Tagging modes

Overview

Alcatel-Lucent 1850 TSS-5 supports the following tagging modes.

• Private Line mode

• VLAN tagging

Private Line mode

The Private Line mode is used to establish simple point-to-point connections between two ports with no Ethernet switching functions applied. No additional Ethernet provisioning is required after the cross-connection is established. Private Line mode can be used to provide either a full rate or sub-rate (fractional rate) dedicated Ethernet link across SONET/SDH networks. No preferential treatment for high priority packets is provided. In a sub-rate service, frames may be dropped due to congestion. Any correctly formatted Ethernet frame received at a source port is transmitted out of the destination port. Private Line mode is supported on VLNC50/52/55 and VLNC35 circuit packs.

The Private Line mode supports the following features:

• Point-to-point topology with only two LAN ports

• Protection is provided at the SONET/SDH network layer by UPSR/SNCP and 1+1 switching

• No spanning tree protocol (supports transparency of customer spanning tree protocol)

• No VLAN ingress filtering or classification (VLAN tags are not verified or added)

• Ethernet PM per port

Table A-6: Private Line mode packet handling

VLAN Tag	VLAN Filtering	Spanning Tree	Priority	Max. Frame Size (Bytes)	Applicable Circuit Packs
N/A	No	No	No (802.1p)	9614	VLNC50/52 VLNC35

802.1Q VLAN mode

In 802.1Q Mode, a VLNC40/42/42B circuit pack can be provisioned to use an incoming frame's VLAN tag, to add a VLAN tag associated with the port for untagged frames, or to drop an incoming frame if its VLAN tagging does not meet provisioned specifications. The priority bits in an incoming frame's VLAN tag can also be used to affect the handling of the frame.

Table A-7: 802.1Q VLAN mode packet handling

VLAN Tag	VLAN Filtering	Spanning Tree	Priority	Max. Frame Size (Bytes)	Applicable Circuit Packs
Yes	Yes	Yes (RST 802.1D) (MST 802.1S up to 4 instances)	Yes (802.1p)	9216	VLNC40 VLNC42 VLNC42B