<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">We have a situation where we get a redirect from a carrier with a list of carriers to send the transaction to in the contact header. None of the carriers in the contact header have q values assigned. <div class=""><br class=""></div><div class="">We have implemented our redirect handling logic using the UAC_REDIRECT module (get_redirects()) with help from TM module (t-load_contacts(), t_next_contact()). (failure_route code is at bottom of this note)</div><div class=""><br class=""></div><div class="">We find that when we receive a contact header with q values, we can launch requests serially using t_next_contact() and individually work through the contact list until we get a positive response. When we get a redirect with no q values in the contact header we find that all contacts get loaded and launched in parallel.</div><div class=""><br class=""></div><div class="">Although not stated in the documentation, it appears that in order to implement serial contact redirect handling, q values must be present in the contact header. Based on this assumption, and knowing that the redirecting carrier cannot include q values, we have attempted to modify the contact header and find that we are unable to add q values to the contact header.</div><div class=""><br class=""></div><div class="">We have attempted without success to use remove_hf("Contact”) followed by append_hf("Contact: $(avp(contact)) \r\n”); where $(avp(contact)) is the avp where we have rewritten the contact header to include q values.</div><div class=""><br class=""></div><div class="">Any guidance on how to handle this issue is appreciated.</div><div class=""><br class=""></div><div class="">_________________________________________________________-</div><div class=""><br class=""></div><div class="">Our failure route code:</div><div class=""><div class=""> if (t_check_status("3[0-9][0-9]")) {</div><div class=""> xlog("L_INFO", "----> REDIRECT Contact Header --> $T_rpl($ct) --- Method $rm --- From $T_req($fu) --- To $T_req($tu) --- Destination $T_req($du) \n");</div><div class=""> get_redirects("*:*");</div><div class=""><br class=""></div><div class=""> if (!t_load_contacts()) {</div><div class=""> xlog("L_INFO", "-t_load_contacts() FAILED /n");</div><div class=""> };</div><div class=""><br class=""></div><div class=""> xlog("L_INFO", "####->LOAD CONTACT LIST $xavp(tm_contacts[0]=>uri) \n");</div><div class=""><br class=""></div><div class=""> if (t_next_contacts()) {</div><div class=""> xlog("L_INFO", "-t_next_contact() loaded successfully /n");</div><div class=""> xlog("L_INFO", "####-> NEXT CONTACT LIST $xavp(tm_contacts[0]=>uri) \n");</div><div class=""> };</div><div class=""> t_on_failure("serial");</div><div class=""><br class=""></div><div class=""> if(t_relay()){</div><div class=""> xlog("L_INFO","----->Relayed in MANAGE_FAILURE --- Method $rm --- Contact Header $ct \n");</div><div class=""> };</div><div class=""> exit;</div><div class=""> } else {</div><div class=""> xlog("L_INFO","-----> NO REDIRECT --- Method $rm --- Contact Header $ct \n");</div><div class=""> exit;</div><div class=""> }</div><div class=""><br class=""></div><div class=""><div class="">failure_route["serial"] {</div><div class=""> xlog ("L_INFO", "Entered failure_route(serial) /n");</div><div class=""> if (t_check_status("3[0-9][0-9]")) {</div><div class=""> xlog("L_INFO", "----> DOUBLE REDIRECT Contact Header --> $T_rpl($ct) --- Method $rm --- From $T_req($fu) --- To $T_req($tu) --- Destination $T_req($du) \n");</div><div class=""> $xavp(tm_contacts[*]) = $null;</div><div class=""> xlog("L_INFO", "XXX-> tm_contacts reset to Null $xavp(tm_contacts[0]=>uri)\n");</div><div class=""><br class=""></div><div class=""> get_redirects("*:*");</div><div class=""><br class=""></div><div class=""> if (!t_load_contacts()) {</div><div class=""> xlog("L_INFO", "-t_load_contacts() FAILED /n");</div><div class=""> };</div><div class=""><br class=""></div><div class=""> xlog("L_INFO", "####-> LOAD 2 CONTACT LIST $xavp(tm_contacts[0]=>uri) \n");</div><div class=""><br class=""></div><div class=""> }</div><div class=""> if (!t_next_contacts()) {</div><div class=""> exit;</div><div class=""> }</div><div class=""><br class=""></div><div class=""> xlog("L_INFO", "-t_next_contact() loaded successfully /n");</div><div class=""> xlog("L_INFO", "####-> NEXT CONTACT LIST $xavp(tm_contacts[0]=>uri) \n");</div><div class=""><br class=""></div><div class=""> t_on_failure("serial");</div><div class=""> if(t_relay()){</div><div class=""> xlog("L_INFO","----->Relayed in failure_route(serial) --- Method $rm --- Contact Header $ct \n");</div><div class=""> };</div><div class="">}</div></div><div class="">
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