[SIPForum-discussion] SIPForum-Firewall influence on SIP

[Jason L. Nesheim]

That would depend on the firewall or router in question and whether NAT is being used. 

Some firewalls such as the Cisco PIX, ASA, and routers with NAT have SIP Application Layer Gateways enabled by default. These ALG engines will manipulate SIP packet contents with the intent to allow NAT traversal to function. Another situation to consider are firewalls with built in back to back user agents that have a licensed call capacity. The Ingate Firewall (http://www.ingate.com/firewalls.php) would be an example of this case. 

The DSCP/ToS code points on SIP packets may be manipulated by policy maps on routers in the network. Many service providers remark SIP and RTP packets at the network edge with what they use to designate the priority queue. It is also possible in some networks that the bandwidth allocated to SIP and RTP queues becomes exhausted as load increases and leads to dropped packets. This typically only occurs if the QoS policies on the routers are improperly configured but is something to be aware of. 




-- 
Jason Nesheim, Senior Network Design Engineer 
Cytek 
www.cytek.biz / 702-885-0815 


----- Original Message ----- 
From: "AMIT ANAND" <amiit.anand at gmail.com> 
To: "sri kuma" <cyberdyne at mail.com> 
Cc: discussion at sipforum.org 
Sent: Friday, July 11, 2008 10:07:32 AM GMT -08:00 US/Canada Pacific 
Subject: Re: [SIPForum-discussion] SIPForum-Firewall influence on SIP 

Hi Sri, 

There should be no effect as such but the Packet Forwarding Rate of that firewall must be appropriate as per the simultaneous call you want to run. 

Amit Anand 
91-9910211901 


On Sun, Jul 6, 2008 at 11:11 AM, sri kuma < cyberdyne at mail.com > wrote: 


hi , 
I woulld like to know whether a firewall(SIP aware) would affect the SIP packets traversal if the number of calls increases and is there 
any influence of the intermediate routers on the SIP ie does the QOS settings in the routers affect the SIP packets 

thank you 


-- 
Be Yourself @ mail.com ! 
Choose From 200+ Email Addresses 
Get a Free Account at www.mail.com ! 
_______________________________________________ 
This is the SIP Forum discussion mailing list 
TO UNSUBSCRIBE, or edit your delivery options, please visit http://sipforum.org/mailman/listinfo/discussion 
Post to the list at discussion at sipforum.org 



_______________________________________________ This is the SIP Forum discussion mailing list TO UNSUBSCRIBE, or edit your delivery options, please visit http://sipforum.org/mailman/listinfo/discussion Post to the list at discussion at sipforum.org 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sipforum.org/pipermail/discussion/attachments/20080711/a111c8ac/attachment-0002.html>