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OSPF 'ip ospf mtu-ignore' Question

Hey Guys,

If I have a router with 3 sub interfaces off of a GigabitEthernet interface which is directly connected to a switch via a trunk, would I need to set 'ip ospf mtu-ignore'?

I'm assuming that if I'm running subinterfaces using dot1q, that the mtu in the DBD packets will be 1504 and which it hits either a router port on a L3 switch or a SVI it would be 1500?

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Super Bronze

Re: OSPF 'ip ospf mtu-ignore' Question

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

John the router's subinterface and the switch's trunk should "hide" the VLAN tags.  I.e. there shouldn't be any need for mtu-ignore (as least I never recall a need for it on such configurations).

2 REPLIES
Super Bronze

Re: OSPF 'ip ospf mtu-ignore' Question

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

John the router's subinterface and the switch's trunk should "hide" the VLAN tags.  I.e. there shouldn't be any need for mtu-ignore (as least I never recall a need for it on such configurations).

Re: OSPF 'ip ospf mtu-ignore' Question

Thanks for this response, I appreciate it. I was a little curious as to how that would work.

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