...and last of all, if you would like to borrow a couple of CSU/DSUs and a T1 x-over cable I would be delighted to loan them out - heck, I'll even set one up as a clock source so you just plug 'em in :)
-----Original Message----- From: Marty Ferguson [mailto:[EMAIL PROTECTED] Sent: Wednesday, August 11, 2004 3:41 PM To: Triangle Linux Users Group discussion list Subject: Re: [TriLUG] throttling bandwidth in a test environment David, I beg to differ. You are correct in that the UARTs on most PC's, off-the-shelf, are limited to 115kpbs. However, there are serial cards on the market which can surpass this data rate by a significant amount. Here's a quad-port PCI serial adapter which provides almost 1mbps per channel: *http://www.mycableshop.com/sku/PCI4S9503V.htm I personally think that the serial card emulation approach is wise. Because: There will be real-world flow-control issues when throttling between ethernet speeds and T1. There is flexibility in using man (8) setserial for configuring the emulated WAN The channels can be individually configured for 7 or 8 bit, thereby supporting test emulation of 56kbps DS0s on a bit-robbed signaling for T1. Full T1, fractional T1 and a pair of T1's/PairGain speed can also be emulated. If the parts are lying around in order to create this hardware test bed, then this is truly a reasonable approach for developing a flexible test environment. My 2 bits. Marty * ==================== David Rasch wrote: >Unfortunately, this isn't going to simulate a T1 very well as a >null-modem cable can only do 115200bps while a T1 can do approximately >1.5Mbps. > >Other than the pf firewall mentioned by Aaron, I've done this previously >with a VPN connection. For example, openvpn has a "--shaper" parameter >which allows you to limit the speed of a connection to an arbitrary >number of bytes/sec. > >David > >On Wed, Aug 11, 2004 at 01:17:21PM -0400, Greg Brown <[EMAIL PROTECTED]> wrote: > > >>I did this once at Oculan.. sort of. I had two ethernet segments with >>a "wan" in the middle... here's how I did it. >> >>Machine 1: ethernet port 192.168.13.1 network 192.168.13.0/24 >> serial port 192.168.14.1 >>Machine 2: serial port 192.168.14.2 >> ethernet port 192.168.16.1 network 192.168.16.0/24 >> >>I connected the serial ports via a null modem cable and, if memory >>serves, I used ppp to connected them together. Or was it slip? No, it >>was slip. I think this is the how-to webpage I used: >> >>http://www.dbaoncall.net/references/ht_connect_2pc.html >> >>That's about all I can recall, other than it worked. Hotgrits on the >>IRC channel might be able to help out with this, as I recall he was a >>wealth of knowledge regarding serial communication and linux. >> >>Greg >> >>On Wednesday, Aug 11, 2004, at 12:50 US/Eastern, Dan Monjar wrote: >> >> >> >>>Anyone know of any techniques to throttle bandwidth on a LAN for >>>testing? We want to see how an application would run across a WAN of >>>varying bandwidth. How would I make a Ethernet segment throttle down >>>to something like T1 speeds? >>> >>>-- >>>Dan Monjar >>>-- >>>TriLUG mailing list : >>>http://www.trilug.org/mailman/listinfo/trilug >>>TriLUG Organizational FAQ : http://trilug.org/faq/ >>>TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ >>>TriLUG PGP Keyring : http://trilug.org/~chrish/trilug.asc >>> >>> >>> >>-- >>TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug >>TriLUG Organizational FAQ : http://trilug.org/faq/ >>TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ >>TriLUG PGP Keyring : http://trilug.org/~chrish/trilug.asc >> >> > > > -- TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug TriLUG Organizational FAQ : http://trilug.org/faq/ TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ TriLUG PGP Keyring : http://trilug.org/~chrish/trilug.asc -- TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug TriLUG Organizational FAQ : http://trilug.org/faq/ TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ TriLUG PGP Keyring : http://trilug.org/~chrish/trilug.asc
