TS7700 Grid interconnect LAN/WAN requirements

This topic gives LAN/WAN requirements for the TS7700 cross-site grid TCP/IP network infrastructure.

The TS7700 Grid TCP/IP network infrastructure must be in place before the grid is activated so that the clusters can communicate with one another as soon as they are online. Two or four1 Gb Ethernet or two Grid Optical LW connections must be in place before grid installation and activation, including the following equipment:
Intranet Ethernet switches
Intranet Ethernet switches are used primarily for private communication between components within a cluster.
ATM switches
Ethernet extenders
An Ethernet extender or other extending equipment is used to complete extended distance Ethernet connections. Extended grid Ethernet connections can be any of the following:
1 Gb copper 10/100/1000 Base-TX
This adapter conforms to the IEEE 802.3ab 1000Base-T standard, which defines gigabit Ethernet operation over distances up to 100 meters using four pairs of CAT-6 copper cabling.
10 Gb optical longwave
This adapter supports a maximum of 10 kilometers of 1310 nm, 9μm, single-mode fiber optic cable. It conforms to the IEEE 802.3ae standard. This adapter requires 9μm single-mode fiber optic cables and uses an LC connector to connect to network infrastructure components.
The default configuration for a TS7700 Server from manufacturing is two dual-ported PCIe 1 Gb Ethernet adapters. For a 3957-VEC you can use FC 1038, 10 Gb dual port optical LW connection to add support for two 10 Gb optical longwave Ethernet adapters. The default configuration for a TS7700 Server from manufacturing is two dual-ported PCIe 1 Gb Ethernet adapters. 10 Gb Ethernet adapters are available as well and are recommended for clusters using the cloud-attach or DS8K Object Store functions. 10 Gb connections improve data copy replication and cloud data transfer rates.

For a 3957-VEC, you can use either FC 1036, 1 Gb Grid dual port copper connection to add support for two 1 Gb copper (RJ-45) Ethernet adaptors or FC 1038, 10 Gb dual port optical LW connection to add support for two 10 Gb optical longwave Ethernet adapters.

For a 3957-VED, you can use either FC 1039, 1 Gb Grid quad port copper connection to add support for to two 1 Gb copper (RJ-45) Ethernet adaptors or FC 1038, 10 Gb dual port optical LW connection to add support for two 10 Gb optical longwave Ethernet adapters.

Configured clusters that use two 10 Gb, four 1 Gb, or two 1 Gb clusters, can be interconnected within the same TS7700 Grid. Adapter types can be mixed within a grid, but not within a single cluster.

Note: A network infrastructure and switches capable of supporting 10 Gb adapters must be in place before installing the 10 Gb optical longwave Ethernet adapters. Refer to the Feature details topic in the section Related information for feature requirements and prerequisites.
Important: Identify, order, and install any new equipment to fulfill grid installation and activation requirements. Prior to grid activation, you must test connectivity and performance of the Ethernet connections. You must ensure installation and testing of this network infrastructure is complete before grid activation.

Bandwidth considerations

The customer network between the TS7700s should have sufficient bandwidth to account for the total replication traffic. For customers that share network switches among multiple TS7700 paths or with other network traffic, the total of bandwidth on that network should be sufficient to account for all of the network traffic.
The TS7700 uses the TCP/IP protocol for moving data between each cluster. Bandwidth is a key factor that affects throughput for the TS7700. Other key factors that can affect throughput include:
  • Latency between the TS7700s
  • Network efficiency (packet loss, packet sequencing, and bit error rates)
  • Network switch capabilities
  • Flow control to pace the data from the TS7700s
  • PCF(Priority Control Flow) is not supported.
  • Inter-switch link capabilities: flow control, buffering, and performance
The TS7700 attempts to drive the network links at the full 1 Gb or 10 Gb rate, which might exceed the network infrastructure capabilities. The TS7700 supports the IP flow control frames so that the network paces the level at which the TS7700 attempts to drive the network. The best performance is achieved when the TS7700 is able to match the capabilities of the underlying network, resulting in fewer dropped packets.
Note: When the system exceeds the network capabilities, packets are lost. This causes TCP to stop, resync, and resend data, resulting in a much less efficient use of the network.
To maximize network throughput, ensure that the underlying network:
  • Has sufficient bandwidth to account for all network traffic that is expected to be driven through the system to eliminate network contention.
  • Can support flow control between the TS7700s and the switches. This allows the switch to pace the TS7700s to the WAN capability. Flow control between the switches is also a potential factor to ensure that the switches can pace their rates to one another. The performance of the switch handles data rates expected from all of the network traffic.
  • PCF(Priority Control Flow) is not supported.
In short, latency between the sites is the primary factor. However, packet loss due to bit error rates or insufficient network capabilities can cause TCP to resend data, thus multiplying the effect of the latency. The TS7700 uses your LAN/WAN to replicate virtual volumes, access virtual volumes remotely, and perform cross-site messaging. The LAN/WAN should have adequate bandwidth to deliver the throughput necessary for your data storage requirements. The cross-site grid network is 1 Gb Ethernet with copper (RJ-45) or 10 Gb Ethernet with longwave optical. For copper networks, Cat 5E or 6 Ethernet cabling can be used for the copper connections, but Cat 6 cabling is recommended to achieve the highest throughput.
Note: To avoid any network conflicts, the following subnets must not be used for LAN/WAN IP addresses (Gridlink) or management interface primary, secondary, or virtual IP addresses:
  • 192.168.251.xxx
  • 192.168.250.xxx
  • 172.31.1.xxx
  • 10.10.10.1
  • 10.10.10.2

Network redundancy

The TS7700 provides twoup to four independent 1 Gb copper (RJ-45) or 10 Gb longwave fiber Ethernet links for grid network connectivity. It is recommended that you connect each through an independent WAN interconnection to be protected from a single point of failure that would disrupt service to both WAN paths from a node.