★ ★ IP phone call delay problem after SRST is enabled

Let's start for SRST, means Survival Remote Site Telephony. This is a feature where the router acts like an IP Telephony for some IP telephones in the network.

Right now, we already have the following network:

The hardware configuration for the MSR3620-X1 is :

1 x MSR3620-X1

1 x AC-PSR150-A1

1 x RT-HMIM-4FXO

1 x RT-HMIM-4FXS

The problem we have is that when the analog phone (1000) calls to any IP phone (for example 2023), there is a delay of 40 seconds between when you finish to dial the annex in the analog phone and the IP phone rings.

Also, when the IP phone 2023 calls IP phone 2024, there also exists a delay of 40 seconds between when you finish to dial the annex in the IP phone and the other IP phone rings.

But when any IP phone calls the analog phone, the analog phone rings immediately.

1.       First check the configuration of the router. As a Survivable server, the configuration looks fine:

#

voice-setup

 allow-connections sip to sip

 #

 voice register global

  mode alive

  max-dn 10

  max-pool 10

 sip log enable

 #

 voice register dn 1

  number 2024$

  priority 1

 #

 voice register dn 2

  number 2023$

  priority 2

 #

 voice register dn 3

  number 2020$

  priority 3

 #

 voice register pool 1

  id ip 192.168.30.16

  number 1 dn 1

  proxy ip 192.168.30.250

  priority 2

 #

 voice register pool 2

  id ip 192.168.30.10

  number 1 dn 2

  proxy ip 192.168.30.250

  priority 3

 #

 voice register pool 3

  id ip 192.168.30.70

  number 1 dn 3

  proxy ip 192.168.30.250

  priority 4

 #

 sip

  registrar 1 ip 192.168.30.250

  registrar server

 #

 dial-program

  #

  entity 1000 pots

   line 5/0

   match-template 1000$

  #

  entity 2020 pots

   match-template 2020$

  #

  entity 2023 pots

   match-template 2023$

  #

  entity 2024 pots

   match-template 2024$

 #

 2.       Check the registration result of SIP UA on Survivable server:

[H3C]display voice register pool all brief

Pool ID              IP Address      Ln DN  Number               State

-----------------------------------------------------------------------------

1    192.168.30.16   192.168.30.16   1  1   2024$                Registered

2    192.168.30.12   192.168.30.12   1  2   2023$                Registered

3    192.168.30.70                   1  3   2020$                Unregistered

3.       Check the dynamic VoIP voice entity information generated by the registration pool. From the information displayed below, it can be seen that registration pool 1 generates two dynamic VoIP voice entities 40001 and 40002. 40001 is a dynamic VoIP voice entity pointing to number 2024, and 40002 is a dynamic VoIP voice entity pointing to a remote server (Remote server). Similarly, registration pool 2 generates two dynamic VoIP voice entities 40003 and 40004. But the remote server does not have a port number.

[H3C]display voice register entity all

Entities created dynamically on register pool 1:

entity 40001 voip

 match-template 2024$

 address sip ip 192.168.30.16 port 5060

 session transport udp

 priority 1

entity 40002 voip

 match-template 2024$

 address sip ip 192.168.30.250

 session transport global

Entities created dynamically on register pool 2:

entity 40003 voip

 match-template 2023$

 address sip ip 192.168.30.12 port 5060

 session transport udp

 priority 2

entity 40004 voip

 match-template 2023$

 address sip ip 192.168.30.250

 session transport global

Entities created dynamically on register pool 3:

There are no entities in this pool.

4.       At this point, check the configuration guide and find that when the survivable server needs to transfer calls to the remote voice server for unified management, in addition to specifying the address information of the remote server in this device, in order to enable the survivable server to take over voice calls when the remote server is unreachable, the keepalive feature must be enabled on this device.

Configuring the keepalive feature

About this task

For a survivable server to regularly check the availability of the remote server, you must configure the keepalive feature.

Configuration guidelines

Perform this task only on survivable servers.

The configuration in a register pool will not be synchronized to dynamic VoIP entities in the register pool.

Procedure

1.     Enter system view.

system-view

2.     Enter voice view.

voice-setup

3.     Create a register pool and enter its view.

voice register pool pool-tag

By default, no register pools exist.

4.     Specify remote voice servers and enable the keepalive feature.

proxy ip ip1 [ port main-port-number ] [ monitor probe sip [ ip2 [ port backup-port-number ] ] ] [ priority priority ]

Enable the keepalive feature when specifying the remote server address in the following registration pool, and the problem is solved.

#

voice register pool 1

  id ip 192.168.30.16

  number 1 dn 1

  proxy ip 192.168.30.250 monitor probe sip

  priority 2

#

voice register pool 2

  id ip 192.168.30.10

  number 1 dn 2

  proxy ip 192.168.30.250 monitor probe sip

  priority 3

#