Citrix has sacked Expand Networks from its Business Partner Alliance, saying that Expand's Compass WAN optimisation devices compete too closely with the NetScaler range which Citrix bought last year.

The decision came to light when Expand was barred from taking part in last week's Citrix iForum event in Edinburgh.

"We would like to have attended iForum, but unfortunately there seems to have been a decision by Citrix that we weren't as good a fit as a partner as they'd like," said Expand's senior marketing director Amy Peraza.

NetScaler and Compass are technologically different - NetScaler is in the application delivery sector, handling tasks such as server offload and load balancing, whereas Compass has more to do with WAN optimisation and WAFS.

Many organisations will need both technologies, as shown by Juniper's acquisition of both Redline and Peribit, and by Citrix's continued alliance with Packeteer, which sponsored a reception at iForum last week. However, the difference isn't always clear to potential customers, Peraza said.

"NetScaler is data centre-only and predominantly HTTP, and has none of the other support we can offer, such as WAFS," she claimed. "Customers say to us, 'NetScaler is competitive' and we have to say no, it's very different."

"Traditional WAN optimisation vendors work solely on the WAN and not on server bottlenecks," agreed Frank Lyonnet, product management director at network performance specialist and Citrix partner Ipanema Technologies.

"NetScaler mainly addresses server bottlenecks, similar to Fineground [now owned by Cisco] and Redline," he added. "There is a bit of overlap - you always find some - but really it's two different topics."

Lyonnet said he suspected that the Citrix-Expand split was due more to commercial issues than technology overlap. "There is a lot of confusion in the market though, and that can lead to difficulty in positioning products within clients," he said.

Expand signed up as a Premier Member of Citrix's Business Partner Alliance in July 2000, and claims over 200 Citrix-using customers. More recently it has worked to broaden the business appeal of its systems, and it's this that seems to have rankled with Citrix.

Asked why it sacked Expand while keeping Packeteer, Ipanema and others on board, Citrix issued a statement, saying that it "regularly conducts reviews with alliance partnerships to ensure that a mutual ongoing investment still makes sense for both parties.

"When it last conducted such a review, it had several discussions with Expand and jointly concluded that there was an increasing overlap between its business goals and those of Citrix's rapidly growing Application Networking Group."