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Introduction to Open Source Networking Technologies EDX MOOC
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Chapter 12. Summary #13

Open anitsh opened 4 years ago

anitsh commented 4 years ago

All Projects on One Page

In this course, we reviewed the multiple layers of open source networking and learned about the available platforms that exist. The following diagram illustrates all the open source networking projects that we explored. Open Source Networking Projects image Next, we will explore a few use cases that can be deployed using open source networking platforms.

anitsh commented 4 years ago

Use Case: Service Provider Transit Network

Service provider transit circuits are mainly based on pseudo-wire and other Layer 2 tunneling technologies to deliver a circuit to a client. Apart from technologies such as SDH (Synchronous Digital Hierarchy), most service providers consider using Ethernet as a transit platform to deliver services to their subscribers. Service providers rely on Ethernet technologies such as 802.1q, Q-in-Q, pseudo-wire, ELAN (Emulated LAN) technologies, etc., to deliver services using the Ethernet frame switching standards. Ethernet packet switching is based on VLAN tags, MAC address learning and switching the frames based on destination MAC addresses with few flexibilities for creating access lists and policy switching. Ethernet standards limit the flexibility of service providers, as they are limited to a few Ethernet switching rules that they need to comply with. Although Ethernet gives high bandwidth and a standard platform, it has its own limitations and fundamentals.

Using open source networking, service providers can build a software defined transit network that simply delivers each subscriber’s packets within the service provider transit network.

Example: Using open source technologies, service providers can build a software defined transit network:

        Bare metal switches
        Bare metal (1G/10G/40G/100G/400G) switches can be used to build the transit network connected to a distributed fiber infrastructure.
        Bare metal optical
        Using new bare metal ODTN (Open Disaggregated Transport Network), service providers can leverage the software defined optical networking.
        Switch operating system
        Service providers can load open source networking operating system such as ONL (Open Network Linux), OpenSwitch or Trellis.
        SDN Controller
        Service providers can use open source SDN controllers such as OpenDaylight or ONOS as a platform to manage and control the transit network. The SDN controllers will be able to automatically populate the flow tables of the transit switches in order to deliver packets to customers and subscribers.
        Orchestration
        Using ONAP as an orchestration platform can help service providers to create an automated orchestration system that can manage not only the network, but also interact with other OSS and BSS services.
        Analytics
        Leveraging PNDA and SNAS can help service providers build a monitoring and analytics platform for their network.
anitsh commented 4 years ago

Use Case: Service Provider Core Network

A service provider core network is another good example of using SDN and open source networking technologies to enhance traffic routing flexibilities. A service provider core network uses different routing technologies, such as MPLS, and a dynamic routing protocol, such as OSPF or BGP, to route customer private network traffic. Service providers offer private VPN services to their customers based on MPLS label switching to ensure customers' traffic is isolated and not mixed with each other.

In a service provider network, the Customer Edge (CE) routers are installed by a service provider at customer premises. The CE routers connect to the service providers' PE (Provider Edge) routers via a transit path. CE and PE routers may have a long distance. The PE routers are responsible for labelling the packets with a unique label ID for each customer. The labelled packets are then sent to the service provider core network to be routed towards their final destination.

The service provider core network is a distributed mesh network of routers located at different locations, providing multiple different redundant paths between the routers. Service providers are conscious about load balancing and using all of their links between the routers to ensure the traffic is perfectly distributed and client SLAs (Service Level Agreements) are met.

One of the main limitation of legacy routing protocols is their inability to influence the routing path. A routing protocol running on a router can only decide which next hop the packet has to be forwarded to. MPLS traffic engineering technologies are implemented in service provider networks to allow them to reserve an end-to-end bandwidth for a particular service.

SDN technologies can help service providers to add flexibility to their core network without even changing the underlying routers and technologies. An SDN controller such as OpenDaylight or ONOS will be able to dynamically inject the required routing to service provider core routers via the BGP-PCEP protocol to override the routing decisions of a core router.

BGP-PCEP (Path Computation Element (PCE) Communication Protocol (PCEP)) is considered to be a southbound protocol, allowing an SDN controller to control the routing and forwarding of a router. PCEP-Based Architecture image

BGP-PCEP is a standard protocol that is available in most of the current routers offered by commercial and open source routers. This means that service providers can add an SDN retrofit to their core network without needing to change their legacy networking devices. To achieve this, a service provider requires the following:

        BGP-PCEP compatible routers in core networks
        An SDN controller that supports BGP-PCEP, such as OpenDaylight or ONOS
        A networking program on top of the SDN controller to be able to enforce the required service provider routing policies to the core routers via BGP-PCEP. This program will need to be able to get an overall and real-time information about the bandwidth and latency status on all service provider links between routers to ensure the best path is selected for routing..
anitsh commented 4 years ago

Use Case: Service Provider uCPE

Service providers looking to build their white-box uCPE solution can leverage open source tools such as IO Visor and FD.io to build a high performance data path on an x86 server. All other open source technologies can also be used for routing, firewalling and load balancing functions.

Service providers have been providing commercial, single function routers to their clients as a CPE device. With the increase in the number of services offered by service providers, such as managed firewall and SD-WAN, service providers started delivering additional appliances to customer premises to deliver the newly required functions. This adds extra cost and management burden to both clients and service providers. uCPE Architecture image

anitsh commented 4 years ago

Use Case: Cloud Providers and Enterprise Datacenters

Cloud and datacenter providers can also leverage the benefits of open source networking tools within their platforms, which can be integrated with the other orchestration tools they are using. From building physical top of the rack Clos-based networking using bare metal switches to managing and provisioning of virtual network functions (VNFs) and service chaining, flexible open source networking tools can be used to build and deliver an automated cloud platform.

Regardless of the virtualization platform that is used by cloud providers (VMware-based, OpenStack, Kubernetes, etc.), open source networking tools can be used to automate the deployment and provisioning of virtual networks.

Example: Using open source networking platforms and tools, cloud providers can build a software defined network and integrate the network and virtual network functions to their cloud management and orchestration platforms:

        Bare metal switches
        Bare metal (1G/10G/40G/100G/400G) switches can be used to deploy a Clos-based leaf-spine switch architecture.
        Switch operating system
        Service providers can load open source networking operating systems such as ONL (Open Network Linux), OpenSwitch or Trellis.
        SDN Controller
        Service providers can use open source SDN controllers such as OpenDaylight or ONOS as a platform to manage and control the transit network. The SDN controllers will be able to automatically populate the flow tables of the transit switches in order to deliver packets to customers and subscribers.