[96008] in North American Network Operators' Group
RE: Thoughts on increasing MTUs on the internet
daemon@ATHENA.MIT.EDU (Leigh Porter)
Fri Apr 13 10:56:39 2007
Date: Fri, 13 Apr 2007 15:52:30 +0100
From: "Leigh Porter" <leigh.porter@ukbroadband.com>
To: <Valdis.Kletnieks@vt.edu>, "Saku Ytti" <saku+nanog@ytti.fi>
Cc: "NANOG list" <nanog@merit.edu>
Errors-To: owner-nanog@merit.edu
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I don't think it matters that everything can use jumbograms or that =
every single device on the Internet supports them. Heck, I still know =
networks with kit that does not support VLSM!
What would be good is if when a jumbogram capable path on the Internet =
exists, jumbograms can be used.
This way it does not matter than some box somewhere does not support =
anything greater than a 1500 byte MTU, anything with such a box in the =
path will simply not support a jumbogram. How do you find out? Just send =
a jumbogram across the path and see what happens.. ;-)
--
Leigh Porter
UK Broadband
-----Original Message-----
From: owner-nanog@merit.edu on behalf of Valdis.Kletnieks@vt.edu
Sent: Fri 4/13/2007 3:36 PM
To: Saku Ytti
Cc: NANOG list
Subject: Re: Thoughts on increasing MTUs on the internet
=20
On Fri, 13 Apr 2007 08:22:49 +0300, Saku Ytti said:
>=20
> On (2007-04-12 20:00 -0700), Stephen Satchell wrote:
> =20
> > From a practical side, the cost of developing, qualifying, and =
selling=20
> > new chipsets to handle jumbo packets would jack up the cost of =
inside=20
> > equipment. What is the payback? How much money do you save going =
to=20
> > jumbo packets?
>=20
> It's rather hard to find ethernet gear operators could imagine using =
in
> peering or core that do not support +9k MTU's.
Note that the number of routers in the "core" is probably vastly =
outweighted
by the number of border and edge routers. There's a *lot* of old eBay =
routers
out there - and until you get a clean path all the way back to the =
source
system, you won't *see* any 9K packets.
What's the business case for upgrading an older edge router to support =
9K
MTU, when the only source of packets coming in is a network of Windows
boxes (both servers and end systems in offices) run by somebody who =
wouldn't
believe an Ethernet has anything other than a 1500 MTU if you stapled =
the
spec sheet to their forehead?
For that matter, what releases of Windows support setting a 9K MTU? =
That's
probably the *real* uptake limiter.
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<P><FONT SIZE=3D2>I don't think it matters that everything can use =
jumbograms or that every single device on the Internet supports them. =
Heck, I still know networks with kit that does not support VLSM!<BR>
<BR>
What would be good is if when a jumbogram capable path on the Internet =
exists, jumbograms can be used.<BR>
<BR>
This way it does not matter than some box somewhere does not support =
anything greater than a 1500 byte MTU, anything with such a box in the =
path will simply not support a jumbogram. How do you find out? Just send =
a jumbogram across the path and see what happens.. ;-)<BR>
<BR>
--<BR>
Leigh Porter<BR>
UK Broadband<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: owner-nanog@merit.edu on behalf of Valdis.Kletnieks@vt.edu<BR>
Sent: Fri 4/13/2007 3:36 PM<BR>
To: Saku Ytti<BR>
Cc: NANOG list<BR>
Subject: Re: Thoughts on increasing MTUs on the internet<BR>
<BR>
On Fri, 13 Apr 2007 08:22:49 +0300, Saku Ytti said:<BR>
><BR>
> On (2007-04-12 20:00 -0700), Stephen Satchell wrote:<BR>
> <BR>
> > From a practical side, the cost of developing, qualifying, and =
selling<BR>
> > new chipsets to handle jumbo packets would jack up the cost of =
inside<BR>
> > equipment. What is the payback? How much money do =
you save going to<BR>
> > jumbo packets?<BR>
><BR>
> It's rather hard to find ethernet gear operators could imagine =
using in<BR>
> peering or core that do not support +9k MTU's.<BR>
<BR>
Note that the number of routers in the "core" is probably =
vastly outweighted<BR>
by the number of border and edge routers. There's a *lot* of old =
eBay routers<BR>
out there - and until you get a clean path all the way back to the =
source<BR>
system, you won't *see* any 9K packets.<BR>
<BR>
What's the business case for upgrading an older edge router to support =
9K<BR>
MTU, when the only source of packets coming in is a network of =
Windows<BR>
boxes (both servers and end systems in offices) run by somebody who =
wouldn't<BR>
believe an Ethernet has anything other than a 1500 MTU if you stapled =
the<BR>
spec sheet to their forehead?<BR>
<BR>
For that matter, what releases of Windows support setting a 9K =
MTU? That's<BR>
probably the *real* uptake limiter.<BR>
<BR>
</FONT>
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