VSS-DOC

© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 1

Virtual Switching System (VSS) on the Catalyst 6500

March 2008

Lila RousseauxConsulting Systems [email protected]

CCIE #6899

© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential 2

Virtual Switching Architecture

Etherchannel Concepts

Integrated Services Routers

Introduction to VSS

Agenda

Hardware Requirements

Conversion Process

Operational Management

High Availability

Quality of Service


Current Network ChallengesEnterprise Campus

Traditional Enterprise Campus deployments have been designed in such a way that allows for scalability, differentiated services and high availability. However they also face many challenges, some of which are listed in the below diagram…

Access

L2/L3 Distribution

L3 Core

FHRP, STP, Asymmetric routing,Policy Management

Extensive routing topology, Routing reconvergence

Single active uplink per VLAN (PVST), L2 reconvergence


Current Network ChallengesData Center

Traditional Data Center designs are requiring ever increasing Layer 2 adjacencies between Server nodes due to prevalence of Virtualization technology. However, they are pushing the limits of Layer 2 networks, placing more burden on loop-detection protocols such as Spanning Tree…

L2/L3 Core

L2 Distribution

L2 Access

Dual-Homed Servers to single switch, Single active uplink per VLAN (PVST), L2 reconvergence

Single active uplink per VLAN (PVST), L2 reconvergence, excessive BPDUs

FHRP, HSRP, VRRPSpanning TreePolicy Management


Virtual Switching SystemIntroduction

Virtual Switching System is a new technology break through for the Catalyst 6500 family…


Virtual Switching SystemEnterprise Campus

A Virtual Switch-enabled Enterprise Campus network takes on multiple benefits including simplified management & administration, facilitating greater high availability, while maintaining a flexible and scalable architecture…

Access

L2/L3 Distribution

L3 Core

No FHRPsNo Looped topologyPolicy Management

Reduced routing neighbors, Minimal L3 reconvergence

Multiple active uplinks per VLAN, No STP convergence


Virtual Switching SystemData Center

A Virtual Switch-enabled Data Center allows for maximum scalability so bandwidth can be added when required, but still providing a larger Layer 2 hierarchical architecture free of reliance on Spanning Tree…

L2/L3 Core

L2 Distribution

L2 Access

Dual-Homed Servers, Single active uplink per VLAN (PVST), Fast L2 convergence

Dual Active Uplinks, Fast L2 convergence, minimized L2 Control Plane, Scalable

Single router node, Fast L2 convergence, Scalable architecture


Virtual Switching SystemWhat is a VSS?


Virtual Switching SystemControl Plane

While the Data Planes in both switches are active, only one switch has an active control plane - hence there is only one management point from which to manage the Virtual Switching System…


Virtual Switching SystemData Plane

The Data Planes in both switches are active - hence each has a full copy of the forwarding tables and Security/QOS policies in hardware such that each can make a fully informed local forwarding decision…


Virtual Switching SystemVirtual Switch Link

The Virtual Switch Link is a special link joining each physical switch together - it extends the out of band channel allowing the active control plane to manage the hardware in the second chassis…


Virtual Switching SystemMulti Chassis Etherchannel

Virtual Switching System introduces new connectivity options such as Multichassis EtherChannel…


Virtual Switching SystemInter Chassis NSF/SSO





Introduction to VSS

Agenda


Conversion Process


High Availability

Quality of Service


Virtual Switch ArchitectureVirtual Switch Link

The Virtual Switch Link is a special link joining each physical switch together - it extends the out of band channel allowing the active control plane to manage the hardware in the second chassis…


Virtual Switch ArchitectureVSL Initialization

Before the Virtual Switch domain can become active, the Virtual Switch Link (VSL) must be brought online to determine Active and Standby roles. The initialization process essentially consists of 3 steps:

Role Resolution Protocol (RRP) used to determine compatible Hardware and Software versions to form the VSL as well as determine which switch becomes Active and Hot Standby from a control plane perspective

Role Resolution Protocol (RRP) used to determine compatible Hardware and Software versions to form the VSL as well as determine which switch becomes Active and Hot Standby from a control plane perspective

LMPLMP LMPLMPRRPRRPRRPRRP

Link Management Protocol (LMP) used to track and reject Unidirectional Links, Exchange ChassisID and other information between the 2 switches Link Management Protocol (LMP) used to track and reject Unidirectional Links, Exchange ChassisID and other information between the 2 switches

Link Bringup to determine which ports form the VSLLink Bringup to determine which ports form the VSL1

2

3


Virtual Switch ArchitectureLink Bringup

Pre-Parse ConfigSwitch 1




Each member of the Virtual Switch domain must determine which links are candidate for VSL very early on in the bootup cycle. The Switch Processor (SP) pre-parses the configuration to determine which links are configured for VSL…

The SP will then bring up the line card/s where the VSL is configured, download the required configuration and initiate Link Management Protocol (LMP)


Virtual Switch ArchitectureLink Management Protocol (LMP)

LMP runs on each individual link that is part of the VSL, and is used to program information such as member details, forwarding indices, as well as perform the following checks:

LMPLMP LMPLMP

LMPLMP LMPLMP

Verify neighbor is Bi-DirectionalEnsure the member is connected to another Virtual SwitchTransmit and receive keepalives to maintain health of the member and the VSL

123

After successful LMP negotiation, a Peer Group (PG) is formed which is a collection of all VSL members that connects to the same VS. For each PG, a Peer Group Control Link (PGCL) is elected to carry further control information…


Virtual Switch ArchitectureRole Resolution Protocol (RRP)

RRP is used to negotiate the role (active or standby) for each chassis:

Determine whether hardware and software versions allow a Virtual Switch to formDetermine which chassis will become Active and Hot Standby from a control plane perspective

12

RRPRRP RRPRRP

RRPRRP RRPRRPVSL


Virtual Switch ArchitectureVSL Configuration Consistency Check

After the roles have been resolved through RRP, a Configuration Consistency Check is performed across the VSL switches to ensure proper VSL operation. The following items are checked for consistency:

Switch Virtual Domain IDSwitch Virtual Domain ID

Switch Virtual Node TypeSwitch Virtual Node Type

Switch PrioritySwitch Priority

Switch PreemptSwitch Preempt

VSL Port Channel Link IDVSL Port Channel Link ID

VSL Port state, interfaces…VSL Port state, interfaces…

Power Redundancy modePower Redundancy mode

Power Enable on VSL cardsPower Enable on VSL cards

Note that if configurations do not match, the standby switch will revert to RPR mode, disabling all non-VSL interfaces…

