Route Reflection Overview
To decrease BGP control traffic and minimize the number of update messages, a BGP route reflector is used in many networks to distribute BGP routes within the AS. Routing Engines on the JCS1200 platform can be configured to act as BGP route reflectors. Because of large memory and 64-bit processor capacity, JCS1200 Routing Engines provide ideal support for route reflection.
Typically, route reflection is performed by a dedicated router. The router is not in the forwarding path (does not forward IP packets) but is equipped with a large memory and a good CPU.
The number of route reflectors in an IP network is much smaller than the number of routers. A network with 30 or more routers might have one route reflector (or possibly two for redundancy). Larger networks with hundreds of routers, might have 20 router reflectors.
Figure 1 shows a typical network with route reflectors. These route reflectors are not in the forwarding path.
Figure 1: Typical Network of Route Reflectors
Figure 2 shows the JCS1200 platform providing four distinct route reflectors and preserving the current network architecture.
Figure 2: Route Reflectors on the JCS1200 Platform
Figure 3 shows an example of route reflector partitioning on the JCS1200 platform. Each JCS1200 chassis can hold up to 12 Routing Engines. You can get route scalability up to 12x as you incrementally add Routing Engines to the JCS1200 chassis and configure them for route reflection. You do not need to buy a new router to increase route reflector capacity.
Figure 3: Route Reflector Partitioning on the JSC 1200 Platform
Note: Support for dual Routing Engines (master and backup) is currently not available, but is planned for a future release.
As shown in Figure 4, each of the 12 Routing Engines can be configured as a standalone route reflector. The 12 Routing Engines on the JCS1200 platform are connected to the JCS switch modules in a dual-star configuration. Each Routing Engine has access to two interfaces (fxp0 and fxp1), one on each switch. These interfaces are used for protocol peerings.
Each JCS switch module has 6 Gigabit Ethernet ports to connect to the outside world for a total of 12 ports. One port on each JCS switch module is used as a management port, three of the remaining ports on each JCS switch module can be used to connect to the network. (The remaining two ports are reserved.) Each Gigabit Ethernet port represents a separate LAN.
Multiple route reflectors can be configured to share the same port and hence be part of the same LAN. Port sharing enables JCS1200 route reflectors to conserve Gigabit Ethernet ports and reduce the cost of adding additional line cards for connectivity to the network. The result is a cost-effective solution for networks where multiple route reflectors are deployed.
Figure 4: Route Reflector Interfaces and Ports