[Openstack] Public network access to VMs without NAT/floating IP

James Kino james.kino123 at gmail.com
Thu Oct 3 06:55:40 UTC 2013


The use case description is as follows,

Application protocol : SIP (http://www.ietf.org/rfc/rfc3261.txt)
Domain: Telecom

SIP client <------> Application running in VM hosted on Openstack

SIP Clinet  (IP_WEB)(  on web) <-----> Openstack NAT (IP_FLOAT) <-------->
Private IP on VM with application(IP_PRIVATE)

- SIP client makes a call  and request is send to IP_FLOAT which will be
translated and send to IP_PRIVATE on  VM(SIP APP)

SIP Client(IP_WEB)---- INVITE (IP_FLOAT)-->Openstack NAT-->IP_PRIVATE (VM)

Now VM  responds with 200OK

VM (IP_PRIVATE) -->200 OK --> NAT -->SIP Client(IP_WEB)

During this dialogue SIP packet Record Routing header ( RR) records the

Now the SIP client  ACKnowledge the 200K but with IP destined to IP_PRIVATE
of SIP App in Openstack

SIP client ( IP_WEB) ---- ACK ( to IP_PRIVATE) ---> NAT ( ********packet
routing fails as its sent to Private IP instead of NAT floating IP******* ).

This is a standard 3GPP implementation telecom application.

So, I would like to know if there is possibility to access SIP application
on openstack  from SIP client using a routed network  without NAT floating

-- James

For telecom application use cases using SIP protocol(
http://www.ietf.org/rfc/rfc3261.txt) records the IP in it packets where it
traverse through.

In case of openstack cloud implementation, VM running with this application
has internal private associated to a floating IP which is not hosted on
this VM. So, when SIP packet
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