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Abner
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MPLS and MTU

Wed Sep 16, 2020 4:46 pm

Hello.
We have about 40 routers MPLS/VPLS network.. Old devices are CCR10xx and new ones CRS317 and CCR2004. There is problems to get VPLS tunnels working properly. Any recomendations to MTU?
Interface Max L2MTU is different between ccr10xx and ccr20xx. Almost all links are Dark Fiber, but some redundancy links are capasity from a third party, and different MTU.
i know that MPLS is sensitive about MTU. Any recommendations / basic rules?


does anyone have any recommendations for a qualified consultant about this?
 
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CZFan
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Re: MPLS and MTU

Wed Sep 16, 2020 9:40 pm

...

does anyone have any recommendations for a qualified consultant about this?

If you are South Africa based, I can assist
 
mada3k
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Re: MPLS and MTU

Sun Sep 27, 2020 12:59 pm

A full regular Ethernet frame is 1514 bytes.
With VPLS [mpls+vpls+cw] tags thats +12 bytes (=1526)
Then you need a Ethernet frame around it (=1540)

We use 1560 as MPLS-MTU and 1580 as L2MTU.

https://wiki.mikrotik.com/wiki/Manual:M ... uterBoards
 
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StubArea51
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Re: MPLS and MTU

Sun Sep 27, 2020 3:23 pm

i know that MPLS is sensitive about MTU. Any recommendations / basic rules?
I typically recommend that most ISPs running MPLS start with the settings below. This is from a presentation I gave at the MikroTik US MUM

https://mum.mikrotik.com/presentations/ ... 279781.pdf

Image

does anyone have any recommendations for a qualified consultant about this?
Feel free to contact us at iparchitechs.com, we run the largest MikroTik consulting firm in the world and have helped hundreds of networks running MikroTik.
 
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Re: MPLS and MTU

Sun Oct 04, 2020 12:55 am

Thanks guys.. We are located EU.

Mikrotik default MPLS mtu is 1530, if I understood correctly, then it must be raised if the end customer needs qinq, for example.
 
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StubArea51
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Re: MPLS and MTU

Tue Oct 06, 2020 7:15 pm

Mikrotik default MPLS mtu is 1530, if I understood correctly, then it must be raised if the end customer needs qinq, for example.

yes if you want QinQ then you'll need at least 1534 to support two tags.

IP ArchiTechs has engineers in the EU (+2 time zone) as well as North and South America.

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