Returning to layers 3 and 4 of the protocol reference model, this chapter introduces some special-purpose networking features, in particular, how networks can be tunneled. In networking, tunneling is the act of encapsulating a packet from one protocol into another one. Among application-specific communication networks, virtual private networks (VPNs) and multiprotocol label switching (MPLS) networks are two important and popular tunnel-based ones discussed in this chapter. These two network infrastructures can also be tied together for certain applications. The main topics covered in of this chapter are
• Virtual private networks (VPNs)
• Multiprotocol label switching (MPLS)
The chapter ...