Figure 5-5. Data Transmissions Between 802.1Q-Compliant Switches - TRENDnet TEG-S224M User Manual

Stackable NWay Ethernet Switch User's Guide
TEG-S224M (SWITCH #2)
Power Console Slot3 Giga1 Giga2 Slot2 S i o 1 S i o 2 S i o 3
S l o t 1
TEG-S244M (SWITCH #1)
Power Console Sl o t3 G i g a 1 G i g a 2 Sl o t2 S i o 1 S i o 2 S i o 3
Slot1
Figure 5-5. Data transmissions between 802.1Q-compliant
Switches
In the above example, step 4 is the key element. Because the packet
has 802.1Q VLAN data encoded in its header, the ingress port can
make VLAN-based decisions about its delivery: whether server #2 is
attached to a port that is a member of VLAN 2 and, thus, should the
packet be delivered; the queuing priority to give to the packet, etc. It
can also perform these functions for VLAN 1 packets as well, and, in
fact, for any tagged packet it receives
number.
If the ingress port in step 4 were connected to a non-802.1Q-
compliant device and was thus receiving untagged packets, it would
48
VLAN 1
Server #1
1 x 3 x 5 x 7 x 9 x 1 1 x 1 3 x 1 5 x 17x
Slot1
U p l i n k
2 x 4 x 6 x 8 x 1 0 x 1 2 x 1 4 x 1 6 x 18x
4. Ingress port (tagging) reads tag,
forwards packet to server
3. Egress port (tagging)
tags packet with VID
1x 3x 5x 7x
Slot1
Uplink
2x 4x 6x 8x
PVID=1
VLAN 1
VLAN 2
Server #2
5. Egress port (untagging)
strips tag
19x
20x
9x 11x 13x 15x 17x 19x
2. Ingress port (untagging)
forwards packet on VLAN 2
10x 12x 14x 16x 18x 20x
PVID=2
VLAN 2
regardless of the VLAN
Switch Management Concepts
1. Station in VLAN 2
transmits packet to
Server #2