Date: Tue, 3 Apr 2001 23:11:53 -0600 From: "Alex Huppenthal" <alex@aspenworks.com> To: <freebsd-atm@FreeBSD.org> Subject: ATM 4.3 and so on Message-ID: <007501c0bcc5$c408bca0$1800a8c0@d7k>
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some may have seen my postings on Freebsd-isp, but I think they are more appropriate here. I'm running a 4.2 FreeBSD machine with Fore PCA200E installed. After some week on and off struggling to understand ATM and also FreeBSD's HARP stack, I finally have an ATM network connection running. After learning that FreeBSD HARP stack doesn't pace outbound cells, we designed an alternative solution. Our FreeBSD system is attached to a Lucent PSAX at OC3 speeds. The PSAX ATM switch talks to the ATM cloud via a DS3. Packets from the BSD system egress at 135 mbits per second, and the ATM cloud starts discarding them after the first 190 bytes or so.. about 4 cells. We're pacing cells by running an OC3 loop on a pair of OC3 cards. This buffers and throttles the network. So far, everything is great, right? Yes. we can send 2000 byte pings to the remote end. The tragic part is that packets are apparently fragmented tcpdump: listening on fxp0 12:30:35.092598 66.28.19.249.nim > 66.28.19.2.domain: 48953+ (16) (frag 13033:24@0+) 12:30:35.093145 66.28.19.249 > 66.28.19.2: (frag 13033:11@24) 12:30:35.094117 66.28.19.2.domain > 66.28.19.249.nim: 48953 1/4/4 A apple.com (206) 12:30:54.316634 66.28.19.249 > 66.28.19.2: icmp: echo request (frag 13101:24@0+) 12:30:54.316702 66.28.19.249 > 66.28.19.2: (frag 13101:24@24+) 12:30:54.316781 66.28.19.249 > 66.28.19.2: (frag 13101:16@48) 12:30:54.316880 66.28.19.2 > 66.28.19.249: icmp: echo reply 12:30:55.318413 66.28.19.249 > 66.28.19.2: icmp: echo request (frag 13115:24@0+) Any clue on what's happening here? I've applied the patch to the Fore system code which addresses the buffering problem. Cheers, -Alex To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-atm" in the body of the message
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