OcNOS-SP : Layer 3 Guide : Neighbor Discovery Command Reference : Neighbor Discovery Commands
Neighbor Discovery Commands
This chapter describes the Neighbor Discovery commands:
• ip arp
arp-ageing-timeout
Use this command to set the ARP aging timeout.
Note: The bridge aging time affects the ARP entries which are dependent upon the MAC addresses in hardware. If a MAC address ages out, it causes the corresponding ARP entry to refresh.
Use no form of this command to set the aging to its default value.
Command Syntax
arp-ageing-timeout <60-28800>
no arp-ageing-timeout
Parameter
<60-28800>
ARP aging timeout.
Default value
By default, the ARP aging timeout is 1500.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#configure terminal
(config)#interface xe2
(config-if)#arp-ageing-timeout 5000
(config-if)#exit
 
(config)#interface xe2
(config-if)#no arp-ageing-timeout
 
arp-reachable-time
Use this command to set the ARP reachable time.
Use no form of this command to set the reachable time to its default value.
Command Syntax
arp-reachable-time <10-3600>
no arp-reachable-time
Parameters
<10-3600>
Specify the ARP reachable time.
Default value
By default, arp-reachable-time is 60
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#configure terminal
(config)#interface xe2
(config-if)#arp-reachable-time 120
(config-if)#exit
 
(config)#interface xe2
(config-if)#no arp-reachable-time
 
clear arp
Use this command to clear dynamic ARP entries.
Command Syntax
clear arp (| A.B.C.D) (| vrf (all | VRFNAME | default))
clear arp IFNAME (| vrf (all | VRFNAME | default))
Parameters
A.B.C.D
Specify the IP address of the ARP entry.
IFNAME
Specify the name of the interface.
all
All VRFs.
VRFNAME
VPN routing/forwarding instance name.
default
Default VRF.
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#clear arp
#clear arp xe1
#clear arp 10.10.10.10
#clear arp vrf VRF1
 
clear ipv6 neighbors
Use this command to clear dynamic neighbor entries.
Command Syntax
clear ipv6 neighbors (|X:X::X:X) (|vrf (all | VRFNAME | default))
clear ipv6 neighbors IFNAME (|vrf (all | VRFNAME | default))
Parameters
X:X::X:X
Specify the neighbor’s IPv6 address.
IFNAME
Specify the name of the interface.
all
All VRFs.
VRFNAME
VPN routing/forwarding instance name.
default
Default VRF.
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#clear ipv6 neighbors
#clear ipv6 neighbors xe1
#clear ipv6 neighbors 2000::3
#clear ipv6 neighbors vrf VRF1
debug ip arp
Use this command to enable debugging for ARP events.
Note: Packet dumps are not available as part of debug logs. Use the tcpdump command to view packets.
Use the no parameter with this command to disable event debugging.
Command Syntax
debug ip arp event
no debug ip arp event
Parameters
event
ARP event debugging.
Command Mode
Exec mode and configure mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#debug ip arp event
 
debug ipv6 nd
Use this command to enable debugging for neighbor events.
Note: Packet dumps are not available as part of debug logs. Use the tcpdump command to view packets.
Use the no parameter with this command to disable event debugging.
Command Syntax
debug ipv6 nd event
no debug ipv6 nd event
Parameters
event
ND event debugging.
Command Mode
Exec mode and configure mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#debug ipv6 nd event
ip arp
Use this command to create a static ARP entry.
Use the no parameter to remove the static ARP entry.
Command Syntax
ip arp A.B.C.D XXXX.XXXX.XXXX (alias|)
no ip arp A.B.C.D
Parameters
A.B.C.D
Specify the IP address of the ARP entry.
XXXX.XXXX.XXXX
Specify the MAC (hardware) address of the ARP entry.
alias
Specify the response to ARP requests for the IP address.
Default value
No default value is specified
Command Mode
Configure mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#configure terminal
(config)#ip arp 10.10.10.10 0000.0001.4566
(config)#no ip arp 10.10.10.10
ip arp vrf
Use this command to create a static ARP entry for the non-default VRF.
Note: This command is supported only for multiple VRF support.
Command Syntax
ip arp vrf NAME A.B.C.D XXXX.XXXX.XXXX (alias|)
Parameter
NAME
Specify VRF name to which entry need to be added.
A.B.C.D
Specify the IP address of the ARP entry.
XXXX.XXXX.XXXX
Specify the MAC (hardware) address of the ARP entry.
alias
Specify the response to ARP requests for the IP address.
Default value
No default value is specified
Command Mode
Configure mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#configure terminal
(config)#ip arp vrf VRF1 10.10.10.10 0000.0001.4566
 
