From owner-freebsd-isp Thu Feb 25 22: 4:43 1999 Delivered-To: freebsd-isp@freebsd.org Received: from rodney.cnchost.com (rodney.concentric.net [207.155.252.4]) by hub.freebsd.org (Postfix) with ESMTP id 1AE7C14DFC for ; Thu, 25 Feb 1999 22:04:41 -0800 (PST) (envelope-from krowett@rowett.org) Received: from kjr-hnet-pc.rowett.org (host96.rowett.org [209.220.46.96]) by rodney.cnchost.com (8.9.3/) id BAA11831; Fri, 26 Feb 1999 01:04:24 -0500 (EST) [ConcentricHost SMTP Relay 1.5] Message-Id: <4.2.0.25.19990225215508.00973690@pop.ncal.verio.com> X-Sender: krowett@rowett.org@pop3.rowett.org X-Mailer: QUALCOMM Windows Eudora Pro Version 4.2.0.25 (Beta) Date: Thu, 25 Feb 1999 22:04:22 -0800 To: isp@FreeBSD.ORG From: "Kevin J. Rowett" Subject: Re: cdrom.com bandwidth limits In-Reply-To: <199902260504.XAA02895@oldzoom.bga.com> References: <36D5AB69.FC915382@admin.us.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Sender: owner-freebsd-isp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org At 09:04 PM 2/25/99 , Fred Gee wrote: >There are two things being discussed here, and they are different. > >First, the issue of HDLC 0-bit stuffing, the term used for inserting >1's where there is a run of 0's that will be difficult to detect. The HDLC bit stuffing is used for (bit) transparency. Frames start and end with an HDLC flag - a sequence of six ones in a row. If the transmitted data contains six ones in a row, then a zero is inserted in the bit stream so that it won't look like a flag and cause the frame to "end prematurely". >This does not affect bandwidth, and is done directly in the hardware Yes it does. The inserted zero is a real bit, and is transmitted across the signaling path. The amount of BW consumed by HDLC zero insertion depends upon the data. KR To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message