Friday, 7 November 2014
Virtual Switching System - VSS on Cisco Catalyst 4500E
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.
The Cisco VSS simplifies
network configuration and operation by providing a loop-free Layer 2 topology
using two Catalyst 4500 switches acting as one big Virtual switch. VSS reduces
number of Layer 3 routing neighbors by providing a Layer 2 connectivity for
access/distribution switches.
A VSS is a pair of combined 4500 switches acting as a single network element with redundancy and load
balancing over port-channels (ether channels). One switch becomes the master or
active chassis and the other one becomes the VSS standby.
VSS Switch Roles
VSS Active:
The active chassis
controls the VSS operation. It runs the control plane, L2 and L3 control
protocols. It also runs the management plane functions like console interface,
logs, file system and even power management.
VSS Standby:
Listens to master,
checks the status, forwards the ingress traffic but sends all control traffic
to the VSS active chassis for processing.
Virtual Switch Link:
To share control
and data traffic between two chassis a VSL – Virtual Switch Link is required. VSL
is implemented as a Port Channel. The control traffic gets higher priority over
data on a VSL and never gets discarded.
Physical vs Logical Topology in a VSS Configuration
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
|
|
No
|
Yes
(SUP7E only) |
Yes
|
|
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: Configure SSO [Statefull Switchover] and assign Virtual Switch Domain and Switch Numbers
SW1#conf t
SW1(config)#redundancy
SW1(config-red)#sso
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[Route Processor Redudancy] 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#
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