i have two 6504E Switches as Core and 17 switches 4506 as a Access

[ITexpert]

Hello Guys,

I am working on this setup, I have to connect each 4506 access  switch with two SFP trunk ports to Core 6504 switches.

According to my knowledge, I have to configure etherchannell for each trunk pair on both sides.

But how I am going to use 6504  Core switches in a redundant way in case one fails but network should still work.

I am confused that two trunk SFP cables from 4506  are going to connect to one same core switch only or one cable on each core  switch.

Thanks

[Seb Rupik]

Hi there,

Providing your 6504#s are configured as a VSS pair, you would connect the 4506 switch to both 6504's to provide resiliency.

cheers,

Seb.

[ITexpert]

Hello Seb,

Can you please Further explain, what is VSS and how to configure it.  

I was thinking to connect all 4506 to one core switch and then configuring the HSRP or VRRP. But then it will lead to shortage of trunk ports on my core switch.

How VSS will work and provide redundancy ?

Thanks

[Deepak Kumar]

Hi,

We recommend to go with VSS and here you can found easy explained configuration by blogger. 

https://www.netcraftsmen.com/vss-configuration/

But you can go with hrsp or VSS or glbp. It is hard to manage. 

After configuration the VSS, one fiber cable will terminat on each core switch.

Regards,

Deepak Kumar 

[ITexpert]

Hello deepak,

I read about VSS and like it more as compared to HSRP or VRRP but still some confusions .

1. after configuring VSS, I have to connect one trunk port of access layer switch to each core switch. For example , I am connecting two trunks on 4506 and then connect 1st port to one core switch and 2nd to other core switch. In this case, Do i need to configure the ether-channel on access switches or not ?

2. what about the Gateway on access switches ?  Like my first core switch have 10.0.0.1 and 2nd have 10.0.0.2 IP address so how i am going to manage default gateway on access switches ?

Thanks

[Seb Rupik]

Hi there,
VSS is a Cisco virtualisation technology which takes physically separate switches and combines them into a single logical switch. A failure of one chassis in a VSS pair will not result in any downtime.

Please familiarise yourself with the Cisco configuration guide for your switch:

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12-2SX/configuration/guide/book/vss.html

In particular:
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/12-2SX/configuration/guide/book/vss.html#wp1020417

cheers,
Seb.

[Joseph W. Doherty]

If you want your network to "survive" the loss of either 6504, then each 4506 needs a link to each 6504 (or a separate physical path to each 6504).

With "paths" to both 6504s you'll likely create L2 loops. STP would logical break the loop, allowing it to provide redundancy if something breaks the logical path between core and edge.

Or, as Seb has noted, with the correct sups and software you can configure your 6504 pair as a VSS cluster (logically they function as one device). In a VSS configuration, each 4506 might again have a link to each 6504, but now, as the 4506s would see just one upstream device, you could Etherchannel the separate uplinks.

As to how to configure VSS, that's requires an extensive answer, and Cisco's main web site has extensive documentation.

[ITexpert]

hello Joseph,

Thanks for help , Now i am bit confident about the VSS but still one question.

As VSS used the active switch config, so I just have to enter the active switch address as an gateway in access devices but after fail-over when standby becomes active switch. Does gateway conflict after that.

Or i just have to enter same IP address on both switches.

Please elaborate on this point.

Thanks

[Joseph W. Doherty · Accepted solution]

With VSS, you config only "one" switch.

If you've ever worked with a Cisco stackable switch, VSS is managed much like it.

What happens, all the line cards port get prefixed with a VSS switch number.

The gateway would be dealt with the down link ports, on different VSS members, much like as if they were on the same physical switch.

[ITexpert]

I really appreciate your time and skills. I will try and write down if I face anything challenging.