ATM Switch Interoperability Fixed!

Webb, Tremayne TWebb at
Tue Jan 19 20:33:04 UTC 1999

It appears that the FORE ASX1000 switches and Ascend Switches do some
manipulation of the settings you give them. The Ascend switches allocate
[SCR (in cells)] * 1.35 as your CAC (Connection Admission Control) and
leaves the PCR untouched. The ASX1000 allocates it as [SCR (in cells)] *
1.75 and leaves the PCR untouched. We recalculated the SCRs to equal out
and this solved the problem.

Trey Webb
Sr. NOC Engineer
BA Global Networks, Inc.

-----Original Message-----
From: Alex Bligh [mailto:amb at]
Sent: Tuesday, January 19, 1999 12:08 PM
To: Steve Murray
Cc: Martin, Christian; danny at; nanog at
Subject: Re: ATM Switch Interoperability 


Formula looks great (interesting). However certainly (Cisco) AIP's don't
shape sufficiently accurately for (Cisco) BPX's not to cause the
occassional discard. I figured Lightstreams might be the same.
In our case the relevant supplier changed CDVT and it fixed this.

Alex Bligh
GX Networks (formerly Xara Networks)

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