Network Virtualization using Extreme Fabric Connect

Network Virtualization Using Extreme Fabric Connect
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Extending the Fabric Across the WAN
This section will explore the possible design choices available for extending the Extreme Networks Fabric
Connect architecture across the WAN / Internet. Applications include extending the fabric from the campus
to the branch offices as well as interconnecting larger locations, for example geo-redundant data centers
for Data Center Interconnect (DCI).
There are essentially two possible design approaches with the Extreme Fabric Connect architecture, as
depicted in Figure 51. The most compelling option is Fabric Extend, where the underlying SPB Fabric is
extended all the way. This presents the advantage that all VSN Fabric services, regardless of type (L2, L3, E-
TREE, IP Multicast), can now be seamlessly extended to any part of the fabric with end-point provisioning.
The Fabric VSN services are transported over the fabric and the WAN operator has no visibility of those
services and no need to participate in IP route advertising if those services are L3-based. On the other hand,
Fabric Extend will result in the Fabric Connect being extended to all nodes across different geographical
locations and the scaling limits of SPB nodes per region will have to be observed.
Caution
An Extreme SPB Fabric can currently scale to a maximum of 500 nodes per region (area),
assuming a range of SPB VSP platforms are in use. (Some VSP platforms can scale higher
than 500; refer to product Release Notes). This figure is dictated by the current generation
of ASICs, but is expected to rise considerably as newer chipsets become available in the
years to come. Future support of Multi-Area Fabric will also allow designs to exceed this
limit.
Figure 51 WAN Extending the Fabric or the VSN Services
The other design approach consists of extending only selected VSNs instead of the SPB Fabric foundation.
This is achieved via the VXLAN Gateway functionality, which allows a Fabric Connect BEB node to map a
SPB L2 VSN (or VLAN) segment into a VXLAN VNI.
Tip
Extreme Networks VSP 4900, 7200, 7400, 8200 & 8400 platforms support the VXLAN
Gateway functionality, which is implemented in hardware switching.
This has the advantage that the SPB Fabrics across the distant locations remain separate and the scaling
limits of SPB nodes per region will only need to be observed within each location.