Note that if configurations do not match, the standby switch will revert to RPR mode, disabling all non-VSL interfaces…


Virtual Switch ArchitectureVSLP Ping

A new Ping mechanism has been implemented in VSS mode to allow the user to objectively verify the health of the VSL itself. This is implemented as a VSLP Ping…

VSL

Switch 1 Switch 2VSLPVSLP VSLPVSLP

VSLPVSLP VSLPVSLP

vss#ping vslp output interface tenGigabitEthernet 1/5/4

Type escape sequence to abort.Sending 5, 100-byte VSLP ping to peer-sup via output port 1/5/4, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 12/12/16 msvss#

vss#ping vslp output interface tenGigabitEthernet 1/5/4

Type escape sequence to abort.Sending 5, 100-byte VSLP ping to peer-sup via output port 1/5/4, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 12/12/16 msvss#

The VSLP Ping operates on a per-physical interface basis and parameters such as COUNT, DESTINATION, SIZE, TIMEOUT may also be specified…


Virtual Switch ArchitectureForwarding Operation

In Virtual Switch Mode, while only one Control plane is active, both Data Planes (Switch Fabric’s) are active, and as such, each can actively participate in the forwarding of data …

Virtual Switch Domain

Switch 1 - Control Plane Active Switch 2 - Control Plane Hot Standby


Switch 1 - Data Plane Active Switch 2 - Data Plane Active


Virtual Switch ArchitectureVirtual Switch Domain

A Virtual Switch Domain ID is allocated during the conversion process and represents the logical grouping the 2 physical chassis within a VSS. It is possible to have multiple VS Domains throughout the network…

The configurable values for the domain ID are 1-255. It is always recommended to use a unique VS Domain ID for each VS Domain throughout the network…The configurable values for the domain ID are 1-255. It is always recommended to use a unique VS Domain ID for each VS Domain throughout the network…

VS Domain 10

VS Domain 20 VS Domain 30


Virtual Switch ArchitectureRouter MAC Address

In a standalone Catalyst 6500 system, the router MAC address is derived from the Chassis MAC EEPROM and is unique to each Chassis. In a Virtual Switch System, since there is only a single routing entity now, there is also only ONE single router MAC address…

Router MAC = 000f.f8aa.9c00Router MAC = 000f.f8aa.9c00

The MAC address allocated to the Virtual Switch System is derived from the MAC EEPROM of the Active Virtual Switch upon initial system bring up. Regardless of either switch being brought down or up, the same MAC address will be retained such that neighboring network nodes and hosts do not need to re-ARP for a new address.





Introduction to VSS

Agenda


Conversion Process


High Availability

Quality of Service


Etherchannel ConceptsAn Etherchannel combines multiple physical links into a single logical link. Ideal for load sharing or link redundancy – can be used by both layer 2 and Layer 3 subsystems…

Physical ViewMultiple ports are defined as being

part of an Etherchannel

group

Logical ViewSubsystems running

on the switch only see one logical link

An Etherchannel can be defined on Ethernet, Fast Ethernet, Gigabit Ethernet or 10 Gigabit Ethernet Ports

An Etherchannel can be defined on Ethernet, Fast Ethernet, Gigabit Ethernet or 10 Gigabit Ethernet Ports


The distribution of traffic across the members of the Etherchannel done through different hash schemes. With the PFC3C running 12.2(33)SXH software, there are 13 possible different hash schemes to choose from:

Etherchannel ConceptsTraffic Distribution and Hashing

Selection of the hash scheme of choice is largely dependent on the traffic mix through the EtherChannelThe hash scheme may only be selected on a global basis.


Etherchannel ConceptsMultichassis EtherChannel (MEC)

Prior to VS, Etherchannels were restricted to reside within the same physical switch. In a Virtual Switch environment, Etherchannels can now also be extended across the 2 physical chassis…As a result, MECs allows for new network designs to be implemented where true layer 2 Multi-pathing can be implemented without the reliance on protocols such as Spanning Tree.

Regular Etherchannel on single chassis Multichassis EtherChannel across 2 VSL-enabled Chassis

Virtual Switch Virtual Switch

Both LACP and PAGP Etherchannel protocols and Manual ON modes are

supported…

Both LACP and PAGP Etherchannel protocols and Manual ON modes are

supported…


Etherchannel ConceptsMultichassis EtherChannel

Support for Etherchannel management is performed by the Control plane on the Active Switch in the Virtual Switch Domain…

Standby Control Plane

Active Control Plane

• MEC links on both the switches in the VS domain are managed by PAgP or LACP running on the Active Switch via internal control messages.

• PAgP or LACP packets destined to a MEC link on the standby core will be sent across VSL

• MEC links on both the switches in the VS domain are managed by PAgP or LACP running on the Active Switch via internal control messages.

• PAgP or LACP packets destined to a MEC link on the standby core will be sent across VSL


Etherchannel ConceptsEtherchannel Hash for MEC

Deciding on which link of a Multi-chassis Etherchannel to use in a Virtual Switch is skewed in favor towards local links in the bundle - this is done to avoid overloading the Virtual Switch Link (VSL) with unnecessary traffic loads…

Link A1 Link B2

Blue Traffic destined for the Server will result in Link A1 in the MEC link bundle being chosen as the destination path…

Orange Traffic destined for the Server will result in Link B2 in the MEC link bundle being chosen as the destination path…

Server

Switch 1 Switch 2


Etherchannel ConceptsEtherchannel Hash for MEC

The Result Bundle Hash (RBH) values are reprogrammed for each core to reflect only the local links that are in the Etherchannel bundle…

Virtual SwitchSwitch 1 Switch 2

RBH (No MEC)8 Link Bundle Example

RBH (No MEC)8 Link Bundle Example

RBH (for MEC)8 Link Bundle Example


Bit 7Bit 7 Link 1Link 1Bit 6Bit 6 Link 2Link 2Bit 5Bit 5 Link 3Link 3Bit 4Bit 4 Link 4Link 4Bit 3Bit 3 Link 5Link 5Bit 2Bit 2 Link 6Link 6Bit 1Bit 1 Link 7Link 7Bit 0Bit 0 Link 8Link 8

