS

Mon Dec 11, 2017 9:07 am

If you ensure a consistent MPLS-MTU throughout your whole network, then any MTU should do.

Mikrotik is doing fragmentation and reassembly automatically if the frame size needed by VPLS is exceeded.
Traffic within VPLS will not notice it has been fragmented and reassembled.
Thus you can transport any framesize through VPLS in a 1500 bytes MTU network.

Still there is a downside: more load on the CPU of the encapsulating and decapsulating router.
 
sri2007
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Re: Minimal mtu for VPLS

Wed Jan 10, 2018 6:51 pm

Hello, we suggest to use a MPLS MTU of 1530bytes.
 
wurstel
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Re: Minimal mtu for VPLS

Wed Feb 14, 2018 7:25 pm

hi
i think is really good a configuration of Tunnel terminator like this but i have a question.. using a pppoe server that is not in the middle of the others u don't have the sum of tx and tx traffic in eth connection? (ex. traffic of all pppoe clients are 1G download and 200M upload. U see in eth that connect router to the network 1.2G in download and 1.2G in up. traffic is go into the pppoe server and go out).
thank you and I hope I have explained well.
 
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mrz
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Re: Minimal mtu for VPLS

Wed Feb 14, 2018 7:33 pm

Take into account that any tunnel adds overhead, so you will have different numbers on tunnel interface and on actual Ethernet interface.

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