通過OpenSIPS對FreeSWITCH進行負載均衡網路上的文章很多，但都是基於老版本的OpenSIPS，目前最新的OpenSIPS LTS版是2.4，如果使用老版本配置檔案，OpenSIPS是執行不起來（當然通過一番修改後還是可以執行起來的）。筆者經過一番折騰，成功實現了OpenSIPS 2.4版本對FreeSWITCH的負載均衡，這裡將折騰的注意項及最終的配置記下來，以免下次真的要用時又重新折騰。筆者對OpenSIPS不是很熟悉，可能有些地方有紕漏，歡迎各位網友指正。

一、環境介紹：

OpenSIPS OS：debian 8

OpenSIPS Version：2.4 LTS

OpenSIPS IP：172.16.100.30/31

OpenSIPS HA：keepalived

OpenSIPS VIP：172.16.100.32

OpenSIPS domain：sofia.superpipi.cn

FreeSWITCH OS：debian 8

FreeSWITCH Version：1.81

FreeSWITCH IP：172.16.100.10/11

DB：Mysql 5.7

注：OpenSIPS的高可用，採用keepalived進行VIP切換實現，目前未新增OpenSIPS的可用性檢測指令碼，僅作VIP切換。

二、組網介紹：

本次試驗採用以下組網結構，兩個節點OpenSIPS採用keepalived進行VIP切換，兩個節點FreeSWITCH實現負荷分擔，OpenSIPS和FreeSWITCH均連線到MySQL（注：FreeSWITCH連線MySQL資料庫，需提取channels建表SQL並將欄位長度改小，然後手工建立channels表

）。在路由器（筆者使用的路由器有Dnsmasq功能）上將域名sofia.superpipi.cn解析到OpenSIPS的VIP（172.16.100.32），SIP分機註冊時通過域名sofia.superpipi.cn進行註冊。至於為何要通過域名註冊，這是因為FreeSWITCH預設的域名是其本地的IP，若註冊的域非FreeSWITCH本地IP，則可能導致註冊不上同時也無法通話，通過修改FreeSWITCH的域名稱可以實現。如果將FreeSWITCH域名修改為OpenSIPS的VIP，那麼VIP只有一個，FreeSWITCH就只能有一個域了，而指向OpenSIPS的VIP的域名可以是多個，這樣就可以實現FreeSWITCH多域。至於FreeSWITCH為何要多個域，主要是方便許可權管控，在實際生產中意義重大。

三、安裝及基礎配置：

3.1、安裝和配置keepalived

3.1.1、安裝keepalived

keepalived安裝直接通過apt安裝即可

apt-get install keepalived

3.1.2、修改keepalived配置：

編輯/etc/keepalived/keepalived.conf，將兩個節點分別按以下配置修改。

• 01節點keepalived配置：

! Configuration File for keepalived
global_defs {
   notification_email {
     acassen
   }
   notification_email_from [email protected]
   smtp_server 172.16.100.251
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    garp_master_delay 10
    smtp_alert
    virtual_router_id 53
    priority 200
    nopreempt
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 915119
    }
    virtual_ipaddress {
        172.16.100.32/24
        172.16.100.32/24 label eth0:1
    }
}

• 02節點keepalived配置：

! Configuration File for keepalived
global_defs {
   notification_email {
     acassen
   }
   notification_email_from [email protected]
   smtp_server 172.16.100.251
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    garp_master_delay 10
    smtp_alert
    virtual_router_id 53
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 915119
    }
    virtual_ipaddress {
        172.16.100.32/24
        172.16.100.32/24 label eth0:1
    }
}

3.2、安裝和配置OpenSIPS

3.2.1、安裝OpenSIPS

筆者安裝OpenSIPS是通過官方deb包直接安裝的，執行步驟如下：

• 新增源：

apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 049AD65B
echo "deb http://apt.opensips.org jessie 2.4-releases" >/etc/apt/sources.list.d/opensips.list

• 更新源和安裝OpenSIPS

apt-get update && apt-get install opensips

3.2.2、配置OpenSIPS

• 建立資料庫

編輯/etc/opensips/opensipsctlrc將以下項去註釋並按實際情況修改，或直接通過echo追加到/etc/opensips/opensipsctlrc

echo "SIP_DOMAIN=sofia.superpipi.cn" >> /etc/opensips/opensipsctlrc
echo "DBENGINE=MYSQL" >> /etc/opensips/opensipsctlrc
echo "DBPORT=3306" >> /etc/opensips/opensipsctlrc
echo "DBHOST=172.16.100.15" >> /etc/opensips/opensipsctlrc
echo "DBNAME=opensips" >> /etc/opensips/opensipsctlrc
echo "DBRWUSER=opensips" >> /etc/opensips/opensipsctlrc
echo "DBRWPW="ligen119"" >> /etc/opensips/opensipsctlrc

