Cisco Cisco Content Switching Module Prospecto
Solution Overview
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Technical Setup and Details
Microsoft Terminal Services Session Directory provides functions that allow a group of terminal
servers to coordinate the reconnection of disconnected sessions from clients. The Remote
Desktop Protocol (RDP) uses routing token information to redirect client sessions to Microsoft
Terminal Servers.
The dynamic routing token will go in the initial data packet of the second (redirected) connection. It
is possible that there will be no routing token. However, if a routing token is present, it will begin at
TCP payload decimal byte offset 11 (0 based) of the first packet that the client sends to the server.
Port 3389 is the standard terminal server connection port. It is also configurable by the user.
Introduced in the Cisco Catalyst 6500 CSM Software Version 4.2, a new environment variable,
MSTS_RDP_VIP_LIST, can be defined to contain a list of Versatile Interface Processor (VIP)
names that support the Microsoft Terminal Services Remote Desktop Protocol (MSTS-RDP). This
new capability makes the Cisco CSM token aware, allowing for improved capability and reliability
for terminal server clients.
The length of the variable is limited to 256 bytes. An MSTS-RDP-enabled VIP is treated as a Layer
7 virtual server (vserver). If the Layer 7 load balancer fails to identify a real server from the routing
token, or if the routing token is empty, the CSM falls back to whatever load-balancing algorithm is
configured for that vserver.
The addresses and topology in the following configurations are presented only as examples for the
purpose of this document. This configuration is a simple routed Cisco CSM configuration and does
not include any other configurations that are unique to the Cisco Catalyst 6500 Series or any other
topology beyond this sample configuration. Also, the vserver and server farm names are examples
only for the purpose of this document and may be different for each environment.
The following commands show how to configure the MSTS_RDP_VIP_LIST variable for a Cisco
CSM that is installed in slot 2. The variable name must be entered exactly as in the example, and
the VIP names must match the vserver names desired to support token redirection.
Router# configure terminal
Enter configuration commands, one per line. End with
CNTL/Z.
Router(config)# mod csm 2
!!! configuring serverfarm
Router(config-module-csm)# variable MSTS_RDP_VIP_LIST VIP_1
Router(config-module-csm)# end
In this sample configuration, the terminal servers that are listed in the server farm
TS_RDP_POOL1 should have their gateways set to the IP address or alias address of the server
VLAN to avoid direct server return. Note that the environment variable MSTS_RDP_VIP_LIST is
also set to enable Session Directory token awareness on each VIP that is listed in the variable.
Figure 1 shows the topology of the sample network.