Bit 7Bit 7 Link 1Link 1Bit 6Bit 6 Link 1Link 1Bit 5Bit 5 Link 2Link 2Bit 4Bit 4 Link 2Link 2Bit 3Bit 3 Link 3Link 3Bit 2Bit 2 Link 3Link 3Bit 1Bit 1 Link 4Link 4Bit 0Bit 0 Link 4Link 4

1 2 3 4 5 6 7 8

MEC

Access-SWA

Access-SWB


Etherchannel ConceptsEtherchannel Hash Distribution Enhancement

A new hash distribution algorithm has been introduced with the 12.2(33)SXH release which allows for members of a port channel to be added or removed without the requirement for all traffic on the existing members to be temporarily dropped…





Flow 1Flow 1 Flow 2Flow 2Flow 4Flow 4 Flow 5Flow 5Flow 7Flow 7 Flow 8Flow 8

Flow 3Flow 3Flow 6Flow 6

The existing hash distribution algorithm requires 100% of flows to be temporarily dropped such that duplicate frames are not sent into the network for the duration of time it takes to reprogram the port ASICs with the new member information…

Link 1Link 1 Link 2Link 2

Flow 1Flow 1 Flow 2Flow 2Flow 3Flow 3 Flow 4Flow 4Flow 5Flow 5 Flow 6Flow 6Flow 7Flow 7 Flow 8Flow 8

Link 1Link 1 Link 2Link 2 Link 3Link 3


Etherchannel ConceptsEtherchannel Hash Distribution Enhancement

Now, when ports are added or removed from an EtherChannel, the load result does not need to be reset on existing member ports, resulting in better recovery times of traffic.Hence it does not affect 100% of the traffic in an Etherchannel. Example below: only Flow 7 and 8 are affected by the addition of an extra link to the Channel





Flow 1Flow 1 Flow 2Flow 2Flow 3Flow 3 Flow 4Flow 4Flow 5Flow 5 Flow 6Flow 6

Flow 7Flow 7Flow 8Flow 8

Link 1Link 1 Link 2Link 2

Flow 1Flow 1 Flow 2Flow 2Flow 3Flow 3 Flow 4Flow 4Flow 5Flow 5 Flow 6Flow 6Flow 7Flow 7 Flow 8Flow 8

Link 1Link 1 Link 2Link 2 Link 3Link 3

vss#conf tEnter configuration commands, one per line. End with CNTL/Z.vss(config)#port-channel hash-distribution adaptivevss(config)# ^Zvss#

vss#conf tEnter configuration commands, one per line. End with CNTL/Z.vss(config)#port-channel hash-distribution adaptivevss(config)# ^Zvss#

Although this new load-distribution algorithm requires configuration for regular EtherChanneland Multi-Chassis EtherChannel (MEC) interfaces, it will be the default load-distribution algorithm used on the VSLs


Etherchannel ConceptsDetermination of Hash Result

vss#sh etherchannel load-balance hash-result interface port-channel 120 ip 192.168.220.10 192.168.10.10

Computed RBH: 0x4Would select Gi1/2/1 of Po120

vss#sh etherchannel load-balance hash-result interface port-channel 120 ip 192.168.220.10 192.168.10.10

Computed RBH: 0x4Would select Gi1/2/1 of Po120

A command can be invoked to allow users to determine which physical link a given flow of traffic will leverage within a port channel group. The user will need to provide inputs to the command and the hashing algorithm will compute the physical link that will be selected for the traffic mix and algorithm.


Virtual Switching SystemDeployment Considerations

VSS will incorporate some deployment considerations as best practice…





Introduction to VSS

Agenda


Conversion Process


High Availability

Quality of Service


Virtual Switching SystemVSL Hardware Considerations

The Virtual Switch Link requires special hardware as noted below…


Virtual Switching SystemOther Hardware Considerations


Virtual Switching SystemSoftware Considerations

Along with the hardware considerations, Virtual Switching System also has some software considerations…

12.2(33)SXH1 is the first version that supports VSS


Hardware RequirementsDistributed Forwarding Cards

Distributed Forwarding Cards (DFCs) improve the performance of the Catalyst 6500 by offloading thelookup processing from the PFC to the ingress linecard. Only DFC3C or DFC3CXL is supported in a Virtual Switch domain. If DFCs are not used on CEF720 modules, a Centralized Forwarding Card (CFC) must be installed in its place…

Note that if a lower revision DFC (3A, 3B or 3BXL) is used in a VSL domain, the system will fall to a lowest common

denominator mode which will not allow support for VSL…

Note that if a lower revision DFC (3A, 3B or 3BXL) is used in a VSL domain, the system will fall to a lowest common

denominator mode which will not allow support for VSL…


Catalyst 6500 SupervisorsPFC3A vs. PFC3B vs. PFC3C

No4KYesYesYes

500K64K (32K)

256K (230K)1M1M

12.2(17d)SXB1

Sup720PFC3B-XL

Yes4KYesYesYes

128K96K(80K)

128K (115K)1M

256K12.2(33)SXH

Sup720-10GbEPFC3C

Yes4KYesYesYes

500K96(80K)

256K(230K)1M1M

12.2(33)SXH 12.2(33)SXH

Sup720-10GbE

PFC3C-XL

12.2(17)SXB / 12.2(18)SXF12.2(17)SXBSW

Sup720 / Sup32Sup720Supervisor

No512NoNoNo

128K64K (32K)

128K (64K)1M

256K

PFC3A

NoVSL4KYesYesYes

128K64K (32K)

128K (115K)1M

256K

PFC3B

ACL LabelsACE CountersEoMPLSNative MPLSIPv6 FIB EntriesMAC TableNetFlow TableAdjacency TableFIB TCAM

Sup/Feature

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/product_data_sheet09186a0080159856_ps4835_Products_Data_Sheet.htmlhttp://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps9336/product_data_sheet0900aecd806ed759.html





Introduction to VSS

Agenda


Conversion Process


High Availability

Quality of Service


Conversion ProcessConversion to VSS

The conversion process requires configuration of both switches that will form part of the Virtual Switch Domain and requires a reboot on the part of both switches during the conversion…

It is recommended to have the interfaces forming the VSL be connected prior to the conversion process as it will minimize the number of times the chassis will be reloaded. It is also recommended to begin the conversion process using a default configuration as the conversion process will remove any previous configuration that pre-exists on the standalone chassis.



