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Table Of Contents
Release Notes for Catalyst 6500 Series Content Switching Module Software Release 3.1(9)
Open Caveats in Software Release 3.1(9)
Resolved Caveats in Software Release 3.1(9)
Open Caveats in Software Release 3.1(8)
Resolved Caveats in Software Release 3.1(8)
Open Caveats in Software Release 3.1(7)
Resolved Caveats in Software Release 3.1(7)
Open Caveats in Software Release 3.1(6)
Resolved Caveats in Software Release 3.1(6)
Open Caveats in Software Release 3.1(5)
Resolved Caveats in Software Release 3.1(5)
Open Caveats in Software Release 3.1(4)
Resolved Caveats in Software Release 3.1(4)
Open Caveats in Software Release 3.1(3)
Resolved Caveats in Software Release 3.1(3)
Open Caveats in Software Release 3.1(2)
Resolved Caveats in Software Release 3.1(2)
Open Caveats in Software Release 3.1(1a)
Resolved Caveats in Software Release 3.1(1a)
Server and Gateway Health Monitoring
Cisco IOS Software Documentation Set
Obtaining Technical Assistance
Cisco Technical Support Website
Definitions of Service Request Severity
Obtaining Additional Publications and Information
Release Notes for Catalyst 6500 Series Content Switching Module Software Release 3.1(9)
November 2, 2004
Previous Releases—3.1(8), 3.1(7), 3.1(6), 3.1(5), 3,1(4), 3,1(3), 3,1(2), 3.1(1a), 3.1(1)
This publication describes the features, modifications, and caveats for the Catalyst 6500 series Content Switching Module (CSM) software release 3.1(9) operating on a Catalyst 6500 series switch with Cisco IOS software Release 12.1(13)E3 or Catalyst operating system software 7.5 or higher.
Note
Except where specifically differentiated, the term "Catalyst 6500 series switches" includes both Catalyst 6500 series and Catalyst 6000 series switches.
Contents
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System Requirements
This section describes the system requirements for the Catalyst 6500 series CSM software release 3.1(9).
Memory Requirements
The Catalyst 6500 series CSM memory is not configurable.
Hardware Supported
The CSM is now supported with either with a Supervisor Engine 1A (MSFC required), Supervisor Engine 2 (MSFC required), or Supervisor Engine 720 (the MSFC is not optional on the Sup720), and a module with ports to connect server and client networks.
Note
Caution
Software Compatibility
Table 1 and Table 2 list the CSM software release compatibility.
The minimum software release that is listed is required to support the CSM hardware with a given supervisor engine to perform basic CSM configuration. The recommended software release is the base release to support new commands for a given CSM release.
Software Release 3.1 Features
Table 3 lists the features that have been added to the CSM software in release 3.1.
Feature Set
Table 4 describes the CSM features and software descriptions.
New and Changed Information
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A new environment variable, REAL_SLOW_START_ENABLE, is included in the 3.1(9) software release to control the rate at which a real server becomes operational when it is put into service. This new variable is only available for a server farm that has been configured with the least connection predictor.
The configurable range for this variable is 0 to 10. The setting of 0 disables the slow start feature. The value from 1 to 10 specifies how fast the newly activated server should become operational. The value of 1 is the slowest rate. The value of 10 specifies that the CSM would assign more requests to the newly activated server. The value of 3 is the default value.
If the configuration value is N, the CSM assigns 2 ^ N (2 raised to the N power) new requests to the newly active server at startup (assuming no connections were terminated at that time). As this server finishes or terminates connections; more connections are assigned. Normal connection assignments resume when the newly activated server has the same number of open connections as the other servers in a serverfarm.
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http://www.cisco.com/cgi-bin/tablebuild.pl/cat6000-intellother
The following file contains the sample scripts: c6slb-script.3-1-6.tcl.
Limitations and Restrictions
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In all releases, when the MINCONNS value is set, once a real server has reached the maximum connections (MAXCONNS) state, no additional session is balanced to it until the number of open sessions to that real server falls below MINCONNS. With the no MINCONNS value set in release 1.1(1), no additional session would be balanced until the number of open sessions to that real server falls to 0. With no MINCONNS value set in release 1.2(1), no additional session is balanced until the number of open sessions falls below MAXCONNS.
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If a health probe is configured on a real server without a configured TCP or UDP port, the CSM chooses the TCP or UDP port to probe from the virtual servers with which the real server is associated. If neither the real server nor the virtual server has a configured port, the CSM simply ignores any configured probes requiring ports to that real server.
