I have two 6509s that operate in HSRP mode to do routing for 40 vlans on my network.
I do NOT have any routed ports on these switches. One of my vlans shares a subnet with the WAN router and that is how my network gets out into the ATM network and internet.
See sketch attached and requirement from new ISP.
We are changing ISPs and ultimately, the WAN router. The new provider requires changing of the MTU setting from its default 1500 and I need an experts opinion on where to apply the setting given my network. Will provide more information as it is necessary to understand my network.