For the purposes of this explanation - let’s assume the following setup is required…

Switch - 1 Switch - 2

VSL Link Bundle T5/4

T5/5

T5/4

T5/5

Port-Channel 1 Port-Channel 2

Switch Virtual Domain #10


Conversion ProcessStep 1: Configure Virtual Switch ID and Domain

On the two switches, configure the same VS Domain number (in this case it is 10), but unique Switch IDs


Router(config)#host VSSVSS(config)#switch virtual domain 10

Domain ID 10 config will take effect onlyafter the exec command 'switch convert mode virtual' is issued

VSS(config-vs-domain)#switch 1VSS(config-vs-domain)#exit

Router(config)#host VSSVSS(config)#switch virtual domain 10

Domain ID 10 config will take effect onlyafter the exec command 'switch convert mode virtual' is issued

VSS(config-vs-domain)#switch 2VSS(config-vs-domain)#exit

Note: The Domain ID is retained in the configuration, but the Switch ID is not – this is stored as a variable in ROMMON. To see this value:


Conversion ProcessStep 2: VSL Configuration – Configure the VSL Port Channel and member portsChoose unique Port Channel IDs for each chassis to form the VSL and configure them with the corresponding Switch IDAdd the ports on each switch to the port channel that corresponds to the respective side of the VSL


VSS(config)#interface port-channel 1! Associates Switch 1 as owner of port channel 1VSS(config-if)#switch virtual link 1

VSS(config-if)#interface range tenG 5/4 - 5! Adds this interface to channel group 1VSS(config-if-range)#channel-group 1 mode on

VSS(config-if)#interface port-channel 2! Associates Switch 2 as owner of port channel 2VSS(config-if)#switch virtual link 2

VSS(config-if)#interface range tenG 5/4 - 5! Adds this interface to channel group 2VSS(config-if-range)#channel-group 2 mode on


Conversion ProcessStep 3: Convert to Virtual Switch Mode

Convert both switches to Virtual Switch mode using the following exec command:


vss#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]: yesConverting interface namesBuilding configuration...[OK]Saving converted configuration to bootflash: ...Destination filename [startup-config.converted_vs-20071031-150039]?

AT THIS POINT THE SWITCH WILL REBOOT

vss#switch convert mode virtual

This command will convert all interface namesto 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]: yesConverting interface namesBuilding configuration...[OK]Saving converted configuration to bootflash: ...Destination filename [startup-config.converted_vs-20071031-150018]?

AT THIS POINT THE SWITCH WILL REBOOT


Conversion ProcessWhen the two switches are brought online, they will proceed with VSL initialization and bring up their respective VSL ports. The two switches communicate with each other and determine Active and Standby role.


SWITCH CONSOLE OUTPUT

<…snip…>System detected Virtual Switch configuration...Interface TenGigabitEthernet 1/5/4 is member

of PortChannel 1 Interface TenGigabitEthernet 1/5/5 is member

of PortChannel 1

<…snip…>00:00:26: %PFREDUN-6-ACTIVE: Initializing as ACTIVE processor for this switchInitializing as Virtual Switch ACTIVE processor

<…snip…>00:01:19: %VSLP-5-RRP_ROLE_RESOLVED: Role resolved as ACTIVE by VSLP00:01:19: %VSL-5-VSL_CNTRL_LINK: New VSL Control Link 5/4

SWITCH CONSOLE OUTPUT

<…snip…>System detected Virtual Switch configuration...Interface TenGigabitEthernet 2/5/4 is member

of PortChannel 2 Interface TenGigabitEthernet 2/5/5 is member

of PortChannel 2

<…snip…>00:00:26: %PFREDUN-6-ACTIVE: Initializing as ACTIVE processor for this switchInitializing as Virtual Switch STANDBY processor

<…snip…>00:01:02: %VSLP-5-RRP_ROLE_RESOLVED: Role resolved as STANDBY by VSLP00:01:02: %VSL-5-VSL_CNTRL_LINK: New VSL Control Link 5/4


Conversion ProcessStep 4: Finalize Virtual Switch Configuration

This command will get the VSL related commands from the Standby Switch and update the startup-configuration with the new merged configurationsNote that only VSL-related configurations are merged with this step – all other configuration will be lost and requires manual intervention.This step is only applicable for a first-time conversion.

Switch - 1SWITCH CONSOLE OUTPUT

<…snip…>vss-demo#switch accept mode virtual

This command will populate the above VSL configuration from the standby switch into the running configuration.The startup configuration will also be updated with the new merged configuration if merging is successful.Do you want to proceed? [yes/no]: yesMerging the standby VSL configuration...

Building configuration...

00:11:33: %PFINIT-SW1_SP-5-CONFIG_SYNC: Sync'ing the startup configuration to the standby Router. [OK]



Configuration for the conversion takes the following path…


vss#sh switch virtualSwitch mode : Virtual SwitchVirtual switch domain number : 10Local switch number : 1Local switch operational role: Virtual Switch ActivePeer switch number : 2Peer switch operational role : Virtual Switch Standbyvss-demo#

vss-sdby>enStandby console disabled

vss-sdby>

Both switches are now converted with Switch 1 as the Master (Active) and Switch 2 as the Standby

Switch 2 console is now disabled for normal console activity…


Conversion ProcessBoot-up Priority

Normal operation is for first switch to boot to assume VS Active role - this behavior can be changed allowing a pre defined switch to assume Active role by specifying a priority (higher priority uses a higher number)…

VSS#sh switch virtual role

Switch Switch Status Preempt Priority Role Session IDNumber Oper(Conf) Oper(Conf) Local Remote

------------------------------------------------------------------LOCAL 1 UP FALSE(N) 110(110) ACTIVE 0 0 REMOTE 2 UP FALSE(N) 100(100) STANDBY 9114 1391

VSS#sh switch virtual role

Switch Switch Status Preempt Priority Role Session IDNumber Oper(Conf) Oper(Conf) Local Remote

------------------------------------------------------------------LOCAL 1 UP FALSE(N) 110(110) ACTIVE 0 0 REMOTE 2 UP FALSE(N) 100(100) STANDBY 9114 1391


Switch PreemptionOnce the active and standby roles have been determined, they cannot be changed without manual interventionIf we need to always prefer a particular physical switch to assume the Virtual Switch Active role, then we can leverage the Switch Preemption feature.Please Note: Use this feature with caution since preemption is not advisable in most designs. The SSO behavior requires that in order for switch 1 to become active switch 2 will have to reboot to come up in standby mode. So unlike HSRP pre-emption where we have reasons to pre-empt and we have very little impact to active traffic flows in the VSS case there is no reason to move the active role (and we do suffer from a full reboot of one of the two switches





Introduction to VSS

Agenda


Conversion Process


High Availability

Quality of Service


Operational ManagementVirtual Switch CLI

Multiple console interfaces exist within a Virtual Switch Domain, but only the active RP/SP consoles are enabled for command interaction…


Operational ManagementReloading the VSS and reloading a member

The command “reload” will reload entire Virtual Switch System (both chassis)To reload each chassis individually we need to specify the Switch ID

vss#reloadWarning: This command will reload the entire Virtual Switching System (Active and Standby Switch).Proceed with reload? [confirm]

1d04h: %SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload Command.

