Multiple Controllers

At this point, we have explored MPLS and PNNI implementations as well as AR and PAR implementations in Cisco Systems, Inc. multiservice switches. This section is intended to glue some of those concepts together by analyzing a complete BPX-8600 and MGX-8850 implementation.

Starting with a BPX-8600, you know that it supports AR (PVCs), MPLS (LVCs), and PNNI (SVCs and SPVCs) coexistence. The "ships in the night" concept (SIN) can be seen in the protocol stack shown in Figure 3-30. The networking software is platform-independent, ensuring consistent features and operation. Also, the controllers act independently. So the SES PNNI controller can be upgraded or removed without affecting the service for the MPLS controllers.

Figure 3-30. Ships in the Night: Different Control Planes in a BPX-8600

A closer look at the BXM card (see Figure 3-31) shows the interfaces between the networking software and the platform software.

Figure 3-31. Resource Partitioning for Multiple Controllers in a BPX-8600

AutoRoute uses commbus messaging as an interface, and all the other controllers (PNNI and redundant MPLS controllers) use VSI.

The resources in a BXM port or trunk are partitioned for AR and VSI. VSI resources are partitioned for different controllers. The end result looks like Figure 3-32.

Figure 3-32. Partitioning of Resources in a BXM/BXM-E

On the PXM-45-based MGX-8850, AutoRoute is not present, and all resources are under the control of the VSI slaves. Some controllers have fixed controller ids: 1 for PAR, 2 for PNNI, and 3 for LSC. Controller-ids 4 to 20 can be used by other instances of LSCs. Except for controller-ids 1, 2, and 3, VSI slaves do not make assumptions about the controller type based on the controller-id. Figure 3-33 shows a multiple-controller implementation in an MGX-8850.

Figure 3-33. Multiple Controllers in a PXM-45-Based MGX-8850

The PNNI controller and MPLS controller use the default control channels shown in Table 3-5.

Table 3-5. Default Control Channels

VPI	VCI	Control Channel	Controller
0	5	SSCOP	PNNI
0	16	ILMI	PNNI
0	18	PNNI	PNNI
0	32	Unlabeled traffic (LDP and IP)	MPLS
0	34	NCDP	PNNI

For MPLS applications, the minVCI in the resource partition defaults to 32. For PNNI, it defaults to 35.