Extreme Networks ExtremeWare 7.7, Command Reference Manual

Page: 2552 / 2620

2552 ExtremeWare 7.7 Command Reference Guide
MPLS Commands—BlackDiamond Switch Only
configure mpls vlan ip-mtu
configure mpls vlan [<vlan name> | all] ip-mtu <number>
Description
Configures the IP MTU for frames transmitted onto MPLS LSPs via the specified egress VLAN. The
range is 42 to 9190(using jumbo frame sizes).
Syntax Description
Default
1500 bytes
Usage Guidelines
This command configures the IP MTU for frames transmitted onto MPLS LSPs via the specified egress
VLAN. The default settings is 1500 bytes. If
all
is selected, the configuring MTU applies to all
MPLS-enabled VLANs.
This command applies to the ingress LSR only when a received IP packet is destined for an MPLS LSP.
In this case, if the length of the IP packet exceeds the configured MTU size for the egress VLAN and the
Don’t Fragment (DF) bit is
not set in the IP header of the packet, the packet is fragmented before it is
forwarded onto an MPLS LSP. If the DF bit is set in the packet header, Path MTU Discovery starts.
Fragmentation is based on either the minimum value of the configured MPLS IP MTU size or the
configured IP MTU size for the egress VLAN. (The IP MTU size is configured using the
configure
ip-mtu <number> vlan <vlan name>
command.)
Configure the MPLS IP MTU so that the addition of the MPLS label stack the link layer header does not
cause the packet to be too large to be transmitted on the egress ports. To avoid potential problems,
enable jumbo frame support on all ports that are members of an MPLS VLAN.
Example
The following command configures the IP MTU for frames transmitted onto MPLS LSPs:
configure mpls vlan vlan1 ip-mtu 1550
History
This command was first available in an ExtremeWare IP Technology Services Release based on
v6.1.8b12.
This command was subsequently incorporated into ExtremeWare 7.0.0.
vlan name Specifies a VLAN name.
all Specifies all VLANs.
number Specifies an IP MTU size.