執行建立資料庫工具（注：如資料庫不在本機，需授權root使用者遠端訪問許可權）

/usr/sbin/opensipsdbctl create

執行以上命令後會提示輸入root密碼，輸入root密碼後提示輸入資料庫字符集（吐槽一下不能選utf8），這裡輸入gbk（後續可能需要儲存中文），其後按嚮導進行資料庫建立。

• 配置啟動引數

啟動引數編輯不是必須，如果生產應用建議還是將記憶體引數做相應的擴大。

編輯/etc/default/opensips將以下項去註釋並按實際情況修改，或直接通過echo追加到/etc/default/opensips 

echo "RUN_OPENSIPS=yes" >>/etc/default/opensips
echo "USER=opensips" >>/etc/default/opensips 
echo "GROUP=opensips" >>/etc/default/opensips 
echo "S_MEMORY=512" >>/etc/default/opensips 
echo "P_MEMORY=32" >>/etc/default/opensips 
echo "DUMP_CORE=yes" >>/etc/default/opensips

• 配置檔案

編輯/etc/opensips/opensips.cfg，清空原配置檔案，將以下內容插入配置檔案。（本配置檔案基本是參考freeswitch官方wiki的配置檔案）

log_level=1  #老版本日誌級別引數為debug，級別範圍1-4，建議生產上設定為1，為3或者4時將產生大量日誌，磁碟空間很快就不夠了
sip_warning=0
log_stderror=no
log_facility=LOG_LOCAL0
log_name="opensips"
debug_mode=no
children=4
dns_try_ipv6=no
auto_aliases=no
listen=udp:172.16.100.30:5062  #另外一個節點設定為udp:172.16.100.31:5062，取本地IP，不新增該監聽項則備用節點無法與負載節點握手，導致備用節點將排程列表的負載節點設定為不可用
listen=udp:172.16.100.32:5060
mpath="/usr/lib/x86_64-linux-gnu/opensips/modules/"
 
loadmodule "db_mysql.so"
loadmodule "signaling.so"
loadmodule "sl.so"
loadmodule "tm.so"
loadmodule "rr.so"
loadmodule "uri.so"
loadmodule "dialog.so"
loadmodule "maxfwd.so"
loadmodule "textops.so"
loadmodule "mi_fifo.so"
loadmodule "dispatcher.so"
loadmodule "load_balancer.so"
loadmodule "sipmsgops.so"
loadmodule "proto_udp.so"
modparam("mi_fifo", "fifo_name", "/tmp/opensips_fifo")
modparam("dialog", "db_mode", 1)
modparam("dialog", "db_url", "mysql://opensips:[email protected]/opensips") 
modparam("rr", "enable_double_rr", 1)
modparam("rr", "append_fromtag", 1)
modparam("tm", "fr_timer", 2)
modparam("dispatcher", "db_url", "mysql://opensips:[email protected]/opensips")
modparam("dispatcher", "ds_ping_method", "OPTIONS")
modparam("dispatcher", "ds_ping_interval", 5)
modparam("dispatcher", "ds_probing_threshhold", 2)
modparam("dispatcher", "ds_probing_mode", 1)
modparam("load_balancer", "db_url", "mysql://opensips:[email protected]/opensips")
modparam("load_balancer", "probing_method", "OPTIONS")
modparam("load_balancer", "probing_interval", 5)
route{
 
        if (!mf_process_maxfwd_header("10")) {
                sl_send_reply("483","Too Many Hops");
                exit;
        }
 
        if (!has_totag()) {
                record_route();
        }
        else {
                loose_route();
                t_relay();
                exit;
        }
        if (is_method("CANCEL")) {
                if ( t_check_trans() )
                        t_relay();
                exit;
        }
        if (is_method("INVITE")) {
                if (!load_balance("1","pstn","1")) {
                        send_reply("503","Service Unavailable");
                        exit;
                }
        }
        else if (is_method("REGISTER")) {
                if (!ds_select_dst("1", "4")) {
                        send_reply("503","Service Unavailable");
                        exit;
                }
        }
        else {
                send_reply("405","Method Not Allowed");
                exit;
        }
        if (!t_relay()) {
                sl_reply_error();
        }
}

