This section describes the bandwidth requirements for 50, 250, 800 and 2000 user systems. Meeting the bandwidth requirements outlined in the section will provide a quality end user experience for your users who host and attend WebEx meetings, and helps ensure that your network can support the traffic demands from the web sharing, audio, and video.
Estimating Bandwidth for End User Sessions
It is important to estimate the network bandwidth to support the traffic demands of video, audio, and web sharing for the size of your user system. The bandwidth requirements for this product are fundamentally the same as for Cisco WebEx cloud services. If you wish to optimize your network provisioning, Cisco WebEx cloud services bandwidth usage is presented in the WebEx Network Bandwidth White Paper.
The information in the following table shows the expected bandwidth for video, audio and web sharing.
WebEx Meeting Component |
Aggregate End User Session Bandwidth |
Video (360p + 6 thumbnails) |
1.5 Mb/s |
Audio |
0.1 Mb/s |
Web sharing (This value assumes you flip a slide every 30 seconds.) |
0.6 Mb/s |
Total maximum bandwidth |
2.2 Mb/s |
Although 2.2 Mb/s is the maximum expected bandwidth for a single user connection, Cisco recommends using the maximum expected bandwidth of 1.5 Mb/s when calculating bandwidth requirements. Because only one-half of the maximum number of users can employ video, audio, and web sharing while the remaining users should use only audio and web sharing, this yields an average bandwidth of approximately 1.5 Mb/s per user connection.
If you refer to the WebEx Network Bandwidth White Paper, you will notice that the bandwidth values in the preceding table are based on worst-case traffic conditions. Average bandwidth utilization is much smaller, but Cisco recommends using worst case numbers for the following reasons:
-
Using the worst case numbers for your calculation should help you provide the needed bandwidth to prevent a degraded user experience as a result of heavy usage.
-
The Cisco WebEx Meetings Server sends the same data simultaneously to all the participants in a meeting. When a WebEx host flips a page on a presentation, an image of that page (possibly comprising several megabytes) is sent separately to each endpoint, simultaneously, and as quickly as possible.
Bandwidth on Network Paths
Use the following process to determine the necessary bandwidth on various network paths.
-
Determine the averaged bandwidth for a user session using the table provided in the preceding section.
-
Determine the maximum number of users you expect to connect simultaneously over that link.
-
Multiply the total bandwidth by the maximum number of users.
Scenario examples:
-
If you expect a maximum of 100 users to connect concurrently from the Internet, you will probably need 1.5 Mb/s x 100 = 150 Mb/s of available bandwidth on your ISP connection and through your external firewall to the Internet Reverse Proxy. For mor details about Internet Reverse Proxy, see Network Considerations for the Internet Reverse Proxy
-
Assume you have a 2000 user system with all connections going through the Internet Reverse Proxy. In this scenario, you need to assume traffic for all 2000 users will connect to the Internet Reverse Proxy, and then from the Internet Reverse Proxy to the internal virtual machines. The aggregate bandwidth coming into the Internet Reverse Proxy from other parts of the network will be 2000 x 1.5 Mb/s = 3 Gb/s. For more details about non-split-horizon, see Non-Split-Horizon Network Topology.
Note |
The same 3 Gb/s of traffic passes inbound and outbound through the Internet Reverse Proxy, requiring the NIC on the Internet Reverse Proxy to handle 6 Gb/s of user traffic. See the next section for more information about bandwidth requirements for the NIC on the Internet Reverse Proxy.
|
-
Assume you have 2000 user system in a split-horizon DNS deployment. In this scenario, your Internet users will connect to the Internet Reverse Proxy while intranet users connect directly to the internal virtual machines. Assume ten percent of your users connect to a meeting using the Internet versus 90 percent of users connect to their meetings through the Intranet. The result is the aggregate bandwidth coming into the Internet Reverse Proxy will now be approximately 300 Mb/s (10 percent of 2000 users times 1.5 Mb/s equals 300 Mb/s). If that same 300 Mb/s of traffic passes from the Internet Reverse Proxy, the NIC on the Internet Reverse Proxy may be required to handle 600 Mb/s of user traffic. This is a dramatically lower bandwidth requirement than with a non-split-horizon DNS deployment described in the previous scenario. The reduction in network traffic has direct bearing on the recommendations for NIC or switch interface speed (see next section) which can result in you being able to deploy less expensive 1 Gb/s NICs on the Cisco UCS Server for the Internet Reverse Proxy or 1 Gigabit Ethernet Switch Infrastructure in DMZ network. For more details about split-horizon, see Split-Horizon Network Topology.
Note |
You may be required to deploy 1 Gigabit Ethernet NICs configured for NIC Teaming if the Internet Reverse Proxy usage is marginally close to the 1000 Mb/s threshold.
|
See NIC Teaming for Bandwidth Aggregation for more details.
Bandwidth on Cisco WebEx Meetings Server Network Interfaces
For direct interfaces between your switching architecture and your system, we recommend provisioning your interface NICs to the maximum speeds shown in the following table. These speeds apply to the connectivity between the Cisco UCS Servers and ports on head-end switches in your local switching infrastructure only. These are the recommended speeds needed to support worst-case traffic requirements.
