Overview
Several Virtual LAN (VLAN) interfaces can be configured on a single Ethernet interface. Once created, a VLAN interface functions the same as any physical interface.
NSM recognizes VLAN interfaces as physical interfaces. Once VLAN interfaces are created in the kernel, and IP addresses are assigned to them, OcNOS commands can be used to configure and display VLAN interfaces the same as any physical interface. OcNOS routing protocols, such as OSPF and BGP can run across networks using VLAN interfaces.
Two systems with physical connectivity (either directly connected or connected through a switch), can communicate with each other via VLAN interfaces that have the same VLAN IDs and belong to the same network.
If the physical interfaces are not directly connected to a switch, the corresponding ports on the switch must be configured as trunks, and should not be associated to any VLANs in the switch. The commands to configure switch ports as trunks depend on the type of the switch, and are beyond the scope of this document.
Topology
Figure 19-129 is used to describe VLAN interface configuration. In this example, there are two routers, R1 and R2, and the eth1 interface of R1 is connected directly to eth2 using an ethernet cable.
Figure 19-129: VLAN Connections
The vlan1.10 VLAN interface is created on R1, and vlan1.10 is created on R2. The VLAN interfaces are configured in the same network: R1 and R2 can reach each other using the VLAN connection.
Note: A VLAN ID of both VLAN interfaces is the same (10). Two systems with different VLAN IDs cannot communicate, even if they are in the same network, since a VLAN ID tags packets sent on a VLAN interface.
Last modified date: 10/16/2023