Date: Wed, 08 Dec 1999 10:36:19 -0500 From: "Louis A. Mamakos" <louie@TransSys.COM> To: Steven Fletcher <stevenf@shellnet.co.uk> Cc: "'John Hay'" <jhay@mikom.csir.co.za>, net@FreeBSD.ORG Subject: Re: Very odd problem with email. Message-ID: <199912081536.KAA29987@whizzo.transsys.com> In-Reply-To: Your message of "Wed, 08 Dec 1999 14:30:21 GMT." <277A0E0FE38ED311A66A00A0C9D43A3D0781F9@data.shellnet.co.uk> References: <277A0E0FE38ED311A66A00A0C9D43A3D0781F9@data.shellnet.co.uk>
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> Hiya > > Thanks for the reply. You are somewhat correct.... just 20 minutes ago we > recived a phonecall from UUnet who told us what was going on. It was in > fact, one of the oddest problems that they've ever seen, caused by many ~'s > in the that is being transferred (belive it or not, I've verified this and > to my amazements it's true!) - it's just not getting through at the Linx. I've run into pattern sensitivity problems like this before. This is likely caused by a marginal or mis-provisioning access circuit. The encoding of '~' is 0x7e. There could be a PPP implementation problem since I think that's the async "flag" character which need to be byte-stuffed. On a leased line circuit, you might be provoking a 1's density problem on the circuit. If the CSU/DSU is configured to assume a B8ZS (rather than AMI) provisioned T-1, then it won't do anything special in the DSU when framing up the data to ensure adequate 1's density. If the circuit is actually provisioned as AMI, this could cause problems. Take a look at the CSU/DSU statistics at either end if possible, and look for line code violations, framing loss or frame slips as you try to deliver that kind of message. Depending on the direction, you might not have access to the CSU/DSU (e.g., the provider's end). louie To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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