Black Box LR11xx Series Router Configurations Guide
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Figure 13 Proxy ARP and Packet Forwarding
1Router 1 broadcasts an ARP request for 200.1.1.1.
2Black Box 1 recognizes that router 200.1.1.1 is reachable via its WAN interface, based on a configured IP
route.
3Black Box 1 Proxy ARPs, responding with the MAC address mapped to bundle WAN1.
4Router 1 unicasts the ping echo request to that MAC address.
5Black Box 1 forwards the echo request for 200.1.1.1 through the WAN1 bundle.
6Black Box 2 receives a packet on WAN2 and forwards it to directly connected router 2.
7The echo reply from router 2 to router 1 is returned in the same manner.
6.1.3 Addressing in IP Multiplexing Networks
IP addressing in an IP Multiplexing design must take into account the fact that the router on the LA N must see the remote
router as residing on the same LAN or IP network. There are a number of addressing schemes that can fulfill this
requirement, including:
Single subnet
���Split subnet
Secondary addressing
Consider the following network, consisting of three remote sites. Two remote sites utilize Black Box equipment,
while the third is a simple router/dsu combination. Five IP addressing schemes are provided below, all refer to the
following network.
Figure 14 Addressing in IP Multiplexing Networks
Tasman 1
e0: 200.1.1.3/29
Tasman 2
e0: 200.1.1.2/29
wan
R
outer 1
e
0: 200.1.1.4/29
Router 2
e0: 200.1.1.1/2
9
Black Box 1 Black Box 2
Router 1
Router 2
POP Rout
er
Router/DSU
e1
e0
e0
e0
e0
e0
e0
s0
e1
e0
POP Tasman
Tasman 1
Tasman 2
wan 1
wan 2
wan 3
Black Box 1
Black Box 2