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Cisco ONS 15454 Reference Manual, R7.0
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Chapter 13 Management Network Connectivity
13.2 13.2.3 IP Scenario 3: Using Proxy ARP to Enable an ONS 15454 Gateway
IP Scenario 3 is similar to IP Scenario 1, but only one ONS 15454 (1) connects to the LAN (Figure 13-3).
Two ONS 15454s (2 and 3) connect to ONS 15454 1 through the SONET DCC. Because all three
ONS 15454s are on the same subnet, proxy ARP enables ONS 15454 1 to serve as a gateway for
ONS 15454 2 and 3.
Note This scenario assumes all CTC connections are to Node 1. If you connect a laptop to either ONS 15454
2 or 3, network partitioning occurs; neither the laptop nor the CTC computer can see all nodes. If you
want laptops to connect directly to end network elements, you must create static routes (see “13.2.5 IP
Scenario 5: Using Static Routes to Connect to LANs” section on page 13-7) or enable the ONS 15454
SOCKS proxy server (see “13.2.7 IP Scenario 7: Provisioning the ONS 15454 SOCKS Proxy Server”
section on page 13-12).
Figure 13-3 IP Scenario 3: Using Proxy ARP
You can also use proxy ARP to communicate with hosts attached to the craft Ethernet ports of
DCC-connected nodes (Figure 13-4). The node with an attached host must have a static route to the host.
Static routes are propagated to all DCC peers using OSPF. The existing proxy ARP node is the gateway
for additional hosts. Each node examines its routing table for routes to hosts that are not connected to
the DCC network but are within the subnet. The existing proxy server replies to ARP requests for these
additional hosts with the node MAC address. The existence of the host route in the routing table ensures
that the IP packets addressed to the additional hosts are routed properly. Other than establishing a static
route between a node and an additional host, no provisioning is necessary. The following restrictions
apply:
• Only one node acts as the proxy ARP server for any given additional host.
• A node cannot be the proxy ARP server for a host connected to its Ethernet port.
CTC Workstation
IP Address 192.168.1.100
Subnet Mark at CTC Workstation 255.255.255.0
Default Gateway = N/A
ONS 15454 #2
IP Address 192.168.1.20
Subnet Mask 255.255.255.0
Default Router = N/A
Static Routes = N/A
ONS 15454 #1
IP Address 192.168.1.10
Subnet Mask 255.255.255.0
Default Router = N/A
Static Routes = N/A
ONS 15454 #3
IP Address 192.168.1.30
Subnet Mask 255.255.255.0
Default Router = N/A
Static Routes = N/A
LAN A
SONET RING