Technical data

BLADE OS 5.1 Application Guide
58
 Chapter 3: VLANs BMD00136, November 2009
Protocol-Based VLANs
Protocol-based VLANs (PVLANs) allow you 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 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 a VLAN to which the frame
belongs. If a frame’s protocol is not recognized as a pre-defined 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)
 Ethernet type—consists of a 4-digit (16 bit) hex value that defines the Ethernet type. You can
use common Ethernet protocol values, or define your own values. Following are examples of
common Ethernet protocol values:
 IPv4 = 0800
 IPv6 = 86dd
 ARP = 0806