Smlt Topologies - Avaya 8800 Planning And Engineering, Network Design

Redundant network design
SMLT and Spanning Tree Protocol
When you configure an SMLT interswitch trunk, Spanning Tree Protocol is disabled on all ports that
belong to the interswitch trunk. As of Release 3.3, you cannot have an interswitch trunk link with
STP enabled, even if the interswitch trunk link is tagged and belongs to other STGs.
Connecting a VLAN to both SMLT aggregation switches with nonSMLT link introduces a loop and is
not a supported configuration. Ensure that the connections from the SMLT aggregation switch pair
are SMLT links or make the connection through routed VLANs.
SMLT scalability
To determine the maximum number of VLANs supported per device on an MLT/SMLT, use the
following formulas.
To calculate the total number of VLANs that you can configure with SMLT/IST with R series
modules, use the following formula:
(number of VLANs on regular ports or MLT ports) + (2 * number of VLANs on SMLT ports) = 1972
The available VLANs in an SMLT setup are based on the following:
• If config sys set max-vlan-resource-reservation enable is enabled, then 2042
VLANs are available for SMLT.
• If config sys set multicast-resource-reservation <value> is configured (range
of value: 64-4084), then the number of available VLANs on the SMLT switch is calculated as
the configured value divided by 2 (VLANs available = <value>/2)
In this case the number of available VLANs on SMLT switch is calculated by using the configured
value and divided by 2 (value/2).
A maximum of one IST MLT can exist on a switch. With R and RS modules, you can have a total of
127 MLT/SMLT groups (128 MLT groups minus 1 MLT group for the IST).
SMLT IDs can be either MLT- or port-based. The maximum value for the Port/SMLT ID is 512, but in
practice, this is limited by the number of available ports on the switch.
Port/SMLT IDs allow only one port per switch to be a member of an SMLT ID; MLT/SMLT allows up
to eight ports to be members of an SMLT ID per switch.
When you use SMLT, the total number of supported MAC addresses (if all records are available for
MAC address learning) is 64 000 for M, R, and RS modules.
For more information about SMLT scalability and multicast routing, see
page 172.
For more information about VLAN scalability, see Avaya Ethernet Routing Switch 8800/8600
Configuration — VLANs and Spanning Tree, NN46205-517.

SMLT topologies

Several common network topologies are used in SMLT networks. These include the SMLT triangle,
the SMLT square, and the SMLT full-mesh.
June 2016 Planning and Engineering — Network Design
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