Patent Application
20210352045
In a software defined wide area network (SD-WAN), wide area network (WAN) links are established between a virtual private network concentrator (VPNC) at a core site of the network and a branch gateway (BG) in a branch or campus site of the network. These WAN links may be provided by an internet service provider (ISP) in lieu of expensive and high-touch dedicated networking infrastructure like Multiprotocol Label Switching (MPLS) links. The ISP may provide, for example, a digital subscriber line (DSL) to a campus or branch site of the network for use as an uplink to the core site.
In some instances, a packet from a client device (e.g. phone, laptop, server, etc.) at the branch site destined for an Internet device (e.g. a cloud server that provides a cloud service) passes through the WAN link to the core site before being routed to the final destination. One purpose of this initial routing through the WAN link is that certain services (e.g. firewall, domain name service) may be provided at or more effectively at the core site. In some other instances, a packet from the client device at the branch site destined for an Internet device is directly routed from the branch site to the final destination. A WAN link between a branch site and a core site may include multiple individual uplinks (e.g. multiple DSL uplinks from ISPs), and the performance of each individual uplink may improve or degrade dependent on specific network conditions for that uplink at a certain time.
Cloud services, such as software as a service (SaaS) applications, often benefit from being handled in a coordinated manner across a network such as a multi-site enterprise network. Cloud services (e.g. network services, SaaS applications, desktop as a service, platform as a service, infrastructure as a service, etc.) may be provided from any one of a number of servers located in geographically and network diverse locations, and network infrastructure (e.g. routers, switches, access points, network controllers, etc.) may implement policies to more efficiently route traffic to and from each cloud service. Examples of cloud services include Amazon Web Services™, Salesforce™, Microsoft Office 365™, and Dropox™, among others. Network controllers for software defined networks (SDNs) can implement a control plane, such as a centralized control plane, hierarchical control plane, or distributed control plane, which is separate from the data switching and routing infrastructure. Devices such as branch gateways (BGs) and virtual private network concentrators (VPNCs) can serve as network controllers. In an SDN context, such as a branch network that implements a software defined wide area network (SD-WAN), a network controller may implement a flow for cloud services on a per-application, per-class, per-group, or pan-SaaS basis.
By controlling cloud service related network traffic at a network level, rather than relying on individual devices to handle the traffic, the network can compile additional information to achieve greater insight into the network conditions between the client devices and the cloud servers. The greater insight may be used to dynamically adjust the routing of cloud service related traffic to follow preferred routes. For example, a network controller, such as a BG, gathers information about the set of cloud servers providing SaaS-A.
The greater insight gathered from across the network may improve the network function by reducing latency in accessing a cloud service, by reducing network response time to changes in the network topology and characteristics that alter cloud service performance, by dynamically healing cloud service outages at particular cloud servers, by reducing administrative burden of the network by automating portions of the network interaction with cloud services.
In this disclosure. SaaS may be used as an example of cloud services generically, not to the exclusion of other cloud services. Where SaaS-A, -B, -C . . . -N is used, it refers to behavior relating to a certain SaaS application, as opposed to SaaS applications on the whole. Such notation may be used to show how different SaaS applications can be handled differently from one another by the network or to show how the system handles SaaS applications on an individual basis. Furthermore, a BG may be used as an example of a network controller, not to the exclusion of other network controllers. The BG may then dynamically gather information about each SaaS-A server, including the health of each server and path health of different paths from the client to each server. The BG may acquire information about the servers as measured from other locations, such as another branch site or a core site of the network.
The BG may gather some or all of the information about the SaaS-A servers by sending out probe packets through the Internet requesting measurements such as jitter, latency, and other performance information. In some examples, the BG sends HTTP probes to avoid having the packets blocked by network infrastructure that is not owned nor configurable by network administrators who administer the BG. The HTTP probes may measure additional performance information, such as the health of the SaaS-A application, that cannot be measured by a traditional “ping” packet.
