Network Virtualization using Extreme Fabric Connect

Network Virtualization Using Extreme Fabric Connect
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Note
Fabric Connect VPN is a licensed software application hosted on XA1400 hardware and
based on VSP Operating System Software (VOSS). Two licensing tiers are available
offering either WAN Bandwidth of 100Mbps (applicable to both XA1440 and XA1480) or
500Mbps (applicable to XA1480 only).
Note
The ONA is a software-driven device attached to VSP4450/4850 used to apply and
remove the VXLAN encapsulation when used in Fabric Extend mode and can therefore do
IP fragmentation.
Use of Fabric Extend with VXLAN fragmentation and reassembly will not, however, scale as much as a non-
fragmented implementation.
Caution
The fragmentation and reassembly is handled in software and throughput rates will be
greatly reduced if the majority of traffic being VXLAN encapsulated requires
fragmentation and reassembly.
Note
Fabric Extend with IP Fragmentation is only possible if an Extreme XA1440/1480 or
VSP4450/4850 with Open Network Adapter (ONA) is deployed at both ends of the
connection. Other Extreme VSP platforms will not support IP fragmentation.
Note
Fabric Extend with IPsec encapsulation is only supported with the Fabric Connect VPN
XA1400 platforms.
The Fabric Extend (VXLAN or IPsec) IP tunnels constitute effectively an IP overlay above the WAN cloud.
Where they run to and from becomes arbitrary, yet they ultimately will determine what fabric topology is
seen by IS-IS. It is important to assess what the expected traffic flows will be over the WAN and then to
deploy the Fabric Extend IP tunnels accordingly. Typical deployments would be hub-star, dual-hub-star,
fully meshed, or any combination thereof. Traffic flows for which no direct IP tunnel exists, will end up
crossing the WAN more than once if they use multiple IP tunnels.
Caution
Extreme Management Fabric Manager supports the Fabric Extend Manager tool to
automate and push down the IP tunnel configuration based on the required Fabric Extend
IP tunnel overlay topology.
The final challenge that Fabric Extend needs to address is that typically WAN deployments have a few head
offices and many (possibly hundreds of) branch offices. In Fabric Connect mode, there is a tight coupling of
physical Ethernet port (or MLT bundle) and IS-IS/SPB interface which are mapped 1:1. For any-to-any type
WAN services (L2 E-LAN or IPVPN), it is clear that all the resulting Fabric Extend IP tunnels will need to be
terminated on a single Ethernet port connecting to the WAN service. This is also true in the case of point-
to-point WAN service types since the WAN provider, at the head office end, will bundle one end of all the
point-to-point circuits into a single Ethernet connection and use 802.1Q tags to differentiate between them.
Fabric Extend addresses this requirement by allowing the creation of logical IS-IS interfaces where many
Fabric Extend IS-IS adjacencies can be terminated on the single Ethernet port (one-to-many mapping).