Table Of Contents
ATM LANE Fast Simple Server Replication Protocol
Related Features and Technologies
Supported Standards, MIBs, and RFCs
ATM LANE Fast Simple Server Replication Protocol
To improve the ATM LAN Emulation (LANE) Simple Server Replication Protocol (SSRP), Cisco has introduced the ATM LANE Fast Simple Server Replication Protocol (FSSRP). FSSRP differs from LANE SSRP in that all configured LANE servers of an Emulated LAN (ELAN) are always active. FSSRP-enabled LANE clients have virtual circuits (VCs) established to a maximum of four LANE servers and broadcast and unknown servers (BUSs) at one time. If a single LANE server goes down, the LANE client quickly switches over to the next LANE server and BUS resulting in no data or LE-ARP table entry loss and no extraneous signalling.
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Supported Standards, MIBs, and RFCs
Feature Overview
The FSSRP feature improves upon SSRP such that LANE server and BUS switchover for LANE clients is immediate. With SSRP, a LANE server would go down, and depending on the network load, it may have taken considerable time for the LANE client to come back up joined to the correct LANE server and BUS. In addition to going down with SSRP, the LANE client would also do the following:
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FSSRP was designed to alleviate these problems with the LANE client. With FSSRP, each LANE client is simultaneously joined to up to four LANE servers and BUSs. The concept of the master LANE server and BUS is maintained; the LANE client uses the master LANE server when it needs LANE server BUS services. However, the difference between SSRP and FSSRP is that if and when the master LANE server goes down, the LANE client is already connected to multiple backup LANE servers and BUSs. The LANE client simply uses the next backup LANE server and BUS as the master LANE server and BUS.
Fast Switchover
With FSSRP, switchover to a backup LANE server and BUS is immediate. Unless all the LANE servers and BUSs go down, the LANE clients continue to stay up. As soon as a single LANE server and BUS is available, the LANE client comes back up. This is a significant advantage over SSRP functionality.
The only disadvantage is the number of VCs that are consumed to maintain the extra connections to the backup LANE servers and BUSs. See the Restrictions section later in this document.
Easy Enable
To activate the FSSRP feature, use a single interface configuration command, lane fssrp (see the description for this command in the Command Reference section later in this document.) This command affects every LANE component and hence all subinterfaces on an interface.
More Information
The show lane client command also has been improved. To display extra LANE server and BUS information in a LANE client pertaining to FSSRP, use the optional new argument detail. See the description for this command in the Command Reference section later in this document.
Seamless Operation
FSSRP is designed to interoperate seamlessly with SSRP. However, for you to receive full benefits from FSSRP, all participating network components must be running the same Cisco IOS version. Although the system will interoperate, the fast switchover benefits will not be realized if you use different versions of the Cisco IOS software on different network components. For Cisco IOS version prerequisites, see the Prerequisites section later in this document.
Benefits
Because the LANE client is joined to up to three additional LANE servers and BUSs, FSSRP speeds up LANE client recovery after a LANE server fails. When one LANE server goes down, the LANE client immeditately switches over to the next LANE server. In addition, resource loads, such as LANE client signalling, are minimized.
Restrictions
Due to the increase in LAN client connections to all LANE servers in an ELAN, FSSRP increases the number of VCs in your network. On a per client basis, up to 12 additional VCs will be added. These include the additional control direct, control distribute, multicast send and multicast forward VCs (times the 3 extra LANE servers and BUSs), which totals 12 additional VCs.
Users should take care to calculate whether or not the number of existing VCs in their network can be maintained with additional VC connections to the secondary LANE servers and BUSs.
A LANE client may connect to up to only 4 LANE servers and BUSs at a time.
Related Features and Technologies
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Related Documents
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Supported Platforms
This feature is supported on these platforms:
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Supported Standards, MIBs, and RFCs
MIBs
MIB support will be released in Cisco IOS Release 12.0(6)T.
For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
None
Standards
None
Prerequisites
LANE
Configure LANE on your router.
IOS Versions
Upgrade network components running Cisco IOS versions as follows:
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LANE Configuration Server Databases
Ensure that the LANE configuration server databases are identical before you bring up your network.
LANE Configuration Server Configuration
You must never bypass the LANE configuration server's configuration phase, by either explicitly configuring a LANE configuration server's address on subinterfaces or any other means, because the restricted ELAN feature will be seriously compromised.
LANE Client Status Changes
If you must change the status of a LANE client on your network, such as moving it from one ELAN to another ELAN, you must first bring the LANE client down before any changes to the LANE configuration server databases are made. Bring up the LANE client only after all the LANE configuration server databases are identical (as stated in LANE Configuration Server Databases.)
Configuration Tasks
See the following section for configuration tasks for the FSSRP. Each task in the list indicates if the task is optional or required.
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Configuring FSSRP
Follow these steps to configure the FSSRP feature:
Verifying FSSRP Configuration
Use the show lane client command to verify FSSRP configuration on a LANE client.
