NE #78 SIP Call HOLD Explained

[@Atisf-b]

I was know it only theoretically but know it is more clear...now i looking carrier in this field ..this video is so helpful for me..

[@prabhatbhalla]

best explaination on hold resume so far..i re-created the same in my lab and was looking for something to make me understand the scenario..thnx a lot for putting the trace analysis explaination too

[@Krblkn]

Wow great explanation. This will help me solve a software ticket at work :)

[@bmuralikrishna8054]

Thanks a lot!! for a clear explanation with the Wireshark traces.

[@Rvshkl8]

Great Expination to leran Hold in SIP Call flow !!!!

[@ViniciusBuscacio]

Thank you very much, really good video

[@MCiD01]

Good explanation. What's not clear to me is who generates the hold tone that B hears. Is the tone generated by A and sent in-band to B, or does B generate it locally upon receiving the sendonly?

[@NetworkEngineeringVideoBlog]

"A" sends SendOnly in its SDP and "B" replies with ReceiveOnly only in its SDP. So "A" must generate the music or comfort noise.

[@brianweston83]

Excellent video.

[@pickylearner6913]

I reckon that ACK after OK is a necessity, cause otherwise, the sender of OK can't be sure that the OK has been received. And probably, retransmissions of OK will have a place

[@TomTamNguyen]

thank you for the video sir and subscribed

[@prabhatbhalla]

can you put up a video for css partition mismatch also..using the sdl traces so that we know what partition is missing from what css i re-created the same and noticed that the css id can be checked above the DA and the filtered partitions but how do we get know what partition or css is missing that needs to be added.

[@NetworkEngineeringVideoBlog]

My friend, you have me stumped with SDL traces. And with css, are you asking about a Calling Search Space? A quick google showed me both SDL and CSS are Cisco Call Manager (CUCM) things. Calling partitions and search spaces are used to route SIP messages and, to my knowledge, don't have any affect on the SIP headers other than maybe a via. I guess Cisco could put in some custom IEs in the SIP message, but I'm not familiar with them if they do. Good luck!

[@bitwamet]

He is explaining about pure the SIP world which is vendor independant knowledge nothing of Cisco, Avaya specific so for CSS/Partition is the basic building block of Calls in CUCM or call manager. Its very basis and you can validate this directly if you use DNA or if you know A and B parties don't need to check the logs pss you can find this information in SDL traces

[@amitkasnale3219]

How do we check that hold announcement played ? Which request tells the Announcement of hold is being played.

[@edmundof2011]

Hi in this video Can you explain Agent user Client-Server How is the transacations? please

[@NetworkEngineeringVideoBlog]

I googled UAS and UAC and here is what I got: A User Agent Client (UAC) is an entity that sends SIP requests and receives SIP responses. ... A User Agent Server (UAS) is an entity that receives SIP requests and sends SIP responses. A UAS will send SIP REGISTER requests, but these are not considered to be session creation messages.

[@edmundof2011]

@@NetworkEngineeringVideoBlog ok, tnks I have issue with call waiting service, I can see changes UAC&UAS when I push flash the call down. Thks for your explanation

[@bogemon1]

thank you very much.. !

[@Julfikarahmadsiddiquei]

How many transaction in call hold

[@seemarana1326]

There might have an update msg too

[@rajeshnanavati8879]

Excellent educational video. Thanks. I am sending small contribution $20 now.

[@NetworkEngineeringVideoBlog]

Thank you!