madhuvarsha
2010-07-16, 02:34 AM
ITU-T G.812 pdf ([Only registered and activated users can see links])
Timing requirements of slave clocks ([Only registered and activated users can see links]) suitable for use as node clocks in synchronization ([Only registered and activated users can see links]) networks ([Only registered and activated users can see links])
This Recommendation outlines minimum requirements for timing devices used as node clocks in synchronization networks. The function of a node clock is to select one of the external synchronization links coming into a telecommunications ([Only registered and activated users can see links]) station as the active synchronization reference, to attenuate its jitter ([Only registered and activated users can see links]) and wander and subsequently to distribute the reference to the telecommunication equipment in the station. The requirements in this Recommendation apply under the normal environmental conditions specified for telecommunications equipment.
This Recommendation specifies node clocks suitable for use in SDH and PSTN ([Only registered and activated users can see links]) network applications. They may provide acceptable performance for other applications, but that has to be investigated for each case individually.In normal operation, a node clock is operating as a slave clock, traceable to a primary reference clock ([Only registered and activated users can see links]). For purposes of redundancy, a node clock will in general have multiple reference inputs. In the event that all links between the master ([Only registered and activated users can see links])(s) and the node clock fail, the node clock should be capable of maintaining operation within prescribed performance limits (the hold-over mode of operation ([Only registered and activated users can see links])).
A node clock can be a separate piece of equipment called a Stand Alone Synchronization Equipment (SASE) or it can be a part of another equipment such as a telephony exchange or an SDH cross-connect.
Timing requirements of slave clocks ([Only registered and activated users can see links]) suitable for use as node clocks in synchronization ([Only registered and activated users can see links]) networks ([Only registered and activated users can see links])
This Recommendation outlines minimum requirements for timing devices used as node clocks in synchronization networks. The function of a node clock is to select one of the external synchronization links coming into a telecommunications ([Only registered and activated users can see links]) station as the active synchronization reference, to attenuate its jitter ([Only registered and activated users can see links]) and wander and subsequently to distribute the reference to the telecommunication equipment in the station. The requirements in this Recommendation apply under the normal environmental conditions specified for telecommunications equipment.
This Recommendation specifies node clocks suitable for use in SDH and PSTN ([Only registered and activated users can see links]) network applications. They may provide acceptable performance for other applications, but that has to be investigated for each case individually.In normal operation, a node clock is operating as a slave clock, traceable to a primary reference clock ([Only registered and activated users can see links]). For purposes of redundancy, a node clock will in general have multiple reference inputs. In the event that all links between the master ([Only registered and activated users can see links])(s) and the node clock fail, the node clock should be capable of maintaining operation within prescribed performance limits (the hold-over mode of operation ([Only registered and activated users can see links])).
A node clock can be a separate piece of equipment called a Stand Alone Synchronization Equipment (SASE) or it can be a part of another equipment such as a telephony exchange or an SDH cross-connect.