****** --- SHUTDOWN NOW ---***

1d04h: %SYS-SP-5-RELOAD: Reload requestedSystem Bootstrap, Version 8.5(1)Copyright (c) 1994-2006 by cisco Systems, Inc.Cat6k-Sup720/SP processor with 1048576 Kbytes of main memory<…snip…>

vss#reloadWarning: This command will reload the entire Virtual Switching System (Active and Standby Switch).Proceed with reload? [confirm]

1d04h: %SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload Command.

****** --- SHUTDOWN NOW ---***

1d04h: %SYS-SP-5-RELOAD: Reload requestedSystem Bootstrap, Version 8.5(1)Copyright (c) 1994-2006 by cisco Systems, Inc.Cat6k-Sup720/SP processor with 1048576 Kbytes of main memory<…snip…>

vss#redundancy reload shelf ?<1-2> shelf id<cr>

vss#redundancy reload shelf 2Reload the entire remote shelf[confirm]Preparing to reload remote shelf

vss#

vss#redundancy reload shelf ?<1-2> shelf id<cr>

vss#redundancy reload shelf 2Reload the entire remote shelf[confirm]Preparing to reload remote shelf

vss#


Operational ManagementSetting the System-wide PFC Mode

• Only PFC/DFC 3C/CXL are supported in a VSS. • It is possible to mix modules in a 3C and 3CXL system: the system will take the lowest

common denominator as the system-wide PFC mode. • In a VSL environment is basically the mode negotiation happens even before the modules

are brought up• A new CLI has been implemented to allow the user to pre-configure the system mode to

prevent modules from not powering up…

vs-vsl#conf tEnter configuration commands, one per line. End with CNTL/Z.vs-vsl(config)#platform hardware vsl pfc mode pfc3cvs-vsl(config)#^Zvs-vsl#

vs-vsl#conf tEnter configuration commands, one per line. End with CNTL/Z.vs-vsl(config)#platform hardware vsl pfc mode pfc3cvs-vsl(config)#^Zvs-vsl#

vs-vsl#sh platform hardware pfc modePFC operating mode : PFC3CConfigured PFC operating mode : PFC3Cvs-vsl#

vs-vsl#sh platform hardware pfc modePFC operating mode : PFC3CConfigured PFC operating mode : PFC3Cvs-vsl#


Operational Management SNMP Support for VSS

The SNMP process for a VSS necessitates support for “Put’s” and “Get’s” across 2 physical chassis, changes to existing MIB’s and support for a new MIB…


Switch 1 - Active Switch 2 - Standby

SNMP Process Active SNMP Process Inactive

SNMP Server

SNMP Get’sSNMP Put’s

SNMP Modified MIB’s

SNMP Modified MIB’s

SNMP New MIB’sSNMP New MIB’s

CISCO-VIRTUAL-SWITCH-MIB has been defined to support SNMP access to the Virtual Switch Configuration - the following MIB variables are accessible to an SNMP manager…


Operational ManagementSlot/Port Numbering

After conversion, port definitions for switches within the Virtual Switch Domain inherit the Chassis ID as part of their naming convention…

Router#show ip interface briefInterface IP-Address OK? Method Status ProtocolVlan1 unassigned YES NVRAM up up Port-channel1 unassigned YES NVRAM up up Te1/1/1 10.1.1.1 YES unset up up Te1/1/2 192.168.1.2 YES unset up up Te1/1/3 unassigned YES unset up up Te1/1/4 unassigned YES unset up up GigabitEthernet1/2/1 10.10.10.1 YES unset up up GigabitEthernet1/2/2 10.10.11.1 YES unset up up <snip>

Router#show ip interface briefInterface IP-Address OK? Method Status ProtocolVlan1 unassigned YES NVRAM up up Port-channel1 unassigned YES NVRAM up up Te1/1/1 10.1.1.1 YES unset up up Te1/1/2 192.168.1.2 YES unset up up Te1/1/3 unassigned YES unset up up Te1/1/4 unassigned YES unset up up GigabitEthernet1/2/1 10.10.10.1 YES unset up up GigabitEthernet1/2/2 10.10.11.1 YES unset up up <snip>

PORT NUMBERING: <CHASSIS-ID><SLOT-NUMBER><PORT-NUMBER>PORT NUMBERING: <CHASSIS-ID><SLOT-NUMBER><PORT-NUMBER>

Chassis-ID WILL ALWAYS be either a “1” or a “2”


After the conversion to a Virtual Switch, some of the File System naming conventions have changed to accommodate the new setup - an example of the new setup is shown below…

Active Supervisor - Slot 5 Hot Standby Supervisor - Slot 5


e.g.OLD: disk0:NEW: sw1-slot5-disk0:

Switch 1 Switch 2

e.g.OLD: slavedisk0:NEW: sw2-slot5-disk0:

