Cabletron Systems MMAC-Plus SFCS-1000, Configuration Manual

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6-2
E-3 Configuration
6.2 Configuring E-3 Mode
There are two modes of operation that the E-3 ports support: PLCP (also
referred to as G.751) and HCS (also referred to as G.832). These modes control
the way ATM cells are delineated within the E-3 data stream.
To change the mode of operation of an E-3 port, log in to the ATM Manage-
ment Interface (AMI). (Please refer to Appendix A of this manual for informa-
tion about logging into AMI). Enter the following parameters to enable PLCP
or HCS framing:
configuration port e3 mode <port> (plcp | hcs)
The <port> variable indicates the E-3 port that is to be modified and the
(plcp|hcs) variable is the mode of operation to be used for the port. It is crit-
ical that both ends of the E-3 link be configured with the same mode, regard-
less of which one is chosen.
hcs is the default. If there are no E-3 ports on the
switch fabric, then this option is disabled.
After the E-3 mode configuration is changed, the switch control processor
(SCP) immediately puts that change into effect on that switch fabric. At the
same time, that information is entered into the configuration database file on
the SCP so that the change will be put into effect every time the switch control
software starts on that particular SCP.
6.3 Configuring E-3 Payload Scrambling
Some equipment is more sensitive than the switch when synchronizing with
the network clock. This equipment requires a greater transition density than
the switch. To work with such equipment, it may be necessary to enable pay-
load scrambling on the SCPs.
When payload scrambling is enabled, a scrambling function
1
is applied to the
48-byte payload of each cell transmitted. To operate with other equipment,
scrambling must be enabled on the other end of the E-3 connection as well so
that the data is properly unscrambled. By default, scrambling is disabled.
1. Cabletron switches use the recommended self-synchronizing scrambler, x
43
+ 1.