• 新增負載節點

在資料庫新增兩個負載節點資訊

INSERT INTO `opensips`.`load_balancer` (`id`, `group_id`, `dst_uri`, `resources`, `probe_mode`, `description`) VALUES ('1', '1', 'sip:172.16.100.10', 'vm=100;conf=100;transc=100;pstn=500', '1', 'FS1');
INSERT INTO `opensips`.`load_balancer` (`id`, `group_id`, `dst_uri`, `resources`, `probe_mode`, `description`) VALUES ('2', '1', 'sip:172.16.100.11', 'vm=100;conf=100;transc=100;pstn=500', '1', 'FS2');

• 允許繫結非本機IP

執行以下命令使OpenSIPS能監聽在本機IP，當VIP飄過來時OpenSIPS服務即可用

echo 'net.ipv4.ip_nonlocal_bind=1' >> /etc/sysctl.conf

• 將日誌輸出到指定檔案

在/etc/rsyslog.conf追加keepalived和OpenSIPS日誌輸出配置。（注：OpenSIPS配置檔案中log_stderror和debug_mode需設定成no，否則可能不能輸出單獨日誌）

echo "local0.*                        /var/log/opensips.log" >>/etc/rsyslog.conf
echo "local1.*                        /var/log/keepalived.log" >>/etc/rsyslog.conf

3.2.3、開始OpenSIPS

• 重啟rsyslog、keepalived、OpenSIPS

service rsyslog restart
service keepalived restart
service opensips restart

• 新增FreeSWITCH到排程列表

執行以下命令將兩個節點新增到排程列表，（這裡新增排程器的命令和1.7版本是有區別的）

opensipsctl dispatcher addgw 1 sip:172.16.100.10 5060 0 50 'FS1' '節點1'
opensipsctl dispatcher addgw 1 sip:172.16.100.11 5060 0 50 'FS2' '節點2'

新增排程列表成功後，在兩個FreeSWITCH的控制通過sofia profile sofia.superpipi.cn siptrace on命令開啟sip訊息跟蹤即可看到兩個OpenSIPS節點不停在跟FreeSWITCH通過”OPTIONS“訊息進行握手，如下：

   ------------------------------------------------------------------------
recv 349 bytes from udp/[172.16.100.31]:5062 at 21:41:43.502417:
   ------------------------------------------------------------------------
   OPTIONS sip:172.16.100.10 SIP/2.0
   Via: SIP/2.0/UDP 172.16.100.31:5062;branch=z9hG4bK2fe7.7ea62cf7.0
   To: sip:172.16.100.10
   From: <sip:[email protected]>;tag=5f8cfd923bd21a2d7f298654cd327b22-8a62
   CSeq: 14 OPTIONS
   Call-ID: [email protected]
   Max-Forwards: 70
   Content-Length: 0
   User-Agent: OpenSIPS (2.4.2 (x86_64/linux))
   
   ------------------------------------------------------------------------
send 735 bytes to udp/[172.16.100.31]:5062 at 21:41:43.503285:
   ------------------------------------------------------------------------
   SIP/2.0 200 OK
   Via: SIP/2.0/UDP 172.16.100.31:5062;branch=z9hG4bK2fe7.7ea62cf7.0
   From: <sip:[email protected]>;tag=5f8cfd923bd21a2d7f298654cd327b22-8a62
   To: <sip:172.16.100.10>;tag=t2y6pUXm66tQH
   Call-ID: [email protected]
   CSeq: 14 OPTIONS
   Contact: <sip:172.16.100.10>
   User-Agent: FreeSWITCH-mod_sofia/1.8.1+git~20180724×××60524Z~b33bc925c5~64bit
   Accept: application/sdp
   Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE
   Supported: timer, path, replaces
   Allow-Events: talk, hold, conference, presence, as-feature-event, dialog, line-seize, call-info, sla, include-session-description, presence.winfo, message-summary, refer
   Content-Length: 0
   
