Cisco Nexus 7000 Series NX-OS Troubleshooting Guide -- Troubleshooting Routing

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Revision as of 19:25, 8 October 2009

This article describes troubleshooting procedures for routing.

Information about Troubleshooting Routing Issues

Layer 3 routing involves determining optimal routing paths and packet switching. You can use routing algorithms to calculate the optimal path from the router to a destination. This calculation depends on the algorithm selected, route metrics, and other considerations such as load balancing and alternate path discovery.

Cisco NX-OS uses the virtual device contexts (VDCs) to provide separate management domains per VDC and software fault isolation. Each VDC supports multiple Virtual Routing and Forwarding Instances (VRFs) and multiple routing information bases (RIBs) to support multiple address domains. Each VRF is associated with a routing information base (RIB) and this information is collected by the Forwarding Information Base (FIB).

See the Cisco NX-OS Unicast Routing Configuration Guide and the Cisco NX-OS Multicast Routing Configuration Guide for more information on routing.

Initial Troubleshooting Checklist

Begin troubleshooting routing issues by checking the following issues first:

Use the following commands to display routing information:

• show ip arp
• show ip traffic
• show tcp statistics udp4
• show ip client
• show tcp client
• show ip fib
• show ip process
• show ip route
• show pktmgr interface
• show frame traffic
• show platform fib
• show platform forwarding
• show platform ip
• show vrf
• show vrf interface

Troubleshooting Routing

To troubleshoot basic routing issues, follow these steps:

1. Verify that the routing protocol is enabled.

switch(config)# show ospf 
                      ^ 
% invalid command detected at '^' marker. 

If the feature is not enabled, Cisco NX-OS reports that the command is invalid. Use the feature command to enable the routing protocol.

2. Verify the configuration for this routing protocol.

switch# show running-config eigrp all 
version 4.0(1) 
feature eigrp 
router eigrp 99 
log-neighbor-warnings 
  log-neighbor-changes 
  log-adjacency-changes 
  graceful-restart 
  nsf 
  timers nsf signal 20 
  distance 90 170 
  metric weights 0 1 0 1 0 0 
  metric maximum-hops 100 
  default-metric 100000 100 255 1 1500 
  maximum-paths 16 
  address-family ipv4 unicast 
    log-neighbor-warnings 
    log-neighbor-changes 
    log-adjacency-changes 
    graceful-restart 
    router-id 192.0.2.1 
    nsf 
    timers nsf signal 20 
    distance 90 170 
    metric weights 0 1 0 1 0 0 
    metric maximum-hops 100 
    default-metric 100000 100 255 1 1500 
    maximum-paths 16 

3. Verify the VRF configuration for this routing protocol.

switch# show running-config eigrp  
version 4.0(1) 
feature eigrp 
router eigrp 99 
  address-family ipv4 unicast 
    router-id 192.0.2.1 
  vrf red 
    stub 

4. Check the memory utilization for this routing protocol.

switch# show processes memory | include isis 
 8913   9293824  bffff1d0/bffff0d0  isis 
32243   8609792  bfffe0c0/bfffdfc0  isis 

5. Verify that the routing protocol is receiving packets.

switch# show ip client pim 
  Client: pim, uuid: 284, pid: 3839, extended pid: 3839 
  Protocol: 103, client-index: 10, routing VRF id: 255 
  Data MTS-SAP: 1519 
  Data messages, send successful: 2135, failed: 0 

6. Verify that the routing protocol is enabled on an interface.

switch# show ip interface loopback0 
loopback0, Interface status: protocol-up/link-up/admin-up, iod: 36, Context:"default" 
  IP address: 1.0.0.1, IP subnet: 1.0.0.0/24 
  ... 
  IP multicast groups locally joined: 
      224.0.0.2  224.0.0.1  224.0.0.13 
  ... 

7. Verify that the interface is in the correct VRF.

switch(config)# show vrf interface loopback 99 
Interface                     VRF-Name                    VRF-ID 
loopback99                    default                          1 

8. Verify that the routing protocol is registered with the RIB.

switch(config)# show routing unicast clients 
CLIENT: am 
 index mask: 0x00000002 
 epid: 3908      MTS SAP: 252       MRU cache hits/misses:        2/1 
 Routing Instances: 
  VRF: management        table: base 
 Messages received: 
  Register          : 1      Add-route         : 2      Delete-route      : 1 
 Messages sent: 
  Add-route-ack     : 2      Delete-route-ack  : 1 
CLIENT: rpm 
 index mask: 0x00000004 
 epid: 4132      MTS SAP: 348       MRU cache hits/misses:        0/0 
 Messages received: 
  Register          : 1 
 Messages sent: 
... 
CLIENT: eigrp-99 
 index mask: 0x00002000 
 epid: 3148      MTS SAP: 63775     MRU cache hits/misses:        0/1 
 Routing Instances: 
  VRF: default           table: base                notifiers: self 
 Messages received: 
  Register          : 1      Delete-all-routes : 1 
 Messages sent: 
... 

9. Verify that the RIB is interacting with the forwarding plane.

switch# show forwarding distribution multicast client 
Number of Clients Registered: 3 
Client-name  Client-id  Shared Memory Name 
igmp         1          N/A 
mrib         2          /procket/shm/mrib-mfdm 
m6rib        3          /procket/shm/m6rib-mfdm

See Also

Cisco NX-OS/IOS BGP (Basic) Comparison

Cisco NX-OS/IOS BGP (Advanced) Comparison

Cisco NX-OS/IOS EIGRP Comparison

Cisco NX-OS/IOS HSRP Comparison

Cisco NX-OS/IOS Layer-3 Virtualization Comparison

Cisco NX-OS/IOS OSPF Comparison

Further Reading

The following links contain further information on this topic from Cisco.com:

Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide

External Links

External links contain content developed by external authors. Cisco does not review this content for accuracy.

Packetlife Routing Cheatsheets