Do I need MPLS to have SIP Trunking?

By Kristine Hegglin
Updated: February 08, 2011


Multi-Protocol Label Switching (MPLS) was created in the 1990s to increase the forwarding speed of routers. However, MPLS has evolved to become a vital technology for large Internet Protocol (IP) networks. MPLS enables rapid data switching through labeled packets for all network protocols. These labels provide routing information to quickly identify the destination of the packet. MPLS provides tunneling of any protocol, which is why it is called “Multi-Protocol”. MPLS is the standard for most network service providers (NSP) and results in an increased speed of network traffic in addition to providing differentiated services based on traffic type and/or service level agreements (SLA).


Session Initiated Protocol (SIP) trunking is a type of Voice over IP (VoIP) service that a business may activate through an Internet Telephony Service Provider (ITSP). Businesses may save on telephone services with SIP trunking because this service can enable a PBX (private branch exchange) to not only work within the business, but also outside the business network with the use of VoIP and an Internet connection. With SIP trunking, businesses can send and receive calls via the Internet both within the company and outside.

While SIP trunking is a service, it is also a global protocol. SIP trunks are available through SIP vendors and cost less when used over an MPLS network. Not only can a business save money with SIP over MPLS, but that business will also benefit from robust functionality. And, with SIP over MPLS, businesses still have the functionality provided by plain old telephone systems (POTS).

Businesses do not need MPLS to have SIP trunking

These services may work independently of one another or together. When these two services work together, SIP acts as the call signaling protocol while MPLS functions as the network forwarding system. When a SIP service is used over an MPLS network, businesses benefit with improved voice quality, improved security, and robust features like video transfer. When the Internet was created, it was not designed to handle VoIP as VoIP was nonexistent at the time.

While the Internet has the ability to handle VoIP, VoIP used with SIP over MPLS networks provides greater benefits and is quickly becoming the new age communication solution. Not only can SIP over an MPLS network handle VoIP, but this new age communication solution can be an asset for cloud computing services. As VoIP continues to replace ISDN (Integrated Services Digital Network) telephony services, we will most likely see more businesses opting to use VoIP with SIP over MPLS versus VoIP with the Internet.

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