   ------------------------------------------------------------------------
recv 349 bytes from udp/[172.16.100.30]:5062 at 21:41:45.769168:
   ------------------------------------------------------------------------
   OPTIONS sip:172.16.100.10 SIP/2.0
   Via: SIP/2.0/UDP 172.16.100.30:5062;branch=z9hG4bKbace.ec1b06f.0
   To: sip:172.16.100.10
   From: <sip:[email protected]>;tag=45af385df62c8fa46b1bdd54b7adb556-4f80
   CSeq: 14 OPTIONS
   Call-ID: [email protected]
   Max-Forwards: 70
   Content-Length: 0
   User-Agent: OpenSIPS (2.4.2 (x86_64/linux))
   
   ------------------------------------------------------------------------
send 735 bytes to udp/[172.16.100.30]:5062 at 21:41:45.770861:
   ------------------------------------------------------------------------
   SIP/2.0 200 OK
   Via: SIP/2.0/UDP 172.16.100.30:5062;branch=z9hG4bKbace.ec1b06f.0
   From: <sip:[email protected]>;tag=45af385df62c8fa46b1bdd54b7adb556-4f80
   To: <sip:172.16.100.10>;tag=UBrZrper3FHaD
   Call-ID: [email protected]
   CSeq: 14 OPTIONS
   Contact: <sip:172.16.100.10>
   User-Agent: FreeSWITCH-mod_sofia/1.8.1+git~20180724×××60524Z~b33bc925c5~64bit
   Accept: application/sdp
   Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE
   Supported: timer, path, replaces
   Allow-Events: talk, hold, conference, presence, as-feature-event, dialog, line-seize, call-info, sla, include-session-description, presence.winfo, message-summary, refer
   Content-Length: 0
   
   ------------------------------------------------------------------------

四、FreeSWITCH配置和驗證

4.1、域名修改

因話機註冊時是通過域名註冊，因此需要修改FreeSWITCH的域為註冊的域名。

編輯../conf/vars.xml，將domain設定為sofia.superpipi.cn。（注：如FreeSWITCH使用多域，則參照多域的方式進行修改，參考：https://www.cnblogs.com/lzpong/p/8573372.html）

<X-PRE-PROCESS cmd="set" data="domain=sofia.superpipi.cn"/>

修改後需重啟FreeSWITCH才能生效

4.2、註冊驗證

筆者分別使用eyeBeam、Linphone、eSpace SoftPhone三種軟電話和一個Fanvil X5硬電話進行註冊測試，均可註冊成功。

在freeswitch所在伺服器執行fs_cli -x "sofia status profile sofia.superpipi.cn reg"

結果如下：

[email protected]:~# fs_cli -x "sofia status profile sofia.superpipi.cn reg"
Registrations:
=================================================================================================
Call-ID:        [email protected]
User:           [email protected]
Contact:        "1004" <sip:[email protected]:6060>
Agent:          Fanvil X5 1.3.256.1566
Status:         Registered(UDP)(unknown) EXP(2018-09-23 22:14:29) EXPSECS(2228)
Ping-Status:    Reachable
Ping-Time:      0.00
Host:           debian
IP:             172.16.100.32
Port:           5060
Auth-User:      1004
Auth-Realm:     sofia.superpipi.cn
MWI-Account:    [email protected]
Call-ID:        YTFjZjBmZDZjNWEyZGQwNTgxMTEzZDcwMTAwNDdiZDQ.
User:           [email protected]i.cn
Contact:        "1000" <sip:[email protected]:51540;rinstance=f8dca36459b0bdec>
Agent:          eyeBeam release 1011d stamp 40820
Status:         Registered(UDP)(unknown) EXP(2018-09-23 22:35:27) EXPSECS(3486)
Ping-Status:    Reachable
Ping-Time:      0.00
Host:           debian
IP:             172.16.100.32
Port:           5060
Auth-User:      1000
Auth-Realm:     sofia.superpipi.cn
MWI-Account:    [email protected]
Call-ID:        SdnqWECcxy
User:           [email protected]
Contact:        "" <sip:[email protected]:64242;transport=udp>
Agent:          Linphone Desktop/4.1.1 (belle-sip/1.6.3)
Status:         Registered(UDP)(unknown) EXP(2018-09-23 21:47:38) EXPSECS(617)
Ping-Status:    Reachable
Ping-Time:      0.00
Host:           debian
IP:             172.16.100.32
Port:           5060
Auth-User:      1002
Auth-Realm:     sofia.superpipi.cn
MWI-Account:    [email protected]
Call-ID:        NzBhNzg3NTY2NWExZmE0M2ZiODdlZGIwYmY1NGVmY2Y.
User:           [email protected]
Contact:        "" <sip:[email protected]:5060;rinstance=b0fff9289f8fbf0c>
Agent:          HUAWEI OpenEye v3.1
Status:         Registered(UDP)(unknown) EXP(2018-09-23 21:42:52) EXPSECS(331)
Ping-Status:    Reachable
Ping-Time:      0.00
Host:           debian
IP:             172.16.100.32
Port:           5060
Auth-User:      1003
Auth-Realm:     sofia.superpipi.cn
MWI-Account:    [email protected]
Total items returned: 4
=================================================================================================

