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ashirkar
Level 7
Level 7

 

Introduction

The Cisco Virtual Switching System is a clustering technology that pools two Cisco Catalyst 4500-E Series Switches with Cisco Catalyst Supervisor Engine 7-E or 7-LE or two Catalyst 4500-X Series Switches into a single virtual switch. In a VSS, the data plane of both clustered switches is active at the same time in both chassis. VSS members are connected by virtual switch links (VSLs) using standard Gigabit or 10 Gigabit Ethernet connections between the VSS members. VSLs can carry regular user traffic in addition to the control plane communication between the VSS members.

Physical vs Logical Topology in a VSS Configuration

 

vss.jpg

 

This document describes how to configure a virtual switching system (VSS) for the Catalyst 4500 series switch (Supervisor Engine 7-E, Supervisor Engine 7L-E).

Some key point to be remembered for Cisco 4500 VSS

1) Configuration/Capability Supported supervisors on Catalyst 4500-E: VSS support Supervisor Engine 7-E or 7-LE (identical pairs).For more information about hardware to support please refer 4500 VSS Hardware requirement

2) Software requirement: Cisco IOS XE 3.4.0SG and ROMMON IOS Version 15.0(1r) SG7 later released support VSS.(Also refer How to Upgrade Cisco 4500 SUP7-E & Sup7L-E ROMMON To support VSS).

3)license requirement : 

To know more on license requirement refer "Release Notes for the Catalyst 4500E Series Switch"

Feature

LAN Base

IP Base

Enterprise Service

  • Virtual Switching System (VSS

 

No

Yes
(SUP7E only)

Yes

  • Support for Layer 3 MEC—VSS with Layer 3 Multichassis EtherChannel (MEC) at the aggregation layer

  • Support for VSLP Fast Hello—With VSLP Fast Hello, the Catalyst 4500-X configured for VSS can now connect Access Switches that do not support the ePAgP protocol.

  • Support for VSL Encryption

  • Support for Asymmetrix chassis

No

Yes (SUP7E)

No (SUP7LE)

Yes (SUP7E)

Yes (SUP7LE)

 

For information about Software Activation Licensing please refer Cisco Catalyst 4500E Supervisor 7-E and 7L-E and Cisco Catalyst 4500-X Series Software Activation Licensing Deployment Guide.

4) Single-sup cross-chassis VSS support: Yes.

5) Quad-sup VSS configuration with in-chassis redundant sups: In-chassis redundant sups in rommon mode with active uplinks.

6) It also supports 10 Gigabit Ethernet Virtual Switch Link (VSL) and 1 Gigabit Ethernet VSL.

7) SSO and nonstop forwarding (NSF) must be configured on each switch. If a VSS does not meet the requirements for SSO redundancy; it will be incapable of establishing a relationship with the peer switch. Catalyst 4500/4500-X series switches' VSS does not support route processor redundancy (RPR) mode.

Prerequisite

Before configuring VSS on Cisco 4500 please verify hardware and software requirement.

SW1#sh ver | in IOS
Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500e-UNIVERSAL-M), Version 03.04.00.SG RELEASE SOFTWARE (fc3)
Cisco IOS-XE software, Copyright (c) 2005-2010, 2012 by cisco Systems, Inc.
All rights reserved. Certain components of Cisco IOS-XE software are
documentation or "License Notice" file accompanying the IOS-XE software,
or the applicable URL provided on the flyer accompanying the IOS-XE

SW1#sh ver | in ROM
ROM: 15.0(1r)SG7
System returned to ROM by power-on 

SW1#sh license image levels 
Module name       Image level Priority Configured Valid license
--------------------------------------------------------------------
WS-X45-SUP7-E     entservices  1         YES        entservices            
                  ipbase       2         NO         ipbase                
                  lanbase      3         NO         lanbase  
 
Module Name     Role           Current Level     Reboot Level
--------------------------------------------------------------------
WS-X45-SUP7-E  Active         entservices       entservices

