display ipv6 pathmtu

Function

The display ipv6 pathmtu command displays information about PMTU entries.

Format

display ipv6 pathmtu [ vpn-instance vpn-instance-name ] { ipv6-address | all | dynamic | static }

Parameters

Parameter	Description	Value
ipv6-address	Displays PMTU entries that match a specified IPv6 address.	The value consists of 128 octets, which are classified into 8 groups. Each group contains 4 hexadecimal numbers in the format X:X:X:X:X:X:X:X.
all	Displays all PMTU entries.	-
dynamic	Displays all dynamic PMTU entries.	-
static	Displays all static PMTU entries.	-
vpn-instance vpn-instance-name	Displays PMTU entries of a specified IPv6 VPN instance.	The value must be an existing VPN instance name.

Views

All views

Default Level

1: Monitoring level

Usage Guidelines

Usage Scenario

If the MTU on the outbound interface of an intermediate routing device is smaller than the MTU of the source host, the path MTU (PMTU) discovery mechanism determines the maximum size of packets that can be transmitted on a path.

The display ipv6 pathmtu command displays information about dynamic and static PMTU entries. The device then fragments packets into a size smaller than the PMTU and forwards the fragmented packets.

Precautions

If no PMTU is set using the ipv6 pathmtu command, no static PMTU entry is displayed after the display ipv6 pathmtu command is run.

If a static PMTU entry is displayed, the remaining lifetime displays "-".

Example

# Display all PMTU entries.

<HUAWEI> display ipv6 pathmtu all
IPv6 Destination Address                ZoneID PathMTU LifeTime(M) Type    FF
FC00::2                                 0      1500    -           Static  NO
-------------------------------------------------------------------------------
Total: 1      Dynamic: 0     Static: 1

**Table 1** Description of the display ipv6 pathmtu command output
Item	Description
IPv6 Destination Address	Destination IPv6 address.
ZoneID	Zone ID.
PathMTU	PMTU of an IPv6 address. To configure the PMTU for an IPv6 address, run the ipv6 pathmtu command.
LifeTime(M)	Remaining lifetime, in minutes. The update interval is 1 minute. This field displays "-" for static entries.
Type	Type of the PMTU entry: Dynamic: dynamic entries Static: static entries (configured through CLI)
FF	Fragmentation flag: YES: Packets are fragmented, and a fragment header is added to a packet. NO: Packets are not fragmented.
Total	The number of total PMTU entry.
Dynamic	The number of dynamic PMTU entry.
Static	The number of static PMTU entry.