[26664] in North American Network Operators' Group
Re: Something very odd on an older 2514 .
daemon@ATHENA.MIT.EDU (Dean Anderson)
Tue Jan 11 17:34:58 2000
Message-Id: <3.0.32.20000111172332.010121cc@odie.av8.com>
Date: Tue, 11 Jan 2000 17:25:02 -0500
To: "Mr. James W. Laferriere" <babydr@baby-dragons.com>,
nanog@merit.edu
From: Dean Anderson <dean@av8.com>
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I think you are hitting a performance wall in the 2514. You can't really
expect much more than 2 x T1 performance, and then you'll hit a wall.
The 2500 series is only a 68040, (old ones are 030's) which "manually"
shuffles packets, and can't handle sustained full ether bandwidth. If you
look closely with a sniffer, you'd see that its dropping packets.
Your FTP slows down because the TCP window is full.
--Dean
Around 07:46 PM 1/10/2000 -0800, rumor has it that Mr. James W. Laferriere
said:
>
>
> Hello All , I've just been doing a few tests on some 2514 routers
> I had laying around . I setup the two ether interfaces & on each
> like the diagram below
>
> +--------+ +--------+
> | 2514 |+----------------------+| 2514 |
> +--------+ +--------+
> + +
> [hub] [hub]
> + +
> +---------+[ ftp source ] +---------+[ ftp source ]
>
> I noticed a drastic lessening of expected bandwidth thru the
> routers . On the range of seeing only 24-25% of available
> ether bandwidth .
> But when I plug the two 'ftp source's into the same hub I am
> getting a more resonable 66-75% of the available ether bandwidth .
>
> Has anyone any info on what might be the cause of the lack of
> expected thru put . Tia , JimL
>
> +----------------------------------------------------------------+
> | James W. Laferriere | System Techniques | Give me VMS |
> | Network Engineer | 25416 22nd So | Give me Linux |
> | babydr@baby-dragons.com | DesMoines WA 98198 | only on AXP |
> +----------------------------------------------------------------+
>
>
>
>
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