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Windows Server 2008: preview, part 2

Alan Stevens ZDNet.co.uk

Published: 16 Jul 2007

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Go to section: Virtualisation Terminal Services, NAP and more

Terminal time
Another big change in Windows Server 2008 is a major revamp of Terminal Services, which Microsoft now likes to refer to as 'presentation virtualisation'. The most notable change here is a bundling of features previously only available through third-party add-ons, from companies like Citrix. In particular, the ability to host individual applications as well as complete desktops via a module called TS RemoteApp. With TS RemoteApp, individual applications can be integrated directly into the local desktop or accessed via a web portal with minimal setup required at the client end.

Printing, another long-time bugbear, is similarly addressed by a new TS Easy Print option where the drivers on the local PC or terminal can be used rather than having to install new server-side drivers into hosted sessions. There’s also a new Terminal Services Gateway to deliver hosted sessions securely over the internet using HTTPS rather than having to configure complex VPN connections.

An updated implementation of the Remote Desktop Protocol is required to support these features — RDP 6.0 — with an updated client included with both Windows Server 2008 and Vista. Versions are also available for Windows Server 2003 and Windows XP SP2, and all incorporate the previously separate ActiveX component for browser-based access.

The new RDP client also adds support for multiple monitors and 32-bit colour displays with resolutions of up to 4,096 by 2,048. Even with these bandwidth-consuming enhancements, Microsoft claims big improvements in performance thanks to a new compression algorithm, claining that multimedia applications can now be hosted using Terminal Services; Plug and Play redirection for USB and other local devices is another useful addition here.

Windows takes a NAP
Yet another new feature in Windows Server 2008 is Network Access Protection (NAP), which is designed to stop infected or poorly configured clients gaining access to a Windows network. Not to be confused with the much simpler Network Access Quarantine Control in Windows Server 2003, NAP is a more pervasive technology designed to protect not just VPN connections, but general IPsec-protected traffic, 802.1x-authenticated connections and those configured using DHCP.

To do this, NAP implements a system of System Health Agents (SHAs) and System Health Validators (SHVs) to perform checks on any PC trying to connect to the network. Working together, these will make sure that each system has the required security patches installed, appropriate antivirus software, a desktop firewall and so on. If it doesn't, NAP can redirect the connection to a quarantine network (typically, using VLAN technology), where, optionally, remediation servers can be configured to bring the client PC into compliance before allowing it onto the network proper.

NAP consists of both client- and server-side components with a client included in Windows Vista and also available for Windows XP SP2. The server-side components are integrated into Windows Server 2008, with System Center management additions also being developed.

Microsoft claims that NAP will be compatible with similar network access control technologies such as Cisco’s Network Admission Control (NAC) and others, but as currently implemented it doesn’t provide very much in the way of granularity. For example, NAP can be used to check whether Windows Firewall is running, and switch it on if it has been disabled. However, it can’t check the firewall's configuration or change the rules setup. Instead, Microsoft is relying on third parties to provide a lot of the more detailed health checking and enforcement functionality.

A lot more besides
Among numerous other enhancements in Windows Server 2008 are major changes to the Windows Server Clustering Services. This is now renamed Windows Server Failover Clustering (WSFC) to better reflect the fact that it’s a disaster protection technology rather than high-performance clustering as provided by Microsoft SoftGrid.

The reliance on a Storage Area Network (SAN) to enable volume sharing between nodes is completely removed in WSFC. You can still use a SAN, but any network share can be used instead, including those on NAS appliances, making clustering a lot more attractive to smaller businesses. Moreover, you no longer have to buy expensive hardware configurations expressly certified for clustering, as a new validation tool can simply check that it will work with what you’ve got. Support for clustering of virtual servers has also been added, while cluster setup and management is vastly simplified in WSFC. All of this should extend the appeal of the technology.

Larger customers are also catered for with support for up to 16 nodes per cluster, larger volumes (greater than 2TB) and the fact that clustered nodes no longer have to be on the same subnet. As such, WSFC can, in theory, now be implemented over ordinary router links instead of having to configure a supporting VLAN. With configurable heartbeats, it should therefore be possible to extend a cluster over much longer distances.

Elsewhere, the TCP/IP stack gets a makeover in Windows Server 2008, with native IPv4 and IPv6 support plus improved performance through hardware acceleration and auto-tuning of the send/receive window to suit prevailing network conditions. The associated network processing can also be balanced across multiple CPUs/cores rather than just one as in previous implementations (Receive Side Scaling), with new Quality of Service (QoS) facilities to prioritise traffic. Filtering at all layers of the protocol stack is also added to support the enhanced firewall built into the new OS.

As already mentioned in the first part of this preview, the management tools in Windows Server 2008 are vastly improved, with a lot more integration and a more intuitive grouping of functionality. A lot of work has also gone into improving performance, although no concrete claims are being made at present and for maximum benefit Windows Vista is required on the client side. Moreover, there could still be a few changes between now and the revised February launch, making it very much a case of 'watch this space' until that happens.

 

Go to section: Virtualisation Terminal Services, NAP and more

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