Solid-core vs. Stranded core of cat5e & cat6 cable
Probably the more important consideration for Pro Audio and Live Sound applications would be whether to use solid-core or stranded Ethernet cable.
Most Ethernet cable you find will be solid-core, constructed using solid insulated bare copper conductors for each of the eight wires in the four twisted pairs of the cable. These cables are meant to be used in permanent and semi-permanent installations and are designed for long distance horizontal and backbone cable runs. All Cat5e and Cat6 solid UTP cables are designated with minimum bend radius for performance standards. Proper cable installation is essential in order to maximize the performance of the cable.
In the case of a mobile live sound operation, with frequent setup and teardown, solid-core Ethernet cable probably isn't the best choice, as it's generally stiffer and not conducive to easy layout and flat deployment runs. Solid-core cables should not be over-flexed, bent, or twisted beyond the cable's recommended specifications, as you risk damaging the cable causing it to underperform or even fail.
Stranded Ethernet cables have multiple strands (typically 7 strands per conductor) of insulated bare copper conductors. These cables are typically used for patch cords/cables connecting devices to the network, but because these cables are more flexible than solid conductors, they are an excellent choice for portable uses and applications where repeated flexing is common, such as frequent setup and teardown of a live sound PA system.
Another variation worth considering is something usually referred to as "Tactical Ethernet Cable." This is Ethernet cable that is intended specifically for harsh environments where repeated deployment is the norm. Tactical cable generally uses stranded-wire construction for flexibility and durability, as well as employing a heavy, often rubberized outer jacket in addition to the lightweight PVC jacket of normal cable (sometimes referred to as "up-jacketed”). Tactical Ethernet cable has the very similar feel and handling characteristics to XLR microphone cable and is much more rugged than common solid-core cable used for in-wall building installation, making it ideal for Pro Audio and Live Sound applications.