4.3、通話驗證

• 使用分機1000撥通1003

172.16.100.10（FS1）節點收到分機1000發來的"INVITE"訊息，並向分機1003發起"INVITE"訊息，訊息跟蹤如下（注：刪除了SDP和省略部分訊息）：

recv 1431 bytes from udp/[172.16.100.32]:5060 at 21:48:29.481716:
   ------------------------------------------------------------------------
   INVITE sip:[email protected] SIP/2.0
   Record-Route: <sip:172.16.100.32;lr;ftag=f104f441;did=83f.44ccd293>
   Via: SIP/2.0/UDP 172.16.100.32:5060;branch=z9hG4bKc6fd.c55828d7.0
   Via: SIP/2.0/UDP 172.16.100.251:51540;received=172.16.100.251;branch=z9hG4bK-d87543-8651904ed85c056f-1--d87543-;rport=51540
   Max-Forwards: 69
   Contact: <sip:[email protected]:51540>
   To: "1003"<sip:[email protected]>
   From: "1000"<sip:[email protected]>;tag=f104f441
   Call-ID: NDkyOTM1YWI4YzhiMGY4MWI0ZDMwYmQzNThjYjE2NzQ.
   CSeq: 2 INVITE
   Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO
   Content-Type: application/sdp
   Proxy-Authorization: Digest username="1000",realm="sofia.superpipi.cn",nonce="e9c8201d-3c8a-461b-a86c-4719edc9cae3",uri="sip:[email protected]",response="07eca040fed8f8ecfb7392671af7cc20",cnonce="44bb05f0c983e2e22b491a7bc82f0ab6",nc=00000001,qop=auth,algorithm=MD5
   User-Agent: eyeBeam release 1011d stamp 40820
   Content-Length: 442

   ------------------------------------------------------------------------
send 354 bytes to udp/[172.16.100.32]:5060 at 21:48:29.502215:
   ------------------------------------------------------------------------
   SIP/2.0 100 Trying
   Via: SIP/2.0/UDP 172.16.100.32:5060;branch=z9hG4bKc6fd.c55828d7.0
   From: "1000"<sip:[email protected]>;tag=f104f441
   To: "1003"<sip:[email protected]>
   Call-ID: NDkyOTM1YWI4YzhiMGY4MWI0ZDMwYmQzNThjYjE2NzQ.
   CSeq: 2 INVITE
   User-Agent: FreeSWITCH-mod_sofia/1.8.1+git~20180724×××60524Z~b33bc925c5~64bit
   Content-Length: 0
   
   ------------------------------------------------------------------------
send 1272 bytes to udp/[172.16.100.251]:5060 at 21:48:30.575115:
   ------------------------------------------------------------------------
   INVITE sip:[email protected]:5060;rinstance=b0fff9289f8fbf0c SIP/2.0
   Via: SIP/2.0/UDP 172.16.100.10;rport;branch=z9hG4bKg7X53ye14956r
   Max-Forwards: 68
   From: "Extension 1000" <sip:[email protected]>;tag=9e7rDt1XcyNZc
   To: <sip:[email protected]:5060;rinstance=b0fff9289f8fbf0c>
   Call-ID: 326006cf-39da-1237-4983-000c2953a0b0
   CSeq: 128519191 INVITE
   Contact: <sip:[email protected]:5060>
   User-Agent: FreeSWITCH-mod_sofia/1.8.1+git~20180724×××60524Z~b33bc925c5~64bit
   Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE
   Supported: timer, path, replaces
   Allow-Events: talk, hold, conference, presence, as-feature-event, dialog, line-seize, call-info, sla, include-session-description, presence.winfo, message-summary, refer
   Content-Type: application/sdp
   Content-Disposition: session
   Content-Length: 246
   X-FS-Support: update_display,send_info
   Remote-Party-ID: "Extension 1000" <sip:[email protected]>;party=calling;screen=yes;privacy=off
   
