Does changing MTU and multicast settings on an interface affect the active user data traffic?

[SThatipelly]

I am adding another OSPF neighbor to a sub interface. This needs a change in MTU size. does this affect the user data traffic on this sub interface?

I am little worried about doing this during business hours but also at the same time, it is a urgent change.

Thanks.

[BPry · Accepted solution]

@SThatipelly,

Raising or lowering MTU? If I was raising the MTU I wouldn't really worry about it that much as long as I know the rest of my network is capable of supporting it. If I was lowering MTU on the interface I absolutely wouldn't do it during business hours unless someone had a very good reason to justify the risk. 

It's not like the interface is going to just drop all the active traffic or anything like that. It's just that your modifying MTU during business hours, and with that comes the risk of modifying the MTU.