Specifications

Cisco ONS 15327 Product Overview
Ethernet
28
Cisco ONS 15327 Product Overview, R3.3
June 2002
quality of timing sources. SSM enables SONET devices such as the ONS 15327
to automatically select the highest quality timing reference and to avoid timing
loops (particularly in ring architecture). Synchronization status messages are
carried in the S1 byte of the SONET line overhead (Line layer) and as a
bit-patterned message in the Extended Super Frame (ESF) datalink of the BITS
DS-1. The ONS 15327 supports BITS inputs with or without SSM.
Ethernet
To maximize Ethernet cost effectiveness, the ONS 15327 integrates Ethernet
access into the same SONET platform that transports voice traffic. Ethernet over
SONET lets service providers augment TDM services with Ethernet, and allows
delivery of data traffic over existing facilities. The ONS 15327 supports layer 2
switching and the ability to classify Ethernet traffic as defined in the IEEE 802.1
Q-tag standard. You can switch tagged traffic onto separate SONET STS channels
to engineer bandwidth by traffic class. The ONS 15327 can also concentrate
Ethernet ports into one or more STS-n circuits to use bandwidth more efficiently.