I am not completely sure what you would find on exchange points, but for pure Internet service I would assume that 1500 (or ~1500) is still the most common MTU mostly because of the support on lower end CPEs and lots of legacy hardware/configuration.
The only real exception I see around is when carriers build modern MetroE and MPLS/VPN cores. They are all being deployed today with higher MTU values as close as possible to the ~9000 Byte MTU value. This is done as there is demand for this kind of services especially from enterprises buying circuits and VPNs to interconnect their DCs etc. Most of the modern devices (or newer modules for older systems) support something close to ~9000 Byte MTUs. Arie -----Original Message----- From: cisco-nsp-boun...@puck.nether.net [mailto:cisco-nsp-boun...@puck.nether.net] On Behalf Of Lawrence E. Bakst Sent: Thursday, March 18, 2010 06:39 To: cisco-nsp@puck.nether.net Cc: l...@iridescent.org Subject: [c-nsp] MTU at Gb/sec transit and higher I apologize if this is somewhat off-topic. I searched for this and found almost no information. I found this, but it's almost 10 years old and it seems like he gave up: http://staff.psc.edu/mathis/MTU/ 1. If I purchase GbE transit from a provider what size is the MTU likely to be? Is it still ~1500 bytes? 2. At any point closer to the core of the "internet" does the MTU step up from 1500 bytes to some larger value and are jumbo frames utilized? Or worse does the MTU step down from 1500 bytes? 3. What size MTU is used at (major) peering points? I am expecting the answers to all the above to be "it's all ~1500 bytes" but I want to confirm that. 4. Does most of the current Cisco gear used by NSPs support jumbo frame on GbE and faster interfaces? If anyone has any insight or comments I'd be happy to get them either on or off list. If off list please use the email below. Best, leb -- l...@iridescent.org _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/