ip proxy-arp
Use this command to enable the proxy ARP feature.
Use the no parameter to disable the proxy ARP feature.
Command Syntax
ip proxy-arp
no ip proxy-arp
Parameter
None
Default value
No default value is specified
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface xe1
(config-if)#ip proxy-arp
(config-if)#no ip proxy-arp
 
ipv6 nd current-hoplimit
Use this command to set an ND (Neighbor Discovery) advertised hop limit for an interface.
Use the no option of this command to set the current hop limit to its default value.
Command Syntax
ipv6 nd current-hoplimit <0-255>
no ipv6 nd current-hoplimit
Parameter
<0-255>
Hop limit.
Default
By default, hop limit is 64
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface eth3
(config-if)#ipv6 nd current-hoplimit 10
(config-if)#no ipv6 nd current-hoplimit
ipv6 nd link-mtu
Use this command to set an advertised maximum transmission unit (MTU).
Use the no option with the command to reset the MTU to the default statute.
Command Syntax
ipv6 nd link-mtu (<1280-65535>)
no ipv6 nd link-mtu
Parameters
<1280-65535>
Link MTU value.
Default
By default, link MTU value is 1500
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#configure terminal
(config)#interface eth3
(config-if)#ipv6 nd link-mtu 1600
(config-if)#no ipv6 nd link-mtu
ipv6 nd managed-config-flag
Use this command to set the managed address configuration flag in the Router Advertisement to be used for the IPv6 address auto-configuration.
Use the no parameter with this command to reset the value to default.
Command Syntax
ipv6 nd managed-config-flag
no ipv6 nd managed-config-flag
Parameters
None
Default
The managed address configuration flag is not set.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface eth3
(config-if)#ipv6 nd managed-config-flag
(config-if)#no ipv6 nd managed-config-flag
ipv6 nd other-config-flag
Use this command to set the other stateful configuration flag in Router Advertisement to be used for IPv6 address auto-configuration.
Use no parameter with this command to reset the value to default.
Command Syntax
ipv6 nd other-config-flag
no ipv6 nd other-config-flag
Parameters
None
Default
Other stateful configuration flag is not set.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface eth3
(config-if)#ipv6 nd other-config-flag
 
ipv6 nd prefix
Use this command to set IPv6 prefix information that is advertised for address auto-configuration.
Use no parameter with this command to remove an IPv6 prefix.
Command Syntax
ipv6 nd prefix X:X::X:X/M <0-4294967295> <0-4294967295> (off-link|) (no-autoconfig|)
ipv6 nd prefix X:X::X:X/M
ipv6 nd prefix valid-lifetime <0-4294967295>
ipv6 nd prefix preferred-lifetime <0-4294967295>
ipv6 nd prefix offlink
ipv6 nd prefix no-autoconf
no ipv6 nd prefix X:X::X:X/M (off-link|) (no-autoconfig|)
no ipv6 nd prefix valid-lifetime
no ipv6 nd prefix preferred-lifetime
Parameters
X:X::X:X/M
IPv6 prefix.
<0-4294967295>
Valid lifetime in seconds. Use the preferred-lifetime value < valid-lifetime.
<0-4294967295>
Preferred lifetime in seconds. Use the preferred-lifetime value < valid-lifetime.
off-link
Do not use prefix for onlink determination.
no-autoconfig
Do not use prefix for autoconfiguration.
Default
By default, valid life time is 2592000 seconds and preferred life time is 604800 seconds
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Defaults
The default valid lifetime is 2592000 seconds.
The default preferred lifetime is 604800 seconds.
Examples
(config)#interface eth3
(config-if)#ipv6 nd prefix 2001:ffff::/64
 
(config)#interface eth3
(config-if)#ipv6 nd prefix no-autoconf
 
(config)#interface eth3
(config-if)#ipv6 nd prefix preferred-lifetime 550000
ipv6 nd ra-interval
Use this command to specify the interval between IPv6 Router Advertisements (RA).
Use no parameter with this command to set the value to its default.
Note: The RA interval will have a random variation from configured interval to avoid synchronization of advertisement with routers.
Command Syntax
ipv6 nd ra-interval <4-1800> (<3-1350>|)
no ipv6 nd ra-interval
Parameter
<4-1800>
RA interval in seconds.
<3-1350>
Minimum RA interval (in seconds).
Default
By default, RA interval is 600 seconds, and Minimum RA interval is 0.33*RA interval.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface eth3
(config-if)#ipv6 nd ra-interval 60 15
(config-if)#ipv6 nd prefix 3ffe:ffff:ffff::/64
 
