IP Addressing issues

IP Addressing issues

Figure 1 – Sample Network Topology



Configure the ONS 15454 to see the IP address on the PC. The personal computer uses the ping and tracert commands to verify the IP connectivity to the ONS 15454.

Link Level Connectivity

The sample network uses two types of Ethernet cable, namely, straight-through and crossover. This table enables you to verify which type of Ethernet cable to use between the various network connections:



Wire wrapped backplane pins

PC or Workstation

Straight through cable


RJ-45 pin 2


RJ-45 pin 1


RJ-45 pin 6



RJ-45 pin 3

Hub or Switch

Cross over cable


RJ-45 pin 6


RJ-45 pin 3


RJ-45 pin 2


RJ-45 pin 1


Figure 2 shows an example of a straight-through Ethernet cable.

Note: The snap tab at both ends is to the back of the connector.

Figure 2 – Example of a Straight-through Ethernet Cable



Figure 3 illustrates an example of a crossover Ethernet cable.

Note: The snap tab at both ends is to the back of the connector.

Figure 3 – Example of a Crossover Ethernet Cable



The sample network uses the cables as shown in Figure 4.

Figure 4 – Cable Usage



If you need to troubleshoot the link level connectivity, the best place to begin is the LEDs on the RJ-45 ports.

Note: No LED is available on the RJ-45 port on the Timing Communication and Control (TCC) card.

In order to troubleshoot link level connectivity, ensure that you check for these issues:

  • Bad cable

  • Incorrect cable or pinouts

  • Bad port on TCC, PC, hub, or router (try another port or swap the port out)

  • Incorrect speed or duplex (the Ethernet port of TCC is 10baseT half duplex)

IP Level Connectivity

You can store upto 16 static routes in the 15454 network element database in order to provide IP connectivity to remote CTC workstations that attach to the 15454 through routers. Provision the static routes on the 15454 network element through the CTC.

Note: The current version of CTC software (v2.2.x) limits the number of concurrent CTC sessions per 15454 node to four. Release 3.x and later can handle up to five concurrent CTC sessions. CTC performance can vary, based upon the volume of activity in each session, network bandwidth, TCCx card load and the size of the DCC connected network.

For example, a Network Operations Center (NOC) can remotely monitor a 15454 through CTC, while at the same time an on-site employee is logged into a 15454 on the network with a separate CTC session.

In order to provision these static routes, you need to configure changes in the 15454 and CTC workstations. The next section provides an example of how to provision a static route on the 15454 for the router linked CTC workstation in the sample network topology.

Configure the 15454

Complete these steps to configure the 15454:

  1. Select the Provisioning > Network tabs from the Node view of CTC.

  2. Select Create in the Static Routes panel.

    The Create Static Route panel appears:

    Figure 5 – Create Static Routes



    The Create Static Route panel provisions a static route to enable the 15454 to establish an IP session through the router to a CTC workstation at the destination IP address that you specify in the static route. In the sample network, the workstation resides in a Class B network with a 16-bit subnet mask. The IP address of the CTC workstation is

    The 15454 resides in a Class A network with an eight-bit subnet mask. The IP address of the Ethernet management interface (cpm0) on the TCC card is On Router-C, the IP address of the Ethernet interface (E1) on the same segment as the 15454 is

    Figure 6 – Static Routes



Troubleshoot the 15454

If you experience problems when you try to configure static routes on the 15454, check for these issues:

  • Incorrect IP address or subnet mask:

    Interfaces on the same network must have IP addresses that are within the same subnet to communicate directly.

  • Duplicate IP addresses:

    IP addresses must be unique. The network portion can be the same for all addresses, but the host portion must be unique.

  • Incorrect or missing default gateway in 15454 gateway node:

    Configure default router on gateway 15454 node as the Ethernet IP address of adjacent routers.

  • Incorrect or missing static routes in 15454 gateway node:

    Configure the destination IP address in the static route to point to the IP address assigned to the CTC workstation. The static route is automatically redistributed to all other 15454 nodes.

Understand the 15454 Routing Table

In order to achieve CTC connectivity to each other, all of the interconnected 15454 network elements in a ring form an Open Shortest Path First (OSPF) area. The nodes use the Synchronous Optical Network (SONET) Data Communication Channel (SDCC) links for communication. The elements advertise the routing table information in the individual nodes to the other 15454s that the DCCs connect.

