Protocol-Based Vlans; Port-Based Vs. Protocol-Based Vlans - Lenovo CN4093 Application Manual

Protocol-Based VLANs

Port-Based vs. Protocol-Based VLANs

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CN4093 Application Guide for N/OS 8.3
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

Each VLAN supports both port-based and protocol-based association, as follows:
 The default VLAN configuration is port-based. All data ports are members of
VLAN 1, with no PVLAN association.
 When you add ports to a PVLAN, the ports become members of both the
port-based VLAN and the PVLAN. For example, if you add port EXT1 to
PVLAN 1 on VLAN 2, the port also becomes a member of VLAN 2.
 When you delete a PVLAN, it's member ports remain members of the
port-based VLAN. For example, if you delete PVLAN 1 from VLAN 2, port
EXT1 remains a member of VLAN 2.
 When you delete a port from a VLAN, the port is deleted from all corresponding
PVLANs.