   ------------------------------------------------------------------------
recv 318 bytes from udp/[172.16.100.251]:5060 at 21:48:30.634089:
   ------------------------------------------------------------------------
   SIP/2.0 100 Trying
   Via: SIP/2.0/UDP 172.16.100.10;rport=5060;branch=z9hG4bKg7X53ye14956r
   To: <sip:[email protected]:5060;rinstance=b0fff9289f8fbf0c>
   From: "Extension 1000" <sip:[email protected]>;tag=9e7rDt1XcyNZc
   Call-ID: 326006cf-39da-1237-4983-000c2953a0b0
   CSeq: 128519191 INVITE
   Content-Length: 0
   
   ------------------------------------------------------------------------
recv 399 bytes from udp/[172.16.100.251]:5060 at 21:48:30.634221:
   ------------------------------------------------------------------------
   SIP/2.0 180 Ringing
   Via: SIP/2.0/UDP 172.16.100.10;rport=5060;branch=z9hG4bKg7X53ye14956r
   Contact: <sip:[email protected]:5060;rinstance=b0fff9289f8fbf0c>
   To: <sip:[email protected]:5060;rinstance=b0fff9289f8fbf0c>;tag=77eb678a
   From: "Extension 1000"<sip:[email protected]>;tag=9e7rDt1XcyNZc
   Call-ID: 326006cf-39da-1237-4983-000c2953a0b0
   CSeq: 128519191 INVITE
   Content-Length: 0
   ------------------------------------------------------------------------

• 使用分機1002撥打1004

在1000與1003通話狀態下，使用分機1002撥打1004，172.16.100.11（FS2）節點收到分機1002發來的"INVITE"訊息，並向分機1004發起"INVITE"訊息，訊息跟蹤如下（注：刪除了SDP和省略部分訊息）：

recv 1935 bytes from udp/[172.16.100.32]:5060 at 21:54:32.072291:
   ------------------------------------------------------------------------
   INVITE sip:[email protected] SIP/2.0
   Record-Route: <sip:172.16.100.32;lr;ftag=0HIj01pcT;did=cdf.8df222c6>
   Via: SIP/2.0/UDP 172.16.100.32:5060;branch=z9hG4bKc54a.a53a6847.0
   Via: SIP/2.0/UDP 172.16.100.251:64242;received=172.16.100.251;branch=z9hG4bK.m5Jiasf70;rport=64242
   From: <sip:[email protected]>;tag=0HIj01pcT
   To: sip:[email protected]
   CSeq: 21 INVITE
   Call-ID: LJD8EMDXo0
   Max-Forwards: 69
   Supported: replaces, outbound
   Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO, UPDATE
   Content-Type: application/sdp
   Content-Length: 898
   Contact: <sip:[email protected]:64242;transport=udp>;+sip.instance="<urn:uuid:bcb91990-4d9b-47ea-8ba8-3af172d27fce>"
   User-Agent: Linphone Desktop/4.1.1 (belle-sip/1.6.3)
   Proxy-Authorization:  Digest realm="sofia.superpipi.cn", nonce="771a93e4-504d-410e-b5ca-4b927a297b61", algorithm=MD5, username="1002",  uri="sip:[email protected]", response="ed40318d6162ef2a623f8f3049995a99", cnonce="3zQAEkGGvoZhNjcE", nc=00000001, qop=auth
   ------------------------------------------------------------------------
send 308 bytes to udp/[172.16.100.32]:5060 at 21:54:32.098044:
   ------------------------------------------------------------------------
   SIP/2.0 100 Trying
   Via: SIP/2.0/UDP 172.16.100.32:5060;branch=z9hG4bKc54a.a53a6847.0
   From: <sip:[email protected]>;tag=0HIj01pcT
   To: sip:[email protected]
   Call-ID: LJD8EMDXo0
   CSeq: 21 INVITE
   User-Agent: FreeSWITCH-mod_sofia/1.8.1+git~20180724×××60524Z~b33bc925c5~64bit
   Content-Length: 0
   