SW<NUMBER>SLOT<NUMBER>FILESYSTEMSW<NUMBER>SLOT<NUMBER>FILESYSTEM

AN EXAMPLE

Operational ManagementFile System Naming


The Filesystems in a VSS environment are completely managed from the Active Switch’s console. All filesystem activities take place at single centralized location…

vs-vsl#dir sw1-slot5-sup-bootdisk:Directory of sup-bootdisk:/

1 -rwx 33554496 Jan 10 2007 14:53:16 +00:00 sea_log.dat2 -rwx 150198412 Feb 7 2007 17:28:56 +00:00 s72033-adventerprisek9_wan_dbg-vz.0124_all

vs-vsl#dir sw1-slot5-sup-bootdisk:Directory of sup-bootdisk:/

1 -rwx 33554496 Jan 10 2007 14:53:16 +00:00 sea_log.dat2 -rwx 150198412 Feb 7 2007 17:28:56 +00:00 s72033-adventerprisek9_wan_dbg-vz.0124_all

vs-vsl#dir sw2-slot5-sup-bootdisk:Directory of slavesup-bootdisk:/

1 -rwx 33554464 Feb 9 2007 16:39:02 +00:00 sea_log.dat2 -rwx 150678668 Feb 9 2007 16:45:14 +00:00 s72033-adventerprisek9_wan_dbg-vz.cef

vs-vsl#dir sw2-slot5-sup-bootdisk:Directory of slavesup-bootdisk:/

1 -rwx 33554464 Feb 9 2007 16:39:02 +00:00 sea_log.dat2 -rwx 150678668 Feb 9 2007 16:45:14 +00:00 s72033-adventerprisek9_wan_dbg-vz.cef



Some filenames have remained the same - others have changed - some examples of file system names in a Virtual Switch include the following…

VIRTUAL SWITCHVIRTUAL SWITCH

sw<number_1>slot<number>disk0:sw<number_1>slot<number>disk0:

PREVIOUSPREVIOUS

disk0:disk0:

sw<number_1>slot<number>bootflash:sw<number_1>slot<number>bootflash:bootflash:bootflash:

sw<number_1>slot<number>sup-bootdisk:sw<number_1>slot<number>sup-bootdisk:sup-bootdisk:sup-bootdisk:

sw<number_1>slot<number>nvram:sw<number_1>slot<number>nvram:nvram:nvram:

sw<number_2>slot<number>disk0:sw<number_2>slot<number>disk0:slavedisk0:slavedisk0:

sw<number_2>slot<number>bootflash:sw<number_2>slot<number>bootflash:slavebootflash:slavebootflash:

sw<number_2>slot<number>sup-bootdisk:sw<number_2>slot<number>sup-bootdisk:slavesup-bootdisk:slavesup-bootdisk:

sw<number_2>slot<number>nvram:sw<number_2>slot<number>nvram:slavenvram:slavenvram:



Operational ManagementNetflow

In a Virtual Switch, with both Data Planes active, Netflow data collection is performed on each Supervisor’s PFC - while Netflow export is only performed by the Control Plane on the VS Active …


VS State : ActiveControl Plane: ActiveData Plane: ActiveNetflow Collection: ActiveNetflow Export: Active

VS State : StandbyControl Plane: StandbyData Plane: ActiveNetflow Collection: ActiveNetflow Export: In-Active

VSL

Netflow operation in a Virtual Switch is similar to the way in which Netflow operates in a single chassis with Distributed Forwarding Card’s (DFC) present…

Switch 1 Supervisor Switch 2 Supervisor


Operational ManagementNetflow Export

The Virtual Switch Link will be used as the transit path to allow the standby Sup to forward Netflow data to the active Supervisor for Netflow export - the VS Link should be dimensioned to accommodate the expected Netflow export load…


VS State : ActiveNetflow Collection: ActiveNetflow Export: Active

VS State : StandbyNetflow Collection: ActiveNetflow Export: In-Active

VSL

NetflowData

NetflowData

NetflowExport

Netflow Collector



IOS Image Upgrade

SW1-Slot5 SW2-Slot5

Switch 1 Switch 2

Full image upgrade process using Fast Software Upgrade (FSU): similar to that of two supervisor engines within a standalone chassis today

NAMENAME CONTROL PLANECONTROL PLANE FABRIC STATEFABRIC STATE

SW1-SLOT5SW1-SLOT5 ActiveActive ActiveActive

SW2-SLOT5SW2-SLOT5 Hot StandbyHot Standby ActiveActive

REDUNDANCYREDUNDANCY

--

SSOSSO


IOS Image UpgradeManually copy the new image or filesystem onto the appropriate flash device of each supervisor. No impact to forwarding. 1

SW1-Slot5 SW2-Slot5

Switch 1 Switch 2





--

SSOSSO


IOS Image Upgrade

1 Commands to copy the new image to the flash file system of both supervisors (Active and Hot Standby)


IOS Image UpgradeModify boot variables to point to the new image or filesystem and reload Switch 2. Switch 2 should reset and boot into the new image in RPR mode. System bandwidth falls to 50%2

SW1-Slot5 SW2-Slot5

Switch 1 Switch 2



SW2-SLOT5SW2-SLOT5 ColdCold StandbyStandby


--

RPRRPR


IOS Image UpgradeModify the boot variable on Switch 1 (Active VS) to point to the new image or file system and save the configuration – this will synchronize the boot variable to Switch 2 (Standby VS) as well.

2.1


IOS Image UpgradeSchedule a change window and when possible, reload Switch 2 (Standby VS). 2.2


<snip>

<snip>

IOS Image UpgradeAfter successful boot up of the Switch 2 (Standby VS), verify the peer relationship between Supervisors are in RPR state (Cold Standby).

2.3


IOS Image UpgradeSwitch over Active supervisor to Switch 2 when desired. System capacity will drop to 0% temporarily and return to 50% once SW2-Slot5 completely boots up and becomes active. SW1-Slot5 will continue to boot up…

3

SW1-Slot5 SW2-Slot5

Switch 1 Switch 2


SW1-SLOT5SW1-SLOT5 ColdCold StandbyStandby



RPRRPR

--


IOS Image UpgradeWhen possible, perform a supervisor or chassis switchover such that Switch 2 (previous Standby VS) now assumes the Active role whilst Switch 1 (previous Active VS) is reloaded. At this time, a total VSS outage will be expected as Switch 2 transitions from an RPR Cold Standby state to the Active state.

3.1


IOS Image UpgradeOnce Switch 2 is completely online, it will re-peer with its neighbors and form any applicable relationships and traffic will be forwarded through the VSS again at 50% capacity while Switch 1 continues to boot up with the new image or filesystem.

3.2


IOS Image UpgradeAfter Switch 1 comes online again, it will return to SSO mode as it will now be running the new version of software and traffic will return to 100% capacity…

4

SW1-Slot5 SW2-Slot5

Switch 1 Switch 2





SSOSSO

--


IOS Image UpgradeAfter Switch 1 is completely brought back online and all interfaces are active, it will enter intoNSF/SSO state with Switch 2.

