This section includes the following topics:
Figure 1 illustrates the core-edge topology where you are recommended to place the IOA interfaces (24/10 port SAN Extension Module and 9250i Switch) in the core switches that interconnect the two sites. The ISLs interconnecting the two sites over a MAN or WAN are typically on the core switches as well, so this becomes a natural place to deploy the IOA service. This deployment provides the following benefits:
Provides consolidation of IOA service at the core.
Allows easy scalability of the IOA service engines based on the desired throughput.
Allows you to plan and transition from FC or FCIP acceleration solutions to IOA. This is because these acceleration solutions will likely be deployed at the core switches already and will allow for a smooth transition to IOA.
Facilitates planning the capacity based on WAN ISL throughput on the core switches themselves.
Provides optimal routing as the flows have to traverse these core switches to reach the remote sites.
Figure 1 illustrates the edge-core-edge topology where you are recommended to place the Cisco MDS 24/10 port SAN Extension Module and Cisco MDS 9250i Switch at the core switches that interconnect the two sites.
Collapsed Core Topology
Figure 1 illustrates the collapsed core toplogy where you are recommended to place the Cisco MDS 24/10 port SAN Extension Module or Cisco MDS 9250i Switch (IOA interfaces) in the core switches that interconnect the two sites.
Extended Core-Edge Topology
Figure 1 illustrates the extended core-edge topology where you are recommended to place the IOA interfaces Cisco MDS 24/10 port SAN Extension Module or Cisco MDS 9250i Switch) in all the core switches. As the IOA service load balances the traffic by selecting any IOA interface from each site and forms the IOA interface pair for a given flow, certain failures may result in suboptimal routing. The recommendation is to interconnect the core switches within each site for maximum availability of the IOA service. The ISLs between the core switches in the specific site has as much throughput as the WAN ISLs between the sites.
Extending Across Multiple Sites
Figure 1 illustrates the IOA implementation where the IOA service is extended across multiple sites. In this example, Site-4 consolidates the tape backup from Site-1, Site-2, and Site-3. Each IOA cluster represents a site pair, which means that there are three unique clusters. This topology provides segregation and scalability of the IOA service across multiple sites. In Site-4, a single switch participates in multiple IOA clusters.
Starting from Cisco MDS NX-OS Release 6.2(1), IOA with IVR is not supported.
For IOA to support IVR flows, we recommend that you place the IOA interfaces on the Cisco MDS 24/10 port SAN Extension Module or Cisco MDS 9250i Switch in the IVR border switches for optimum routing. IOA must always be deployed on the host and target VSANs. Packets from the host get redirected to the IOA interface in the host VSAN, traverses the IVR transit VSANs for routing, and again gets redirected to the IOA interface in the target VSAN before it reaches the target and vice-versa. IVR transit VSANs are used only for FC routing. IOA is not supported or deployed on transit VSANs.
For more information, refer to the Cisco MDS 9000 Family NX-OS Inter-VSAN Routing Configuration Guide .
In certain other topologies, the edge switches are connected across the WAN. With these topologies, we recommend that you do the following:
- Transition the WAN links from the edge to core switches to provide consolidation and optimal routing services.
- Deploy the IOA service in the core switches.