The BG may also send out domain name service (DNS) probe packets to gather a list of the set of SaaS-A servers available. DNS caching servers provided by a given ISP for a BG in a given geolocation or routing location may not contain a canonical list of all available SaaS-A servers available. Rather, the ISP may statically improve the list based on rudimentary factors (number of hops between source and destination, for example). However, a detailed analysis of regularly collected performance information may reveal additional SaaS-A servers that are “less optimal” but actually provide higher quality of service. For example, a BG may acquire DNS records, path health information, server health information, and other relevant information from a gateway in another branch or in a core site of the network and use the acquired information to put together a more comprehensive view of the SaaS-A server topology across the Internet.
The figures herein follow a numbering convention in which the first digit corresponds to the drawing figure number and the remaining digits identify an element or component in the drawing. For example, reference numeral 224 refers to element “24” in
The client device 108 is an electronic device that can include processing circuitry (e.g., a processor, an application specific integrated circuit, a field programmable gate array, etc.) and memory (e.g., a machine-readable medium). The client device 108 can be capable of receiving inputs and providing outputs to a human user and capable of communicating with a network. Examples of client devices include desktop computers, smartphones, notebooks, tablets, touchscreen devices, computing devices embedded within an automobile or another machine, or the like. The client device 108 can be connected to the branch site network 106 in a wired or wireless manner.
A BG 110 or other network device can connect the branch site network 106 to the rest of the SD-WAN. In some examples, the BG 110 can also function as a network controller for the SD-WAN or a portion thereof. In some examples, other network devices can provide a control plane for the SD-WAN (not specifically illustrated). A network controller can be capable of receiving, transmitting, processing, routing, and/or providing packets traversing the SD-WAN. A network controller can manage the SD-WAN by performing careful and adaptive traffic engineering by assigning new transfer requests according to current usage of resources such as links. A packet is a communication structure for communicating information, such as a protocol data unit (PDU), a packet, a frame, a datagram, a segment, a message, a block, a cell, a frame, a subframe, a slot, a symbol, a portion of any of the above, or another type of formatted or unformatted unit of data capable of being transmitted via a network.
The BG 110 can connect the branch site network 106 to the core site network 118 via a virtual private network concentrator (VPNC) 120 and the Internet 102. The VPNC 120 is a type of networking device that provides secure creation of virtual private network (VPN) connections and delivery of messages between VPN nodes. The VPNC 120 can function analogously to a router, but for creating and managing VPN communication infrastructures. In some examples, the VPNC 120 can also function as a network controller for the SD-WAN or a portion thereof. In some examples, other network devices can provide a control plane for the SD-WAN (not specifically illustrated). More specifically, the BG 110 can be connected to the VPNC 120 through the Internet 102 via a first tunnel 116-1 using a first uplink 112-1 and a second tunnel 116-2 using a second uplink 112-2. The tunnels 116 can be implemented over various connections such as a telecommunications connection such as an LTE or 4G connection facilitated by a telecommunications tower, a wireless Internet connection facilitated by a Wi-Fi access point, and/or an Ethernet connection facilitated by a switch. In some examples, a different quantity of tunnels can be used to connect the BG 110 to the VPNC 120.
As further shown in
The instructions can be executed to proxy 232-3 a response for a name query for the cloud service using a virtual IP address and to direct 232-4 traffic for the virtual IP address to the preferred cloud server using the identifying information. The name query can be received by the network controller 224 from a client device and the instructions to proxy 232-3 the response can cause the network controller 224 to respond with the virtual IP address assigned to the cloud service for which the name query was received. The instructions to direct 232-4 the traffic can include instructions to apply destination network address translation to the virtual IP address so that it is directed to the real IP address of the selected preferred cloud server.
The instructions to select 232-2 the preferred cloud server can include instructions to select 232-2 the preferred cloud server irrespective of the name query. For example, the preferred cloud server can be selected before and/or without a name query being received by the network controller 224. Such functionality can beneficially direct any subsequent traffic for the cloud service to the selected preferred cloud server without delay that might otherwise be caused by performing selection of the preferred cloud server in response to receiving the name query. The instructions to proxy 232-3 the response can include instructions to proxy 232-3 the response without updating the list 234-1 of cloud servers and/or without updating the preferred cloud server. Such functionality can beneficially provide a response to the source of the name query without delay that might otherwise be caused by updating the list 234-1 of cloud servers and/or without updating the preferred cloud server in response to receiving the name query.
