Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Switched Digital Video TweetChat

Join Gary Springer as he takes your questions about how SDV allows operators to add video services without requiring additional bandwidth in the network.

Gary is a distinguished engineer in Cisco's Access and Transport Technology Group in Atlanta, Ga. He is a control system architect specializing in video system control and one of the lead architects of the Cisco Switched Digital Video (SDV) solution. His team developed the SDV Server. Springer joined Cisco with the acquisition of Scientific-Atlanta, where he had worked since 1984. Springer holds a bachelor's degree in electrical engineering from North Carolina State University.

This TweetChat is the second in a series from our Ask the Experts group and will take place on Tuesday, June 15 from 10:00am – 11:00am  PT using the #ciscosupport hashtag.

Submit questions in advance to @ciscosupport with the hashtag #ciscosupport or submit by posting a comment below (log in with userid to post a comment).

What is a TweetChat?

Tweet chats are online conversations, held at a  pre-arranged time, between a group of Twitter users, and using a specific Twitter hashtag to identify the discussion.

How Do I Participate?

On the day of the event, go to to follow the #ciscosupport hashtag. Alternatively, you can use your favorite Twitter client (i.e. Tweet Grid, TweetDeck) or TwitterSearch to follow the chat hashtag.  During the event, you can follow the discussion,  contribute questions, and submit your own comments by using the same hashtag.

Version history
Revision #:
1 of 1
Last update:
‎06-11-2010 10:57 AM
Updated by:

Answers and tips on Switched Digital Video from our expert, Gary  Springer.  This is a transcript of the TweetChat session held on June  15, 2010. More on this topic can be found at

Q: What do you do when switch digital video exceeds the network  capacity?
A: Add more QAM channels to the service group. Our solution supports up  to 48 QAM channels per service group.

Q: How much bandwidth is consumed for switching digital video while T1  is not available?
A:  Typical digital video rates are 3.75-Mbps for standard definition  and 15-Mbps for high definition programs. Non-broadcast digital video is  typically clamped to not exceed a bandwidth value. The number  represents the clamped (i.e. upper limit) bandwidth.

Q: When does a edge device report an interface alarm?
A: When (1) the device fails to accept a setup or teardown command or  (2) the device fails to respond to a status query.

TIP: If the log files are too large to use with tools, set MaxFileSize  under LogManager>Configuration to limit size of files.

Q: How do I inhibit alarms for an edge device that is being repaired?
A: Set the AdminState for the device to the Maintenance state. This will  inhibit alarms from the device and also prevent its attempted use.

Q: Can the SDV sources be prioritized?
A: Yes.The SdvSm->Source Priority page allows configuration of the  priority of SDV sources. The software will prioritize the list of  sources using this configuration.

TIP: To force a program to always be active, set the program OfferState  to Static.

Q: Can you connect switched digital video with teleconferencing?
A: It hasn't been done yet but our SDV solution exposes interfaces to  allow external systems to request resources. So it is possible.

Q: What algorithm or configuration selects how many programs are active  and the set of active programs? 
A: The operator configures the minimum active bandwidth. The active  programs are selected by first, the number of users viewing the program  and then the provisioned priority.

Q:What do the log levels (Min,Normal,Max,Capture) represent?
A: Normal corresponds to normal recording keeping. Min selects only  error messages. Max selects all transactions. Capture selects binary  messages.