Specifications

1-9
Cisco BPX 8600 Series Installation and Configuration
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
Chapter 1 The BPX Switch: Functional Overview
BPX Switch Operation
Virtual Private Networks
This section is a brief description of the BPX switch’s support for Virtual Private Networks (VPN). For
additional information, refer to the Cisco MPLS Controller Software Configuration Guide
Conventional VPNs that use dedicated lease lines or Frame Relay Private Virtual Circuits (PVC) and a
meshed network (Figure 1-2) provide many advantages, but typically have been limited in efficiency
and flexibility.
Instead of using dedicated leased lines or Frame Relay PVCs, and so on, for a VPN, an IP virtual private
network uses the open connectionless architecture of the Internet for transporting data as shown in
Figure 1-2.
An IP virtual private network offers these benefits:
• Scalability
– Avoids VC mesh configuration
– Easy to add a new site since IP is connectionless
– Service provider handles router service management
• Efficient
– Rapid provisioning for networks
– Supports any to any intranets
Figure 1-2 IP VPN Service Example
MPLS Virtual Private Networks
MPLS virtual private networks combine the advantages of IP flexibility and connectionless operation
with the QoS and performance features of ATM (Figure 1-3).
The MPLS VPNs provide the same benefits as a plain IP Virtual Network plus:
• Scaling and Configuration
– Existing BGP techniques can be used to scale route distribution
– Each edge router needs only the information for the VPNs it supports
adding
new site
IP Based VPNs
VPN A
VPN B
VPN B
VPN D
VPN D
VPN A
VPN A
VPN D
VPN B
VPN C
VPN C
Conventional VPNs, Leased Lines, etc.
VPN A
VPN B
VPN B
VPN D
VPN D
VPN A
VPN A
VPN D
VPN B
VPN C
VPN C
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