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Radiotech
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MPLS network not passing traffic

Tue May 25, 2021 3:24 am

Afternoon

I have recently deployed an MPLS network using RB2011L's and for the switch's CSS326's. This network is setup to connect multiple remote communications sites via Microwave. I have 6 different VLAN's, each network needs to be isolated as they each carry information serving different agencies/customers. Only Vlan 30 and 40 have active DHCP as they are the only networks I really want touching the internet automatically for end devices.

I have included the config files for a couple of my routers, the switches are setup to have 1 trunk port and then the rest are partitioned out to the different vlans. Outside site 1, I am not able to get access to web pages, I can ping dns servers just fine, just can actually get to any web site. The main Ubiquity firewall serves also as the VLAN internet pipes and DHCP server via a trunk line hooked to the Site1 switch. Again at site 1 everything is great, but once is goes over the MPLS/VPLS pipe things start to fail.

I am looking at my Microwave links as well to see if they are an issue, but my old network that was just switches connected at each end passed internet just fine. Included diagram of old and new network.

Just looking for places to look at for possible issues, I know I have probably flub it up somewhere in the path.

Thank you.
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StubArea51
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Re: MPLS network not passing traffic

Tue May 25, 2021 8:00 pm

This sounds like a classic MTU issue with MPLS transport.

Your configs show MPLS MTU at 1530 which is the minimum for tagged VPLS but your VPLS MTUs for mtu and l2mtu as higher (1598 and 2028). You can't transport MTUs in VPLS higher than the underlying MPLS transport of 1530 or you need a higher MPLS MTU
 
Radiotech
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Re: MPLS network not passing traffic

Wed May 26, 2021 7:30 pm

Thank you for getting back to me,

MTU is something that always hurts my brain. I set my MTU on the MPLS settings to 1500, and now I have good internet flow. I am wondering if there is a device on the Microwave links that can not go above a certain MTU. At least things are flowing better now, see if I can tune it up a bit, but good for now.

Thank you again very much!
 
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StubArea51
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Re: MPLS network not passing traffic

Thu May 27, 2021 3:45 pm

Thank you again very much!

You're welcome! MTU math takes a while to understand so don't feel bad :)

Don't forget to mark the solution as "solved"

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