We study problems in job scheduling in the presence of communication constraints incurred as a result of the underlying machine network. We consider types of communication constraints: delay constraints and bandwidth constraints.In the delay constraints model, jobs represent precedence-constrained tasks to be executed on machines. Communication delays lower bound the time between completiing of a job and executing its successors on different machines.Our objective is to minimize makespan. Duplication of jobs is permitted. When scheduling on related machines with uniform delay, we provide an asymptotic polylogarithmic approximation. We also consider non-uniform delays where the delay between completing a predecessor job on one machine and executing its successor on another machine is given as an summation of the out-delays of the predecessor job and machine, and the in-delays of the successor job and maching.In this setting, we provide polylogarithmic asymptotic approximations for unit size jobs and related machines. For the uniform delay setting and the symmetric in/out-delay setting we convert our asymptotic approximations into true approximations when duplication is not allowed. We also demonstrate lower bounds on the solutions attainable using our LP-based methods, as well as a general lower bound when delays can arbitrarily depend on the job and machine being communicated to.When scheduling with bandwidth constraints, jobs or flows consist of pairs of machine nodes and represent communication requests between machines. Flows have release times and demands, and nodes have a capacity on how much demand can be satisfied from adjacent flows in a given round. We provide algorithms for several different models. Online and offline settings are considered, as well as settings where jobs may be fractionally executed across multiple rounds or must be scheduled all at once. We also consider optimizing maximum and average response times, and the simultaneous optimization of both. We present algorithms for various models, each using resource augmentation in the form of augmenting the capacities of the machine nodes. We also present lower bounds for offline and online approximations.