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Caveats
These sections describe the open and resolved caveats in CSM for all 3.1(x) software releases:
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Open Caveats in Software Release 3.1(9)
Note
This section describes known limitations that exist in CSM software release 3.1(9).
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The CSM reserves 141 KB of memory on the PowerPC control processor for each TCL scripted health probe item configured on the CSM. A probe item is an instance of a probe object associated with a single real server.
This memory usage is much higher than anticipated. The PowerPC "Available Memory" counter from the show module csm slot tech-support utilization command should not be less than 40 MB.
Workaround: None.
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When you configure a CSM in a fault-tolerant configuration and you have a fault-tolerant priority of 254, the CSM may take over the active role from the other CSM at startup. This situation could occur even when the fault-tolerant preempt option is disabled.
Workaround: Use fault-tolerant priority values lower than 254.
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The CSM does not support pipelines (multiple HTTP requests sharing the packet boundary) with the persistent rebalance feature.
Workaround: None.
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The CSM might not replicate the sticky entries for sticky group zero when it is configured under the virtual server. Because of the configuration download order, the active and redundant CSM may be assigned different group numbers when a group was not specified in the configuration.
Workaround: Configure a sticky group with a specific number, and assign it to the virtual server.
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When using Cisco IOS Release 12.1(19)E or later with CSM 3.1(x) software, the sticky timeout is displayed as zero for all sticky entries, and the total entries count (CurrCount) for each sticky is also displayed as zero. These counters are supported only in CSM software release 3.2(1).
Workaround: Use the corresponding Cisco IOS software Release 12.1(13)E, which displays the configured timeout instead of the current timeout.
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The set port cdp, set port trap, set spantree portpri, and set spantree link-type restricted CSM port commands return the "failure" message instead of the "feature not supported" message.
Workaround: None.
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Token Ring and FDDI VLANs should not be configured on CSM trunk ports.
Workaround: None.
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The CSM drops packets because the multilayer switch (MLS) module and the multilayer switch feature card (MSFC) use different MAC addresses. This problem remains in software releases earlier than the Catalyst operating system softare release 7.5.1. If any Supervisor Engine 2 in the switch is still operating with a software release earlier than the Catalyst operating system software release 7.5.1, and the traffic is forwarded by that switch, the CSM drops the packet.
Workaround: None.
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During a CSM reset, the show module command displays that the module is faulty when it should be displayed as "Other."
Workaround: None.
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When Internet Group Management Protocol (IGMP) snooping is enabled on the Catalyst 6500 series switch, some CSM connection replication frames might be dropped.
Workaround: Disable IGMP snooping on both the active and standby CSM modules. To disable IGMP snooping, use the no ip igmp snooping command in global configuration submode on the Catalyst 6500 series switch.
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TCL script probes are sensitive to network overload, congestion, and delay.
Workaround: To avoid spurious health monitoring results in which real servers are considered unhealthy due to network delay or congestion, we recommend that you set the "retry" to a value that is greater than one for all TCL script probes.
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Established FTP connections are not replicated to the redundant CSM when the redundant CSM becomes operational. To enable an FTP connection for replication from an active CSM to a redundant CSM, the redundant CSM must be operational at the time the FTP connection is opened. If the FTP connection is opened prior to the redundant CSM booting and becoming operational, the FTP connection never replicates to the backup.
Workaround: None.
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For optimal performance of CSM TCL script probes and TCL standalone scripts, we recommend the following:
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When multiple CSM users perform a do copy xx running-config from a CSM submode in Cisco IOS software, the next command entered will fail with the message "% CSM parser state not found." This problem occurs only if the file copied to running-config contains at least one CSM command. When the CSM command in the file copied to running-config is entered, it overwrites the current CSM configuration parser state.
Workaround: Do not perform a do copy xx running-config operation from a CSM configuration submode. You can also exit out to the top level configuration submode and then reenter the desired CSM configuration submode.
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Beginning with Cisco IOS software Release 12.1(13)E, it is possible for multiple users to simultaneously issue configuration commands for the same CSM. When you use this capability, it is possible to corrupt the configuration. In particular, if one user changes the "type" of an object while another user is simultaneously configuring that same object, the configuration will be corrupted. For example, if a user changes probe "FOO" from type "script" to type "http" while another user is configuring probe "FOO," the configuration will be corrupted.
Workaround: Ensure that multiple users do not simultaneously modify the CSM configuration with different object types.
