Avaya 8800 Planning And Engineering, Network Design page 77

• SMLT full-mesh recommendations with OSPF
SMLT redundancy
The following figure shows an SMLT configuration that contains a pair of Ethernet Routing Switch
acting as aggregation switches (E and F). Four separate wiring closet switches are shown, labeled
A, B, C, and D (MLT-compatible devices).
Figure 21: SMLT configuration with switches as aggregation switches
B and C are connected to the aggregation switches through multilink trunks that are split between
the two aggregation switches. For example, SMLT client switch B can use two parallel links for its
connection to E, and two additional parallel links for its connection to F. This provides redundancy.
The SMLT client switch C may have only a single link to both E and F. Switch A is configured for
MLT, but the MLT terminates on only one switch in the network core. Switch D has a single
connection to the core. Although you could configure both switch A and switch D to terminate across
both of the aggregation switches using SMLT, neither switch would benefit from SMLT in this
network configuration.
The SMLT client switches are dual-homed to the two aggregation switches, yet they require no
knowledge of whether they are connected to a single switch or to two switches. SMLT intelligence is
required only on the aggregation switches. Logically, they appear as a single switch to the edge
switches. Therefore, the SMLT client switches only require an MLT configuration. The connection
between the SMLT aggregation switches and the SMLT client switches are called the SMLT links.
The client switch can use any proprietary link aggregation protocol, such as MLT or EtherChannel,
in addition to standards-based LACP.
Figure 21: SMLT configuration with switches as aggregation switches
stations connected to each of the switches. End stations a, b1, b2, c1, c2, and d are typically hosts,
while e and f may be hosts, servers, or routers. SMLT client switches B and C can use any method
to determine which multilink trunk link to use to forward a packet, so long as the same link is used
for a given Source/Destination address (SA/DA) pair (regardless of whether or not the DA is known
by B or C).
Packet over SONET (POS), and Ethernet interfaces are supported as operational SMLT links.
June 2016
on page 86
Planning and Engineering — Network Design
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Network redundancy
on page 77 also includes end
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