How to select a tunnel among multiple tunnels working in load balancing mode

13

If the number of tunnels is set to 6 for load balancing, how to select six LSP tunnels from eight ones during tunnel iteration?

If the selected tunnels enter the Down state, how to re-select tunnels?

If the selected tunnels go Up from the Down state, how to re-select tunnels?

The TNLM randomly selects six tunnels and then returns them to the RM.

If the status of the selected tunnels changes (for example, the first tunnel enters the Down state), the TNLM randomly selects another tunnel from two candidate ones.

If the tunnels go Up from the Down state and there are fewer than six tunnels for load balancing, the TNLM is triggered to re-select six tunnels and then returns them to the RM. Otherwise, the status of tunnels does not affect load balancing.

Other related questions:
In the case of multi-load balancing of S-series switches, how does tunnel management select tunnels in multiple tunnels?
If the selected tunnel state changes, such as the first down, a tunnel is randomly selected from the alternate tunnel.

How does the tunnel management module select tunnels in multi-path load balancing on S series switches
Q: How does the tunnel management module select tunnels in multi-path load balancing? If the number of tunnels for load balancing is set to 6 and eight LSP tunnels are available, how are tunnels selected during tunnel iteration? If a selected tunnel is in Down state, what will the tunnel management module select tunnels? If the selected tunnel becomes Up, what will the tunnel management module select tunnels? Q: TNLM randomly selects six tunnels and returns the tunnels to RM. If the state of a selected tunnel changes, for example, the Down state, TNLM selects one tunnel from the two alternate tunnels. If the selected tunnel becomes Up and the number of tunnels for load balancing is smaller than 6, TNLM selects another six tunnels for RM. Otherwise, the Up and Down states of a tunnel have no impact on load balancing.

How load balancing is implemented on S series switches when link aggregation is configured
For S series switches (except the S1700), there are two load balancing modes: per-packet load balancing and per-flow load balancing. 1. Per-packet load balancing mode When there are multiple physical links between the two devices of the Eth-Trunk, the first data frame of a data flow is transmitted on one physical link, and the second data frame is transmitted on another physical link. In this case, the second data frame may arrive at the peer device earlier than the first data frame. As a result, packet mis-sequencing occurs. 2. Per-flow load balancing mode This mechanism uses the hash algorithm to calculate the address in a data frame and generates a hash key value. Then the system searches for the outbound interface in the Eth-Trunk forwarding table based on the generated hash key value. Each MAC or IP address corresponds to a hash key value, so the system uses different outbound interfaces to forward data. This mechanism ensures that frames of the same data flow are forwarded on the same physical link and implements flow-based load balancing. Per-flow load balancing ensures the correct sequence of data transmission, but cannot ensure the bandwidth usage. Notes: Currently, S series switches support only per-flow load balancing mode, including the following: 1. Load balancing based on the source MAC address of packets; 2. Load balancing based on the destination MAC address of packets; 3. Load balancing based on the source IP address of packets; 4. Load balancing based on the destination IP address of packets; 5. Load balancing based on the source and destination MAC addresses of packets; 6. Load balancing based on the source and destination IP addresses of packets; 7. Enhanced load balancing for L2, IPv4, IPv6, and MPLS packets based on the VLAN ID and source physical interface number. When you configure load balancing modes, follow these guidelines: The load balancing mode only takes effect on the outbound interface of traffic. If load is unevenly distributed on the inbound interfaces, change the load balancing mode on the uplink outbound interfaces. Configure load balancing to ensure data flow is transmitted on all active links instead of only one link, preventing traffic congestion and ensuring normal service operation. For example, if data packets have only one destination MAC address and IP address, you are advised to configure load balancing based on the source MAC address and IP address. If you implement load balancing based on the destination MAC address and IP address, the data flow may be transmitted on only one link, causing traffic congestion.

What is the default load balancing mode
By default, Eth-Trunks work in manual load balancing mode.

If you have more questions, you can seek help from following ways:
To iKnow To Live Chat
Scroll to top