[Kamailio-Users] Transparent bridge mode

[Vikram Ragukumar]

Daniel,

Thanks once again for your reply. I present below a more detailed system 
description. The first ASCII sketch depicts the setup we have in our lab 
here and the second ASCII sketch depicts the dataflow we are working 
towards.

System setup:
-------------

  ------------
|  Internet  |
  ------------
        |
        |
  ------|------------------------
|      |  CentOS v5.4           |
|   ---|----          --------  |
|  |  NIC1  |<------>|  NIC2  | | <- Server 1
|  |  eth0  | bridge |  eth1  | |
|   --------          ----|---  |
|       Rtpproxy,Kamailio |     |
  -------------------------|-----
                           |
                           |<- Cross over cable
                           |
                     -----------
                    |CentOS v5.4|
                    | Asterisk  |  <- Server 2
                     -----------

Dataflow:
---------

------------------
|SIP Caller's     |
|Encrypted SIP    |
|(Port9090)  +    |
|UDP              |
|(Port10000-20000)|
  -----------------
     |
     |Public IP
  ---|-----------------------
| --|----          -------  |  Public IP
||  NIC1 |<------>| NIC2  | |  -----------
||  eth0 | bridge | eth1  |->-| Asterisk  |
| --|-----         --|--|-  | |CentOS v5.4|
|   v port 9090      |  |   | | Server 2  |
| --|--------------- |  |   |  -----------
||Libnetfilter_queue||  |   |
| --|--------------- |  |   |
|   v                |  |   |
| --|-------         |  |   |
||Decryption|        ^  ^   |
| -|------|--        |  |   |
|  |      v port 5060|  |   |
|  |   ---|----      |  |   |
|  |  |Kamailio|--->-   |   |
|  v   --------         |   |
|  |                    |   |
|  |UDPports            |   |
| -|--      --------    |   |
||srtp|->--|rtpproxy|->-    |
| ----      --------        |
|   Server 1,CentOS v5.4    |
  ---------------------------

Questions:
----------
1) Is it common practice to implement "Decryption" and "srtp" as shown 
in the dataflow diagram? If not, what is a more appropriate place to 
implement them ?
2) Once deployed, will such as system be capable of handling several 
hundreds or thousands of calls ?

Wish you all a Merry Christmas and a Happy New Year.

Thanks and Regards,
Vikram.

PS : Here is the script used to setup the bridge between eth0 and eth1

brctl addbr br0
brctl stp br0 on
brctl addif br0 eth0
brctl addif br0 eth1
ifdown eth0 1>/dev/null 2>&1
ifdown eth1 1>/dev/null 2>&1
ifconfig eth0 0.0.0.0 up
ifconfig eth1 0.0.0.0 up
ifconfig br0 64.221.148.221 netmask 255.255.255.224 up
route add default gw 64.221.148.220
for file in br0 eth0 eth1
do
echo "1" > /proc/sys/net/ipv4/conf/${file}/proxy_arp
echo "1" > /proc/sys/net/ipv4/conf/${file}/forwarding
done;
echo "1" > /proc/sys/net/ipv4/ip_forward


Daniel-Constantin Mierla wrote:
> 
> 
> On 12/18/09 10:08 PM, Vikram Ragukumar wrote:
>> Daniel,
>>
>> Thank you for your reply. Let me briefly explain what i am trying to 
>> achieve over here.
>>
>> _____  eth0  _____    eth1   ______
>> |_____|------|_____|--------|______|    Internet        
>> Server1            Server2
>>                    2 NIC's             1 NIC
>>                                            (Public IP)
>>
>> I show above a sketch of the desired setup.
>>
>> Server1 - Runs Kamailio and rtpproxy. It has 2 NIC's installed.
>> Server2 - Runs Asterisk. It must be assigned a Public IP.
>>
>> I need to use rtpproxy to intercept data being sent to Server 2, 
>> process them and let them continue along their original path. Are 
>> there any references you can point me to, that show how to use 
>> rtpproxy to achieve this bridging? Does the connection between eth1 of 
>> Server1 and eth0 of Server2 have to made using a crossover cable ?
> 
> probably your diagram is not displayed properly by the email client, 
> since I do not really get what you wanted to draw.
> 
> However, in the kamailio server, if you have two network interfaces, run 
> kamailio to listen on both and rtpproxy in bridging mode between them. 
> Then rtpproxy will get packets coming on eth0 and send onver eth1 and 
> viceversa. I gave you the path in the source three where you find an 
> example to start with (in my previous email).
> 
> Cheers,
> Daniel
> 
> 
> 
>>
>> Daniel-Constantin Mierla wrote:
>>> Hello,
>>>
>>> On 12/18/09 12:38 AM, Vikram Ragukumar wrote:
>>>> Hello All,
>>>>
>>>> I am trying to setup a test scenario, where i have Kamailio and 
>>>> rtpproxy running on one CentOS box (Server1) and i have Asterisk 
>>>> running on another CentOS box (Server2). Server1 has 2 NIC's eth0 
>>>> and eth1 that are both assigned Public IP's. There is a transparent 
>>>> bridge br0 connecting eth0 and eth1 which also has its own Public 
>>>> IP. Finally eth0 on Server2 also has a Public IP.
>>>>
>>>> Server2 must be assigned a Public IP.
>>>>
>>>> My goal is to modify rtpproxy so that i can intercept packets 
>>>> traveling to Server2, process them and let them resume along their 
>>>> original path.
>>>> I would like to know if there is another way of setting this up so 
>>>> that i dont use as many Public IP's ?
>>>> Do any of you see a problem with this setup, things that may not 
>>>> work eventually, or any other concerns ?
>>>>
>>> rtpproxy can do bridging of two interfaces -- see the example cfg:
>>>
>>> modules/nathelper/examples/alg.cfg
>>>
>>> Cheers,
>>> Daniel
>>>
>>
>>
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>