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Some FTP connections may not replicate. For example, an FTP connection through an active CSM is not replicated if no data channel has been set up for the connection. Data channels are typically established when the client uses a get or put command on a file or performs a directory listing.
Workaround: None.
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CSM software release 3.1(2) does not support the Real Time Streaming Protocol (RTSP) and User Datagram Protocol (UDP) streaming when a client NAT is enabled. If this configuration is set up, the server attempts to open a UDP connection. Some RTSP clients then fall back to interleaved mode (inline TCP). This mode works in the application software, although the connection is sent to fastpath.
Workaround: None.
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The CSM does not support creating more than 127 virtual servers with the same virtual IP (VIP) address, even though the CLI does allow you to configure more than 127 virtual servers. If you use the CLI to configure more than 127 virtual servers, the 128th and subsequent virtual servers will not function properly.
Workaround: Do not configure more than 127 virtual servers on the same VIP.
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In firewall configurations using an HTTP 1.1 redirect virtual server, a connection going through the firewalls may remain open after a redirect virtual server connection is established.
Workaround: None. This connection closes when it times out.
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You cannot configure different fault-tolerant pairs to use the same fault-tolerant VLAN.
Workaround: Use a different fault-tolerant VLAN for each fault-tolerant CSM pair.
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Entering the clear interface gigabit slot/port command for a CSM gigabit port may not clear the counters.
Workaround: None.
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In the CSM, it is important that packets transmitted from the CSM toward a client (server) are transmitted on the same VLAN as packets received by the CSM from that same client (server). This constraint may be satisfied as follows:
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Router(config)# module csm 4Router(config-module-csm)# vlan 10 clientRouter(config-slb-vlan-client)# gateway 1.1.1.1Router(config-module-csm)# vlan 20 clientRouter(config-slb-vlan-client)# gateway 2.2.2.2To make this configuration valid, delete the gateway command from either VLAN 10 or VLAN 20.
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Router(config)# module csm 4Router(config-module-csm)# vlan 10 clientRouter(config-slb-vlan-client)# route 10.0.0.0 255.255.255.0 gateway 1.1.1.1For load balancing to function properly, all traffic arriving from the 10.0.0.0/24 subnet must reach the CSM through VLAN 10.
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The output from the show interface gigabit slot/port command may erroneously indicate that one or more of the CSM gigabit ports are down.
Workaround: Disregard the display.
Resolved Caveats in Software Release 3.1(9)
Note
This section describes the caveats resolved in CSM software release 3.1(9).
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When you configure the CSM to perform Global Server Load-Balancing (GSLB) for a destination IP that is also a local Virtual IP (VIP) on the module, the CSM does not properly take this local VIP out-of-service. The CSM keeps responding to the DNS request with a VIP address that is out-of-service. The CSM also reports to KAL-AP (keep-alive probe) with the incorrect load value for this local VIP.
Workaround: None.
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When you perform an SNMP MIB request for the packet counter "ifHCOutUcastPkts," the CSM Gigabit interfaces may display incorrect 64-bit values.
Workaround: None.
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When the CSM load-balances more than one HTTP request of a persistent connection to the same server with destination port translation, the CSM will send incorrect RST (reset) packets to this server when the CSM rebalances the connection to another server. The incorrect RST packet contains the virtual server port instead of the port configured for the real server.
Workaround: None.
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The CSM sends an invalid RST packet when it rebalances an HTTP persistent connection from a serverfarm with the predictor forward parameter applied to another serverfarm with real servers. This action creates two problems:
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This caveat exists in CSM releases 3.1(5), 3.1(6), 3.1(7), 3.1(8), 3.2(2) and 4.1(1).
Workaround: None.
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The CSM listens on these UDP ports: 5002 used for the CAP protocol and port 53 used for GSLB. The CSM silently discards the packets to port 53 and port 5002 with GSLB features disabled.
Workaround: None.
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With Global Server Load Balancing (GSLB) configured for HTTP probes, the show module csm x gslb probe command output does not show the HTTP counters incrementing.
Workaround: None.
Open Caveats in Software Release 3.1(8)
Note
This section describes known limitations that exist in CSM software release 3.1(8).
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The CSM reserves 141 KB of memory on the PowerPC control processor for each TCL scripted health probe item configured on the CSM. A probe item is an instance of a probe object associated with a single real server.
This memory usage is much higher than anticipated. The PowerPC "Available Memory" counter from the show module csm slot tech-support utilization command should not be less than 40 MB.
