How The Max Initiates A Bridged Wan Connection - Lucent Technologies MAX 6000 Configuration Manual

Configuring Packet Bridging
Introduction to Lucent bridging

How the MAX initiates a bridged WAN connection

When you configure the MAX unit for bridging, it accepts all packets on the Ethernet network
and forwards only those that have one of the following:
•
•
The important thing to remember about bridging connections is that they operate on physical
and broadcast addresses, not on logical (network) addresses.
Physical addresses and the bridge table
A physical address is a unique, hardware-level address associated with a specific network
controller. A device's physical address is also called its Media Access Control (MAC) address.
In an Ethernet network, the physical address is a six-byte hexadecimal number assigned by the
Ethernet hardware manufacturer. For example:
0000D801CFF2
If the MAX unit receives a packet whose destination MAC address is not on the local network,
it first checks its internal bridge table. (For a description of the table, see "Transparent
bridging" on page 13-4). If it finds the packet's destination MAC address in its bridge table,
the unit dials the connection and bridges the packet.
If the address is not specified in its bridge table, the unit checks for active sessions that have
bridging enabled. If there are one or more active bridging links, the unit forwards the packet
across all active sessions that have bridging enabled.
Broadcast addresses
Multiple nodes in a network recognize a broadcast address. For example, the Ethernet
broadcast address at the physical level is:
FFFFFFFFFFFF
All devices on the same network receive all packets with that destination address. The MAX
discards broadcast packets when you configure the MAX as a router only. When you configure
the MAX as a bridge, it forwards packets with the broadcast destination address across all
active sessions that have bridging enabled.
Address Resolution Protocol (ARP) broadcast packets that contain an IP address specified in
the bridge table are a special case. For details, see "Configuring proxy mode on the MAX" on
page 13-17. (ARP is a protocol that maps an IP address to a physical hardware address, thus
enabling a unit to identify hosts on an Ethernet LAN.)
13-2
A physical address that is not on the local Ethernet segment (the segment to which the unit
connects).
A broadcast address.
MAX 6000/3000 Network Configuration Guide