CHAPTER
ATM and Frame Relay SVCs, and SPVCs 8-1
8
ATM and Frame Relay SVCs,
and SPVCs
This chapter provides a brief overview of switched virtual circuits and soft permanent virtual circuits
with respect to the BPX switch and co-located Extended Services Processor. For additional
information, refer to the Cisco WAN Service Node Extended Services Processor Installation and
Operation Release 2.2 document.
This chapter contains the following:
• ATM and Frame Relay SVCs and SPVCs
• BPX Switch and ESP Interfaces
• Signaling Plane
• Network Interworking Between Frame Relay and ATM
• Extended Services Processor
• Network Management
• Resource Partitioning
ATM and Frame Relay SVCs and SPVCs
With a co-located Extended Services Processor (ESP), the BPX switch adds the capability to support
ATM and Frame Relay switched virtual circuits (SVCs) in addition to support for permanent virtual
circuits (PVCs) as shown in Figure 8-1.
The Private Network to Network Interface (PNNI) protocol is used to route SVCs across the
network. PNNI provides a dynamic routing protocol which is responsive to changes in network
availability and will scale to large networks.
BPX switch resources, such as port VPI range and trunk bandwidth are partitioned between SVCs
and PVCs. This provides a firewall between the two types of connections so that any SVCs that come
on-line and off-line do not affect the availability of existing PVC services.
The following connections are supported with Release 9.1:
• Frame Relay SVC connections between Frame Relay end users over an ATM network (Network
Interworking)
• ATM SVC connections between ATM end users
• SPVCs
