Forum Discussion

Paco_GP's avatar
Paco_GP
Icon for Nimbostratus rankNimbostratus
May 19, 2017

SIP ALG Configuration

Hello,   I am trying to configura a load balancing for a SIP application, basically a Polycom device registring a Cisco CUCM. THE SIP INVITES packets are reaching without problem the end CUCM serv...
application delivery
BIG-IP
LTM
Nazir_52641's avatar
Nazir_52641
Icon for Cirrus rankCirrus
May 19, 2017

Hi Paco GP,

You can insert/update/delete SIP headers using iRules.

You can write a mini-SIPProxy functionality in F5 by doing the following
a) Virtual server with SIP Profile
b) Add iRule to virtual server which does the following
   i) Add Via header on receiving request/ remove Via header during response
   ii) For REGISTER request update Contact header with F5 NAT IP and on receiving 200 OK for REGISTER you may have to change the Contact header

Following SIP events are triggerred

1) SIP_REQUEST

2) SIP_REQUEST_SEND

3) SIP_RESPONSE

4) SIP_RESPONSE_SEND

You can insert SIP header using command

SIP::insert Via "actual SIP header content"

Hopes this help. You have to understand how F5 does connection mapping for SIP and how request are routed.

Thanks

Syed Nazir

  • Paco_GP's avatar
    Paco_GP
    Icon for Nimbostratus rankNimbostratus
    May 23, 2017

    Hello Nazir,

     

    Thank you so much for the hint. I thought I was going to be able to make it without using irules but I will try with your proposal.

     

    Regards Paco

     

  • torzillo_89761's avatar
    torzillo_89761
    Historic F5 Account
    Oct 07, 2018

    If you configure this with CGNAT, you can apply an LSN pool and then the SDP information is modified automatically by the ALG profile without requiring any iRules.