Configuring Manual TE FRR
Pre-configuration Tasks
Manual TE FRR is a local protection mechanism used on MPLS TE networks. TE manual FRR switches traffic on a primary MPLS TE tunnel to a manually configured bypass tunnel if a link or node on the primary tunnel fails.
- Configure a dynamic MPLS TE or DS-TE tunnel. For details, see Configuring a Dynamic MPLS TE Tunnel or Configuring a Dynamic DS-TE Tunnel.
- Enable MPLS, MPLS TE and RSVP-TE in the system view and interface view of each node along a bypass tunnel.
- Enable CSPF on a PLR.
NOTE: To implement fast switching within milliseconds, configure BFD association. For details about BFD, see Configuring Association Between the BFD Session and the Interface Status in Huawei AR100&AR120&AR150&AR160&AR200&AR1200&AR2200&AR3200&AR3600 Series Enterprise Routers Configuration Guide - Reliability. When associating a BFD session with an interface, ensure that the interface is protected by the bypass tunnel.
Enabling TE FRR
Configuring a Bypass Tunnel
Context
A bypass tunnel provides protection for a link or node on a primary tunnel. An explicit path and attributes must be specified for a bypass tunnel when TE manual FRR is being configured.
Bypass tunnels are established on selected links or nodes that are not on the protected primary tunnel. If a link or node on the protected primary tunnel is used for a bypass tunnel and fails, the bypass tunnel also fails to protect the primary tunnel.
NOTE: FRR does not take effect if multiple nodes or links fail simultaneously. After FRR switching is performed to switch data from the primary tunnel to a bypass tunnel, the bypass tunnel must remain Up when forwarding data. If the bypass tunnel goes Down, the protected traffic is interrupted and FRR fails. Even though the bypass tunnel goes Up again, traffic is unable to flow through the bypass tunnel but travels through the primary tunnel after the primary tunnel recovers or is reestablished.
By default, the system searches for an optimal manual FRR tunnel for each primary tunnel every 1 second and binds the bypass tunnel to the primary tunnel if there is an optimal bypass tunnel.
Perform the following configurations on the PLR.
Procedure
- Run system-view
The system view is displayed.
- Run interface tunnel tunnel-number
The tunnel interface view of a bypass tunnel is displayed.
- Run either of the following commands to configure the IP
address for the tunnel interface:
To configure an IP address for the interface, run:
ip address ip-address { mask | mask-length } [ sub ]
To configure the tunnel interface to borrow an IP address of another interface, run:
ip address unnumbered interface interface-type interface-number
A tunnel interface must have an IP address to forward traffic. The MPLS TE tunnel is unidirectional and does not need to configure a separate IP address for the tunnel interface. The tunnel interface usually borrows the IP address of the local loopback interface used as an LSR ID.
- Run tunnel-protocol mpls te
MPLS TE is configured as a tunnel protocol.
- Run destination ip-address
The LSR ID of an MP is specified as the destination address of the bypass tunnel.
- Run mpls te tunnel-id tunnel-id
The tunnel ID is set for the bypass tunnel.
- (Optional) Run mpls te path explicit-path path-name
An explicit path is specified for the bypass tunnel.
Before using this command, ensure that the explicit path has been created using the explicit-path command. Note that physical links of a bypass tunnel cannot overlap protected physical links of the primary tunnel.
- (Optional) Run either of the following commands to set the bandwidth
for the bypass tunnel:
Configure a single CT.
In non-IETF mode, run the mpls te bandwidth { ct0 ct0-bw-value | ct1 ct1-bw-value } command.
In IETF mode, run the mpls te bandwidth { ct0 bw-value | ct1 bw-value | ct2 bw-value | ct3 bw-value | ct4 bw-value | ct5 bw-value | ct6 bw-value | ct7 bw-value } command.
Configure multiple CTs.
In IETF mode, run the mpls te bandwidth { ct0 bw-value | ct1 bw-value | ct2 bw-value | ct3 bw-value | ct4 bw-value | ct5 bw-value | ct6 bw-value | ct7 bw-value } * command.
