MTU size

trudeau02 · 09-26-2008, 09:35 AM

Hi,

Does anyone know if the MTU size must be the same on both sides of a link? If my MTU on Router A is set to 1500 and is connected to Router B which has an MTU of 9600, will my data still traverse the link? My understanding is that if RTRA sends packets greater than 1500, it will be fragmented, therefore, would router B be able to unfragment the packet?

For example:

RTRA ------- Ethernet ------- RTRB
MTU1500 MTU9600

Thanks,

**johnwill** · 09-27-2008, 10:14 AM

You are obviously talking about jumbo packets on the one router. In order to use jumbo packets, you need all the equipment to support them. What will actually happen is the jumbo packet will come in and be rejected, then it will have to be retransmitted again in the proper size. This will make the performance really suck!

09-26-2008, 09:35 AM	#1 (permalink)
trudeau02 Registered User Join Date: Sep 2008 Posts: 1 OS: xp	MTU size Hi, Does anyone know if the MTU size must be the same on both sides of a link? If my MTU on Router A is set to 1500 and is connected to Router B which has an MTU of 9600, will my data still traverse the link? My understanding is that if RTRA sends packets greater than 1500, it will be fragmented, therefore, would router B be able to unfragment the packet? For example: RTRA ------- Ethernet ------- RTRB MTU1500 MTU9600 Thanks,

09-27-2008, 10:14 AM	#2 (permalink)
johnwill Manager, Networking Forums Join Date: Sep 2002 Location: S.E. Pennsylvania, US Posts: 41,654 OS: Windows 7, XP-Pro, Vista, Linux Blog Entries: 1	Re: MTU size You are obviously talking about jumbo packets on the one router. In order to use jumbo packets, you need all the equipment to support them. What will actually happen is the jumbo packet will come in and be rejected, then it will have to be retransmitted again in the proper size. This will make the performance really suck! __________________ If TSF has helped you, Tell us about it! or Donate to help keep the site up! Microsoft MVP - Windows Desktop Experience