This article explains how bandwidth is dynamically shared between 3G and LTE traffic passing through the VLA1130 interface, which is configured as a domain-type bridge interface (SIM realm) with a total available bandwidth of 45 Mbps.

Varying bandwidth utilization observed between 3G and LTE traffic

Possible fluctuations in throughput when LTE traffic increases

Uncertainty around how bandwidth is allocated between logical units

Shared Bandwidth Concept:

The total 45 Mbps is not statically divided. Instead, bandwidth is shared dynamically between 3G and LTE traffic based on shaping and policy configuration.

Dynamic Allocation Behavior:

• Bandwidth distribution changes based on traffic load and priorities.
• At one time, 3G might use 5 Mbps while LTE uses 40 Mbps.
• At another time, 3G might use 10 Mbps while LTE drops to 35 Mbps.
• In some cases, all bandwidth may be utilized by either 3G or LTE depending on demand.

Configuration Dependency:

• If guaranteed rates (CIR) or shaping policies are configured, they guide the minimum or maximum bandwidth per logical unit.
• Unused bandwidth is reallocated dynamically to other active flows.

Example Scenario:

• Interface is shaped to 45 Mbps.
• LTE traffic has a higher CIR than 3G.
• During high LTE load, LTE may consume up to 40+ Mbps.
• When LTE load drops, 3G can use the available surplus.

Conclusion:

Bandwidth distribution across 3G and LTE logical units on the VLAN interface is flexible and governed by shaping rates, CIR policies, and real-time traffic conditions.