Vlan Configuration And Setup; Setting The Ingress And Egress Modes - 3Com IntelliJack NJ205 Features Manual

3 C O M ® N J 2 0 5 I N T E L L I J A C K
VLAN Configuration
and Setup
™ S W I T C H — V L A N S & T R A F F I C P R I O R I T I Z AT I O N
Forwarding Outbound-Traffic to the LAN
For most outbound data traffic, the PAN ports add VID tags to the Ethernet frames prior
to them reaching the LAN (uplink) port. In this case, the LAN port simply delivers the
outbound traffic to the network. Once on the network, the VID-tagged traffic can be
forwarded and segmented by any 802.1Q enabled switch port.
For broadcast, multicast, and unicast traffic, the outgoing Ethernet frames are tagged at
the LAN port. This tagged traffic is subsequently identified and forwarded by 802.1Q-
enabled upstream network switches.
For a step-by-step guide on setting up outbound traffic tags for the LAN port, please
refer to the section titled, Setting the Outgoing Tag Scheme.

Setting the Ingress and Egress Modes

Although the NJ205 IntelliJack Switch does not use VLAN tags, these tags are needed
by many other network devices—such as upstream switches or a VoIP phone connected
to a PAN port. To ensure traffic is appropriately tagged as it enters and exits, the NJ205
switch can be configured to add tags, remove tags, or leave frames unmodified.
The ingress mode uses the receiving port buffer to inspect and process inbound traffic.
The egress mode uses the transmitting port buffer to inspect and process outbound traf-
fic. The four settings are summarized in Table 2.
Table 2. Ingress and Egress Control Settings
Inbound Outbound
Traffic Traffic
Tagged Tagged
Tagged Untagged
Untagged Untagged
Untagged Tagged
Ingress Mode Egress Mode
Setting Setting
Frames received unmodified Frames transmitted unmodified
Remove 802.1 tag if present Frames transmitted unmodified
Frames received unmodified Frames transmitted unmodified
Frames received unmodified Add 802.1 tag to untagged frame
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