Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 121)

Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide 97
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Configuring MPLS
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• The Maximum Bandwidth TLV indicates the maximum outbound bandwidth that can be used
on the interface. Maximum Bandwidth is the operating speed of the port. When calculated for
a LAG, the Maximum Bandwidth is the operating speed of the primary port multiplied by the
number of active ports in the LAG. Hence, this reflects the actual physical bandwidth of the
interface. This TLV is not configurable by the user.
• The Maximum Reservable Bandwidth TLV indicates the maximum bandwidth that can be
reserved on the interface. By default, the Maximum Reservable Bandwidth is the same as the
Maximum Bandwidth for the interface. The user can optionally change the reservable
bandwidth to an amount greater or less than the maximum available bandwidth of the
interface. When a Maximum Reservable Bandwidth is configured on the primary port within a
LAG, the value configured applies to the entire LAG regardless of any change to the number of
active ports within the LAG. By default, the Maximum Reservable Bandwidth for the LAG is the
same as its Maximum Bandwidth.
• The Unreserved Bandwidth TLV indicates the amount of bandwidth not yet reserved on the
interface. This TLV consists of eight octets, indicating the amount of unreserved bandwidth (in
kbits second) at each of eight priority levels. The octets correspond to the bandwidth that can
be reserved with a hold priority of 0 through 7, arranged in increasing order, with priority 0
occurring at the start of the TLV, and priority 7 at the end of the TLV. The value in each of the
octets is less than or equal to the maximum reservable bandwidth. The Unreserved Bandwidth
TLV itself is not user-configurable, although it is affected by modifications to the reservable
bandwidth on an interface, as well as changes to LSPs.
Optionally, the user can change the amount of reservable bandwidth on an MPLS-enabled
interface (that is, modify the value in the Maximum Reservable Bandwidth TLV in OSPF-TE LSAs or
IS-IS TE LSPs sent out for the interface). The maximum reservable bandwidth on an MPLS-enabled
interface can be configured in either of two ways: as an absolute value, or as a percentage of the
total interface bandwidth.
NOTE
The maximum reservable bandwidth on an MPLS-enabled interface is supported on Brocade MLX
series, Brocade NetIron XMR, and Brocade NetIron CER and Brocade NetIron CES devices.
Configuration considerations
The reservable-bandwidth command is configurable on an MPLS-enabled interface at any time.
The configuration of the command takes effect immediately upon preemption of the LSP. When
LSP preemption occurs, when the reservable bandwidth required for a specific LSP is not
supported on the interface, then the LSP immediately goes down. When this occurs, an IGP
advertisement of this configuration change is triggered and flooded throughout all ports on the
network because the maximum reservable bandwidth configured on the interface is different from
the value that was previously configured.
NOTE
When the maximum reservable bandwidth is configured as a percentage value for LAGs and VE
interfaces, and ports go down, or new ports are added to the interface, the reservable bandwidth is
recalculated as a percentage of the newly available bandwidth for that interface.
To configure the maximum reservable bandwidth as an absolute value for MPLS LSPs on the
interface, enter the following commands as displayed in the following example.
Brocade(config-mpls)# mpls-interface ethernet 1/1
Brocade(config-mpls-if-e1000-1/1)# reservable-bandwidth 10000