Black Box LRU4240 manual Bridging Configuration, Overview of the Configuration

Dual Trunk E1 Router

Bridging Configuration

OVERVIEW OF THE CONFIGURATION

The LRU4240 supports bridging and routing packet processing modes. This chapter contains procedures on configuring your device for layer 2 bridging applications.

Bridging provides the capability to connect two or more physically separate LAN segments over the WAN, to create a single logical LAN. Bridging occurs at layer 2 and uses the MAC address assigned to each LAN device, to either forward or filter frames. Routing forwards IP packets between two or more IP networks.

NOTE: With the availability of Bridging mode, the proprietary IP Fast Forwarding mode available in the menu will no longer be supported in the future, and is thereore not documented...

Table 5-1 Bridging configuration procedure

Procedure	Description	Menu	Reference
Setting bridging mode	To configure the unit for Bridging or VLAN Bridging.	Menu-$A	page 50
	In bridging mode, all traffic types including IP is
	bridged.
Configuring static MAC	To map statically up to 50 MAC addresses to specific	Menu -$GA	page 50
Bridge routes	ports in the MAC to port map table. The entries will be
	stored in non-volatile RAM (NVRAM) and are
	restored at boot time.
Displaying MAC to port	To display the MAC to port map table. View both	Menu -$GB	page 51
map table	learnt and static MC to port mapping entries.

BRIDGING CONFIGURATION

Bridging operates at layer 2 of the OSI model to bridge Ethernet traffic between the LAN and the WAN and requires little configuration. All traffic types including IP is bridged. The bridge learns which addresses lay on each side of the bridge and maintains the following information in a MAC to port map table:

•MAC address

•Physical interface (Ethernet or Network ports)

•DLCI, in Frame Relay mode

The MAC to port map table is used by the bridge in its forwarding decisions.

On a Frame Relay connection, using InverseARP, the bridge discovers the remote subnets connected on each DLCI and fills the remote end router’s MAC address and the DLCI on which it was discovered.

On the LAN side as packets flow on the Ethernet, the bridge learns which hosts resides on the local LAN by storing the source host address in its MAC to port table.

Dual Trunk E1 Router User’s Guide TECHNICAL: 0118 96 56 000 47