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Using SubVS for UDP traffic





When creating a TCP virtual service (VS), there is an option to create a SubVS, but when creating a UDP VS there is not. 


Product: LoadMaster

Version: Any

Platform: Any

Application: Any

Question/Problem Description:

Is it possible to have two real servers and when both fail, traffic can move to the other real server under the UDP-based VS without SubVS configuration?

Steps to Reproduce:  
Error Message:  
Defect Number:  
Enhancement Number: KLM-I-979
Cause: SubVSs are not available under UDP based VS.

TCP based VSs can have both real servers/SubVSs allowed to be created whereas for UDP service we can only add new Real Servers under the UDP service-type VS. 

User Datagram Protocol(UDP) primarily operates at the network's transport layer (layer 4). The purpose of SubVSs is basically to allow content switching via rules, which requires the kind of packet analysis that is only possible at the network application layer (layer 7). This is why SubVSs cannot be developed to be working with UDP based VS.

Load Balancing with condition on real servers without having SubVS in place is therefore not possible.

Notes: Add subvs feature for UDP VS | Kemp Ideas Portal (

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