How does the military try to work around jamming attempts, particularly related to data communcations?

(all links are Wikipedia pages)

jamming (ECM)

counter-jamming (ECCM)

strategy: stay with RF, but modify the signal to reduce the effects of jamming

use various types of RF agility, concentrate the signal in a specific part of the spectrum to increase SNR, and constantly move the concentrated area around
use the same techniques as described in the agility section, but use several channels simultaneously — AKA diversity combining [2]
- spread spectrum and ultra-wideband
point-to-point communication
- microwave communication
- sidelobe blanking

strategy: use non-RF methods to communicate, particularly point-to-point methods

strategy: destroy the jammer

ARM (anti-radiation missile)

generally

radar jamming countermeasures

layer 1 protocols designed with ECCM in mind

generally