> I a bit unclear on how a UA should > handle a 300 (Multiple choice) response. > Initially, it will handle it exactly like > a 302 (i.e. ACK the 300 and then send and > INVITE on to the 1st entry in the Contact list).
Both the 300 and 302 can contain multiple contacts. The main difference is that the 300 is used by the UAS to indicate that the "user" might like to pick among the multiple contacts. > However, this is where I am a bit fuzzy. > If this INVITE returns a 4xx response (or no > response), how is the UA supposed to behave? For 300 responses, visibly refreshing the list of tried/non-tried contacts is a possibility. Advancing contacts based upon order or q-value is also an option when the user interaction is not possible. Unfortunately contact correlation has not been well standardized for automatic contact advancing. For example a 302 with 4 contacts is received: 1) <sip:[EMAIL PROTECTED];user=phone>;q=0.5 2) <sip:[EMAIL PROTECTED];user=phone>;q=0.4 3) <sip:[EMAIL PROTECTED];user=phone>;q=0.3 4) <sip:[EMAIL PROTECTED];user=phone>;q=0.2 If a 486 is received for 1, it would be nice to skip to 3 instead trying 2. Potentially solved by creating an SRV entry grouping/prioritizing lowdoller.com and highdoller.com. If no response is received for 1, it would be nice to try 2. Potentially solved by the above mentioned SRV entry. If a 600 is received for 1, it would be nice to try 3 instead of not advancing. No currently specified solution exists unless the 600 is treated like a 486. > Is it mandatory that it should try the > next entry in the Contact header? No redirection is mandatory. However contact advancing would typically be desired.
winmail.dat
Description: application/ms-tnef
