LiveNX Routing is a technology module that provides real-time routing-layer visualizations for Cisco networks, including Virtual Routing and Forwarding (VRF) tables. In addition, the module’s policy-based routing feature provides a high degree of control, allowing users to route traffic easily and predictably over user-specified paths.
Applications and Benefits
Network Architecture Analysis
- Identify routing protocols in use
- Establish baseline nominal routing behavior
- Perform Virtual Routing and Forwarding
- Rich routing topology visualizations
- Identify hijacked routes
- Track routes for suspicious flows to source-specific hostnames or IPs
- Zero in on specific traffic by filtering routes by destination or type
The LiveNX routing feature can be used to detect the following information and conditions:
- Static routes
- Black holes
- PBR applied, but forgotten
- Summarization errors
- Route loops
- Asymmetric routing
- EIGRP, IS-IS and OSPF Adjacency conditions
How LiveNX Routing Works
LiveNX shows routes in both tabular and graphical formats. The graphical topology view is given in the context of the physical interfaces on each network device. Each subnet is represented as a “cloud,” and route arrows originate at router interfaces and terminate at the subnet “cloud” to which they route. In this way, LiveNX gives a bird’s-eye view of routing across multiple devices.
LiveNX Routing Topology View—the Routing module retrieves routing information by opening a CLI connection (either Telnet or SSH) to the device and issuing a “show” command (show IP route for the route table and show route-map for the PBR statistics). This data is kept in a database on the LiveNX server.
LiveNX Tip—The “Other” Interface
The interface labeled Other in each network device shown in the topology view is a catchall for any routing points in the network device that are not otherwise shown. In the case where Null traffic is not displayed separately, routes attached to Null would be shown using the Other interface.
LiveNX Routing Views
The Routing system-level view makes it easy to visualize routing across your network. The system-level routing visualization shows the routes of all devices in a graphical format. The route paths and the interfaces that are routing them are indicated by arrows. The directional arrows are also color coded to indicate whether the route is a static route or derived from a particular routing protocol. You can apply a filter to display routes based on specific protocols and/or destinations.
The Protocol option filters by protocol or destination IP. LiveNX parses the routing information collected to determine the route for a particular protocol or destination network (in CIDR format). Click on the Protocol tab to display route filter options.
Route displays are refreshed manually. To refresh the routing tables and the information in the system topology view, click Refresh Routes in the Routing toolbar and select an option. If Refresh Specified Routes is selected, indicate the route IP address and mask pair, as shown below.
NOTE: The following describes the Cisco IP address and mask pair prefix according to Cisco’s command reference, “When the longer-prefixes keyword is included, the address and mask pair becomes the prefix, and any address that matches that prefix is displayed.”
For more information, go to: http://www.cisco.com/en/US/docs/ios/12_2/iproute/command/reference/1rfindp2.html#wp1022511
Refresh Timeout Limit
Some refresh operations may take a long time due to one or more of the following factors:
- The device has a very large routing table.
- There is a very high load on the CPU running LiveNX.
- The device is connected to LiveNX over a high-latency path.
If the route display refresh is not completed within 30 seconds, LiveNX will time out and show an error message. If this happens, reduce the load by limiting the refresh operation to specific routes that match the specified IP address and mask pair prefix, rather than refreshing all routes.
NOTE: The refresh operation applies only to the display, and does not affect the device’s configuration or any of the routes themselves.
The Protocol tab displays neighbor adjacencies for the EIGRP and OSPF routing protocols. This information is displayed visually on the system level topology within the Protocol sub tab and in table form within the Adjacency Table. Adjacency information can be displayed with protocol filter information or each type of data shown exclusively by using the Display drop down in the Protocol tab.
The adjacencies will show up as edges from router interface to adjacent router interface. In cases where the interface of the adjacency cannot be determined the edge will show from the router itself and not from any particular interface. The adjacency will be colored either green, orange or red. For the case of OSPF, green indicates a FULL state, DOWN state is red and all other states such as INIT, ATTEMPT, 2WAY, LOADING, EXSTART, LOADING, EXCHANGE are in orange.
Next-Hop Routing provides a graphical representation of next-hop entries in route tables. This provides you with an easier means of understanding system-level routing across their networks.
A path in the Next-Hop visualization is a set of edges that describes the route from the source point to the destination. Endpoints in the topology can be one of three types: interface, network, or node. A network interface on a device loaded into the system can be the source or destination point of the routing algorithm. An IP network connected to an interface loaded into the system can also be the source or destination point of the routing algorithm. The third endpoint type, node, must be an IP address of a node that is contained in a network loaded into the system. If the node address does not exist in a network in the system, the node cannot be used as a source address; no routing will be performed in this case. If the node is a destination, routing will progress to the last device in the system that can route the packet, and the node will be represented by a “missing node” object.
To access Next-Hop Routing visualization, click on the Routing tab. Below the system topology toolbar, select Next-Hop.
Use the parameters below to set up Next-Hop Routing. Click Show Routes to execute Next-Hop Routing visualization, or click Clear to reset the view.
Next-Hop Routing visualization in the system topology view is displayed as a bold, light purple-colored line. If the destination address is not represented in the current set of network devices, as in the example below, a new icon representing the destination device is created.
Routing Device-Level View
The device-level view provides a graphical visualization of routes associated with a specific device. The route paths and the interfaces, which route them are indicated by arrows. The directional arrows are also color coded to indicate whether the route is a static route or derived from a particular routing protocol.
The upper portion of the screen shows the device’s route table in tabular format. You can also apply a filter to display routes based on specific protocols and/or destinations.
NOTE: There is no interface-level view on the Routing tab. Clicking on an interface will bring up the device-level view for the router associated with that interface.
In the routing topology home view, click on an individual device and then click on Routing Table in the menu bar within the Routing tab to view the Routing Table specific to that device.
In the routing topology home view, click on the Adjacency Table in the menu bar within the Routing tab to view all neighbor adjacencies. Tabs are available to see all neighbors or neighbor devices filtered by routing protocol.