Converged protocols
Protocols that carry traffic which once needed its own separate network, such as storage or voice, over a shared network, usually an Ethernet or IP network.
A converged protocol carries a kind of traffic that used to need its own dedicated network over a shared one, usually Ethernet or IP. The ISC2 exam outline gives four examples. iSCSI carries storage commands over IP. Voice over IP moves telephone calls onto the data network. InfiniBand over Ethernet carries the low-latency InfiniBand transport over Ethernet. Compute Express Link joins processors and memory over one interconnect. Fibre Channel over Ethernet and MPLS are commonly described as converged protocols too.
The benefit is one infrastructure instead of several. The cost is that the specialised traffic inherits the threats of the shared network. Storage traffic that once lived on an isolated fabric can now be sniffed, spoofed or disrupted by anything that reaches the same segment. Convergence also concentrates availability risk, since one network failure can take out storage, voice and data together. The usual responses are network segmentation to put the converged traffic on its own logical network, and quality of service to protect time-sensitive traffic.
Exam relevance: questions in this area tend to ask for the security consequence of moving storage or voice onto the data network. Candidates are expected to answer with loss of isolation and shared failure, and to name segmentation as a first control.