Black Box LR1102A-T1/E1, LR1112A-T1/E1 manual Virtual LAN Forwarding, Managing Vlan Traffic

26

VIRTUAL LAN FORWARDING

26.1 Managing VLAN Traffic

Figure 43 VLAN Forwarding: Multi-Tenant Internet Access

Untagged Customer LANs	LR1104A	Ethernet
		Switch
	Channelized T3	Gigabit
		Ethernet
Ethernet	Telco
Switch
		Internet
Tagged VLAN
Trunk	POP Router
LR1114A
Multi-Tenant Building

The example above shows each multi-tenant customer represented as a separate VLAN on the Ethernet switch. The connection in the customer office can be routed or bridged, depending on whether the provider will be hosting customer applications at the POP. The Ethernet switch passes a VLAN trunk to the Black Box LR1114A that forwards traffic, based on the VLAN tags, from this interface to the multilink bundle.

At the POP, tagged traffic is forwarded to a VLAN trunk port on the Ethernet switch. Routing between customer VLANs is provided by the POP router using sub-interfaces on the Gigabit Ethernet VLAN trunk. The customer LAN subnet is extended all the way to the POP router making remote management of LAN services (e.g., DHCP, file servers. SMTP) possible.

The VLAN forwarding feature has the added benefit of being able to support non-IP traffic since all traffic is forwarded based only on the Layer 2 VLAN tag. Although Black Box products do not communicate using non-IP Layer 3 protocols, Black Box systems can forward these protocols.

The management VLAN feature provides in-band communication with the Black Box systems as well as the Ethernet switches while remaining separate from customer traffic. The Black Box systems will examine the destination IP address of any packets received on the management VLAN. If the destination is the Black Box, the address of the