Virtual Switching System (VSS) is network system virtualization technology that pools multiple Cisco Catalyst 6500 Series Switches into one virtual switch, increasing operational efficiency, boosting nonstop communications, and scaling system bandwidth capacity to 1.4 Tbps. At the initial phase, a VSS will allow two physical Cisco Catalyst 6500 Series Switches to operate as a single logical virtual switch called a virtual switching system 144.
his session will provide an opportunity to learn and ask questions about how to implement, configure and troubleshoot VSS in Cisco Catalyst Switches 6500 and 4500.
Ask questions from Monday, September 7 to Friday, September 18, 2015
Featured Experts
InayathUlla Sharieff is a Customer support engineer in High-Touch Technical Services (HTTS) team supporting LAN Switching and Data center Products. His areas of expertise include Cisco Catalyst 2000,3000,4000 ,6500 and Cisco Nexus 7000 Switches. Shariff has over 8 years of industry experience working with large enterprise and Service Provider networks. He holds Bachelors in Computer Sciences degree and these Cisco certifications: CCNA, CCNP (in Routing and Swtiching), and CCIE in R&S (# 43263). He is pursuing the CCIE in Data Centers.
Suresh Vs is a Customer Support Engineer in High-Touch Technical Services (HTTS) at Cisco Bangalore, India. He has over 11 years of industry experience working with large Enterprise and Service Provider networks. He has been working with HTTS from past 4 years and supporting LAN Switching and Data center Products. His areas of expertise include Cisco Catalyst 2000, 3000, 4000, 6500 and Cisco Nexus 7000 Switches. Suresh holds a Bachelor's of Sciences in Electrical and Electronics Engineering from Madras University. He has these certifications: CCNA, CCNP, CCIE Data Center (# 46658).
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Thiyagarajan,
Yes if you have confiugred the dual active recovery once the VSL link is resotred the switch will recover itself and UP as standby.
Please find complete explanation below which will help you to understand in details:-
VSL failure
The failure of a single VSL link is discovered by the active supervisor engine, either through a link-down event or through the failure of periodic VSLP messages sent across the link to check the VSL link state. Availability is not affected for those data flows that do not use the VSL.
The active supervisor engine discovers the failure of the “entire” VSL either through a link-down event or through the failure of the periodic VSLP messages sent across the member links to check the VSL link status. From the perspective of the active virtual switch chassis, the standby virtual switch is lost. The standby virtual switch chassis also views the active virtual switch chassis as failed and transitions to active virtual switch state through an SSO switchover. This scenario is known as a dual-active scenario and the duplication of this configuration can possibly have adverse effects to the network topology and traffic.
To avoid this disruptive scenario, you should configure one of these methods:
- Enhanced PAgP
- Layer 3 BFD
- Fast Hello
In this case the Fast hello link method is implemented.
Upon detecting the dual-active condition, the original active chassis enters intorecovery mode and brings down all of its interfaces except the VSL and nominated management interfaces. This effectively removes the device from the network.
