| 摘要 |
An ATM device includes means for increasing the number of UTOPIA ports and means for avoiding head of line blocking. Data for a plurality of UTOPIA PHY ports are multiplexed over a first UTOPIA PHY port and backpressure information is provided to the ATM device via a second UTOPIA PHY port. The backpressure information is preferably formatted in a single 56-byte UTOPIA cell. The means for avoiding head of line blocking includes a scheduler, at least one multicast queue, at least one unicast queue, a multicast session table, a multicast timer, and a problem PHY vector. Scheduling is alternated between multicast queue(s) and unicast queue(s). If a PHY device in a multicast session is inactive, it is skipped and the next PHY in the session is serviced. When the session has serviced all of the active PHYs and there remain only inactive PHYs in the session table, the session is ended. |