 

SW2#sh ver | in IOS
Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500e-UNIVERSAL-M), Version 03.04.00.SG RELEASE SOFTWARE (fc3)
Cisco IOS-XE software, Copyright (c) 2005-2010, 2012 by cisco Systems, Inc.
All rights reserved. Certain components of Cisco IOS-XE software are
documentation or "License Notice" file accompanying the IOS-XE software,
or the applicable URL provided on the flyer accompanying the IOS-XE

SW2#sh ver | in ROM
ROM: 15.0(1r)SG7
System returned to ROM by power-on

SW2#sh license image levels
Module name       Image level Priority Configured Valid license
--------------------------------------------------------------------
WS-X45-SUP7-E     entservices  1         YES        entservices            
                  ipbase       2         NO         ipbase                
                  lanbase      3         NO         lanbase 

Module Name     Role           Current Level     Reboot Level
--------------------------------------------------------------------
WS-X45-SUP7-E   Active        entservices       entservices

 

Configuration Steps

STEP1: Assigning Virtual Switch Domain and Switch Numbers

First you have to configure the same virtual switch domain number on both switches of the VSS. The virtual switch domain is a number between 1 and 255.After domain number you must configure one switch to be switch number 1 and the other switch to be switch number 2.

SW1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
SW1(config)#switch virtual domain 10
Domain ID 10 config will take effect only
after the exec command 'switch convert mode virtual' is issued
SW1(config-vs-domain)#switch 1
SW1(config-vs-domain)#exit
SW1(config)#

 

SW2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
SW2(config)#switch virtual domain 10
Domain ID 10 config will take effect only
after the exec command 'switch convert mode virtual' is issued
SW2(config-vs-domain)#switch 2
SW2(config-vs-domain)#exit
SW2(config)#

 

STEP2: Configuring VSL Port Channel

Then you need to configure VSL with a unique port channel on each switch. During the conversion, the VSS configures both port channels on the VSS Active switch. If the VSS Standby switch VSL port channel number has been configured for another use, the VSS comes up in RPR mode. To avoid this situation, check that both port channel numbers are available on both of the switches.

SW1(config)#int port-channel 5
SW1(config-if)#switchport
SW1(config-if)#switch virtual link 1
SW1(config-if)#no shut
SW1(config-if)#exit
*Jan 24 05:19:57.092: %SPANTREE-6-PORTDEL_ALL_VLANS: Port-channel5 deleted from all Vlans

 

SW2(config)#int port-channel 10
SW2(config-if)#switchport
SW2(config-if)#switch virtual link 2
SW2(config-if)#no shut
SW2(config-if)#exit
SW2(config)#
*Jan 24 05:14:17.273: %SPANTREE-6-PORTDEL_ALL_VLANS: Port-channel10 deleted from all Vlans

 

STEP3: configure the VSL ports

You need to add the VSL physical ports to the port channel. In the following example, interfaces Gigabit Ethernet 7/3 and 7/4 on Switch 1 are connected to interfaces Gigabit Ethernet 4/45 and 4/46 on Switch 2.

SW1(config)#int range gig7/3 - 4
SW1(config-if-range)#switchport mode trunk
SW1(config-if-range)#channel-group 5 mode on
WARNING: Interface GigabitEthernet7/3 placed in restricted config mode. All extraneous configs removed!
WARNING: Interface GigabitEthernet7/4 placed in restricted config mode. All extraneous configs removed!
SW1(config-if-range)#exit

 

SW2(config)#int range gig4/45 - 46
SW2(config-if-range)#switchport mode trunk
SW2(config-if-range)#channel-group 10 mode on
WARNING: Interface GigabitEthernet4/45 placed in restricted config mode. All extraneous configs removed!
WARNING: Interface GigabitEthernet4/46 placed in restricted config mode. All extraneous configs removed!
SW2(config-if-range)#exit

 

Note: Once the interfaces are put into VSL port-channel with “channel-group" command, then the interfaces goes into “notconnect” status. Interface status will show UP, but the line protocol will be down. The interface will be in UP/down (not connect) status, till the switch is rebooted in step 4.

