Date: Fri, 03 Jan 2003 11:07:10 -0500 From: fkittred@gwi.net To: Evren Yurtesen <eyurtese@turkuamk.fi> Cc: Michael Sierchio <kudzu@tenebras.com>, dmagda@ee.ryerson.ca, freebsd-stable@FreeBSD.ORG, wpaul@ctr.columbia.edu Subject: Re: wi0 and mtu setting [bad idea] Message-ID: <200301031607.h03G7PX17718@valen.gwi.net> In-Reply-To: Your message of "Fri, 03 Jan 2003 02:22:34 %2B0200." <Pine.A41.4.10.10301030220070.16002-100000@bessel.tekniikka.turkuamk.fi>
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On Fri, 3 Jan 2003 02:22:34 +0200 (WET) Evren Yurtesen wrote: > I definetely agree and obviously since mikrotikos supports this then linux > should do since mikrotikos is built on linux. Why shouldnt FreeBSD support > setting mtu of wireless interfaces higher than 1500 Setting a "wireless interface" to a MTU of higher than 1500 octets is ill-advised unless you are in very specific, unusual conditions. The subject header talks about "wi0", which implies IEEE Ethernet 802.11b standard interface. The IEEE maintains the Ethernet standards. Start with: http://www.ieee.org or http://www.ieee802.org From a quick glance at the standard: "IEEE Std 802.11b-1999 (Supplement to ANSI/IEEE Std 802.11, 1999 Edition) Supplement to IEEE Standard for Information technology Telecommunications and information exchange between systems Local and metropolitan area networks Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: Higher-Speed Physical Layer Extension in the 2.4 GHz Band" it is not clear to me that MTU > 1500 octets are legal with 802.11b. If your system is connected to the Internet, setting the MTU on your FreeBSD system, which is probably not a core router, to anything above 1500 is a stupid idea. If you don't already know this, and don't understand the reasons why, you would be best advised not to mess with the MTU at all. Stick with the default until you gain more experience. You might want to read up on "packet fragmentation" and "MTU discovery" for explanations why this is a good idea. good luck, fletcher To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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