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Re: 10 gige experience
From: Greg Maxwell <gmaxwell () martin fl us>
Date: Thu, 10 May 2001 08:31:46 -0400 (EDT)


On Fri, 11 May 2001, Chris Wedgwood wrote:

    Anyone know any good articles on 10GB ethernet? I am specifically
    intrested if they have removed some of the legacy requirements
    that hamper gigabit ethernet (such as a default MTU of 1500,
    half-duplex, etc.)

Not answering your question, but GigE can use larger frames than 1500
bytes, however, if you wish to send these outside your network,
you'll likely need to fragment them this somewhat less useful... of
course, Jumbo Frames are still useful within your network, but then
again most switches don't support them[1].

Which is why I said 'default' MTU of 1500. I think it should have been a
requirement of all 100TX devices to be able to accept FDDI sized packets,
a requirement of GIGE to switch FDDI sized packets, etc.. Thats not what
happened.

The problem is that there is no graceful way to handle mixed MTU's at that
layer. As a result, the default is to use legacy sized MTUs, which results
in new equpment which can not handle the larger MTUs, resulting in the
further delay of end-to-end jumbogram support.

At some point, they need to draw a line and say that reception and
switching of large >1500 byte packets must be supported and generation of
such packets should be an option. This will finally make is possible for
people to jumbogram enable their networks.
 



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