According to the VSS configuration chapter of the IOS-XE 3.4.0 configuration guide, SSO/NSF need to be enabled for VSS to work properly. It even helpfully links to the SSO chapter. In that chapter it says that to enable SSO use these commands:
However these commands do not exist and are not accepted on the command line. Is the documentation misleading, am I missing something, or does this happen automatically when I run the "switch convert mode virtual" command to enable VSS?
Can you please let me know what you get when you type redundancy under config mode from the switch?
Switch# config t
Switch-config# redundancy ?
Also If I remember if you configure the below cmd this will set the mode to SSO:
! The following command sets the redundancy mode to SSO.
The reason of having SSO for VSS is below:
SSO (stateful switchover) and NSF (Non Stop Forwarding) are both are used to provide high availability in the event of loss of the active supervisor and failover to the standby supervisor.
With SSO, the 2 supervisors share state so that should the standby supervisor need to take over, it has all the state information needed to continue processing packets.
NSF deals with the layer 3 routing protocols and their topology tables. When the standby supervisor takes over, the Vlan SVIs reset which normally would result in the loss of any Layer 3 routing protocol neighbors. This would cause a routing protocol re-convergence and layer 3 forwarding of packets would be interrupted. However, with NSF, packets continue to be forwarded while neighbor relationships and topology tables are rebuilt. This only works if the neighboring routers are NSF aware. In other words, the neighboring router must be able to exchange special NSF messages with the NSF capable 6500 to help the 6500 rebuilt its topology table.
Without SSO and NSF, loss of the active supervisor will result in disruption of existing traffic flows. So you want to use them both.
*Plz rate the usefull posts.
Yes, I understand the need for, and mechanismis used by, SSO and NSF. It's just that the required commands are not available.
% Unrecognized command
% Invalid input detected at '^' marker.
the command simply does not exist on this IOS/Sup/mode combination but the instructions say I need it. Stuck.
Here it is:
Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500e-
UNIVERSAL_LITE-M), Version 03.04.00.SG RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2012 by Cisco Systems, Inc.
Compiled Wed 05-Dec-12 06:53 by prod_rel_team
Cisco IOS-XE software, Copyright (c) 2005-2010, 2012 by cisco Systems, Inc.
All rights reserved. Certain components of Cisco IOS-XE software are
licensed under the GNU General Public License ("GPL") Version 2.0. The
software code licensed under GPL Version 2.0 is free software that comes
with ABSOLUTELY NO WARRANTY. You can redistribute and/or modify such
GPL code under the terms of GPL Version 2.0. For more details, see the
documentation or "License Notice" file accompanying the IOS-XE software,
or the applicable URL provided on the flyer accompanying the IOS-XE
Switch uptime is 1 day, 1 hour, 14 minutes
System returned to ROM by reload
Running default software
Jawa Revision 7, Snowtrooper Revision 0x0.0x1C
Last reload reason: reload
License Information for 'WS-X45-SUP7-E'
License Level: ipbase Type: Permanent
Next reboot license Level: ipbase
cisco WS-C4506-E (MPC8572) processor (revision 10) with 2097152K/20480K bytes of
Processor board ID FXS1705Q1LZ
MPC8572 CPU at 1.5GHz, Supervisor 7
Last reset from Reload
2 Virtual Ethernet interfaces
96 Gigabit Ethernet interfaces
4 Ten Gigabit Ethernet interfaces
511K bytes of non-volatile configuration memory.
Configuration register is 0x2101
Ive come across with thread after having a few VSS failover problems.
Im curious about NSF. If i enabled NSF and one OSPF neighbor didn't support this feature. What would happen? Would it still from neighbor Ajd etc?