A method of operating a data processing system comprising a control processor, the method comprising: communicatively coupling endpoint devices (1161, 1162) over a communication fabric (1151-1155, 1150); and establishing, by the control processor, a peer-to-peer arrangement between the endpoint devices (1161, 1162) over the communication fabric (1151-1155, 1150) by at least providing an isolation function in the communication fabric (1151-1155, 1150) configured to isolate a device fabric address domain associated with the endpoint devices (1161, 1162) from at least a local fabric address domain associated with a host processor that initiates the peer-to-peer arrangement between the endpoint devices (1161, 1162) isolating, by the isolation function, the device fabric address domain from the local fabric address domain by at least establishing synthetic endpoint devices (1141, 1142), by the control processor, representing the endpoint devices (1161, 1162) in the local fabric address domain; redirecting traffic transferred by the host processor for the endpoint devices (1161, 1162) in the local fabric address domain for delivery to corresponding ones of the endpoint devices (1161, 1162) in the device fabric address domain; and responsive to peer-to-peer traffic from a first of the endpoint devices (1161, 1162) indicating the second of the endpoint devices (1161, 1162) as a destination in the local fabric address domain, employing a peer-to-peer address trap (1171, 1172) in the isolation function to receive the peer-to-peer traffic and transfer the peer-to-peer traffic to the second of the endpoint devices in the device fabric address domain. communicatively coupling endpoint devices (1161, 1162) over a communication fabric (1151-1155, 1150); and establishing, by the control processor, a peer-to-peer arrangement between the endpoint devices (1161, 1162) over the communication fabric (1151-1155, 1150) by at least providing an isolation function in the communication fabric (1151-1155, 1150) configured to isolate a device fabric address domain associated with the endpoint devices (1161, 1162) from at least a local fabric address domain associated with a host processor that initiates the peer-to-peer arrangement between the endpoint devices (1161, 1162) isolating, by the isolation function, the device fabric address domain from the local fabric address domain by at least establishing synthetic endpoint devices (1141, 1142), by the control processor, representing the endpoint devices (1161, 1162) in the local fabric address domain; redirecting traffic transferred by the host processor for the endpoint devices (1161, 1162) in the local fabric address domain for delivery to corresponding ones of the endpoint devices (1161, 1162) in the device fabric address domain; and responsive to peer-to-peer traffic from a first of the endpoint devices (1161, 1162) indicating the second of the endpoint devices (1161, 1162) as a destination in the local fabric address domain, employing a peer-to-peer address trap (1171, 1172) in the isolation function to receive the peer-to-peer traffic and transfer the peer-to-peer traffic to the second of the endpoint devices in the device fabric address domain.