Workaround: None.
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When you configure a CSM in a fault-tolerant configuration and you have a fault-tolerant priority of 254, the CSM may take over the active role from the other CSM at startup. This situation could occur even when the fault-tolerant preempt option is disabled.
Workaround: Use fault-tolerant priority values lower than 254.
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The CSM does not support pipelines (multiple HTTP requests sharing the packet boundary) with the persistent rebalance feature.
Workaround: None.
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The CSM might not replicate the sticky entries for sticky group zero when it is configured under the virtual server. Because of the configuration download order, the active and standby CSM may be assigned different group numbers when a group was not specified in the configuration.
Workaround: Configure a sticky group with a specific number, and assign it to the virtual server.
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When using Cisco IOS Release 12.1(19)E or later with CSM 3.1(x) software, the sticky timeout is displayed as zero for all sticky entries, and the total entries count (CurrCount) for each sticky is also displayed as zero. These counters are supported only in the CSM software release 3.2(1).
Workaround: Use the corresponding Cisco IOS Release 12.1(13)E, which displays the configured timeout instead of the current timeout.
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The set port cdp, set port trap, set spantree portpri, and set spantree link-type restricted CSM port commands return the "failure" message instead of the "feature not supported" message.
Workaround: None.
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Token Ring and FDDI VLANs should not be configured on CSM trunk ports.
Workaround: None.
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The CSM drops packets because the multilayer switch (MLS) module and the multilayer switch feature card (MSFC) use different MAC addresses. This problem remains in software releases earlier than the Catalyst 7.5.1 software release. If any Supervisor Engine 2 in the switch is still operating with a software release earlier than the Catalyst 7.5.1 software release, and the traffic is forwarded by that switch, the CSM drops the packet.
Workaround: None.
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During a CSM reset, the show module command displays that the module is faulty when it should be displayed as "Other."
Workaround: None.
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When Internet Group Management Protocol (IGMP) snooping is enabled on the Catalyst 6500 series switch, some CSM connection replication frames might be dropped.
Workaround: Disable IGMP snooping on both the active and standby CSM modules. To disable IGMP snooping, use the no ip igmp snooping command in global configuration submode on the Catalyst 6500 series switch.
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TCL script probes are sensitive to network overload, congestion, and delay.
Workaround: To avoid spurious health monitoring results in which real servers are considered unhealthy due to network delay or congestion, we recommend that you set the "retry" to a value that is greater than one for all TCL script probes.
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Established FTP connections are not replicated to the standby CSM when the standby becomes operational. To enable an FTP connection for replication from an active CSM to a standby CSM, the standby CSM must be operational at the time the FTP connection is opened. If the FTP connection is opened prior to the standby CSM booting and becoming operational, the FTP connection never replicates to the backup.
Workaround: None.
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For optimal performance of CSM TCL script probes and TCL standalone scripts, we recommend the following:
a.
b.
c.
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When multiple CSM users perform a do copy xx running-config from a CSM submode in Cisco IOS software, the next command entered will fail with the message "% CSM parser state not found." This problem occurs only if the file copied to running-config contains at least one CSM command. When the CSM command in the file copied to running-config is entered, it overwrites the current CSM configuration parser state.
Workaround: Do not perform a do copy xx running-config operation from a CSM configuration submode. You can also exit out to the top level configuration submode and then reenter the desired CSM configuration submode.
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Beginning with Cisco IOS Release 12.1(13)E, it is possible for multiple users to simultaneously issue configuration commands for the same CSM. When you use this capability, it is possible to corrupt the configuration. In particular, if one user changes the "type" of an object while another user is simultaneously configuring that same object, the configuration will be corrupted. For example, if a user changes probe "FOO" from type "script" to type "http" while another user is configuring probe "FOO," the configuration will be corrupted.
Workaround: Ensure that multiple users do not simultaneously modify the CSM configuration with different object types.
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Some FTP connections may not replicate. For example, an FTP connection through an active CSM is not replicated if no data channel has been set up for the connection. Data channels are typically established when the client uses a get or put command on a file or performs a directory listing.
Workaround: None.
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CSM software release 3.1(2) does not support the Real Time Streaming Protocol (RTSP) and User Datagram Protocol (UDP) streaming when a client NAT is enabled. If this configuration is set up, the server attempts to open a UDP connection. Some RTSP clients then fall back to interleaved mode (inline TCP). This mode works in the application software, although the connection is sent to fastpath.
