General Information and Issues

Reserved VLAN Identifiers

When creating VLANs, use VLAN identifiers 2 through 4094. According to the IEEE 802.1Q specification, VLAN ID 0 is used for the priority tag, and VLAN ID 1 is usually reserved for a switch or bridge management VLAN.

Jumbo Frames

Consider the following issues for Jumbo Frames:

• True Jumbo Frames are not supported.

• The maximum MTU is limited by the MTU of the InfiniBand fabric.

• The MTU of the HCA is 2048 by default, but can be increased up to 4096.

• The default MTU of the I4 switch chip and BridgeX chips is 4096.

The gateway supports Jumbo Frames up to the InfiniBand limit of 4096 bytes.

You must configure the entire InfiniBand fabric to use a 4096 MTU. This configuration includes configuring the Subnet Manager, InfiniBand devices, and the ConnectX HCAs. You can configure a ConnectX HCA by activating the set_4k_mtu parameter of the HCA's mlx4_core module.

Subnet Manager

Access to the VNICs through the gateway requires an active Subnet Manager for the InfiniBand fabric. The management controller within the gateway is already configured with a Subnet Manager. You can enable the Subnet Manager with the enablesm command.

Snapshot Dataset Information

The normal, fruid, and full datasets of the snapshot utility are currently equivalent and contain the same data in the snapshot.