View Cached Destination Information

View the destination cache to see next-hop addresses for destinations.

The destination cache is only populated or updated when IPv6 packets originate locally on the central processor of the switch.

The main purpose of the destination cache is to store, on a per-destination basis, the dynamic Path MTU value currently used when transmitting packets from the local system to the remote destination.

The system uses the PMTU value to calculate how many bytes can fit into an individual packet before fragmentation should be applied.

About this task

The command output shows the following information:

  • the IPv6 destination address

  • the IPv6 address for the next hop to the destination

  • the path maximum transmission unit (MTU) for the destination

  • the time, in seconds, since an ICMPv6 packet-too-big message was received

Not all parameters are available in non-default VRFs.

Procedure

  1. To enter User EXEC mode, log on to the switch.
  2. View the destination cache for all interfaces:

    show ipv6 dcache [vrf WORD<1–16> | vrfids WORD<0–512>]

  3. View the destination cache for a brouter port:

    show ipv6 dcache gigabitethernet {slot/port[/sub-port]}

  4. View the destination cache for a management port:

    show ipv6 dcache mgmtethernet mgmt

    Note

    Note

    This step applies to VSP 8600 Series only.

    Note

    Note

    This step only applies to hardware with a dedicated, physical management interface.

  5. View the destination cache for a specific tunnel ID:

    show ipv6 dcache tunnel <1–2000>

  6. View the destination cache for a VLAN:

    show ipv6 dcache vlan <1-4059>

  7. Clear the destination cache:

    clear ipv6 dcache [gigabitethernet {slot/port[/sub-port]}] [mgmtethernet {slot/port[/sub-port]}][tunnel <1–2000>][vlan <1-4059>] [vrf WORD<1–16> | vrfids WORD<0–512>]

    Note

    Note

    mgmtEthernet is supported on VSP 8600 Series only.

Example

Switch:1(config-if)#show ipv6 dcache  
=======================================================================================================================================
                                           IPv6 Destination Cache Information - GlobalRouter
=======================================================================================================================================
Destination Address                         NEXT HOP                                VID/BID/TID  IF_TYPE   IF_DATA   PMTU    PMTU_AGE
---------------------------------------------------------------------------------------------------------------------------------------
ff02:0:0:0:0:0:0:1                          0:0:0:0:0:0:0:0                         V-22         real      -         1500    0      
---------------------------------------------------------------------------------------------------------------------------------------

1 out of 1 Total Num of Destinaton Cache Entries displayed.

Variable definitions

Use the data in the following table to use the show ipv6 dcache and clear ipv6 dcache commands.

Variable

Value

<1-4059>

Specifies the VLAN ID in the range of 1 to 4059. By default, VLAN IDs 1 to 4059 are configurable and the system reserves VLAN IDs 4060 to 4094 for internal use. On switches that support the vrf-scaling and spbm-config-mode boot configuration flags, if you enable these flags, the system also reserves VLAN IDs 3500 to 3998. VLAN ID 1 is the default VLAN and you cannot create or delete VLAN ID 1.

{slot/port[/sub-port]}

Identifies a single slot and port. If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.

vrf WORD<1–16>

Specifies the VRF name.

vrfids WORD<0–512>

Specifies the VRF ID.
9036830-00 Rev AD