System Capacity |
NIC or Switch Interface Speed |
50 user system |
1 Gb/s |
250 user system |
1 Gb/s |
800 user system |
10 Gb/s 1 |
2000 user system |
10 Gb/s2 |
1 You may optionally choose to reduce network infrastructure costs by deploying NIC Teaming using two or more Gigabit Ethernet NICs on the UCS Server and NIC Teaming on the head-end switch.
2 If you have a non-split-horizon DNS deployment, the 10 Gb/s requirement pertains to the IRP and internal virtual machines. If you have a split-horizon DNS deployment, you may be able to reduce the network infrastructure demands on your IRP (and DMZ network), which can result in you being able to deploy less expensive 1 Gb/s NICs on the Cisco UCS Server for the Internet Reverse Proxy or 1 Gigabit Ethernet Switch Infrastructure in DMZ network, as described in the "Bandwidth on Network Paths" section. However the 10 Gb/s speed requirement holds true for the internal virtual machines (and internal network).
See the following section "Bandwidth Considerations for Split-Horizon DNS Deployments" for more information about using 1 Gb/s NICSs and Ethernet switches for a split-horizon DNS deployment.
Assumptions for NIC Speed Calculations:
-
The aggregate end-user session bandwidth (1.5 Mb/s) was used to calculate the NIC speeds shown in the preceding table.
-
The inter-virtual machine control traffic must be free of congestion. This especially applies to 2000 user systems and any system provisioned for high availability. Severe congestion on virtual machine links can result in system instability and consequent interruption of service.
-
The connections to NAS storage, used for recording and database backup, must not be congested.
-
Protocol overhead and implementation inefficiencies will result in usable link bandwidth that is significantly less than the 1 Gb/s or 10 Gb/s speed labels.
-
If a large percentage of your traffic will hit the Internet Reverse Proxy when users log in to meetings, you need to remember that every user connection passes twice through the NIC on the Internet Reverse Proxy (inbound and outbound). Using the 2000 user system as an example, this means the NIC on the Internet Reverse Proxy may be required to handle 6 Gb/s of user traffic (2000 users times 1.5 Mb/s equals 3 Mb/s, times two for inbound and outbound traffic equals 6 Mb/s).
Conservatively, we ask that the local connections be no more than 60 percent used for end user media traffic, allowing the remaining 40 percent to be available for other traffic, unusual traffic bursts, and network overhead. Using the 800 user system as an example, we estimate the end user traffic at 1.2 Gb/s for the Admin and Media virtual machines and 2.4 Gb/s for the Internet Reverse Proxy virtual machine. Applying the 60 percent rule, we want the NIC to be capable of handling 2 Gb/s for the Admin and Media virtual machines (1.2 estimated user traffic for the Admin and Media virtual machines divided by 60 percent estimated normal bandwidth consumption equals 2.0 Gb/s) and 4 Gb/s for the Internet Reverse Proxy virtual machine.
Note |
The NIC speeds shown in the preceding table do not account for bandwidth used for accessing SAN storage. If Fibre Channel over Ethernet (FCoE) is used for a SAN connection, it should be provisioned to use an independent network interface.
|
Bandwidth Considerations for Split-Horizon DNS Deployments
With a split-horizon DNS deployment, some of your users will be logging in to meetings from the Internet and that traffic will hit the Internet Reverse Proxy, while the majority of users who are on the internal network will be logging into meetings without hitting the Internet Reverse Proxy. With a split-horizon DNS deployment, if you speed up your network and segment your traffic so that most of your traffic stays within the internal network (as opposed to hitting the Internet Reverse Proxy), you can potentially use NIC Teaming and provision a lower-end NIC (1 Gb/s NIC) on the Internet Reverse Proxy and provision the switching infrastructure between the Internet Reverse Proxy and the Internet to be 1 Gb/s, or at least lower than the recommended 10 Gb/s, for a 2000 user system.
For example, if a company has 100 users who want to access a 2000 port user system from the Internet concurrently, you would need a bandwidth of 150 Mb/s (1.5 Mb/s aggregate user session bandwidth * 100 users = 150 Mb/s). This implies that a network infrastructure from the DMZ network to the Internet Reverse Proxy can be 1 Gb/s Ethernet switches, and the Ethernet NIC interface on the Internet Reverse Proxy can be 1 Gb/s, as opposed to the stated 10 Gb/s interface requirement. Even when you factor in that the Internet Reverse Proxy sees double the traffic (meaning its NIC would have to handle 300 Mb/s of user traffic), applying the 60 percent rule (explained in the "Bandwidth on Cisco WebEx Meetings Server Network Interfaces" section) translates to 500 Mb/s. A 1 Gb/s link is still sufficient, but it would not be sufficient if we assumed 250 users instead of 100 users.
Note |
The optimization of bandwidth is only applicable for the NIC on the Internet Reverse Proxy in a split-horizon DNS deployments.
|
For non-split-horizon DNS deployments, you must deploy 10 Gb/s Ethernet switches and Ethernet NIC interfaces on the Internet Reverse Proxy.