Date: Tue, 21 Apr 1998 15:42:17 -0700 From: Paul Norton <pnorton@ccnvhi.com> To: "Larry S. Lile" <lile@stdio.com> Cc: Paul Norton <pnorton@ccnvhi.com>, tokenring@FreeBSD.ORG Subject: Re: Current work... Message-ID: <199804212242.PAA00550@grumpy.ccnvhi.com> In-Reply-To: <Pine.SUN.3.91.980421175810.15079A-100000@heathers2.stdio.com> References: <199804212055.NAA01835@grumpy.ccnvhi.com> <Pine.SUN.3.91.980421175810.15079A-100000@heathers2.stdio.com>
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Larry S. Lile writes: > All the AIX boxen I admin run a MTU of 1492 on their token ring interfaces, > any clue at to the 8 byte diff? Were basically going to need a > /usr/src/sys/net/iso88025.h which would contain: 1492 is the MTU for Ethernet II(??), I believe, but I'd have to go back and reference Stevens to be sure. Are you in a bridged environment? > #define ISO88025_TYPE_LEN 2 /* Assumed */ > #define ISO88025_CRC_LEN 4 /* Assumed */ You'll never see the TR MAC CRC. It is stripped from the frame before the driver gets it. > #define ISO88025_HDR_LEN (ISO88025_ADDR_LEN*2+ISO88025_LEN) /* +RIF? */ > #define ISO88025_MIN_LEN x /* No clue */ 802.5 can have a zero-length payload. > #define ISO88025_MAX_LEN 1518 /* Assumed same as ethernet */ 17,960 for total frame size at 16 Mbps. > #define ISO88025_IS_VALID_LEN(foo) \ > ((foo) >= ISO88025_MIN_LEN && (foo) <= ISO88025_MAX_LEN) This should be determined by the driver after initialization. If the adapter has 8K shared-RAM configured, you'll only be able to support about a 3K MTU. If they have 64K configured the MTU can go to 17K. At any rate you will only be able to determine this after the driver/adapter has initialized. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-tokenring" in the body of the message
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