Displaying GRE tunneling information

This section describes the show commands that display the GRE tunnels configuration, the link status of the GRE tunnels, and the routes that use GRE tunnels.

To display GRE tunneling Information, use the following commands:

show ip interface
show ip route
show ip interface tunnel
show ip tunnel traffic
show interface tunnel
show statistics tunnel

The following shows an example output of the show ip interface command, which includes information about GRE tunnels.

device# show ip interface
Interface  IP-Address  OK?  Method  Status  Protocol VRF           
Tunnel 1   101.1.1.1   YES  NVRAM   up 	    up       red             
Tunnel 3   89.1.1.1    YES  NVRAM   up 	    up       default-vrf

For field definitions, refer to the FastIron Command Reference.

Syntax: show ip interface

The show ip route command displays routes that are pointing to a GRE tunnel as shown in the following example.

device# show ip route
Total number of IP routes: 3, avail: 79996 (out of max 80000)
B:BGP D:Connected  R:RIP  S:Static  O:OSPF *:Candidate default
     Destination     NetMask         Gateway        Port       Cost   Type
1    10.1.1.0        255.255.255.0   0.0.0.0         7          1      D
2    10.1.2.0        255.255.255.0   10.1.1.3        7          1      S
3    10.34.3.0       255.255.255.0   0.0.0.0         tn3        1      D

For field definitions, refer to FastIron Command Reference.

Syntax: show ip route

The show ip interface tunnel command displays the link status and IP address configuration for an IP tunnel interface as shown in the following example.

device# show ip interface tunnel 64
Interface Tunnel 64
  port enabled
  port state: UP
  ip address: 223.224.64.0/31 
  Port belongs to VRF: default-vrf
  encapsulation: GRE, mtu: 1476, metric: 1
  directed-broadcast-forwarding: disabled
  proxy-arp: disabled
  ip arp-age:  10 minutes
  No Helper Addresses are configured.
  No inbound ip access-list is set
  No outgoing ip access-list is set

Syntax: show ip interface tunnel [ tunnel-ID ]

The tunnel-ID variable is a valid tunnel number between 1 and 72.

The show interface tunnel command displays the GRE tunnel configuration and the pmtd aging timer information.

device# show interface tunnel 10
Tunnel10 is up, line protocol is up 
  Hardware is Tunnel
  Tunnel source  1.1.41.10
  Tunnel destination is 1.1.14.10
  Tunnel mode gre ip
  Port name is GRE_10_to_VR1_on_ICX_STACK
  Internet address is 223.223.1.1/31, MTU 1476 bytes, encapsulation GRE
  Keepalive is not Enabled
  Path MTU Discovery: Enabled, MTU is 1428 bytes, age-timer: 10 minutes 
  Path MTU will expire in 0 minutes 50 secs

Syntax: show interface tunnel [ tunnel-ID ]

Table 11 show interface tunnel output descriptions
Field	Definition
Hardware is Tunnel	The interface is a tunnel interface.
Tunnel source	The source address for the tunnel.
Tunnel destination	The destination address for the tunnel.
Tunnel mode	The tunnel mode. The gre specifies that the tunnel will use GRE encapsulation (IP protocol 47).
Port name	The port name (if applicable).
Internet address	The internet address.
MTU	The configured path maximum transmission unit.
encapsulation GRE	GRE encapsulation is enabled on the port.
Keepalive	Indicates whether or not GRE link keepalive is enabled.
Path MTU Discovery	Indicates whether or not PMTUD is enabled. If PMTUD is enabled, the MTU value is also displayed.
Path MTU	The PMTU that is dynamically learned.
Age-timer	Indicates the pmtd aging timer configuration in minutes.The default is 10. The range is from 10 - 30.
Path MTU will expire	Indicates the time after which the learned PMTU expires. This line is displayed only when a PMTU is dynamically learned.

The show ip tunnel traffic command displays the link status of the tunnel and the number of keepalive packets received and sent on the tunnel.

device# show ip tunnel traffic
IP GRE Tunnels
      Tunnel Status  Packet Received  Packet Sent  KA recv  KA sent
  1   up/up          362              0            362      362
  3   up/up          0                0            0        0
  10  down/down      0                0            0        0

Syntax: show ip tunnel traffic

The show statistics tunnel command displays GRE tunnel statistics for a specific tunnel ID number. The following shows an example output for tunnel ID 1.

device(config-tnif-10)# show statistics tunnel 1
IP GRE Tunnels
      Tunnel Status  Packet Received  Packet Sent  KA recv  KA sent
  1   up/up          87120            43943        43208    43855

RFC 2784 supports GRE tunnel ports. The show statistics tunnel command output now includes information from the hardware counters for each tunnel. For example:

IP GRE Tunnel 1 HW Counters:
      InOctets                      0           OutOctets                0
      InPkts                        0           OutPkts                  0

Syntax: show statistics tunnel [ tunnel-ID ]

The tunnel-ID variable specifies the tunnel ID number.

Table 12 show ip tunnel traffic output descriptions
Field	Description
Tunnel Status	Indicates whether the tunnel is up or down. Possible values are: Up/Up - The tunnel and line protocol are up. Up/Down - The tunnel is up and the line protocol is down. Down/Up - The tunnel is down and the line protocol is up. Down/Down - The tunnel and line protocol are down.
Packet Received	The number of packets received on the tunnel since it was last cleared by the administrator.
Packet Sent	The number of packets sent on the tunnel since it was last cleared by the administrator.
KA recv	The number of keepalive packets received on the tunnel since it was last cleared by the administrator.
KA sent	The number of keepalive packets sent on the tunnel since it was last cleared by the administrator.

Contents

Displaying GRE tunneling information