Layer 3

When troubleshooting Layer 3 issues, verify:

The IP address assigned to each VLAN (Virtual LAN) router interface.
1. To display summary information for all of the VLANs configured on the device, use the show vlan command.
That IP forwarding is enabled, the routing protocol is globally enabled, and the routing protocol is enabled for a VLAN.
1. To display the configuration information for a specific VLAN, use one of the following commands:
  
  show ipconfig {ipv4} {vlan vlan_name}—IPv4 environment
  
  show ipconfig ipv6 {vlan vlan_name | tunnel tunnelname}—IPv6 environment
Which destination networks are in the routing table and the source of the routing entry.
1. To display the contents of the routing table or the route origin priority, use one of the following commands:
  
  show iproute—IPv4 environment
  
  show iproute ipv6—IPv6 environment
2. To display the contents of the routing table only for routes of a specified origin, use one of the following commands:
  
  show iproute origin—IPv4 environment
  
  show iproute ipv6 origin—IPv6 environment
That the IP Address Resolution Protocol (ARP) table has the correct entries.

Note
The ARP table is applicable only in IPv4 environments.
1. To display the contents of the IP ARP table, use the show iparp command.
That the Neighbor Discovery (ND) cache has the correct entries.

Note
The ND cache is applicable only in IPv6 environments.
1. To display the contents of the ND cache, use the show neighbor-discovery cache ipv6 command.
IP routing protocol statistics for the CPU of the switch.
1. Only statistics of the packets handled by the CPU are displayed. To display IP statistics for the CPU of the switch, use one of the following commands:
  
  show ipstats—IPv4 environment
  
  show ipstats ipv6—IPv6 environment
Your OSPF (Open Shortest Path First) configuration, including the OSPF area ID, router state, link cost, OSPF timers, interface IP address, and neighbor list.

Note
OSPF is applicable only in IPv4 environments.
1. To display OSPF information, use the following commands:
  
  show ospf—Displays global OSPF information for the switch
  
  show ospf area—Displays information related to OSPF areas
  
  show ospf area—Displays detailed information related to OSPF areas
  
  show ospf interfaces detail—Displays detailed information about OSPF interfaces
Your OSPFv3 (Open Shortest Path First version 3) configuration, including the OSPFv3 area ID, router state, link cost, OSPFv3 timers, interface IP address, and neighbor list.

OSPFv3 is applicable only in IPv6 environments.
1. To display OSPFv3 information, use the following commands:
  
  show ospfv3—Displays global OSPFv3 information for the switch
  
  show ospfv3 area—Displays information related to OSPFv3 areas
  
  show ospfv3 interfaces—Displays detailed information about OSPFv3 interfaces
Your RIP (Routing Information Protocol) configuration, including RIP poison reverse, split horizon, triggered updates, transmit version, and receive version.

Note
RIP is applicable only in IPv4 environments.
1. To display detailed information about how you have RIP configured on the switch, use the show rip command.
RIP activity and statistics for all VLANs on the switch.

Note
RIP is applicable only in IPv4 environments.
1. To display RIP-specific statistics for all VLANs, use the show rip interface detail command.
Your RIPng (Routing Information Protocol Next Generation) configuration, including RIPng poison reverse, split horizon, triggered updates, transmit version, and receive version.

Note
RIPng is applicable only in IPv6 environments.
1. To display detailed information about how you have RIPng configured on the switch, use the show ripng command.
RIPng activity and statistics for all VLANs on the switch.

Note
RIPng is applicable only in IPv6 environments.
1. To display RIPng-specific statistics for all VLANs, use the show ripng interface command.
End-to-end connectivity.
1. To test for connectivity to a specific host, use the ping command.
The routed path between the switch and a destination end station.
1. To verify and trace the routed path, use the traceroute command.

Published March 2020prev | next

Email this topic

Print this page Print this page

Leave feedback Feedback