(config-if)#no ipv6 nd ra-interval
ipv6 nd ra-lifetime
Use this command to specify the Router Advertisement (RA) lifetime for this device to act as a default gateway for the network.
Use no parameter with this command to reset the value to default.
Command Syntax
ipv6 nd ra-lifetime <0-9000>
no ipv6 nd ra-lifetime
Parameter
<0-9000>
RA lifetime duration in seconds.
Default
The default RA lifetime is 1800 seconds.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface eth3
(config-if)#ipv6 nd ra-lifetime 9000
(config-if)#no ipv6 ra-lifetime 9000
 
ipv6 nd reachable-time
Use this command to specify the reachable time in the Router Advertisement to be used for detecting unreachability of the IPv6 neighbor.
Use the no parameter with this command to set the value to its default.
Command Syntax
ipv6 nd reachable-time <0-3600000>
no ipv6 nd reachable-time
Parameter
<0-3600000>
Reachable time in milliseconds.
Default
By default, reachable time is zero (0) milliseconds.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface eth3
(config-if)#ipv6 nd reachable-time 1800000
(config-if)#no ipv6 nd reachable-time 1800000
ipv6 nd retransmission-time
Use this command to set an IPv6 advertised retransmission time for the current interface.
Use the no form of the command to set the retransmission time to its default value.
Command Syntax
ipv6 nd retransmission-time (0-4294967295)
no ipv6 nd retransmission-time
Parameter
<0-4294967295>
Retransmission time in milliseconds
Default
By default, retransmission time is zero (0) milliseconds.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface eth3
(config-if)#ipv6 nd retransmission-time 1200
(config-if)#no ipv6 nd retransmission-time
ipv6 nd suppress-ra
Use this command to suppress IPv6 Router Advertisement (RA) transmission for the current interface. Router Advertisement is used for IPv6 stateless auto-configuration.
Use the no parameter with this command to enable Router Advertisement transmission.
Command Syntax
ipv6 nd suppress-ra (mtu |)
no ipv6 nd suppress-ra (mtu |)
Parameters
mtu
Send maximum transmission unit (MTU) in Router Advertisement messages
Default
By default, ipv6 nd suppress-ra is disabled.
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#configure terminal
(config)#interface eth3
(config-if)#ipv6 nd suppress-ra
ipv6 neighbor
Use this command to add a static neighbor entry.
Use the no form of this command to remove a static neighbor entry.
Command Syntax
ipv6 neighbor X:X::X:X IFNAME XXXX.XXXX.XXXX
no ipv6 neighbor X:X::X:X IFNAME
Parameter
X:X::X:X
Specify the neighbor’s IPv6 address.
IFNAME
Specify the name of the interface.
XXXX.XXXX.XXXX
Specify the MAC hardware address.
Default value
No default value is specified
Command Mode
Configure mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#ipv6 neighbor 2000::3 xe1 0000.0002.3dc1
(config)#no ipv6 neighbor 2000::3 xe1
 
nd-ageing-timeout
Use this command to set the neighbor ageing timeout value.
Use no form of this command to set the ageing to its default value.
Command Syntax
nd-ageing-timeout <60-28800>
no nd-ageing-timeout
Parameters
<60-2880>
ND ageing timeout in seconds.
IFNAME
Specify the name of the interface.
XXXX.XXXX.XXXX
Specify the MAC hardware address.
Default value
By default, nd-ageing-timeout is 1500 seconds
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#configure terminal
(config)#interface xe1
(config-if)#nd-ageing-timeout 3600
(config-if)#no nd-ageing-timeout
 
nd-reachable-time
Use this command to set neighbor reachable time value.
Use no form of this command to set the reachable time to its default value.
Command Syntax
nd-reachable-time <10-3600>
no nd-reachable-time
Parameter
<10-3600>
ND reachable time in seconds.
Default value
By default, nd-reachable-time is 60 seconds
Command Mode
Interface mode
Applicability
This command was introduced before OcNOS version 1.3.
Examples
#configure terminal
(config)#interface xe1
(config-if)#nd-reachable-time 300
(config-if)#no nd-reachable-time
 
no debug all
Use this command to disable all ARP and the neighbor debugging.
Command Syntax
no debug all
undebug all
Parameters
None
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#no debug all
 
show arp
Use this command to display ARP entry information.
Command Syntax
show arp (| (A.B.C.D | detail | static) (| vrf (all | VRFNAME | default)))
show arp IFNAME (| vrf (all | VRFNAME | default))
show arp summary (|IFNAME) (| vrf (all | VRFNAME | default))
Parameters
detail
Display detailed information.
static
Display static ARP entries.
A.B.C.D
Specify the IP address of the ARP entry.
IFNAME
Specify the name of the interface.
all
All VRFs.
VRFNAME
VPN routing/forwarding instance name.
default
Default VRF.
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#show arp
 
Flags: D - Static Adjacencies attached to down interface
 
IP ARP Table for context default
Total number of entries: 2
Address Age MAC Address Interface State
10.12.18.1 00:00:18 44e4.d982.274b eth0 REACHABLE
10.10.10.20 00:02:33 a8b1.d433.4140 xe1 STALE
 
#show arp summary vrf default
 
IP ARP Table - Adjacency Summary
 
Resolved : 2
Incomplete : 0
Unknown : 0
Total : 2
Table 1-81 explains the show commmand output fields.
 
