Overview of Layer 3 Connectivity for Virtual IP Pools
By default data connections between client devices and the VAST Cluster use Layer 2. Layer 2 (Data Link Layer) handles communication within the same network segment using MAC addresses, focusing on local data transfer between devices, such as on a switch.
Alternatively, you can enable Layer 3 for these communications. Layer 3 facilitates communication between different networks using IP addresses, It determines the best path for data across multiple networks, typically through routers. BGP (Border Gateway Protocol), a key Layer 3 protocol, is used for routing between different autonomous systems (ASes) on the internet, helping manage data paths based on network policies and availability. To use this option, switches must be L3 enabled.
Layer 2 should be used if clients connect to the cluster locally, using simple networks. Layer 3, with BGP, should be used if clients are connecting across complex networks, and customer switches support BGP.
Numbered and Unnumbered BGP Configurations
You can configure the BGP to be numbered or unnumbered. In numbered BGP, CNodes and routers (also referred to as peers) in the network use assigned IP addresses for BGP communication. These are configured on the VAST Web UI.
Configuring Layer 3 Connectivity
Follow these steps to configure Layer 3 connectivity using BGP. A single BGP configuration is used for the entire cluster.
Navigate to the Network Access page, and select the BGP Configurations tab.
Click Create BGP.
In the General tab, enter these values:
Name
The name of the BGP configuration, as it will appear in the table.
VAST ASN
The ASN presented by CNodes to upstream routers.
Method
Select whether Numbered or Unnumbered BGP is used.
External ASN
The ASN expected to be presented to CNodes by upstream routers.
Select one of these options:
Use any. Any value can be used.
Set manually. Enter a specific ASN value.
If Numbered BGP is selected for the Method in the previous step, go to the VIPs tab and select addresses for peer-to-peer connections between the CNodes in the cluster, and the customer switch. The range must allow for one address for each CNode and one for each switch port.
Rack
Select the rack from the list.
IP Range
An even-numbered range of contiguous IP addresses for the CNodes in the rack, and the switch ports that are connected to the CNodes. For example: 10.10.0.1-40. The range must be twice the number of CNodes, allowing one address for each CNode and one for each switch port.
Even/Odd
Select how the IP addresses from the range of addresses are allocated to CNodes and switch ports:
Even - even-numbered addresses are allocated to CNodes, and odd-numbered addresses to switch ports.
Odd - odd-numbered addresses are allocated to CNodes, and even-numbered addresses to switch ports.
Click Create. The configuration appears in the list of configuration in the table.
In the Network Access page, select Virtual IP Pools.
Click Create Virtual IP Pool, Follow the steps in Managing Virtual IP Pools to define the pool.
In the Advanced section, toggle Enable L3 on.
Select the BGP configuration from the list.
Click Create or Update.
In the Network Access page, select DNS.
Right-click the existing DNS configuration, and select Edit, or click Create DNS to create a new one. If you are creating a new DNS, follow the steps in Configuring the VAST Cluster DNS Service.
In the L3 section, toggle Enable L3 on.
Select the BGP configuration from the list.
Click Create or Update.