4

<snip>

<snip>


IOS Image UpgradeThe following graph illustrates the aggregate traffic for the VSL system during the full image upgrade:

1 43.23.12.32.22.1

1] Copy new image in both switches

2.1] Change bootvar in both switches

2.2] Reboot SW2

2.3] SW2 comes back in RPR

3.1] Switchover from SW1 to SW2

3.2] SW2 comes back from the Cold Standby mode

4] SW1 is completely rebooted and comes back in SSO mode





Introduction to VSS

Agenda


Conversion Process


High Availability

Quality of Service


High AvailabilityRedundancy Schemes

The default redundancy mechanism between the 2 VSS chassis and their associated supervisors is NSF/SSO, allowing state information and configuration to be synchronized. Only in NSF/SSO mode does the Standby supervisor PFC, Switch Fabric, modules and their associated DFCs become active…

VSL

Should a mismatch of information occur between the Active and Standby Chassis, the Standby Chassis will revert to RPR mode, where all the modules will be powered down (except for the VSL ports)

Switch 112.2(33)SXH1Active

Switch 212.2(33)SXH1NSF/SSO

VSL

Switch 112.2(33)SXH1Active

Switch 212.2(33)SXH2RPR


High AvailabilityDual-Active Detection

In a Virtual Switch Domain, one switch is elected as Active and the other is elected as Standby during bootup by VSLP. Since the VSL is always configured as a Port Channel, the possibility of the entire VSL bundle going down is remote, however it is a possibility…


VS State : ActiveControl Plane: ActiveData Plane: Active

VS State : StandbyControl Plane: StandbyData Plane: Active

VSL


It is always recommended to deploy the VSL with 2 or more links and distribute those interfaces across multiple modules to ensure the greatest redundancy

It is always recommended to deploy the VSL with 2 or more links and distribute those interfaces across multiple modules to ensure the greatest redundancy


High AvailabilityDual-Active Detection

If the entire VSL bundle should happen to go down, the Virtual Switch Domain will enter a Dual Active scenario where both switches transition to Active state and share the same network configuration (IP addresses, MAC address, Router IDs, etc…) potentially causing communication problems through the network…




VSL


2 mechanisms have been implemented in the initial release to detect and recover from a Dual Active scenario:

Enhanced Port Aggregation Protocol (PAgP+): uses MEC links to communicate between the two chassis

Dual-Active Detection over IP-BFD: uses a backup Ethernet connection.

1

2


High AvailabilityDual-Active Detection - Enhanced PAgP

PAgP+ adds new TLV (switch ID of the active switch) to remote devices connected via EtherChanneled to the Virtual Switch Domain. During normal operation the Virtual Switches will send the ID of the Active VS to the PAgPneighbor, and it will respond with the same Active ID…

Switch 1 Switch 2

Active: Switch 1 Active: Switch 1

Switch 1 Switch 2


Should the VSL go down, the Standby switch will transition immediately to Active state and start sending PAgP message with the new Active switch ID



The Enhnaced PAgP-capable neighbor will send the new Active Switch ID to all ports of the port channel that it received the new Active Switch ID onThis includes the the previous-active Virtual switch (Switch 1) …

Switch 1 Switch 2




Switch 1 Switch 2


Switch 1 Switch 2

Active: Switch 2

When Switch 1 receives PAgP messages with Active Switch = 2, it will know that a Dual-Active scenario has occurred Recovery Mode: Switch 1 will then bring down all non-VSL interfaces (except interfaces configured to be excluded from shutdown)

Dual-Active!!Dual-Active!!


vs-vsl#sh switch virtual dual-active pagp

Channel group 20 dual-active detect capability w/nbrsDual-Active version: 1.1Dual-Active configured: Yes

Dual-Active Partner Partner PartnerPort Detect Capable Name Port VersionGi1/8/1 Yes vs-access-1 Gi5/1 1.1Gi2/8/1 Yes vs-access-1 Gi5/2 1.1

vs-vsl#sh switch virtual dual-active pagp

Channel group 20 dual-active detect capability w/nbrsDual-Active version: 1.1Dual-Active configured: Yes

Dual-Active Partner Partner PartnerPort Detect Capable Name Port VersionGi1/8/1 Yes vs-access-1 Gi5/1 1.1Gi2/8/1 Yes vs-access-1 Gi5/2 1.1


vs-vsl#conf tEnter configuration commands, one per line. End with CNTL/Z.vs-vsl(config)#switch virtual domain 10vs-vsl(config-vs-domain)#dual-active detection pagpvs-vsl(config-vs-domain)#dual-active trust channel-group 20vs-vsl#

vs-vsl#conf tEnter configuration commands, one per line. End with CNTL/Z.vs-vsl(config)#switch virtual domain 10vs-vsl(config-vs-domain)#dual-active detection pagpvs-vsl(config-vs-domain)#dual-active trust channel-group 20vs-vsl#

Dual-Active Detection capabilities require that the neighboring device be Dual-Active Detection Aware. This can be verified with the following command…


High AvailabilityDual-Active Detection - IP-BFD

This method uses a dedicated L3 direct link heartbeat mechanism between the Virtual Switches. IP-BFD (Bi-Directional Forwarding Detection) is used to assist the fast detection of a failed VSL

If the VSL goes down, both chassis create BFD neighbors, and try to establish adjacency.If the original active chassis receives an adjacency message, it realizes that this is dual-active

scenario

If the VSL goes down, both chassis create BFD neighbors, and try to establish adjacency.If the original active chassis receives an adjacency message, it realizes that this is dual-active

scenario

VSL

IP-BFD Heartbeat LinkSwitch 1 Switch 2

VSL

IP-BFD Heartbeat LinkSwitch 1 Switch 2

BFDBFD BFDBFD


High AvailabilityDual-Active Detection - IP-BFD

vss(config)#interface gigabitethernet 1/5/1vss(config-if)#no switchportvss(config-if)#ip address 200.230.230.231 255.255.255.0vss(config-if)#bfd interval 100 min_rx 100 multiplier 50vss(config-if)#interface gigabitethernet 2/5/1vss(config-if)#no switchportvss(config-if)#ip address 201.230.230.231 255.255.255.0vss(config-if)#bfd interval 100 min_rx 100 multiplier 50vss(config)#switch virtual domain 100vss(config-vs-domain)#dual-active detection bfdvss(config-vs-domain)#dual-active pair interface g 1/5/1 interface g 2/5/1 bfd