   ------------------------------------------------------------------------
send 1427 bytes to udp/[172.16.100.110]:6060 at 21:54:33.154929:
   ------------------------------------------------------------------------
   INVITE sip:[email protected]:6060 SIP/2.0
   Via: SIP/2.0/UDP 172.16.100.11;rport;branch=z9hG4bKecU1j8vy36H9r
   Max-Forwards: 68
   From: "Extension 1002" <sip:[email protected]>;tag=v4c83jm6gtF0H
   To: <sip:[email protected]:6060>
   Call-ID: 0a7d51fd-39db-1237-2d8d-000c29916959
   CSeq: 128519372 INVITE
   Contact: <sip:[email protected]:5060>
   User-Agent: FreeSWITCH-mod_sofia/1.8.1+git~20180724×××60524Z~b33bc925c5~64bit
   Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE
   Supported: timer, path, replaces
   Allow-Events: talk, hold, conference, presence, as-feature-event, dialog, line-seize, call-info, sla, include-session-description, presence.winfo, message-summary, refer
   Content-Type: application/sdp
   Content-Disposition: session
   Content-Length: 455
   X-FS-Support: update_display,send_info
   Remote-Party-ID: "Extension 1002" <sip:[email protected]>;party=calling;screen=yes;privacy=off
   ------------------------------------------------------------------------
recv 378 bytes from udp/[172.16.100.110]:6060 at 21:54:33.338614:
   ------------------------------------------------------------------------
   SIP/2.0 100 Trying
   Via: SIP/2.0/UDP 172.16.100.11;rport=5060;branch=z9hG4bKecU1j8vy36H9r
   From: "Extension 1002" <sip:[email protected]>;tag=v4c83jm6gtF0H
   To: <sip:[email protected]:6060>
   Call-ID: 0a7d51fd-39db-1237-2d8d-000c29916959
   CSeq: 128519372 INVITE
   Allow: INVITE, ACK, OPTIONS, BYE, CANCEL, REFER, NOTIFY, INFO, PRACK, UPDATE, MESSAGE
   Content-Length: 0
   
   ------------------------------------------------------------------------
recv 349 bytes from udp/[172.16.100.31]:5062 at 21:54:33.541289:
   ------------------------------------------------------------------------
   OPTIONS sip:172.16.100.11 SIP/2.0
   Via: SIP/2.0/UDP 172.16.100.31:5062;branch=z9hG4bKe86c.f1b595f2.0
   To: sip:172.16.100.11
   From: <sip:[email protected]>;tag=5f8cfd923bd21a2d7f298654cd327b22-a1e0
   CSeq: 14 OPTIONS
   Call-ID: [email protected]
   Max-Forwards: 70
   Content-Length: 0
   User-Agent: OpenSIPS (2.4.2 (x86_64/linux))
   
   ------------------------------------------------------------------------
send 735 bytes to udp/[172.16.100.31]:5062 at 21:54:33.542155:
   ------------------------------------------------------------------------
   SIP/2.0 200 OK
   Via: SIP/2.0/UDP 172.16.100.31:5062;branch=z9hG4bKe86c.f1b595f2.0
   From: <sip:[email protected]>;tag=5f8cfd923bd21a2d7f298654cd327b22-a1e0
   To: <sip:172.16.100.11>;tag=XD605D59D35jD
   Call-ID: [email protected]
   CSeq: 14 OPTIONS
   Contact: <sip:172.16.100.11>
   User-Agent: FreeSWITCH-mod_sofia/1.8.1+git~20180724×××60524Z~b33bc925c5~64bit
   Accept: application/sdp
   Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE
   Supported: timer, path, replaces
   Allow-Events: talk, hold, conference, presence, as-feature-event, dialog, line-seize, call-info, sla, include-session-description, presence.winfo, message-summary, refer
   Content-Length: 0
   
   ------------------------------------------------------------------------

五、後記

OpenSIPS通過keepalived進行主備切換高可用，再對FreeSWITCH進行負載均衡的試驗算是完成，但還有一些地方需要進一部完善，比如sip訊息中的From: <sip:[email protected]>，還有官方提到的來電的IP地址只能記錄到OpenSIPS的IP問題，還有OpenSIPS代理媒體的問題，還有OpenSIPS可用性檢測指令碼等。

總之，在生產應用FreeSWITCH，高可用方案是必須要考慮的，上一篇折騰筆記已經介紹了通過keepalived進行FreeSWITCH主備切換的高可用，這裡再把負載均衡的高可用方式折騰一番。也許你會問：為何不採用官方的”Corosync+Pacemaker“方式進行主備切換的高可用，主要是因為我對keepalived較熟悉一點，同時”keepalived+檢測指令碼“的切換效率也是很高的。