H3C Technologies H3C S10500 Series Switches - Manual (Page 165)

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transmitted over the tunnel. For creation and configuration of a service loopback group, see Layer
2—LAN Switching Configuration Guide.
• In standalone mode, when active/standby switchover occurs or the standby card is removed,
tunnels configured on the active or standby card still exist. To delete tunnels, use the undo interface
tunnel command.
• The tunnel bandwidth command does not change the actual bandwidth of the tunnel interface, but
sets a bandwidth value for dynamical routing protocols to calculate the cost of a tunnel path. You
can determine the value according to the bandwidth of the output interface.
• The switch fragments IP unicast packets larger than the MTU on the tunnel interface, and sends an
ICMP error packet to the source device to inform it to modify its MTU.
• The switch fragments IPv6 unicast packets larger than the MTU on the tunnel interface, and sends
an ICMPv6 error packet to the source device to inform it to modify its MTU. The minimum MTU value
in the ICMPv6 error packet is 1280 bytes, and you must configure a MTU no smaller than 1280
bytes for the tunnel (such as an IPv6 over IPv4 tunnel or an IPv6 over IPv6 tunnel).
• By default, sending of ICMP destination unreachable packets is disabled. To enable it, use the ip
unreachables enable command.
Configuration procedure
Follow these steps to configure a tunnel interface:
To do… Use the command… Remarks
Enter system view system-view —
Create a tunnel interface and enter its
view
interface tunnel number
Required
By default, no tunnel interface is
created.
Configure the description for the
interface
description text
Optional
By default, the description of a
tunnel interface is Tunnelnumber
Interface.
Reference a service loopback group
service-loopback-group
number
Required
By default, the tunnel does not
reference any service loopback
group.
Set the MTU of the tunnel interface mtu size
Optional
64000 bytes by default.
• An MTU set on any tunnel
interface is effective on all
existing tunnel interfaces.
• You can set multiple MTUs for a
tunnel interface, but only the last
configuration tales effect.
Set the bandwidth of the tunnel
interface tunnel bandwidth
bandwidth-value
Optional
By default, the bandwidth of the
tunnel interface is 64 kbps.
Restore the default setting default Optional