Additional Smlt Considerations - Avaya 8600 Configuration Manual

the other does not, or some other potential
issue, or maybe a mis-configuration. If the
system that is reset is requesting sync, it will
keep all the ports locked down until the IST
comes up properly and sync has occurred.
We display the error message after 5
minutes.

Additional SMLT considerations

Avaya does not support an additional redundant IST_MLT group between two IST peers. Use
of a second MLT connection (non-IST) is supported, but such designs are not
recommended.
For an IPVPN-lite configuration, where an edge 8800/8600 Cluster is configured to use a SMLT
configuration toward the core (most likely square or full-mesh RSMLT), SMLT fast failover
cannot always be guaranteed for this portion of the network. (CR Q2016922)
Note:
All tested failover times for SMLT/RSMLT operation are sub-second. With this release, all
tested fail-back or recovery times have been improved, especially for very large scaled
environments, to be within 3 seconds. This worse-case value is used in order to provide
required recovery time for converged networks, especially IP phone operation. These values
are for unicast traffic only; this includes voice traffic. Not all IP Multicast failover or fail-back/
recovery situations can provide such times today, as many situations depend on the IPMC
protocol itself recovering. For best IPMC recovery in SMLT/RSMLT designs, the use of static
RPs for PIM-SM is recommended, with the same CLIP address assigned to both Core IST
Peers within the Cluster, and to all switches within a full-mesh or square configuration.
Failover or fail-back/recovery times for any situations that involve high-layer protocols, such
as OSPF, BGP, etc., can not always be guaranteed. Reference the Network Design Guide
for your specific code release for recommendations on best practices, in order to achieve
best results. The 3 second recovery time is supported in Avaya SMLT/RSMLT designs which
utilize VLACP. Designs that do not use VLACP or consist of a mixed vendor environment
cannot be guaranteed to have a 3 second fail-back or recovery time. Avaya continues to
support SMLT designs with non-Avaya devices, but recovery times for these designs cannot
always be expected to be within 3 seconds.
Note:
VLACP configuration should now use values of 500 msec short timer (or higher) and a
minimum timeout-scale of 5. Lower values can be used, but should any VLACP 'flapping'
occur, the user will need to increased one or more of the values. These timers have been
proven to work for any large scaled environments (12,000 MACs), and also provide the 3
second recovery time required for converged networks (5 x 500 = 2.5 seconds). Using these
values may not increase re-convergence or fail-back/recovery times, but instead guarantee
these times under all extreme conditions. (CR Q01925738-01 and Q01928607) As well,
Configuration — Link Aggregation, MLT, and SMLT
Case
SMLT/RSMLT operational improvements
Message
ANY action with the peer at
this time CPU5 [05/15/08
05:33:55] MLT ERROR SMLT
initial table sync is delayed
or failed. Please check the
peer switch for any partial
config errors. All the ports
in the switch except IST will
remain locked
January 2012 41