The instructions to generate 232-1 the list 234-1 of cloud servers can include instructions to transmit a name query to a name server (e.g., a DNS server) and receive a response from the name server including the identifying information 234-2. The instructions to generate 232-1 the list 234-1 of cloud servers can include instructions to transmit a name query to another network controller and receive a response from the other network controller including additional information for a plurality of additional cloud servers that provide the cloud service. For example, the other network controller can be in a geographically different location than the original network controller 224. By way of example with respect to
The memory 230 can store instructions to update the list 234-1 of cloud servers periodically. Such functionality can be beneficial, for example, in allowing the network controller 224 to become aware of new or different cloud servers that provide the cloud service. Likewise, such functionality can be beneficial in allowing the network controller 224 to become aware of cloud servers that no longer provide the cloud service, so they may be removed from the list 234-1 of cloud servers. Updating the list 234-1 of cloud servers can also include updating the identifying info 234-2 and/or the network performance info 234-3 for the cloud servers, such as by sending additional probes.
In some examples, the memory 230 can store instructions to assign a respective unique virtual IP address to each of a plurality of cloud services that are configured on the network controller 224, generate a respective list of cloud servers that provide each of the plurality of cloud services, and select a respective preferred cloud server from each respective list. The memory 230 can store instructions for the network controller 224 to proxy a response for a name query for any one of the plurality of cloud services using the respective virtual IP address and direct traffic for the respective virtual IP address to the respective preferred cloud server.
Discovering as many (or all) of the cloud servers that provide the cloud service can be beneficial for routing traffic from the client device to the cloud service. Depending on network conditions and/or the health and status of various cloud servers or links thereto, different cloud servers or links thereto may provide a better quality of service than other cloud servers. In some examples, a particular cloud server that provides a best quality of service for the client device can be selected as the preferred cloud server for the client device.
To handle HTTP probing, a fully qualified domain name (FQDN) and the uniform resource indicator (URI) can be specified per cloud service. In some examples, this information can be stored in response to a new cloud application being requested by a client device. The information can be used to configure probe packets for the cloud service. The network controller 224 can configure a definition of the cloud service, which can be used in firewall, route, and/or dynamic path selection (DPS) policies. For example, a deep packet inspection (DPI) cloud service identifier can be allocated to the cloud application and referenced by the firewall, route, and/or DPS policies. In some examples, the network controller 224 can include a programmable option that controls whether the HTTP probing controls the liveness of any overlay tunnels (e.g., tunnels 116 illustrated in
Since the default name server used by a client device may not be reliable to respond with the preferred cloud server, particularly in an SD-WAN setting, the network controller can maintain a list of name servers reachable over the uplinks (e.g., uplinks 112 illustrated in
At 449, the method includes mapping the virtual IP address of the cloud service to an IP address of the first preferred cloud server. At 451, the method includes directing first traffic to the first preferred cloud server before selecting the second preferred cloud server at 457.
At 453, the method includes periodically updating the network performance information 443 for each cloud server of the list of cloud servers to generate updated network information 455. At 457, the method includes selecting the second preferred cloud server based on the updated network information 455 and/or the locale 445 of the client device. At 459, the method includes remapping the virtual IP address of the cloud service to a second preferred cloud server. At 461, the method includes directing traffic to the second preferred cloud server after selecting the second preferred cloud server at 457.
The DNS name server 542 can provide a DNS response 548 with SaaS-A provider information. The SaaS-A provider information can include identifying information of the cloud servers, such as an IP address. This information can be used to identify and classify the cloud application (e.g., when the first packet is received) to avoid a network address translation (NAT) issue that might otherwise occur when a flow might switch from one uplink to another during DPS.