- Run mpls te bypass-tunnel
The bypass tunnel function is enabled.
After a bypass tunnel is configured, the system automatically records routes related to the bypass tunnel.
NOTE:
A tunnel interface cannot be used for both a bypass tunnel and a backup tunnel. A protection failure will occur if the mpls te bypass-tunnel and mpls te backup commands are both configured on the tunnel interface.
A tunnel interface cannot be used for both a bypass tunnel and a primary tunnel. A protection failure will occur if the mpls te bypass-tunnel and mpls te fast-reroute commands are both configured on the tunnel interface.
- Run mpls te protected-interface interface-type interface-number
An interface to be protected by a bypass tunnel is specified.
NOTE:
A bypass tunnel protects a maximum of six physical interfaces.
A tunnel interface cannot be used for both a bypass tunnel and a backup tunnel. A protection failure will occur if the mpls te protected-interface and mpls te backup commands are both configured on the tunnel interface.
- Run mpls te commit
The configuration is committed.
(Optional) Configuring a TE FRR Scanning Timer
Context
A TE FRR-enabled device periodically refreshes the binding between a bypass CR-LSP and a primary LSP at a specified interval. The PLR searches for the optimal TE bypass CR-LSP and binds it to a primary CR-LSP. A TE FRR scanning timer is set to determine the interval at which the binding between a bypass CR-LSP and a primary CR-LSP is refreshed.
Perform the following configurations on the PLR.
Procedure
- Run system-view
The system view is displayed.
- Run mpls
The MPLS view is displayed.
- Run mpls te timer fast-reroute [ weight ]
Set the interval at which the binding between a bypass CR-LSP and a primary CR-LSP is refreshed.
By default, the time weight used to calculate the interval is 300. And the actual interval at which the binding between a bypass CR-LSP and a primary LSP is refreshed depends on device performance and the maximum number of LSPs that can be established on the device.
(Optional) Changing the PSB and RSB Timeout Multiplier
Context
To help allow TE FRR to operate during the RSVP GR process, the timeout multiplier of the Path State Block (PSB) and Reservation State Block (RSB) can be set. The setting prevents the situation where information in PSBs and RSBs is dropped due to a timeout before the GR processes are complete for a large number of CR-LSPs.
Perform the following configurations on the PLR.
Procedure
- Run system-view
The system view is displayed.
- Run mpls
The MPLS view is displayed.
- Run mpls rsvp-te keep-multiplier keep-multiplier-number
The PSB and RSB timeout multiplier is set.
The default timeout multiplier is 3.
NOTE:
Setting the timeout multiplier to 5 or greater is recommended for a network where a large number of CR-LSPs are established and RSVP GR is configured.
Verifying the Manual TE FRR Configuration
Procedure
- Run the display mpls lsp lsp-id ingress-lsr-id session-id lsp-id [ verbose ] command to check information about a specified primary tunnel.
- Run the display mpls lsp attribute bypass-inuse { inuse | not-exists | exists-not-used } command to check information about the attribute of a specified bypass LSP.
- Run the display mpls lsp attribute bypass-tunnel tunnel-name command to check information about the attribute of a bypass tunnel.
- Run the display mpls te tunnel-interface [ tunnel interface-number | auto-bypass-tunnel [ tunnel-name ] ] command to check detailed information about the tunnel interface of a specified primary or bypass tunnel.
- Run the display mpls te tunnel path [ [ [ tunnel-name ] tunnel-name ] [ lsp-id ingress-lsr-id session-id lsp-id ] | fast-reroute { local-protection-available | local-protection-inuse } | lsr-role { ingress | transit | egress } ] command to check information about paths of a specified primary or bypass tunnel.
- Run the display mpls rsvp-te statistics fast-reroute command to check TE FRR statistics.
- Run the display mpls stale-interface [ interface-index ] [ verbose ] command to check the information about MPLS interfaces in the Stale state.