Help need in configuration of VSS

[ITexpert]

Hello Guys,

I have two core switches 6504E connected with each other by two 10 gigabit SFP ports.

Each access layer switch is connected to both these switches By SFP ports.

 I have some confusions :

1. If I successfully configure the VSS on my core switches , Do i need to configure Port channel on access switches as Core switches will act as single switch.

2. What If I leave access switches without configuring the VSS ?

3.  Why to use VSS instead of HSRP or VRRP ?

4.  common Challenges i will face during this implementation ? 

Thanks

[ma.ahmed.ali]

1. Yes you need to configure a port channel on your access switches. 

2. you don't necessarily have to configure a VSS configuration on your access layer, that would complicate your setup. Just configure a Portchannel on each of your access switches to uplink to both Core switches part of VSS.  

3.  VSS gives you the advantage of System Virtualization over HSRP or VRRP which only provides a virtual IP for gateways to point to. 

VSS increases operational efficiency, seamless failover increasing system backplane capacity or the switching bandwidth

4.  Just ensure you keep a backup of all your interface configurations, since VSS will rewrite the switch interface numbers into this format Gig 1/2/3 (1 - switch number, 2 - blade/module number & 3 - port number).  

Also IOS upgrades will be a little different. 

Good luck!

[ITexpert]

Right now all the switches are in default state , only i change trunk interfaces with switchport trunk encapsulation dot1q , switchport mode trunk commands.

so when i configure the VSS on core switches and it act as a one switch , Before configuring Ether-channel on Access layer switches, does all access layer switches will stop working or it will continue to work?