From owner-freebsd-net Wed Aug 8 12:58:22 2001 Delivered-To: freebsd-net@freebsd.org Received: from smtp1.sentex.ca (smtp1.sentex.ca [199.212.134.4]) by hub.freebsd.org (Postfix) with ESMTP id 5693B37B411 for ; Wed, 8 Aug 2001 12:58:13 -0700 (PDT) (envelope-from mike@sentex.net) Received: from simoeon.sentex.net (pyroxene.sentex.ca [199.212.134.18]) by smtp1.sentex.ca (8.11.2/8.11.1) with ESMTP id f78Jw3688741; Wed, 8 Aug 2001 15:58:03 -0400 (EDT) (envelope-from mike@sentex.net) Message-Id: <5.1.0.14.0.20010808155054.04d25380@marble.sentex.ca> X-Sender: mdtpop@marble.sentex.ca X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Wed, 08 Aug 2001 15:51:49 -0400 To: Jun-ichiro itojun Hagino , Jeroen Ruigrok/Asmodai From: Mike Tancsa Subject: Re: gif MTU of 1280 ? Cc: freebsd-net@freebsd.org In-Reply-To: <20010808194325.D1B9E7BB@starfruit.itojun.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org At 04:43 AM 8/9/01 +0900, Jun-ichiro itojun Hagino wrote: > as others noted, if you set gif MTU to 1500, then you will see a lot > of fragmented packet exchanges (= poor performance). if you use > IPv4 as the outer header, MTU <= 1480 avoids fragmentation and > more performant. as 1280 <= 1480, we avoid fragmentation with the > current default configuration. If the Internal IPs are RFC 1918, will hinder PMTU ? Am I better off to use real ones on the inside ? ---Mike To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message