You will see the following messages on the active virtual switch to indicate that a dual-active scenario has occurred:
CiscozineVSS# Jan 23 11:57:37.647: %VSLP-SW1_SP-3-VSLP_LMP_FAIL_REASON: Te1/5/5: Link down Jan 23 11:57:37.647: %VSLP-SW1_SP-2-VSL_DOWN: Last VSL interface Te1/5/5 went down Jan 23 11:57:37.735: %VSLP-SW1_SP-2-VSL_DOWN: All VSL links went down while switch is in ACTIVE role Jan 23 11:57:37.799: %LINEPROTO-SW1_SP-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/5/5, changed state to down Jan 23 11:57:37.803: %LINEPROTO-SW1_SP-5-UPDOWN: Line protocol on Interface Port-channel1, changed state to down Jan 23 11:57:37.803: %LINK-SW1_SP-3-UPDOWN: Interface Port-channel1, changed state to down Jan 23 11:57:37.807: %LINK-SW1_SP-3-UPDOWN: Interface TenGigabitEthernet1/5/5, changed state to down Jan 23 11:57:37.875: %DUAL_ACTIVE-SW1_SP-1-DETECTION: Fast-hello running on Gi1/2/1 detected dual-active condition Jan 23 11:57:37.875: %DUAL_ACTIVE-SW1_SP-1-RECOVERY: Dual-active condition detected: Starting recovery-mode, all non-VSL and non-excluded interfaces have been shut down CiscozineVSS(recovery-mode)#
The following messages on the standby virtual switch console indicate that a dual-active scenario has occurred:
CiscozineVSS-sdby# Jan 23 11:57:37.647: %VSLP-SW2_SPSTBY-3-VSLP_LMP_FAIL_REASON: Te2/5/5: Link down Jan 23 11:57:37.647: %VSLP-SW2_SPSTBY-2-VSL_DOWN: Last VSL interface Te2/5/5 went down Jan 23 11:57:37.651: %VSLP-SW2_SPSTBY-2-VSL_DOWN: All VSL links went down while switch is in Standby role Jan 23 11:57:37.651: %DUAL_ACTIVE-SW2_SPSTBY-1-VSL_DOWN: VSL is down - switchover, or possible dual-active situation has occurred Jan 23 11:57:37.651: %PFREDUN-SW2_SPSTBY-6-ACTIVE: Initializing as Virtual Switch ACTIVE processor Jan 23 11:57:39.559: %LINK-3-UPDOWN: Interface TenGigabitEthernet2/5/5, changed state to down Jan 23 11:57:39.559: %LINEPROTO-SW2_SP-5-UPDOWN: Line protocol on Interface TenGigabitEthernet2/5/5, changed state to down Jan 23 11:57:40.579: %OIR-SW2_SP-6-INSREM: Switch 1 Physical Slot 1 - Module Type LINE_CARD removed Jan 23 11:57:40.899: %OIR-SW2_SP-6-INSREM: Switch 1 Physical Slot 2 - Module Type LINE_CARD removed Jan 23 11:57:40.991: %OIR-SW2_SP-6-INSREM: Switch 1 Physical Slot 3 - Module Type LINE_CARD removed Jan 23 11:57:41.107: %OIR-SW2_SP-6-INSREM: Switch 1 Physical Slot 5 - Module Type LINE_CARD removed Jan 23 11:58:00.335: %VSLP-SW2_SP-2-VSL_DOWN: All VSL links went down while switch is in ACTIVE role CiscozineVSS#
This is confirmed by the show command:
CiscozineVSS#show switch virtual redundancy
My Switch Id = 2
Peer Switch Id = 1
Last switchover reason = active unit removed
Configured Redundancy Mode = sso
Operating Redundancy Mode = sso
Switch 2 Slot 5 Processor Information :
-----------------------------------------------
Current Software state = ACTIVE
Uptime in current state = 0 minutes
Image Version = Cisco IOS Software, s72033_rp Software (s72033_rp-ADVENTERPRISEK9-M), Version 15.1(2)SY, RELEASE SOFTWARE (fc4)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2013 by Cisco Systems, Inc.
Compiled Wed 04-Sep-13 13:05 by prod_rel_team
BOOT = bootdisk:s72033-adventerprisek9-mz.151-2.SY.bin,12;
Configuration register = 0x2102
Fabric State = ACTIVE
Control Plane State = ACTIVE
Peer information is not available because
it is in 'DISABLED' state
CiscozineVSS#
When the VSL is restored, the following messages are displayed on the console and the switch in recovery mode (previous active virtual switch) reloads:
Jan 26 13:23:34.877: %DUALACTIVE-1-VSL_RECOVERED: VSL has recovered during dual-active situation: Reloading switch 1 Jan 26 13:23:34.909: %SYS-5-RELOAD: Reload requested Reload Reason: Reload Command.
After the reloading, the VSS is recovered; the control plane remains active on the previous standby virtual switch. To force a switchover use the command:
redundancy force-switchover
HTH
Inayath
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