Workaround: None.
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The CSM does not support creating more than 127 virtual servers with the same virtual IP (VIP) address, even though the CLI does allow you to configure more than 127 virtual servers. If you use the CLI to configure more than 127 virtual servers, the 128th and subsequent virtual servers will not function properly.
Workaround: Do not configure more than 127 virtual servers on the same VIP.
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In firewall configurations using an HTTP 1.1 redirect virtual server, a connection going through the firewalls may remain open after a redirect virtual server connection is established.
Workaround: None. This connection closes when it times out.
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You cannot configure different fault-tolerant pairs to use the same fault-tolerant VLAN.
Workaround: Use a different fault-tolerant VLAN for each fault-tolerant CSM pair.
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Issuing the clear interface gigabit slot/port command for a CSM gigabit port may not clear the counters.
Workaround: None.
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In the CSM, it is important that packets transmitted from the CSM toward a client (server) are transmitted on the same VLAN as packets received by the CSM from that same client (server). This constraint may be satisfied as follows:
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Router(config)# module csm 4Router(config-module-csm)# vlan 10 clientRouter(config-slb-vlan-client)# gateway 1.1.1.1Router(config-module-csm)# vlan 20 clientRouter(config-slb-vlan-client)# gateway 2.2.2.2To make this configuration valid, delete the gateway command from either VLAN 10 or VLAN 20.
Note
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Router(config)# module csm 4Router(config-module-csm)# vlan 10 clientRouter(config-slb-vlan-client)# route 10.0.0.0 255.255.255.0 gateway 1.1.1.1For load balancing to function properly, all traffic arriving from the 10.0.0.0/24 subnet must reach the CSM through VLAN 10.
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The output from the show interface gigabit slot/port command may erroneously indicate that one or more of the CSM gigabit ports are down.
Workaround: Disregard the display.
Resolved Caveats in Software Release 3.1(8)
Note
This section describes the caveats resolved in CSM software release 3.1(8).
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CLI commands sent to the CSM may fail when the servers in a server farm reaches the configured maximum connections (max-conns) value. When the maximum connection value has been met, the servers would not be selected, generating system messages to notify users of the change in the server state. In software release 3.1(8), the configurable global variable INBAND_STATE_CHANGED_MSG_RATE is introduced to control the rate at which these messages are generated and written into the system message log. You must configure a value of zero to suppress the messages from being sent.
Workaround: Remove the max-conns configuration from the server. The max-conns value can be configured at the virtual server level.
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The server configured with "inservice standby" becomes active after it fails and recovers from a health probe check. The server should not start accepting load-balancing traffic after it recovers from health probe failure and should go back to standby mode where it accepts only those connections with the sticky or backup role.
Workaround: None
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When a TCP request with a multicast destination MAC address reaches the CSM, the CSM sends a reset (RST) back to this host. This is a problem even when the TCP request contains the unicast destination IP address that is not owned by the CSM.
Workaround: None.
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The CSM may respond with an acknowledgement (ACK) message instead of synchronization-acknowledgement (SYN-ACK) message for the repeated synchronization (SYN) packet from the client to a Layer 7 virtual server.
Workaround: None
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The CSM may fail to respond if it has to replicate over 256,000 unique sticky entries and replicate over 30,000 new connections per second.
Workaround: Configure the appropriate subnet mask for IP sticky to reduce the number of sticky entries in the CSM database.
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The clear module csm slot sticky command does not clear the sticky entries on the standby CSM.
Workaround: Enter the clear module csm slot sticky command on the standby CSM.
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If the first reply packet from the server is an "HTTP 100 Continue" type reply, then the CSM does not learn the HTTP "Set-Cookie" information from the subsequent "HTTP 200 OK" reply from the server. In this case, the cookie sticky option will not work for the subsequent "HTTP 100 Continue" packet.
Workaround: Reconfigure the server so that it sends the Cookie information in the "HTTP 100 Continue" packet as well.
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The CSM incorrectly replicates the FTP connections to the standby CSM if connection replication is enabled for the FTP server. If the FTP traffic reaches the standby CSM due to bridge flooding, the standby CSM also forwards this traffic. This situation causes the Catalyst switch to recognize that the source MAC address belongs to the standby CSM instead of the active CSM. This situation might cause all other traffic to be incorrectly forwarded to the standby CSM, where the packets will be dropped.
Workaround: Turn off connection replication for the FTP virtual server.
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When you configure the CSM for persistent rebalancing of each HTTP request f
