SIP basic call flow 

The 100 (Trying) response indicates that the INVITE has been received and that the proxy is working on her behalf to route the INVITE to the destination

Great Presentation . I was very impatient to read the entire stuff online & learn . But this presentation has made it in a very short time . Now I am clear with the basic working of the SIP protocol . Please continue the same method of teaching . 1. 100 is sent to avoid re-transmission of Invite (much like a TCP-ACK ) , informing the sender that "I have received the invite packet " 2. I am not sure about the second question . I am not aware of the fields in the SIP protocol .Since I am from the ip domain , I could give you an answer wrt the IP DOMAIN . If the route for the destination (1002 ) is through the proxy , then it would obviously pass through it . (It would answer this , after looking into the information at the SIP layer ) Venky .

Thanks a lot for this helpful video and explanation. Greetings from Venezuela

Vishal JI I like your videos and expect more videos from you ...understandble format...

Thank You, for making me understand the Basics of SIP

Than you very much!!!!!!!!Very nice video for basic understanding of SIP. 100 trying is sending bcz to stop the retransmission of SIP. Proxy has to add Record Route header it'self if he want to bypass all message and response.

Very informative, looking forward to watching more from you. Thank you Vishal.

Excellent.....Practical Learning......

proxy will add the record-route header field in the message to include itselves in all signalling path for all messages.

Hi Vishal...Thank you some much for sharing this vedio and i understood very easily even i started as a beginner

Very good introduction to SIP. Looking forward coming videos.

Many thanks for giving this video and it gave me more idea about SIP .. Its really helpful for the beginners ..looking forward to ur next video Message Header Exp ....

Awesome video Vishal. Thank you for your patience to explain every bit of it :)

Good one session Patel. Its help me to understand basic concept..

Thank You Vishal... This video gives a clear understanding of the SIP Basic Call Flow. Please share more related videos.

Hi Vishal !. This is very good guide and very clear. Thanks Vishal

Thanks, helped me better understand in a few minutes

Superb presentation.. Hats off !!!

Good guide, very clear! Thank You, Vishal! Some extracts from rfc could be also useful here for someone who're looking for understanding of SIP dialogs: 1) A dialog is identified at each UA with a dialog ID, which consists of a Call-ID value, a local tag and a remote tag. 2) Dialogs are created through the generation of non-failure responses to requests with specific methods. Within this specification, only 2xx and 101-199 responses with a To tag, where the request was INVITE, will establish a dialog.

Its awesome.. Please share some more video.

very nice video in sip call flow i understanding clearly so thank u....

It is very impressive and helpful with SIP experiment demo. Thank you very much for sharing your your knowledge with the experiment. However you lost the audio after you make the SIP call. I could not hear your explanation very well after the call set up.

100 trying is for indication for client as INVITE has been received , so client won't send the INVITE request again...if 100trying was not received then the client send continuously INVITE requests.

Excellent Vishal

very Nice Vishal .. help us in reading full trace of each SIP message.

superb !!!!!!!!!!!!!!!!!

very useful video :) thanks very much

Thanks for your series of videos, i liked your explanation and practical series the most!! Probably you can improve on your accent a bit and make it more neutral, that's my only suggestion.

Proxy adds record route header to include itselves in all signalling path for messages like ack and bye.

Thank you for such an informative video. I have a question that how we get to know where the file was captured?

only 4 videos pl add more videos about SIP trunking addition and SIPp tool lg anaysis

thank you very much

Thank you Vishal

ans for 1st question is we need to get register in proxy before INVITE request , hence 100 Trying signal is response .

Thanks

Thank You :)

Thanks please suggest a material for Sigtran learning in a similar way via Wireshark Please

U da man

Hi Vishal, Thanks for the great explanation. One Question is always irritating me !> Why ACK is termed as seperate transaction when Invite goes with C-SEQ = 1 Invite from Invite to 20Ok , ACK has C-SEQ = 1 ACK and BYE C-SEQ = 2 BY E so it clearly show only 2 transactions right. Why ACK is termed as SEPERATE TRANSACTIONS.

i want to to know "100 trying from proxy server"

it would be better if u can upload that Ms_powerpoin

Thank you very much