Juniper JUNOSE 11.1.X - LINK LAYER CONFIGURATION 4-7-2010, Configuration Manual

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Bridged Ethernet Application
Figure 41 on page 444 shows an example of a client computer using IP/PPP/PPPoE
and an Internet gaming system running IP, connecting to the E Series router over
the same ATM PVC. The client computer and gaming system can connect to an E
Series router via an xDSL modem over a single ATM PVC, and the router can forward
these two data streams independently. When the router receives the two data streams,
it uses the Ethertype contained in the bridged Ethernet header to select which upper
interface (IP or PPPoE) receives the frame.
In Figure 41 on page 444, IP and PPPoE interfaces are configured so that the
non-PPPoE IP traffic is received by the IP interface, and the IP/PPP/PPPoE traffic is
received by the PPPoE interface. Since the router receives these data streams on
different IP interfaces, they may be routed independently.
Figure 41: Bridged Ethernet Topology, Router Terminating and Routing Traffic
Assigning MAC Addresses
When you create a bridged Ethernet interface, the system media access control
(MAC) address is assigned to the interface by default. However, you can assign a
specific MAC address to each statically configured bridged Ethernet interface. For
example, if multiple statically configured bridged Ethernet interfaces are connected
to the same device, using specific MAC addresses enables the connected device to
select the correct ATM port or VC to use.
You configure a specific MAC address when you create the bridged Ethernet interface.
If you want to modify an existing MAC address, you must remove the interface and
create it again. Also, you cannot configure multicast MAC addresses on bridged
Ethernet interfaces.
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Overview
JUNOSe 11.1.x Link Layer Configuration Guide