Fast Reroute Supported Vendors
This document covers Cisco and Juniper implementations in particular. However, NorthStar Planner also supports FRR for additional router vendors, such as Alcatel and Tellabs.
There are two methods of FRR protection for Juniper. One method is one-to-one (fast reroute) backup protection in which case detour(s) are created to protect the nodes and links traversed by a single primary LSP. These detours are dedicated in the sense that they can only be used for one primary LSP. To configure for one-to-one protection, the user should configure the primary tunnel using the “fast-reroute” statement.
The other method of local protection for Juniper is many-to-one (facility) backup. In facility backup, a bypass tunnel is used to route around a facility (node or link), and the bypass tunnel can be used to protect multiple primary LSPs using the facility that are enabled for FRR. For Juniper’s facility backup, two things need to be configured:
The primary tunnel is configured to enable link protection or node-link protection.
The link interface(s) are configured to enable local protection. Node protection can be turned off for a particular interface if only link protection desired.
After these configurations are made, bypass tunnels will be created for the FRR-enabled facilities along the paths of the FRR-enabled primary tunnels-- either next-hop bypasses to circumvent the primary tunnel’s links in the case of link-protection or next-next-hop bypasses to circumvent the primary tunnel’s nodes in the case of node-link-protection. NorthStar Planner can be used to configure the primary tunnels for facility backup and to simulate the creation of the bypass tunnels for each facility of the primary tunnel.
An additional feature provided by Juniper for facility backup is the option to use multiple bypass LSPs to protect an interface. (By default, only one bypass LSP protects one interface.) In this case, the user can configure additional parameters to specify the bandwidth and subscription factor of the multiple bypasses to be created. NorthStar Planner can be used to simulate the creation of multiple bypasses or to design diverse paths for the multiple bypass tunnels and to generate the corresponding LSP configlets.
Finally, for diffserv-te, users can also configure what type of LSPs to protect (single-class, multi-class or any). In the case of single-class LSPs, the user can configure the class type (CT0, CT1, CT2, or CT3). In the case of multi-class LSPs, users can configure a percentage for each class type.
For Cisco’s FRR implementation, three things need to be configured:
The primary tunnel is configured to enable FRR
The backup tunnel is configured for each link of the primary tunnel, and
The protected link is configured to use the backup tunnel.
NorthStar Planner can be used to automate the creation of the backup tunnels given either the primary tunnel configuration (1) or the links to be protected (3). Configlets can be created for the backup tunnels to help automate the configuration of the backup tunnels.
An additional feature provided by Cisco is the option to specify the bandwidth pool (sub-pool, global-pool, or any) the traffic must belong to in order to be protected by the backup tunnel.