An ivory tower comment on that: The current discussions in the IRTF Routing Research Group, and in particular the LISP proposal, strongly suggest a future in which a lot of inter-ISP traffic will be encapsulated, in order to avoid unbounded growth in the BGP4 table. So it would be wise for IXs to allow for a reasonable encapsulation header on top of 1500B. LISP currently needs a 56B header for IPv6 encapsulation. See section 5 of http://tools.ietf.org/id/draft-farinacci-lisp Among other things, it says: Based on informal surveys of large ISP traffic patterns, it appears that most transit paths can accommodate a path MTU of at least 4470 bytes. Brian On 2008-09-22 10:47, Alastair Johnson wrote:
Hi,
I was wondering if anyone has seen a general trend to supporting >1500B MTUs on Internet transit and peering sessions?
I recall from years ago that AGC/ANC/PacNet supported interface-default MTUs, meaning that ATM connected customers had 4470B MTU.
Obviously these days with most people running GE or XE in their networks with MPLS and 802.1Q you are looking at networks capable internally of jumbograms, but is anyone running this across network boundaries?
Are there any plans for the NZ IXs to be jumbo-capable?
I'd be interested in hearing from anyone who is jumbo-enabled on their transit connections, and particularly interested in hearing if they are seeing any significant number of packets that are >1500B on the Internet.
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