Brocade Communications Systems IP250 user manual Bypass LSP

28 LSP

From the Fast Reroute tab you can configure an LSP to request a facility backup provided by a bypass LSP in the event of a failure along the LSP path. Each LSR in an LSP except the egress router may act as a Point of Local Repair (PLR). If a failure occurs on an LSP, the PLR tries to initiate a bypass LSP to provide a backup route for the protected path. The PLR then becomes the ingress of a bypass LSP. The bypass LSP carries the traffic of the LSPs it protects around the break. The point past the break where traffic re-enters is called the merge point.

In Figure 343, R2 is the PLR. The double line that originates at R2 and then traverses R6 and R7 to terminate at R4 is the bypass LSP. The bypass LSP terminates in R4 and traffic merges back into the protected LSPs. This router is the merge point and the egress router for the bypass LSP.

R1 R2 R3 R4 R5

R6R7

FIGURE 343 Bypass LSP

When you use fast reroute to request a facility backup, the characteristics of the backup LSP should match well with the LSP that is requesting the facility backup:

-The value specified in the Detour Bandwidth/Backup LSP and the Hop Limit fields should be the same as the requesting LSP.

-Select the Request Facility Backup checkbox to enable the facility backup request.

-Setup Priority and Hold Priority should be the same as the requesting LSP.

-Admin group Include All, Include Any, and Exclude Any selections should be the same as the requesting LSP. Use the Select buttons to display the Admin Groups Selector dialog box (Figure 339).

862	Brocade Network Advisor IP User Manual
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