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What do WebEx QoS and Phone Troubleshooting Have in Common? Part 1

April 15, 2014 - 1 Comment

What do WebEx QoS and Phone Troubleshooting have in Common?

The answer is Medianet, which in conjunction with a Cisco network can provide an innovative solution for two very different real life problems. In Part 1 of this 2 Part blog we’re going to discuss how customers can use Medianet Metadata to provide a robust QoS mechanism for the WebEx cloud service within their Enterprise Networks. Keep an eye out for Part 2  where we’re going to take a look at how we can extend Medianet’s Mediatrace capability to Cisco’s 79XX, 89XX and 99XX IP Phone portfolio. I’ll also point out the benefits for each of these completely different Medianet use cases.

WebEx is a SaaS Conferencing service providing web based data, audio and video conferencing for millions of users. As it’s a cloud service, it’s inherently secure and in a lot of use cases it will tunnel all its media streams within HTTPS. That’s great for secure transport, but it’s resultantly challenging to map the constituent parts of the WebEx application into a granular Enterprise QoS policy. Why would we want to do that anyway? Isn’t it good enough to mark all the WebEx traffic the same?  As the saying goes, there is a method to our madness.The tunnelled WebEx traffic contains control packets, data-sharing traffic and possibly VoIP, which are relatively low bandwidth media streams. On the flip side any tunnelled video traffic will likely be bandwidth hungry by nature. The challenge we want to circumvent is how to ensure the WebEx video traffic does not “swamp” the other types of meeting traffic. Ultimately, we want to allow end users to enable the video service they have paid for, without the risk of video having a negative impact on the overall quality of the online conference. We do everything with the end user in mind to make sure you have the best possible experience.

For those of you that don’t know, a WebEx client can generate Medianet Metadata. In simple terms, Metadata is a way for a Cisco application to announce itself to a Cisco network. In the case of WebEx, different Metadata packets are transmitted onto the network, uniquely identifying all the component media streams (including video) that comprise a WebEx conference. This allows a Cisco network to useWebEx Metadata to differentiate between any WebEx traffic types, even when securely tunnelled over a HTTPS connection. The figure below provides an illustration of the different Metadata packets that will be generated for different types of WebEx traffic.

Figure 1 – Identifying Different Flows using Metadata

Figure 1 – Identifying Different Flows using Metadata

This means we can now apply a different QoS policy to our WebEx video traffic, so it is treated differently to the WebEx control, data-sharing and VoIP traffic across the network. To help you have the best experience possible, we ccan make sure the WebEx video traffic never interferes with the other WebEx traffic and only uses bandwidth that was unused by other more important business applications. The following diagram shows Switch A using Metadata to QoS mark the different media types, which allows them to be queued appropriately across the network.

Figure 2 – Using Metadata to QoS Mark WebEx Traffic Types

Figure 2 – Using Metadata to QoS Mark WebEx Traffic Types

The historical issue with this approach is that the WebEx cloud does not actually support the creation and transmission of Metadata, so QoS can only be applied in one direction; from the client to the cloud. This obviously breaks a Medianet based approach for WebEx QoS within an Enterprise. What’s changed?

Quite simply, Cisco has introduced a new router feature that can allow the Metadata created by a WebEx client to be looped back at the edge of the Internet, which makes it look like Metadata is now emanating from the WebEx cloud. The “reversed” Metadata can be used to identify the different types of WebEx traffic from the edge of a network towards the WebEx clients. This means Medianet can provide a robust QoS marking solution for all WebEx’s various media streams, in both directions, even when HTTPS tunnelling is used to secure the traffic. The ensuing schematic shows Metadata originating from the WebEx client being looped back in the reverse direction (IP addresses and Ports are transposed), which subsequently allows the WebEx traffic from the Cloud to be easily classified, marked and queued.

Figure 3 – Reversing Metadata within a Cisco Network

Figure 3 – Reversing Metadata within a Cisco Network

This enhancement is a large step forward for many customers who were previously nervous about enabling WebEx video on their networks. Reverse Metadata can be used to enforce strict QoS marking for all of the WebEx streams,  to ensure that if there is network bandwidth congestion the different WebEx flows will not be treated equally!

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  1. Great article, what is the name of the new reverse metadata feature & which ISRs has it?