Guidance has been produced by NICC for the use and secure implementation of SIP (Session Initiation Protocol) ALG (Application Layer Gateways).
NICC is the the technical forum for the UK communications sector that develops interoperability standards for public communications networks and services in the UK.
SIP ALG is often enabled in routers to prevent problems caused by Network Address Translation (NAT) and firewall functions that interfere with the SIP traffic. This can be an issue for VoIP calls, causing phone registrations, inbound calls and call transfers to fail.
Many routers are shipped with SIP ALG enabled by default with limited simple guidance to disable this feature, which causes disruption for consumers while also being incredibly time consuming and expensive for ITSPs and ISPs to fix.
The guidance produced by NICC recommends:
SIP ALGs being disabled by default
SIP ALGs being easily enabled or disabled by end-users as part of the normal administration of the equipment
Configuration status displays clearly indicating that a SIP ALG is either disabled or enabled
Eli Katz, chair of ITSPA, has welcomed the guidance. “This is an issue that has long been a problem for ITSPA members. We are very pleased that they decided to undertake a review into this area, resulting in the production of this beneficial guidance.
“The problems around SIP ALG hurts us all, but particularly consumers who understandably find these technical issues incredibly frustrating. The aim now is to educate the internet industry to ensure that future router purchases bear this guidance in mind and resolve these unnecessary problems.”