Part 3: Enhanced Application Experience with Cisco AppQoE

As enterprise application data traverses WAN networks, the data can encounter congestion and packet losses that result in increasing latencies, resulting in sub-optimal experience for the workforce and machine-to-machine communications. My previous blog post illustrated how Cisco Software-Defined WAN (SD-WAN), with advanced Application-Aware Routing based on network and application health telemetry, provides intelligent path selection and data policy enforcement. These contribute to an optimal application experience by enabling the network to automatically adapt to the changing needs of workflows based on end-point location, health of the WAN, and health of the often-disaggregated applications. Now Cisco is providing even more capabilities in SD-WAN to enhance the application experience throughout the distributed enterprise.

Introducing Cisco SD-WAN AppQoE

This blog post explores how Cisco SD-WAN AppQoE works along with and complements SD-WAN application-aware dynamic best path selection to enhance application experience multifold. Cisco AppQoE boosts application performance by primarily mitigating end-to-end network path latency by employing multiple application WAN optimization techniques including:

  • TCP Optimization fine tunes the TCP protocol—the most widely used application transport protocol—to perform better over WANs by making the best use of available WAN capacity.
  • Data Redundancy Elimination (DRE) – Identifies and eliminates redundant traffic patterns across applications and peers, substantially reducing the amount of application traffic traversing the WAN, thus reducing latency and enhancing application experience.

Example 1: Multifold Application Performance Improvement with AppQoE

Cisco AppQoE with the TCP Optimization and DRE techniques provides significant improvements in data transfer rates, thus improving application experience, especially over the long-haul international links as well as high-latency and lossy WAN links. Table 1 provides the results of using these techniques in a real-world vSAT use case.

Application Performance Improvement with AppQoE
Figure 1. Application Performance Improvement with AppQoE

Application Performance Challenges over WANs

The challenge of improving application experience and performance over WANs is as old as the WAN itself. Applications that perform well over LANs suffer over WANs for multiple reasons. One of the obvious reasons is that WAN bandwidth is relatively limited compared to local area networks. Adding SLA guarantees to improve reliability also increases the cost. So, WANs are often a shared resource among several organizations, resulting in over-subscription, contention, and congestion, leading to packet drops and delays. There are also inefficiencies associated with data transmitted over long distances, often traversing multiple providers. Combined, these factors contribute significantly to application performance degradation.

WAN Challenges for Applications
Figure 2. Factors Impacting Application Performance over WAN

There are multiple technologies and solutions that aim to mitigate the degradation of application experience over WANs. However, the many different existing point solutions from multiple vendors typically address specific aspects of the application experience challenges over WANs. Cisco SD-WAN provides a combination of Application SLA routing and AppQoE to address all the different WAN challenges to provide the best application experience possible.

Cisco SD-WAN Provides Both WAN-Bandwidth Mitigation and Application-SLA Paths

Cisco SD-WAN mitigates the limited and expensive WAN capacity problem by augmenting bandwidth with less expensive Internet access as transport. SD-WAN simplifies the use of hybrid WANs—MPLS, 5G/LTE, and direct internet—by applying the Software-Defined Architecture principle to abstract different physical WAN network into logical networks based on overlays.

WAN Bandwidth Mitigation and App-SLA Routing with Cisco SD-WAN
Figure 3. WAN Bandwidth Mitigation and App-SLA Routing with Cisco SD-WAN

Cisco SD-WAN goes a step further and provides applications with guaranteed SLAs in real time by constantly monitoring WAN link quality while simultaneously detecting and dynamically steering applications over the WAN links that meet an application’s SLA requirements.

Cisco SD-WAN AppQoE Latency Mitigation

Cisco AppQoE mitigates latency and improves application performance over WANs by addressing the inefficiencies associated with the transport and the application layer protocols and the data traversing the WAN.

Latency Mitigation with Cisco AppQoE
Figure 4. Latency Mitigation with Cisco AppQoE

While the WAN challenges such as over-subscription and latency cannot be completely avoided, AppQoE splits the client-to-server TCP connection and then owns and optimizes the TCP connection over WAN using multiple techniques as shown in Figure 4.

AppQoE Optimization Techniques
Figure 5. AppQoE Optimization Techniques

The optimization techniques are applied at SD-WAN edge devices, transparent to the traffic endpoints – users and applications. As TCP is the most widely used transport protocol, Cisco AppQoE mainly focuses on TCP protocol for transport optimization, TCP-based applications for application optimization, and TCP payload for data compression.

Optimize Any Application for Any Endpoint Anywhere

Cisco AppQoE offers deployment flexibility to optimize performance and experience wherever applications are deployed, ranging from on-premises data centers to IaaS and SaaS providers to public cloud platforms.

AppQoE for Any Application, Any Endpoint Anywhere
Figure 6. AppQoE for Any Application, Any Endpoint Anywhere

Cisco AppQoE can be deployed at small branches using AppQoE services integrated into the SD-WAN edge routers. IT can deploy Cisco AppQoE at scale to support complex sites, such as data centers, using a cluster of AppQoE external service nodes. AppQoE service nodes are fully integrated into SD-WAN and managed from vManage.

AppQoE deployed at scale at large sites such as SD-WAN regional hubs can be leveraged by remote branch sites that are not AppQoE capable, thus enabling AppQoE to be offered as a centralized service to remote sites that are not AppQoE capable.

The network of AppQoE enabled regional SD-WAN hubs deployed on-prem, in public clouds or co-locations, can act as an optimized middle mile. The optimized middle mile can be Enterprise owned or offered as a service by a provider.

A Comprehensive Solution to Improve Application Performance

With a combination of Application SLA routing and AppQoE, Cisco SD-WAN provides a comprehensive solution to address application performance challenges. Whether traffic over WANs is traveling to applications hosted in on-prem data centers or to multi-cloud platforms across the globe, Cisco SD-WAN provides the best possible application quality of experience to the workforce. Cisco SD-WAN AppQoE is an indispensable solution for long-haul transcontinental and international WAN links, as well as for the high latency and lossy WANs such as Satellite WANs.

For more information on enhancing application performance with SD-WAN, visit:

Application Aware Networking with Cisco SD-WAN, Part 1: Seamless Connectivity From Anywhere

Application Aware Networking with Cisco SD-WAN Part 2 Part 2: Optimizing Application Experience

Cisco SD-WAN Cloud Hub with Google Cloud Delivers Enterprise Connectivity Over Global Cloud Network

SD-WAN and SASE: The new landscape of networking


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Ram Singh

Vice President of Engineering

Catalyst Engineering