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To: "wu haijun" <haggai.wu@huawei.com>
Cc: freebsd-net@freebsd.org, brian@Awfulhak.org
Subject: Re: A question for PPPoE 's MTU: 
In-Reply-To: Message from "wu haijun" <haggai.wu@huawei.com> 
   of "Fri, 10 Nov 2000 17:50:06 +0800." <001f01c04afb$9b6e07a0$1b22690a@huawei.com.cn> 
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Date: Fri, 10 Nov 2000 22:10:45 +0000
From: Brian Somers <brian@Awfulhak.org>
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haggai.wu@huawei.com said:
> Hi:
> =

> The MTU=A0of PPPoE is 1492 Bytes. But=A0if the PPPoE Server receives
> IP=A0 packets from the WAN and the packets's will be always 1514
> Bytes,so the Server must fragment the Packets=A0to fit in the PPPoE
> packets ,and this will degrade the performance of the Server.
> =

> Why not suggest that PPPoE header didn't be included in the MTU
> calculation, just like VLAN encapsulation?

The 1492 MTU limit is imposed because the PPPoE header is 8 bytes =

big.  The total header + data cannot exceed 1500 - the maximum =

ethernet payload.

> Regards
> =

> Wu Haijun
> Huawei Tech. Corp. LTD=A0=A0in CHINA
> Senior Firmware Engineer

-- =

Brian <brian@Awfulhak.org>                        <brian@[uk.]FreeBSD.org=
>
      <http://www.Awfulhak.org>                   <brian@[uk.]OpenBSD.org=
>
Don't _EVER_ lose your sense of humour !




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