Configuring Dynamic Bandwidth Reservation
Context
A reservable bandwidth value is set on each interface along an MPLS TE tunnel. The MPLS TE module checks whether links meets the bandwidth requirements of all tunnels based on the reservable bandwidth. If a reservable bandwidth value is set on an interface and the physical bandwidth changes on the interface, the MPLS TE module cannot correctly evaluate link bandwidth resources because the available bandwidth may be less than the configured reservable bandwidth. For example, an Eth-Trunk interface has 20 Gbit/s physical bandwidth. Its maximum reservable bandwidth is set to 16 Gbit/s, and its reserved bandwidth in the BC0 pool is set to 12 Gbit/s. If a trunk member fails, the Eth-Trunk interface has its physical bandwidth reduced to 10 Gbit/s, which fails to meet the requirements for the maximum reservable bandwidth or the bandwidth in the BC0 pool. The MPLS TE module, however, still attempts to reserve the configured bandwidth, and the bandwidth reservation attempt fails.
- mpls te bandwidth max-reservable-bandwidth dynamic: sets the proportion of the maximum reservable bandwidth to the physical bandwidth on the interface.
- mpls te bandwidth dynamic: sets the proportion of the bandwidth in each BC pool to the maximum reservable bandwidth.
The two proportions are used to enable MPLS TE to detect physical bandwidth changes along links and preempt the bandwidth of an MPLS TE tunnel that requires bandwidth exceeding the available link bandwidth. If soft preemption is supported by the preempted tunnel, traffic on the tunnel can be smoothly switched to another links with sufficient bandwidth. The smooth traffic switchover is also performed when an interface fails, which minimizes traffic loss.
Perform the following configurations on each node of the MPLS TE tunnel.
Procedure
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number
The view of an MPLS TE-enabled interface is displayed.
- On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
The mode switching function takes effect when the interface only has attribute configurations (for example, shutdown and description configurations). Alternatively, if configuration information supported by both Layer 2 and Layer 3 interfaces exists (for example, mode lacp and lacp system-id configurations), no configuration that is not supported after the working mode of the interface is switched can exist. If unsupported configurations exist on the interface, delete the configurations first and then run the undo portswitch command.
If many Ethernet interfaces need to be switched to Layer 3 mode, run the undo portswitch batch interface-type { interface-number1 [ to interface-number2 ] } &<1-10> command in the system view to switch these interfaces to Layer 3 mode in batches.
- Run mpls te bandwidth max-reservable-bandwidth dynamic bw-value-percentage
The proportion of the maximum reservable bandwidth to the physical bandwidth is set.
By default, the proportion of the maximum reservable bandwidth to the physical bandwidth is not set.
When both the mpls te bandwidth max-reservable-bandwidth dynamic command and the mpls te bandwidth max-reservable-bandwidth command are run in a random order on an interface, the last executed command takes effect.
- Run mpls te bandwidth dynamic bc0 bc0-bw-percentage
The proportion of the bandwidth in the BC pool to the maximum reservable bandwidth is set.
By default, the proportion of the bandwidth in the BC pool to the maximum reservable bandwidth is not set.
When both the mpls te bandwidth dynamic command and the mpls te bandwidth command are run in a random order on an interface, the last executed command takes effect.
- Run commit
The configurations are committed.
