Specifications

56 Implementing IBM System Networking 10Gb Ethernet Switches
As shown in Figure 2-5, the tagged packet remains unchanged as it leaves the switch through
port 5, which is configured as a tagged member of VLAN 2. However, the tagged packet is
stripped (untagged) as it leaves the switch through port 7, which is configured as an untagged
member of VLAN 2.
Figure 2-5 802.1Q tagging (after 802.1Q tag assignment)
2.1.3 Protocol-based VLANs
You can use protocol-based VLANs (PVLANs) to segment network traffic according to the
network protocols in use. Traffic for supported network protocols can be confined to a
particular port-based VLAN. You can give different priority levels to traffic generated by
different network protocols.
With PVLAN, the switch classifies incoming packets by the Ethernet protocol of the packets,
not by the configuration of the ingress port. When an untagged or priority-tagged frame
arrives at an ingress port, the protocol information carried in the frame is used to determine
the VLAN to which the frame belongs. If a frame’s protocol is not recognized as a predefined
PVLAN type, the ingress port’s PVID is assigned to the frame. When a tagged frame arrives,
the VLAN ID in the frame’s tag is used.
Each VLAN can contain up to eight different PVLANs. You can configure separate PVLANs
on different VLANs, with each PVLAN segmenting traffic for the same protocol type. For
example, you can configure PVLAN 1 on VLAN 2 to segment IPv4 traffic, and PVLAN 8 on
VLAN 100 to segment IPv4 traffic.
To define a PVLAN on a VLAN, configure a PVLAN number (1 - 8) and specify the frame type
and the Ethernet type of the PVLAN protocol. You must assign at least one port to the PVLAN
before it can function. Define the PVLAN frame type and Ethernet type as follows:
򐂰 Frame type: Consists of one of the following values:
– Ether2 (Ethernet II)
– SNAP (Subnetwork Access Protocol)
– LLC (Logical Link Control)