adding a static route 200.230.230.0 255.255.255.0 Gi2/5/1 for this dual-active pairadding a static route 201.230.230.0 255.255.255.0 Gi1/5/1 for this dual-active pair

vss(config)#interface gigabitethernet 1/5/1vss(config-if)#no switchportvss(config-if)#ip address 200.230.230.231 255.255.255.0vss(config-if)#bfd interval 100 min_rx 100 multiplier 50vss(config-if)#interface gigabitethernet 2/5/1vss(config-if)#no switchportvss(config-if)#ip address 201.230.230.231 255.255.255.0vss(config-if)#bfd interval 100 min_rx 100 multiplier 50vss(config)#switch virtual domain 100vss(config-vs-domain)#dual-active detection bfdvss(config-vs-domain)#dual-active pair interface g 1/5/1 interface g 2/5/1 bfd

adding a static route 200.230.230.0 255.255.255.0 Gi2/5/1 for this dual-active pairadding a static route 201.230.230.0 255.255.255.0 Gi1/5/1 for this dual-active pair

Two directly-connected interfaces must be configured as BFD message links…The IP-BFD Heartbeat link may exist on any interface but must have an IP address assigned to it on a different network

Static routes are automatically added for the remote addresses and will only be installed in the RIB should a Dual-Active scenario occur. As a result of this, no packets will be forwarded between the switches via the heartbeat interfaces until the VSL is brought downIf the Virtual Switch Standby has taken over as active, a BFD “adjacency up” event will be generated, indicating a Dual-Active situation has occurred.


High AvailabilityDual-Active Detection - Exclude Interfaces

Upon detection of a Dual Active scenario, all interfaces on the previous-Active switch will be brought down so as not to disrupt the functioning of the remainder of the network.

The exception interfaces include VSL members as well as pre-determined interfaces which may be used for management purposes…

vs-vsl#conf tEnter configuration commands, one per line. End with CNTL/Z.vs-vsl(config)#switch virtual domain 100vs-vsl(config-vs-domain)#dual-active exclude interface Gig 1/5/1vs-vsl(config-vs-domain)#dual-active exclude interface Gig 2/5/1vs-vsl(config-vs-domain)# ^Zvs-vsl#

vs-vsl#conf tEnter configuration commands, one per line. End with CNTL/Z.vs-vsl(config)#switch virtual domain 100vs-vsl(config-vs-domain)#dual-active exclude interface Gig 1/5/1vs-vsl(config-vs-domain)#dual-active exclude interface Gig 2/5/1vs-vsl(config-vs-domain)# ^Zvs-vsl#


High AvailabilityDual-Active Recovery

The network administrator is notified of the Dual-Active situation through the CLI, syslog,etcUpon the restoration of one or more VSL interfaces, VSLP will detect this and will proceed to reload Switch 1 so that it may be able to re-negotiate Active/Standby role after bootup…

After role has been resolved and SSO Hot Standby mode is possible, interfaces will be brought up and traffic will resume back to 100% capacity…

VSL Up! Reload…VSL Up! Reload…

Switch 1 Switch 2

Switch 1 Switch 2VSLPVSLP VSLPVSLP





Introduction to VSS

Agenda


Conversion Process


High Availability

Quality of Service


Quality of ServiceClassification & Policing

Classification and Policing functions are handled by PFC QoS, and is executed by either the PFC on the Active and Hot Standby Supervisor, or the ingress linecard DFC. There are 2 important caveats which must be understood

Policies must either be applied on L3 interfaces (SVIs or Physical interfaces), or Port Channels. Policies on L2 interfaces are not supported in this release.

1

policy-map CLASSIFYclass class-defaultset ip dscp 40

interface GigabitEthernet 2/3/48switchportservice-policy input CLASSIFY


interface GigabitEthernet 2/3/48switchportservice-policy input CLASSIFY


interface PortChannel 10switchportservice-policy input CLASSIFY


interface PortChannel 10switchportservice-policy input CLASSIFY


policy-map POLICEclass class-defaultpolice average 10000000

Interface GigabitEthernet 1/2/10channel-group 20 mode desireable


interface PortChannel 20service-policy input POLICE

policy-map POLICEclass class-defaultpolice average 10000000



interface PortChannel 20service-policy input POLICE

Quality of Service - Classification & PolicingAggregate policers that are applied on SVIs or Port Channels that have interfaces distributed across multiple forwarding engines are subject to Distributed Policing caveats…

2


Quality of ServiceQoS on the VSL

The VSL itself has QoS provisioned by default and in the FCS release of the software, it is not configurable. A few important aspects relating to VSL QoS are as follows:

VSLP and other Control frames are always marked as Priority packets and are always queued and classified as such

1

VSL is always configured as “Trust CoS” and hence ingress queuing is enabled2

Service Policies are not supported on the VSL3

VSL

Switch 1 Switch 2

VSLPVSLPFTPFTPHTTPHTTP

CoS Maps, Thresholds and Queues are not configurable on the VSL4


Allows two physical Catalyst 6500’s to operate as a single logical Catalyst 6500 switchVSS reduces number of routing nodes and routing protocol overheadMulti-Chassis Etherchannel provides new benefits for STP elimination and improved resiliencyDual Active Recovery mechanisms for VSL failure VSS simplifies network complexity and management overhead by 50 percent, thus increasing operational efficiency and lowering operating expenses (OpEx).

Virtual Switching SystemSummary


Want more?

VSS Solution Overviewhttp://www.cisco.com/en/US/partner/prod/collateral/switches/ps5718/ps9336/product_solution_overview0900aecd806fa5d0.html

Whitepaper: Cisco Catalyst 6500 Series Virtual Switching System (VSS) 1440http://www.cisco.com/en/US/partner/prod/collateral/switches/ps5718/ps9336/prod_white_paper0900aecd806ee2ed.html

Virtual Switching System (VSS) Q&A http://www.cisco.com/en/US/partner/prod/collateral/switches/ps5718/ps9336/prod_qas0900aecd806ed74b.html

For a list of other Cisco products that support enhanced PAgP, refer to Release Notes for Cisco IOS Release 12.2(33)SXH and Later Releases.Partner Education Connection

http://www.partnerelearning.com


Q and A


Documents

VSS-DOC