Assume that the 15454 in the sample network topology was one of four nodes in a Bi-Directional Line Switch Ring (BLSR) ring (see Figure 7).

Figure 7 – BLSR



The Node advertises the static route that you configured to the other three nodes in the ring.

Figure 8 indicates that the top left 15454 ( advertises the static route to the other three nodes in the ring. All the nodes now share the static route in their routing tables.

Figure 8 – Advertises the Static Route



Troubleshoot the 15454 Routing Table

Here are the possible causes of SDCC connectivity problems:

  • You have not configured SDCC terminations, or configured the terminations incorrectly. When you configure the SDCC, never change the area ID or Disable OSPF on the SDCC unless you want to divide the network into different OSPF areas for management purposes. You would generally use these parameters when you integrate the ONS network with OSPF on the LAN.

  • Fiber path is not established (Loss of Signal (LOS) and Loss of Frame (LOF) alarms and signal degradation).

  • Optical Carrier, level N (OC-N) ports are not in service.

  • You have not configured SDCC tunnels.

Configure the Router

This section extends the sample network topology to include the four-node BLSR ring (see Figure 9):

Figure 9 – Network Topology with the 4-Node BLSR



The four nodes in the BLSR form an internal OSPF area, and redistribute the static routes learned among themselves. However, the OSPF area does not advertise the learned routes out of the Ethernet management interface (cpm0) on the TCC card on each of the nodes.

Router-C learns the IP address of 15454-1 because the router sees the node as directly connected. However, the other three class A subnets that form the OSPF area within the BLSR are not directly connected to Router-C, and remain hidden. 15454-1 does not advertise the routes of these nodes out of the cpm0 interface to Router-C.

Note: From Cisco ONS15454 Release 3.3 onwards, Proxy server functionality is available. This functionality allows the Gateway ONS15454 to act as proxy for all nodes behind the gateway. This action alleviates the need for the router to have routes that point to all subnets behind the Gateway ONS15454.

Hence, Router C requires that you configure static routes for the three nodes to which the router is not directly connected. The static routes have the next hop IP address assigned to interface cpm0 on 15454-1 to which Router-C is directly connected. View the static route statements in the configuration of Router C, as shown here:

	! hostname Router-C ! . . interface Ethernet0 ip address ! interface Ethernet1 ip address ! . . ip route ip route ip route !. . line con 0 exec-timeout 0 0 password 7 131200 login line aux 0 line vty 0 4 password 7 010411 login ! end Router-C#

Figure 10 shows the output from the show ip route command on Router-C. Both Ethernet interfaces are directly connected, and the three 15454 nodes that are not directly connected are reachable via static routes.

Figure 10 – Output of the show ip route Command on Router-C



Refer to the IP Routing Scenario 5 section of this document for an example of how to define static routes.

Troubleshoot the Router

Here are the common issues to check for in the enterprise network:

  • Verify IP connectivity between the IP subnets of the CTC workstations and the 15454 gateway nodes.

    • Check whether the routers in the enterprise Internet between the CTC workstation and 15454 gateway node have entries in the forwarding table for the CTC workstations IP subnet/major/super net, and the 15454 gateway nodes subnet/major/super net.

    • From router adjacent to 15454 gateway node, perform ping sourced from 15454 gateway nodes default gateway to CTC workstations default gateway.

  • Configure static routes for non-gateway 15454 nodes IP address subnet/major/super net in router adjacent to 15454 gateway node:

    • Ping from the router adjacent to the 15454 gateway node to each 15454 node.

      Note: In networks that use the Proxy Server feature, only a SOCKS V5-aware ping application is successful.

  • Redistribute static routes into enterprise network:

    • Check whether static routes are redistributed into enterprise networks dynamic routing protocol or statically configured on each router between CTC workstation and 15454 gateway node?

    • Ping from the CTC workstation to each 15454 node.

      Note: In networks that use the Proxy Server feature, only a SOCKS V5-aware ping application is successful.

    • Verify whether the nodes have a name in CTC map view. In other words, ensure that the nodes are not greyed out with just their IP address showing up.

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