Enabling ILMI Keepalive Timeout
If enabled, ILMI sends keepalive messages on an ongoing basis on the active physical (PHY) to the switch,
and the switch responds. If the response is not obtained for the last four polls, the ILMI timer times out and
the Dual PHY changes from active PHY to backup PHY. This feature is useful only if the two PHYs are
connected to two different switches.
By default, this feature is disabled. To enable it, start a session to the ATM module (using the session
command), and then enter the following commands:
ATM> enable
ATM# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
ATM(config)# interface atm0
ATM(config-if)# atm ilmi-keepalive 4
ATM(config-if)# end
ATM#
These commands enable the transmission of ILMI keepalive messages and set the time between ILMI
keepalive messages to 4 seconds.
Using UNI 3.1 Signalling Support
The ATM LANE Dual PHY module supports backward compatibility with ATM switches for UNI version
3.1. On startup, ILMI negotiates between UNI versions 3.0 and 3.1, which requires no configuration. If the
ILMI link autodetermination is enabled on the interface, the router or switch accepts the UNI version
returned by ILMI. If the ILMI link autodetermination is unsuccessful or if ILMI is disabled, the UNI
version defaults to 3.0. You can override the version number by entering the atm uni-version command. If
ILMI is enabled when you enter the no version of the command, the UNI version is set to the version
returned by ILMI and the link autodetermination is successful. Otherwise, the version reverts to 3.0. Enter
the no atm uni-version command to override the UNI version.
Note
Each ELAN is a separate subnetwork.
Configuring Fast SSRP for Redundant LANE Services
With FSSRP, you can configure redundant LES/BUS pairs for each ELAN. With FSSRP, which differs
from the previously implemented SSRP, all configured LESs of an ELAN are active which means FSSRP-
aware redundant LES/BUS pairs can accept join requests from any FSSRP-aware client.
LECs that are FSSRP aware have VCs established to every single LES/BUS in the ELAN. Because VC
connections already exist between all LECs and LES/BUS pairs in the ELAN, the LECs can switch over to
another LES/BUS pair without any noticeable delay should a failure occur.
When you configure more than one LES/BUS pair for an ELAN, one LES/BUS takes precedence over
others based on the order in which they are entered into the LECS database.
Note
Redundant LES/BUS pairs for a single ELAN should be configured on different ATM LANE modules in
the LANE network for maximum fault tolerance.
Configuring redundant LES/BUS pairs for an ELAN is a two-part process:
Configuring Redundant LANE Services
Enabling ILMI Keepalive Timeout
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