User's Manual

PTP 250 User Guide Ethernet bridging
phn-2182_002v000
May 2011
1-23
Ethernet bridging
This section describes how the PTP 250 controls Ethernet data in the customer and
management networks.
Customer network
Transparent Ethernet service
The PTP 250 provides an Ethernet service between the Ethernet port at a local ODU
and the Ethernet port at an associated remote ODU. The Ethernet service is based on
conventional layer two transparent bridging, and is equivalent to the Ethernet Private
Line (EPL) service defined by the Metro Ethernet Forum (MEF).
The service is transparent to untagged frames, standard VLAN frames, priority-tagged
frames, provider bridged frames, and provider backbone bridged frames. In each case,
the service preserves MAC addresses, VLAN ID, Ethernet priority and Ethernet
payload in the forwarded frame. The maximum frame size for bridged frames is
2000 octets.
Layer two control protocols
The PTP 250 is transparent to layer two control protocols (L2CP) including:
• Spanning tree protocol (STP), rapid spanning tree protocol (RSTP)
• Multiple spanning tree protocol (MSTP)
• Link aggregation control protocol (LACP)
• Link OAM, IEEE 802.3ah
• Port authentication, IEEE 802.1X
• Ethernet local management interface (E-LMI), ITU-T Q.933.
• Link layer discovery protocol (LLDP)
• Multiple registration protocol (MRP)
• Generic attribute registration protocol (GARP)
The system does not generate or respond to any L2CP traffic.