手法を比較

	ソフトウェア定義ネットワーク（SDN）	Border Gateway Protocol (BGP)	Multiprotocol Label Switching (MPLS)	OSPF（Open Shortest Path First）
分野	通信工学	通信工学	通信工学	通信工学
系統	Process / pipeline	Process / pipeline	Process / pipeline	Process / pipeline
提唱年	2008	1989	2001	1998
提唱者	Nick McKeown et al.	IETF Routing Protocols Working Group	IETF MPLS Working Group	John Moy
種類	programmable network paradigm	path-vector routing protocol	label-based forwarding paradigm	link-state routing protocol
原典	McKeown, N., Anderson, T., Balakrishnan, H., et al. (2008). OpenFlow: enabling innovation in campus networks. ACM SIGCOMM Computer Communication Review, 38(2), 69-74.	Rekhter, Y., Li, T., & Hares, S. (2006). A Border Gateway Protocol 4 (BGP-4). RFC 4271.	Rosen, E. C., Viswanathan, A., & Callon, R. (2001). Multiprotocol Label Switching Architecture. RFC 3031.	Moy, J. T. (1998). OSPF Version 2. RFC 2328.
別名	network virtualization, programmable networks	exterior gateway protocol, inter-domain routing	label switching, traffic engineering	link-state routing, intra-domain routing
関連	4	2	4	2
概要	Software-Defined Networking (SDN) is a network architecture paradigm that decouples the control plane (routing decisions) from the data plane (packet forwarding). Introduced by McKeown et al. (2008) with OpenFlow, SDN enables network programmability by centralizing control logic in software-based controllers that direct forwarding behavior of simple programmable switches. SDN has transformed network operations, enabling rapid service deployment, traffic engineering, and cloud integration. It is now foundational in data centers and service provider networks.	BGP is the de facto standard routing protocol for interconnecting autonomous systems (ASs) on the Internet. Since its introduction in 1989, BGP has scaled the Internet to millions of routers and trillions of destinations. BGP is path-vector-based, using a flexible policy system to control route propagation and selection. While BGP convergence can be slow and policies complex, it remains the only viable protocol for Internet-scale inter-domain routing.	Multiprotocol Label Switching (MPLS) is a forwarding paradigm that prepends a short label to packets, enabling routers to make forwarding decisions based on the label rather than IP destination address. Introduced by IETF (2001), MPLS was designed to enable traffic engineering, VPN creation, and fast rerouting in IP networks. While MPLS complexity is high, it remains foundational in service provider backbones for traffic engineering and Quality of Service (QoS) provisioning.	OSPF is a link-state interior gateway protocol (IGP) for routing within an autonomous system. Introduced by John Moy in 1998, OSPF converges faster than distance-vector protocols and supports equal-cost multipath (ECMP). It remains widely deployed in enterprise and ISP networks for intra-domain routing, though IS-IS is increasingly preferred in large backbones.