RuggedCom RX1100 manual Configuring Ethernet Interfaces, Ethernet Interface Fundamentals, Vlan Tag

Chapter 5 – Configuring Ethernet Interfaces

Chapter 5 – Configuring Ethernet Interfaces

Introduction

This chapter familiarizes the user with:

∙Reading the Ethernet LEDs

∙Configuring Ethernet Network Interfaces

∙Configuring VLANs

∙Configuring PPPoE

Ethernet Interface Fundamentals

RuggedCom manufactures dual Ethernet Interface boards in a variety of formats. Some (most notably the optical interfaces) have the same outward appearance but different order numbers. A complete set of descriptions is displayed on the console during boot and can be found after boot in the file /var/cache/ruggedrouter/inventory.

LED Designations

The RuggedRouter includes two sources of LED indicated information about Ethernet ports, the front panel LEDs and the LED Panel.

A LED is associated with each port, next to the Ethernet interface RJ45 socket. This LED is off when the link is disconnected, remains solidly on when the link is established and flashes briefly from on to off when traffic occurs.

The LED Panel also summarizes this information. LEDs 1-4 reflect traffic on Ethernet port 1-4. LEDs 5-8 reflect the link status of the same ports.

VLAN Interface Fundamentals

A virtual LAN (VLAN) is a group of devices on one or more LAN segments that communicate as if they were attached to the same physical LAN segment. VLANs are extremely flexible because they are based on logical instead of physical connections. When VLANs are introduced, all traffic in the network must belong to one or another VLAN. Traffic on one VLAN cannot pass to another, except through an intranetwork router or layer 3 switch.

The IEEE 802.1Q protocol specifies how traffic on a single physical network can be partitioned into VLANs by “tagging” each frame or packet with extra bytes to denote which virtual network the packet belongs to.

VLAN Tag

A VLAN tag is the identification information that is present in frames in order to support VLAN operation. The 4-byte VLAN tag is inserted into the Ethernet frame between the Source MAC Address field and the Length/Type field. The first 2-bytes of the VLAN tag consist of the "802.1Q Tag Type" and are always set to a value of 0x8100.

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