The network controller 524 can send HTTP probe packets 550 to the identified cloud servers 544. In some examples, the network controller 524 can add a keepalive keyword to the HTTP probes 550 to indicate to the system that the probe results affect tunnels built to reach the cloud service endpoint. The network controller 524 can initiate the HTTP probes 550 for each cloud server 544 using the FQDN and/or the URI from the cloud server configuration, the name server list, and/or the cloud server list. The results 552 of the HTTP probes can be responses from the cloud servers 544 including network performance information, which may also be referred to as “network performance metrics (NPM)”.
The results 552 of the HTTP probes 552 and the DNS response 548 can be used by the network controller 524 to create a cloud server list 553 (“generation of SaaS-A provider device list using DNS response and NPM responses). The cloud server list can include a correspondence between cloud servers and name servers. The cloud server list can be used along with the name server list to route HTTP probes 550 over the correct next hop without having to specifically install static routes for each discovered cloud server. The results 552 of the HTTP probes 552 can be used in the DPS policy for the cloud service.
The network controller 524 can select a preferred cloud server 554 from the list of cloud servers (“selection of a preferred device from SaaS-A providers using criteria provided from admin/client/etc.”). The network controller 524 can proxy a response for a name query for the cloud service using a virtual IP address 556 (“proxy response for name query with virtual IP”). The network controller 524 can direct traffic 558 for the virtual IP address to the preferred cloud server using the identifying information (“direct traffic for virtual IP to preferred device”).
The network controller 524 can initiate a session 560 with the preferred cloud server (“initialization of SaaS-A session with preferred device”) for client traffic. For traffic steering, the network controller 524 can periodically update a DPS list that includes a correspondence between a respective preferred cloud server/next hop for the preferred cloud server and each cloud service. The DPS list can be used to respond to DNS requests as well as for traffic steering. Thus, DPS can be performed in the background periodically instead of when the session to the cloud service is created.
The example illustrated in
The network controller 624 can send HTTP probe packets 650 to the identified cloud servers 644 (including the additionally identified cloud servers). For example, the network controller 624 can probe each of the plurality of cloud servers 644 based on results 648 of the plurality of name queries 646 already sent by the network controller 624. The results 652 of the HTTP probes can be responses from the cloud servers 644 including network performance information. The results 652 of the HTTP probes 652 and the DNS response 648 can be used by the network controller 624 to create a cloud server list 653. The network controller 624 can create a DPS policy for traffic from the client device 608 to the cloud service based on results 652 of the probes.
The client device 608 can initiate a name query 664 for a cloud service (“DNS request for SaaS-A”), which can be intercepted by the network controller 624. The network controller 624 can intercept the name query 664 from the client device 608 without changing name query settings of the client device 608. The client device 608 could be using an arbitrary name server and the results it returns may not yield the preferred server. Name queries from the client device 608 for non-cloud services can default to existing behavior. The network controller 624 can select a preferred cloud server 654 from the list of cloud servers.
Although the name query 664 is illustrated as occurring after the generation of the cloud server list 653, the name query 664 can also occur before the network controller 624 sends the DNS request 646 for SaaS-A providers 646. In other words, in some examples, the cloud service may initially be requested by the client device 608 before the network controller has taken any actions to configure the cloud service. However, the illustration of the name query 664 from the client device 608 occurring before selection of the preferred cloud server indicates that the network controller 624 can select the preferred server at or near the time of the name query 664 so that the network controller 624 does not respond with stale information (e.g., a server that no longer qualifies as preferred due to changing conditions in the SD-WAN).
The network controller 624 can proxy a response to the name query 664 from the client device 608 by proxying a response 666 with a virtual IP address (“DNS response with virtual IP for SaaS-A”). Although not specifically illustrated in
In the foregoing detailed description of the present disclosure, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration how examples of the disclosure can be practiced. These examples are described in sufficient detail to enable those of ordinary skill in the art to practice the examples of this disclosure, and it is to be understood that other examples can be utilized and that process, electrical, and/or structural changes can be made without departing from the scope of the present disclosure.
Elements shown in the various figures herein can be added, exchanged, and/or eliminated so as to provide a number of additional examples of the disclosure. In addition, the proportion and the relative scale of the elements provided in the figures are intended to illustrate the examples of the disclosure and should not be taken in a limiting sense.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2018/058126 | 10/30/2018 | WO | 00 |