Table 1-81: show arp output details
Entry
Description
Address
ARP entry’s IP address in the device.
Age
The number of minutes before the ARP entry was refreshed. If this value reaches the ARP aging period, the entry is removed from the table. Static entries do not age out.
MAC Address
Physical address of the host.
Interface
Logical address to connect the device over network.
State
INCOMPLETE – first ARP request sent, send ARP request.
REACHABLE – normal expiration reset use counter.
STALE – still usable; needs verification reset use counter; change state to delay.
DELAY – schedule ARP request; needs verification reset use counter.
PROBE – sending ARP request reset use counter.
FAILED – no response received send ARP request.
NOARP – normal expiration; never verified reset use counter.
PERMANENT – never expires; never verified reset use counter.
Note: INCOMPLETE/FAILED state entries are only cleared if the total number of ARP entries is more than 2048. It might take up to 60 seconds to clear the entries. This is an optimization to improve ND performance.
 
Network devices are considered adjacent if they can reach each other with a single hop. The summary command shows the count of the state of devices that are adjacencies.
Table 1-82 explains the show command output fields.
 
Table 1-82: show arp summary output details
Field
Description
Resolved
Count of working/known adjacencies.
Incomplete
Count of yet to be established adjacencies.
unknown
Count of adjacencies not currently in ARP table.
Total
Total count of all adjacencies.
show debugging ip arp
Use this command to display debugging information for ARP.
Command Syntax
show debugging ip arp
Parameters
None
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#show debugging ip arp
ND IP Debugging status:
ND ip arp event debugging is off
ND ip arp packet debugging is off
 
show debugging ipv6 nd
Use this command to display debugging information for the neighbor.
Command Syntax
show debugging ipv6 nd
Parameters
None
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#show debugging ipv6 nd
ND IPV6 Debugging status:
ND ipv6 event debugging is off
ND ipv6 packet debugging is off
 
show ipv6 neighbors
Use this command to display the neighbor information.
Command Syntax
show ipv6 neighbors (| (X:X::X:X | detail | static) (| vrf (all | VRFNAME | default)))
show ipv6 neighbors IFNAME (| vrf (all | VRFNAME | default))
show ipv6 neighbors summary (| IFNAME) (| vrf (all | VRFNAME | default))
Parameters
detail
Show detail information of neighbor.
static
Static entry.
X:X::X:X
Specify the neighbor’s IPv6 address.
IFNAME
Specify the name of the interface.
all
All VRFs.
VRFNAME
VPN routing/forwarding instance name.
default
Default VRF.
Command Mode
Exec mode
Applicability
This command was introduced before OcNOS version 1.3.
Example
#show ipv6 neighbors
 
R - Reachable, I - Incomplete, S - Stale, F - Failed, P - Probe,
D - Delay, PR - Permanent
 
Flags: (D) - Static neighbors attached to down interface
 
IPv6 Neighbor Table for context default
Total number of entries:2
Address Age MAC Address Source Interface State
fe80::210:18ff:fe7f:f758
00:43:04 0010.187f.f758 icmpv6 eth0 S
2000::5 00:55:25 0000.0001.0242 icmpv6 xe1 S
 
#show ipv6 neighbors summary
 
IPv6 Neighbors Table - Adjacency Summary
 
Resolved : 2
Incomplete : 0
Unknown : 0
Total : 2
Table 1-83 shows the status codes displayed at the start of a route entry.
 
Table 1-83: status code output details
Status Code
Field
Description
R
Reachable
Normal expiration reset use counter.
I
Incomplete
First ARP request sent, send ARP request.
S
Stale
Still usable; needs verification reset use counter; change state to delay.
F
Failed
ARP requests response not received.
P
Probe
ARP request reset use counter.
D
Delay
Schedule ARP request; needs verification reset use counter.
PR
Permanent
Never expires; never verified reset use counter.
 
Table 1-84 explains the show command output fields.
 
Table 1-84: show ipv6 neighbors output details
Field
Description
Address
ARP entry’s IP address in the device.
Age
The number of minutes before the ARP entry was refreshed. If this value reaches the ARP aging period, the entry is removed from the table. Static entries do not age out.
MAC Address
Physical address of the host.
Source
ARP request source in the interface.
Interface
Logical address to connect the device over network.
State
ARP request state that is being handled by the IPv6 neighbor session.
 
Table 1-85 explains the show command output fields.
 
Table 1-85: show arp summary output details
Field
Description
Resolved
Count of working/known adjacencies.
Incomplete
Count of yet to be established adjacencies.
unknown
Count of adjacencies not currently in ARP table.
Total
Total count of all adjacencies.