Router# show lane clientATM# show lane client detailLE Client ATM1/0.1 ELAN name:xxx Admin:up State:operationalClient ID:2 LEC up for 5 days 40 minutes 45 secondsELAN ID:0This client is running in FSSRP mode.Join Attempt:14Known LE Servers:1Configured Idle Time:5 secondsLast Fail Reason:Config VC being releasedHW Address:00e0.8fcf.d820 Type:ethernet Max Frame Size:1516ATM Address:47.0091810000000061705B0C01.00E08FCFD820.01VCD rxFrames txFrames Type ATM Address0 0 0 configure 47.00918100000000613E5A2F01.006070174823.00LEC ID:2, State:LESBUS_ACTIVE52 1778 3556 direct 47.00918100000000613E5A2F01.00000C5A0C59.0153 1778 0 distribute 47.00918100000000613E5A2F01.00000C5A0C59.0154 0 0 send 47.00918100000000613E5A2F01.00000C5A0C5A.0155 0 0 forward 47.00918100000000613E5A2F01.00000C5A0C5A.01LEC ID:3, State:LESBUS_ACTIVE93 122 234 direct 47.00918100000000613E5A2F01.00000ABCD001.0994 122 0 distribute 47.00918100000000613E5A2F01.00000ABCD001.0997 0 0 send 47.00918100000000613E5A2F01.00000ABCD002.0908 0 0 forward 47.00918100000000613E5A2F01.00000ABCD002.09Troubleshooting Tips
Use the show lane command options "server" and "client" to check if FSSRP is enabled. The following is sample output from the show lane server command for an Ethernet-emulated LAN:
Router# show lane serverLE Server ATM2/0.2 ELAN name:elan2 Admin:up State: operationaltype: ethernet Max Frame Size: 1516ATM address: 39.020304050607080910111213.00000CA05B41.02LECS used: 39.020304050607080910111213.00000CA05B43.00 connected, vcd 51control distribute: vcd 57, 2 members, 2 packetsproxy/ (ST: Init, Conn, Waiting, Adding, Joined, Operational, Reject, Term)lecid ST vcd pkts Hardware Addr ATM Address1 O 54 2 0000.0ca0.5b40 39.020304050607080910111213.00000CA05B40.022 O 81 2 0060.2f55.7940 39.020304050607080910111213.00602F557940.02Use the show version command to check if you are running the correct version of Cisco IOS (see Prerequisites.)
Configuration Examples
This section provides an FSSRP configuration example.
Router# configure terminalRouter(config)# int atm 2/0Router(config-if)# lane fssrpRouter(config)# exitCommand Reference
This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command reference publications.
This section documents the new command that configures the FSSRP feature.
In Cisco IOS Release 12.0(1)T or later, you can search and filter the output for show and more commands. This functionality is useful when you need to sort through large amounts of output, or if you want to exclude output that you do not need to see.
To use this functionality, enter a show or more command followed by the "pipe" character (|), one of the keywords begin, include, or exclude, and an expression that you want to search or filter on:
command | {begin | include | exclude} regular-expression
Following is an example of the show atm vc command in which you want the command output to begin with the first line where the expression "PeakRate" appears:
show atm vc | begin PeakRate
For more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module titled CLI String Search.
lane fssrp
To enable the special LANE features such that LANE components (such as, the LANE configuration server, the LANE client, the LANE server, and the BUS) become aware of FSSRP, use the lane fssrp interface configuration command. Use the no form of this command to disable the LANE FSSRP configuration.
lane fssrp
no lane fssrpSyntax Description
There are no arguments or keywords for this command.
Defaults
FSSRP is not enabled by default.
Command Modes
Interface configuration
Command History
Usage Guidelines
You must execute this command on all ATM interfaces to enable FSSRP capability for all LANE components on that interface and hence all its subinterfaces.
Examples
The following example enables FSSRP on an ATM interface:
lane fssrpRelated Commands
show lane client
To generate additional FSSRP information about a LANE client, use the show lane client detail EXEC command. The information typically includes, but is not limited to, the extra connection information that may be available to the client as a result of being simultaneously connected to multiple LANE servers and BUSs.
show lane client detail
Syntax Description
Command Modes
EXEC
Command History
11.0
This command was introduced.
12.0(5)T
Added detail option and command output line "This client is running in FSSRP mode."
Examples
The following is sample output from the show lane client detail command.
ATM# show lane client detailLE Client ATM1/0.1 ELAN name:xxx Admin:up State:operationalClient ID:2 LEC up for 5 days 40 minutes 45 secondsELAN ID:0This client is running in FSSRP mode.Join Attempt:14Known LE Servers:1Configured Idle Time:5 secondsLast Fail Reason:Config VC being releasedHW Address:00e0.8fcf.d820 Type:ethernet Max Frame Size:1516ATM Address:47.0091810000000061705B0C01.00E08FCFD820.01VCD rxFrames txFrames Type ATM Address0 0 0 configure 47.00918100000000613E5A2F01.006070174823.00LEC ID:2, State:LESBUS_ACTIVE52 1778 3556 direct 47.00918100000000613E5A2F01.00000C5A0C59.0153 1778 0 distribute 47.00918100000000613E5A2F01.00000C5A0C59.0154 0 0 send 47.00918100000000613E5A2F01.00000C5A0C5A.0155 0 0 forward 47.00918100000000613E5A2F01.00000C5A0C5A.01LEC ID:3, State:LESBUS_ACTIVE93 122 234 direct 47.00918100000000613E5A2F01.00000ABCD001.0994 122 0 distribute 47.00918100000000613E5A2F01.00000ABCD001.0997 0 0 send 47.00918100000000613E5A2F01.00000ABCD002.0908 0 0 forward 47.00918100000000613E5A2F01.00000ABCD002.09Related Commands