Design Reference

• For a Layer 3 VSN, the I-SID is associated with a customer VRF, which is also virtualized
across the backbone. Layer 3 VSNs are always full-mesh topologies. Layer 3 VSNs associate
one VRF per I-SID.
• For a Layer 3 VSN with multicast, the BEB associates a data I-SID with the multicast stream
and a scope I-SID that defines the scope as a Layer 3 VSN. A multicast stream with a Layer 3
VSN scope can only transmit a multicast stream for the same Layer 3 VSN.
• For IP shortcuts with multicast, the BEB associates a data I-SID with the multicast stream and
defines the scope as Layer 3 Global Routing Table (GRT). A multicast stream with a scope of
Layer 3 GRT can only transmit a multicast stream for the Layer 3 GRT.
Encapsulating customer MAC addresses in backbone MAC addresses greatly improves network
scalability (no end-user C-MAC learning is required in the core) and also significantly improves
network robustness (loops have no effect on the backbone infrastructure).
The following figure shows the components of a basic SPBM architecture.
Figure 31: SPBM basic architecture
Related Links
SPBM design guidelines on page 71
VLANs without member ports
The Avaya Ethernet Routing Switch 8800 manages VLANs without member ports differently than
the VSP 9000 and VSP 4000.
• The ERS 8800 always designates the VLAN as operationally up if there is an attached I-SID.
• The VSP 9000 and VSP 4000 designate the VLAN as operationally up only if there is a
matching I-SID in the SPBM network. For more information, see the following sections.
VLANs without member ports
December 2014 Network Design Reference for Avaya VSP 4000 Series 73
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