Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 565)

Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide 541
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Configuring MPLS VLLs
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By default, MTU checking is off. The user can use the [no] form of the command to disable VLL MTU
checking when it is on.
NOTE
The user must save the configuration and reload the software for this command to take effect.
Specifying a VLL MTU
Previously, every VLL configured on a Brocade device used the system default max-frame-size as
the VLL MTU while establishing the LDP session with its peer. When this value is changed, the
configuration needs to be saved and the router rebooted for the new value to take effect. The
change in this value affects all VLLs configured on the router. This parameter is used as the
max-frame-size expected on each port of the router and consequently the data plane does not
accept or transmit packets larger than this size.
The user can now use the vll-mtu command that allows the user to specify an MTU value per-VLL.
When an MTU value is not specified for a VLL, the router continues to use the default
max-frame-size for establishing the LDP session with the peer. The MTU value configured per-VLL
can be changed dynamically and takes effect immediately. Consequently, the label (when already
advertised) is withdrawn from the peer and re-advertised using the new MTU. This occurs
irrespective of the state of the VLL. When MTU enforcement checks are enabled and when the
MTUs don't match, the VLL stays down with the reason code “MTU mismatch”.
NOTE
This parameter is not enforced on the data plane. Consequently, the user can still send and receive
packets larger than the configured MTU.
To configure a new MTU value for a VLL, use the vll-mtu command as shown in the following.
Brocade(config-mpls)# vll foundry 40000
Brocade(config-mpls-vll-foundry)# vll-mtu 1000
Syntax: [no] vll-mtu mtu-value
The mtu-value variable can be set to any value between 64 - 9190.
Generating traps for VLLs
The user can enable and disable SNMP traps for VLLs. VLL traps are enabled by default.
To enable VLL traps after they have been disabled, enter the following command.
Brocade(config)# snmp-server enable traps mpls vll
Syntax: [no] snmp-server enable traps mpls vll
Use the [no] form of the command to disable VLL traps.