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farm. The session directory keeps a list of sessions indexed by username and server name. This enables a user, after disconnecting a session, to reconnect to the correct
Terminal Server where the disconnected session resides in order to resume working in that session. This reconnection will work even
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multi-layer switches officially don't support MS NLB in multicast. Even though it does work, it will lead to high CPU utilization - affecting (other) traffic in the switch and on other switches one might have other limitations such that the switch to which the NLB NICs are connected can't be the same
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and these same examples can be used for switches from many other vendors. As with NLB in unicast mode: incoming traffic towards the cluster will be flooded to all ports in the switch/VLAN and not all vendors support this setup. To limit the flooding, MS NLB now supports IGMP which should lead to the
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Session balancing does just that, it balances sessions across each WAN link. When Web browsers connect to the
Internet, they commonly open multiple sessions, one for the text, another for an image, another for some other image, etc. These sessions can be balanced across the available connections.
156:'s in the NLB cluster use this same MAC address. This setup will cause all incoming traffic for the cluster to be flooded to all ports of the switch as unknown unicast frames: even to hosts that are not joining in the cluster. To keep flooding minimal you would need to use a dedicated
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to spread traffic over multiple hosts without the need for a hardware based load balancer, e.g. when you host a busy web-server application where a single host wouldn't be able to manage all the traffic. And in more recent applications it would be used in
Windows clusters for
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In addition to the before mentioned, to configure a terminal server cluster, one needs a load-balancing technology such as
Network Load Balancing (NLB) or DNS round robin. A load balancing solution will distribute client connections to each of the terminal servers.
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application only uses a single session so it is not balanced; however if a secondary FTP connection is made, then it may be balanced so that the traffic is distributed across two of the various connections and thus provides an overall increase in throughput.
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entry on the router (layer 3) in the attached network. Not all vendors will allow you to create an ARP entry where you use a unicast IP address and a multicast MAC address. Cisco publishes some examples how to set up MS NLB on
Catalyst switches running
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operating at 1.5 Mbit/s. They wish to add a second broadband (cable, DSL, wireless, etc.) connection operating at 2.5 Mbit/s. This would provide them with a total of 4 Mbit/s of bandwidth when balancing sessions.
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which can either be built into the system, or provided by an external service or system. Having the dynamic DNS service within the system is generally thought to be better from a cost savings and overall control point of view.
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records is one form of cluster load balancing. It works by creating multiple host records (usually A and/or AAAA) for one machine. As clients make requests, DNS rotates through its list of records.
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Microsoft has also purchased a technology that it renamed
Network Load Balancing (NLB) that allows for efficient utilization of multiple network cards. MS NLB can be configured in
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Finally, most network load balancing systems also incorporate the ability to balance both outbound and inbound traffic. Inbound load balancing is generally performed via
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so that in the event of a WAN link outage, access to network resources is still available via the secondary link(s). Redundancy is a key requirement for
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Terminal Server
Session Directory is a feature that allows users to easily and automatically reconnect to a disconnected session in a load balanced
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This capability balances network sessions like Web, email, etc. over multiple connections in order to spread out the amount of
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215:. Clusters can use network load balancing whereby simultaneous cluster request are distributed between cluster servers.
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user, thus increasing the total amount of bandwidth available. For example, a user has a single WAN connection to the
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272:"Microsoft purchases clustering company | Windows Server content from Windows IT Pro"
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using this MAC address with the cluster IPv4 address so one would need to create a static
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Trying to limit switch flooding from a
Microsoft Windows Network Load Balacing (NLB)
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Additionally, network load balancing is commonly used to provide network
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MAC address. The hosts is in the cluster will never send traffic to the
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plans and generally used in conjunction with critical applications like
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if the user connects from a different client computer.
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switches learning which ports are actually using the
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is the ability to balance traffic across two or more
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211:When multiple servers are joined to create a
120:MS NLB was introduced for the first time in
113:mode where in multicast mode you can enable
27:Ability to balance computer network traffic
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343:KB283028: IGMP Snooping support on NLB
176:address of the cluster is linked to a
365:, February 2012. Visited: 8 June 2013
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310:MS NLB in unicast and multicast mode
152:) to a virtual MAC address and all
144:mode MS NLB reassigns the stations
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341:Microsoft Support knowledge base:
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203:switch that does the IP routing.
168:Another option is to make NLB in
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323:Catalyst configuration examples
243:Network Load Balancing Services
148:(which applies to the clusters
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37:links without using complex
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386:Load balancing (computing)
248:Load balancing (computing)
308:VMware knowledge base:
354:Dell Tech Communities:
31:Network load balancing
18:Network Load Balancing
381:Internet architecture
345:, visited 8 June 2013
332:, visited 8 June 2013
299:, visited 8 June 2013
207:Server load balancing
312:, visited 8 May 2013
131:Microsoft SQL Server
79:business continuity
361:2013-10-05 at the
328:2014-01-31 at the
172:mode. The unicast
200:Dell PowerConnect
196:multicast address
160:for the cluster.
122:Windows NT server
39:routing protocols
16:(Redirected from
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363:Wayback Machine
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136:Unicast mode
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94:dynamic DNS
375:Categories
282:2015-10-18
259:References
150:IP address
75:redundancy
178:multicast
170:multicast
111:multicast
50:bandwidth
359:Archived
326:Archived
295:TechNet
237:See also
58:Internet
321:Cisco:
213:cluster
142:unicast
127:Hyper-V
107:unicast
182:switch
109:or in
41:like
174:IPv4
158:VLAN
87:VoIP
85:and
83:VPNs
191:IOS
186:ARP
154:NIC
140:In
129:or
67:FTP
65:An
54:LAN
43:BGP
35:WAN
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