STEP4: Converting the Switch to Virtual Switch Mode:

You need to enter the “switch convert mode virtual” command on Switch 1 for Converting to Virtual Switch Mode .After you enter this command it will prompted to confirm the action. Enter yes. The system creates a converted configuration file, and saves the file to the bootflash:

SW1#switch convert mode virtual 

This command will convert all interface names
to naming convention "interface-type switch-number/slot/port",
save the running config to startup-config and
reload the switch.
Do you want to proceed? [yes/no]: yes
Converting interface names
Building configuration...
Compressed configuration from 6551 bytes to 2893 bytes[OK]
Saving converted configuration to bootflash: ...
Destination filename [startup-config.converted_vs-20130124-062921]?
Please stand by while rebooting the system...
Restarting system. 

Rommon (G) Signature verification PASSED  
Rommon (P) Signature verification PASSED  
FPGA   (P) Signature verification PASSED

Similarly you need to enter the “switch convert mode virtual” command on Switch 2 for converting to Virtual Switch Mode.

 

SW2#switch convert mode virtual​ 

This command will convert all interface names
to naming convention "interface-type switch-number/slot/port",
save the running config to startup-config and
reload the switch.
Do you want to proceed? [yes/no]: yes
Converting interface names
Building configuration...
Compressed configuration from 6027 bytes to 2774 bytes[OK]
Saving converted configuration to bootflash: ...
Destination filename [startup-config.converted_vs-20130124-052526]?
Please stand by while rebooting the system...
Restarting system. 

Rommon (G) Signature verification PASSED  

Rommon (P) Signature verification PASSED  

FPGA   (P) Signature verification PASSED 

************************************************************
*                                                          *
* Welcome to Rom Monitor for   WS-X45-SUP7-E System.       *
* Copyright (c) 2008-2012 by Cisco Systems, Inc.           *
* All rights reserved.                                     *
*                                                          *
************************************************************

 

After you confirm the above commands on both switches, the running configuration is automatically saved as the startup configuration and the switch reboots. After the reboot, the switch is in virtual switch mode, so you must specify interfaces with three identifiers (switch/module/port).

When switches are being converted to VSS, you should not set them to ignore startup-config. If done, the switch can be enabled to parse the startup-config at the rommon prompt. Ignoring startup-config in VSS mode causes a switch to boot in a semi-VSS mode, which can only be corrected by a reboot and by enabling the parsing of startup-config.

Verification

1) To displays the virtual switch domain number, and the switch number and role for each of the switches you can use “show switch virtual” command.

SW1#sh switch virtual 

Executing the command on VSS member switch role = VSS Active, id = 1 

Switch mode                  : Virtual Switch
Virtual switch domain number : 10
Local switch number          : 1
Local switch operational role: Virtual Switch Active
Peer switch number           : 2
Peer switch operational role : Virtual Switch Standby 

Executing the command on VSS member switch role = VSS Standby, id = 2  

Switch mode                  : Virtual Switch
Virtual switch domain number : 10
Local switch number          : 2
Local switch operational role: Virtual Switch Standby
Peer switch number           : 1
Peer switch operational role : Virtual Switch Active

 

2) Once both switches cluster in single virtual switch, you will only have Active switch console and your Standby switch console appears as follow:

SW2-standby> 
Standby console disabled

3) To displays the role, switch number, and priority for each of the switch in the VSS use “show switch virtual role” command.

