ETSI TISPAN, the European standards body for the fixed-line half of the Next Generation Network world, this week agreed terms with mobile standards body, the 3GPP, on how to prevent the fixed and mobile versions of IMS from wandering apart.

IMS originated with TISPAN before being taken up by 3GPP for UMTS R99/5, but since then, the fixed-line and co-ax people have become more interested in the idea again. Both standards committees have been co-existing peacefully but perhaps not as happily as one might like.

The development of a Common IMS – common to fixed, cable and mobile networks – is going to go ahead in a 3GPP group, Services Specification SA-1, after a decision at last week’s 3GPP plenary meeting in Busan, South Korea.

The job has to be done by the end of 2007 in order to be ready for the launch of UMTS Release 8, or “the IMS you can deploy” as some people call it.

Stephen Hayes, of Ericsson and 3GPP TSG-SA chair, said: “Over the next few months we must stabilise the Release 8 requirements and absorb the incoming Common IMS work.”