SW1#sh switch virtual role 

Executing the command on VSS member switch role = VSS Active, id = 1 

RRP information for Instance 1 

--------------------------------------------------------------------
Valid Flags   Peer     Preferred Reserved
               Count     Peer       Peer  

--------------------------------------------------------------------
TRUE   V       1           1         1  

Switch Switch Status Preempt       Priority Role     Local   Remote
       Number         Oper(Conf)   Oper(Conf)         SID     SID
--------------------------------------------------------------------
LOCAL   1     UP     FALSE(N )     100(100) ACTIVE   0       0
REMOTE  2     UP     FALSE(N )     100(100) STANDBY 6834   6152  

Peer 0 represents the local switch  

Flags : V - Valid
In dual-active recovery mode: No  

Executing the command on VSS member switch role = VSS Standby, id = 2 

RRP information for Instance 2  

--------------------------------------------------------------------
Valid Flags   Peer     Preferred Reserved
               Count     Peer       Peer  

--------------------------------------------------------------------
TRUE    V       1           1         1  

Switch Switch Status Preempt       Priority Role     Local   Remote
       Number         Oper(Conf)   Oper(Conf)         SID     SID
--------------------------------------------------------------------
LOCAL   2     UP     FALSE(N )     100(100) STANDBY  0       0
REMOTE  1     UP     FALSE(N )     100(100) ACTIVE   6152   6834 

Peer 0 represents the local switch

Flags : V - Valid
In dual-active recovery mode: No

 

4) To Displays information about the VSL use “show switch virtual link” command.

SW1#sh switch virtual link  

Executing the command on VSS member switch role = VSS Active, id = 1 

VSL Status : UP
VSL Uptime : 3 minutes
VSL Control Link : Gi1/7/4  

Executing the command on VSS member switch role = VSS Standby, id = 2 

VSL Status : UP
VSL Uptime : 3 minutes
VSL Control Link : Gi2/4/45

 

5) You can also verify information about the VSL port channel using “show switch virtual link port-channel”command.

SW1#sh switch virtual link port-channel 

Executing the command on VSS member switch role = VSS Active, id = 1 

Flags: D - down       P - bundled in port-channel
       I - stand-alone s - suspended
       H - Hot-standby (LACP only)
       R - Layer3     S - Layer2
       U - in use     N - not in use, no aggregation
       f - failed to allocate aggregator         

       M - not in use, no aggregation due to minimum links not met
       m - not in use, port not aggregated due to minimum links not met
       u - unsuitable for bundling
       d - default port  
       
       w - waiting to be aggregated  

Group Port-channel Protocol   Ports
------+-------------+-----------+-------------------
5     Po5(SU)          -       Gi1/7/3(P) Gi1/7/4(P)
10    Po10(SU)         -       Gi2/4/45(P) Gi2/4/46(P)  

Executing the command on VSS member switch role = VSS Standby, id = 2  

Flags: D - down       P - bundled in port-channel
       I - stand-alone s - suspended
       H - Hot-standby (LACP only)
       R - Layer3     S - Layer2
       U - in use     N - not in use, no aggregation
       f - failed to allocate aggregator         
       
       M - not in use, no aggregation due to minimum links not met
       m - not in use, port not aggregated due to minimum links not met
       u - unsuitable for bundling
       d - default port  
       
       w - waiting to be aggregated 

Group Port-channel Protocol   Ports
------+-------------+-----------+-------------------
5     Po5(SU)          -       Gi1/7/3(P) Gi1/7/4(P)
10    Po10(SU)         -       Gi2/4/45(P) Gi2/4/46(P) 

SW1#

Reference

Comments
marek.golha
Level 1
Level 1

Hi,

I read the section in configuration guide - but as you already stated it is not so clear (from my point of view)... In the presentation slide there is specifically stated that you must use the same base model 16 or 32 for 4500-X to configure VSS. I didnt tested the combination of 16 and 32 4500-X models in one VSS pair - maybe some people did (please comment)?

It could be that it works, but another question is: Is this supported? (I dont know...)

 

Marek

Kin Tak Lau
Level 1
Level 1

Hi,

 

I want to know if i can use the rest of  twelve 10giga uplink ports on Sup 8E in VSS mode(Total sixteen 10giga ports four used for vss).

 

Thanks

cshaw5901
Level 1
Level 1

After the VSS conversion, both SUP mods will become the same name, (Core1 in your case) as they sync and share the configuration.  You can only make config changes on the active switch and they will sync the changes within a few minutes.  There will be a log event to show if you watch carefully. 

For example, Lets say you had SW1 and SW2 that you were putting in VSS, after the conversion and if SW1 rebooted first, the VSS config sync happens between the two switches and they both become SW1.  Vice versa is true as well, if during the initial VSS conversion SW2 reboots first, both SUP mods will become SW2 until after you apply a new hostname during your configurations.  Even though they are logically two different SUP mods, VSS treats them as a Supervisor and it's identical twin backup.  I believe you can even assign a virtual mac address for them to share as well to help the arp tables when failover does occur. 
 

cshaw5901
Level 1
Level 1

All the access ports in both chassis' will be active, however the standby supervisor will only accept config updates/sync on the VSL from the active Sup mod.  Nothing can be manually done to the standby. 

jamesdanielkirk
Level 1
Level 1

Good Article and it helped me a great deal setting up my first one. Thanks a lot!

Indy Wijayathilaka
Community Member

Hi, If all the configuration is correct, how long(minutes) VSS pair takes to boot up to get the console access? What would be the maximum time in minutes that 4500x vss pair takes to boot up from cold start and function normally. Are there any Cisco documentation about different models of switch start up times.

cshaw5901
Level 1
Level 1

In my experience, 4507 and 4510 chassis take around 8 minutes for start up and another 4 or so minutes for full VSS sync to occur.  I've implemented dozens of VSS pairs over the last year. 

cshaw5901
Level 1
Level 1

Let it be known that with 03.06.01 image, you have to hardcode the trunking to the port-channels.  Port-channel 1/switch virtual link one, will show up as a trunk still.  However, there is a bug that prevents the Port-channel 2/switch virtual link 2 as showing up as a trunk when "show run" is used.  "Show interface trunk and show interface status" still shows the link as trunk and VSS failover will still occur, but without adding "switchport mode trunk" to the port-channels themselves, "show run" will not show the second port-channel and it's corresponding interfaces as trunks.

SW2(config)#int port-channel 10
SW2(config-if)#switchport
SW2(config-if)#switch virtual link 2
SW2(config-if)#switchport mode trunk  <-- must add this to both port-channels now...
SW2(config-if)#no shut
yeowtiongt
Level 1
Level 1

Hi nice article... I was trying out with Cisco quad sup on 4510... I understand that quad sup with ultra high availability is not available as of now...The 2nd sup engine on each vss switch would have to be in rmon mode right?

Q: How can we always ensure that redundant sup always stay in rmon?

 

Q: in the event of the active or standby sup failure , how do we bring the rmon sup into operation? How can we sync the configuration ? 

 

Thx 

Robert.cotterman
Community Member

I have spent the last 4 hours trying to get a 16 and 32 to talk with no success. I have a feeling that it must be the same model.

It keeps booting the standby into rommon. and ignores a ton of other settings during this.

marek.golha
Level 1
Level 1

As far as I know - the switches in VSS must be the same model.

Marek

MDBC_cisco
Level 1
Level 1

hi you need to configure manually VSS on the ICS sup 

MDBC_cisco
Level 1
Level 1

quad-sup work 4507R+E Sup 8E cisco IOS 3.8.0

yeowtiongt
Level 1
Level 1

Hi, any good documentation or example for that? Thx!

MDBC_cisco
Level 1
Level 1

I used two chassis C4507R+E and two sup-8E per chassis running cisco IOS-XE 03.08.00.E work perfect the active sup use SSO and ISC use RPR is the only solution for quad sup on 4500 series

http://pastebin.com/329X8fD7

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